Gender Differences of Endowed Professorship in Obstetrics and Gynecology Departments at Top Academic Institutions

Background: Gender equity is a critical issue in academic medicine. Whether there is equitable access to the prestige and resources of endowed professorships merits evaluation. We investigated this question in obstetrics and gynecology, a field that focuses on the health of women and in which women are much better represented than other specialties of medicine. Materials and Methods: We compiled a list of the top 25 United States departments of obstetrics and gynecology and contacted department chairs (and used department websites) to obtain lists of faculty and their positions. Scopus, department websites, and National Institutes of Health (NIH) RePORTER were used to collect h-Index, number of publications and citations, graduation year, degrees, gender, and NIH-funding. We conducted a bivariate comparison of endowed professorship attainment by gender using a chi-square test and created a multiple variable regression model. Results: Of the 680 obstetrics and gynecology faculty across 23 departments that had endowed chairs, 64 out of 400 women (16%) and 66 out of 280 men (24%) held endowed chairs (p = 0.01). The multivariable model suggested no independent gender difference in attainment of an endowed chair after adjusting for covariates. Conclusion: To our knowledge, this study is the first to examine gender as a variable in endowed chair allocation in top obstetrics and gynecology academic departments. Our findings suggest a significant gender difference in the allocation of endowed chairs. That difference is driven by gender differences in academic rank, graduation year, publications, and funding. To promote the intraprofessional equity necessary to optimally advance women's health, further research and intervention are necessary.

Healing is not linear: Using photography to describe the day-to-day healing journeys of undergraduate women survivors of sexual violence

The purpose of this study was to describe the day-to-day healing processes of women who experienced undergraduate sexual violence. We engaged 19 women in a photo-elicitation experience with follow-up individual interviews to identify themes of both healing and darker moments in survivors' everyday lives. Healing was found to function on a continuum influenced by darker moments (i.e., moments that elicited fear, anxiety, loneliness, guilt, anger, and worthlessness) and healing moments (i.e., rebuilding moments of self-care, self-love, connection, hope, peace, and freedom). Responses to darker moments included feeling overwhelmed, disconnected, and intentional vulnerability. Healing moments were influenced by self-reflection, authentic interactions, and resource utilization. The photographs taken in this study shed light on the impact of sexual violence in women's daily lives long after these traumatic and unjust experiences. This knowledge can be used to foster a sense of universality in survivors who are currently struggling and growing after their experiences as well as give service providers greater insight into what survivors' day-to-day needs may be.

Collaborative study for the establishment of erythropoietin BRP batch 5

The European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) for erythropoietin (EPO) is used as a working standard for potency determination of EPO preparations by in vivo bioassay as prescribed in Ph. Eur. monograph 1316 'Erythropoietin concentrated solution'. BRP batch 4 (BRP4) was calibrated in 2014 and its stocks are depleted. The European Directorate for the Quality of Medicines and HealthCare (EDQM) thus endorsed a project (BSP147) to calibrate a replacement batch in International Units against the 3rd WHO International Standard (IS) for erythropoietin, recombinant, for bioassay (11/170). The amount of material contained in the vial of BRP4 greatly exceeded the amount needed for one bioassay, sometimes leading to considerable waste. It was thus decided to prepare a candidate material with a lower EPO content. The collaborative study involved eight laboratories in Europe, the USA and Australia. Based on the outcome of the study, the Ph. Eur. Commission adopted the proposed standard as Erythropoietin BRP batch 5 in June 2018 for use as a reference preparation solely for the polycythaemic and normocythaemic mouse bioassays, with an assigned potency of 2000 IU/ampoule. Furthermore, the potency of BRP batch 4 was confirmed during the study thus warranting a good continuity of the International Unit.

Establishment of an erythropoietin CRS with stable measurable dimer content for SEC system suitability qualification

The European Pharmacopoeia (Ph. Eur.) monograph 1316 'Erythropoietin concentrated solution' prescribes that the dimer content of therapeutic erythropoietin (EPO) preparations must not exceed 2% as determined by Size-Exclusion Chromatography (SEC). This report describes the evaluation of a candidate Chemical Reference Substance (cCRS) to serve as system suitability reference material for the qualification of SEC systems used to assess dimer and oligomer content in EPO solutions. The study organised by the European Directorate for the Quality of Medicines & HealthCare (EDQM) was performed with the participation of six European laboratories which tested the candidate material and the EPO for physicochemical tests CRS batch 1. The candidate material was shown to be a suitable reference material for the determination of the resolving capability of the SEC system for separation of dimer and higher oligomers from monomeric EPO. The cCRS was adopted by the Ph. Eur. Commission as Erythropoietin for SEC system suitability CRS batch 1 following consideration of the report. The importance of the resolving capability of the SEC system, as defined by the peak ratios or the peak-to-valley resolution, together with the asymmetry of the peaks eluted, and the linear response of the UV detector were all seen as critical parameters. Therefore, the monograph Erythropoietin concentrated solution (1316) was revised concomitantly to take account of the CRS and to set acceptance criteria for these critical parameters..

BET inhibition represses miR17-92 to drive BIM-initiated apoptosis of normal and transformed hematopoietic cells

The BET (bromodomain and extraterminal domain) bromodomain-containing proteins, such as BRD4, are highly promising targets for treating lymphoid and myeloid malignancies. They act to modulate the expression of multiple genes that control diverse cellular processes including proliferation, survival and differentiation that are consequentially disrupted by small-molecule BET bromodomain inhibitors such as JQ1. By assessing the impact of these inhibitors on normal mouse hematopoietic cells or their transformed counterparts, we establish definitively that their cytotoxic action in vitro and in vivo relies predominantly on the activation of BAX/BAK-dependent mitochondrial (intrinsic) apoptosis. In large part, this is triggered by marked upregulation of the BH3-only protein BIM when the BET inhibitors suppress miR-17-92, a key post-transcriptional repressor of BIM expression. Thus, our study strongly suggests that mutations that permit the evasion of apoptosis (for example, BCL2 overexpression, BIM inactivation) are likely to blunt the activity of the BET bromodomain inhibitors and should be anticipated when therapy resistance develops. Strikingly, we also found that certain normal hematopoietic cells, especially those of lymphoid origin, are as prone to apoptosis induced by the BET inhibitors as their transformed counterparts, indicating that their susceptibility to BET inhibitors did not arise from oncogenic transformation.

Abstract P2-09-01: Targeting BCL-2 with the BH3 mimetic ABT-199 in ER-positive breast cancer

Background: Impairment of apoptosis is a hallmark of cancer and can result in resistance to therapy. Over-expression of the pro-survival protein BCL-2 is common in breast cancer, with elevated levels found in approximately 85% of luminal tumors. Although BCL-2 has been shown to be an important prognostic marker, its role as a therapeutic target has yet to be fully explored. Small molecule inhibitors termed ‘BH3 mimetics’ that mimic the action of pro-apoptotic BH3-only proteins have recently been developed. These bind and neutralize BCL-2 pro-survival proteins. We have previously shown that the BH3 mimetic ABT-737 (which neutralizes BCL-2, BCL-XL and BCL-W) synergizes with docetaxel in BCL-2-positive patient-derived xenograft (PDX) models. Recently, a potent BCL-2-specific inhibitor, ABT-199, has been developed that is showing considerable promise in early phase studies of lymphoid malignancies. Since BCL-2 expression is prominent in the luminal B tumors, we sought to determine whether it might be feasible to target luminal B tumors with combination therapy comprising endocrine therapy (tamoxifen) and a BH3 mimetic (ABT-737 or ABT-199), using novel PDX models of luminal B breast cancer.

Methods and Results: A panel of 36 primary breast tumor xenografts (including 15 luminal tumors) was generated in immunocompromised (NOG) mice. Three BCL-2-positive luminal B models (23T, 315T, 50T), as determined by Ki-67 immunostaining and gene expression profiling, and a control BCL-2-positive, ER-negative model (838T) were selected for further study. Cohorts of mice bearing tumor xenografts were treated with either ABT-737 (50 mg/kg i.p. d1-10), tamoxifen or both agents in q21d cycles. Tumor response and overall survival were significantly improved by combination therapy in all three ER-positive xenograft models, when compared to tamoxifen alone (p<0.005). Despite abundant BCL-XL expression in tumors, similar efficacy was observed with the selective BCL-2 inhibitor ABT-199 (50 mg/kg o.g. d1-5 and 8-12 q21d) and tamoxifen (p<0.005), revealing that BCL-2 is a crucial target. Unexpectedly, both BH3 mimetics were found to counteract the side effect of tamoxifen-induced endometrial hyperplasia. In addition, we observed that BH3 mimetics synergized with dual PI3K/mTOR inhibitors in the induction of apoptosis. In the 315T model, where AKT was found to be activated, triple therapy with ABT-737, a PI3K/mTOR inhibitor (PKI-587) and tamoxifen further augmented tumor response in vivo, when compared to ABT-737 and tamoxifen (p<0.004).

Discussion: Patient derived xenograft models of luminal B breast cancer have been derived that recapitulate the phenotype of the primary tumor. Here we have demonstrated that concomitant targeting of BCL-2 confers marked benefit above tamoxifen alone. Moreover, synergy between BH3 mimetics and PI3K/mTOR inhibitors could be exploited by targeting of both survival pathways, a strategy that appeared both safe and effective. Collectively, our findings provide a rationale for clinical evaluation of BH3 mimetics in early phase studies in breast cancer. Here, BCL-2 protein or mRNA expression (as determined by immunohistochemistry or RT-PCR, respectively) could provide a suitable companion biomarker for patient selection.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-09-01.

Translation inhibitors induce cell death by multiple mechanisms and Mcl-1 reduction is only a minor contributor

There is significant interest in treating cancers by blocking protein synthesis, to which hematological malignancies seem particularly sensitive. The translation elongation inhibitor homoharringtonine (Omacetaxine mepesuccinate) is undergoing clinical trials for chronic myeloid leukemia, whereas the translation initiation inhibitor silvestrol has shown promise in mouse models of cancer. Precisely how these compounds induce cell death is unclear, but reduction in Mcl-1, a labile pro-survival Bcl-2 family member, has been proposed to constitute the critical event. Moreover, the contribution of translation inhibitors to neutropenia and lymphopenia has not been precisely defined. Herein, we demonstrate that primary B cells and neutrophils are highly sensitive to translation inhibitors, which trigger the Bax/Bak-mediated apoptotic pathway. However, contrary to expectations, reduction of Mcl-1 did not significantly enhance cytotoxicity of these compounds, suggesting that it does not have a principal role and cautions that strong correlations do not always signify causality. On the other hand, the killing of T lymphocytes was less dependent on Bax and Bak, indicating that translation inhibitors can also induce cell death via alternative mechanisms. Indeed, loss of clonogenic survival proved to be independent of the Bax/Bak-mediated apoptosis altogether. Our findings warn of potential toxicity as these translation inhibitors are cytotoxic to many differentiated non-cycling cells.

The novel JAK inhibitor CYT387 suppresses multiple signalling pathways, prevents proliferation and induces apoptosis in phenotypically diverse myeloma cells

Janus kinases (JAKs) are involved in various signalling pathways exploited by malignant cells. In multiple myeloma (MM), the interleukin-6/JAK/signal transducers and activators of transcription (IL-6/JAK/STAT) pathway has been the focus of research for a number of years and IL-6 has an established role in MM drug resistance. JAKs therefore make a rational drug target for anti-MM therapy. CYT387 is a novel, orally bioavailable JAK1/2 inhibitor, which has recently been described. This preclinical evaluation of CYT387 for treatment of MM demonstrated that CYT387 was able to prevent IL-6-induced phosphorylation of STAT3 and greatly decrease IL-6- and insulin-like growth factor-1-induced phosphorylation of AKT and extracellular signal-regulated kinase in human myeloma cell lines (HMCL). CYT387 inhibited MM proliferation in a time- and dose-dependent manner in 6/8 HMCL, and this was not abrogated by the addition of exogenous IL-6 (3/3 HMCL). Cell cycling was inhibited with a G(2)/M accumulation of cells, and apoptosis was induced by CYT387 in all HMCL tested (3/3). CYT387 synergised in killing HMCL when used in combination with the conventional anti-MM therapies melphalan and bortezomib. Importantly, apoptosis was also induced in primary patient MM cells (n=6) with CYT387 as a single agent, and again synergy was seen when combined with conventional therapies.

Correlates of serum dioxin to self-reported exposure factors

The aim of the current analysis was to examine the determinates of lipid-adjusted body levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) from occupational histories, age, body mass index, and self-reported information from a questionnaire. We collected serum from 346 workers at a New Zealand chemical plant that manufactured and formulated the herbicide, 2,4,5-trichlorophenoxyacetic acid (2,4,5-T). Age, body mass index, and employment history were significant determinates of TCDD. The self-reported data on occupation, residence, and general diet were not predictive of serum levels and we observed no evidence of increased TCDD levels from living close to the site. For participants with putative occupational exposure, employment history and personal factors were important to understand the range of TCDD serum levels. For employees without direct occupational exposure, and resulting lower dioxin levels, we recommend further efforts to develop and validate questionnaires to better evaluate environmental sources of dioxins.

Chlorpyrifos exposure and biological monitoring among manufacturing workers

AIM

To use biological monitoring data to evaluate the soundness of job based exposure classifications.

METHODS

The authors studied 52 chlorpyrifos manufacturing workers and 60 referent workers to compare chlorpyrifos exposure estimations from job titles and work areas to urinary excretion of 3,5,6 trichloro-2-pyridinol (TCP), a metabolite of chlorpyrifos. Work history records and industrial hygiene monitoring data were used to establish cumulative interim exposure. Chlorpyrifos exposure during the study year was assessed biologically by urinary excretion of TCP.

RESULTS

Exposure as measured by three urinary TCP samples was significantly higher among the chlorpyrifos workers (188 microg/l) than it was for the referent subjects (7 microg/l). Urinary TCP also correlated well with specific exposure categories of negligible (0.73-1.98 mg/m3 days), low (1.99-4.91 mg/m3 days), and moderate (4.92-15.36 mg/m3 days). The weighted Kappa coefficient was 0.80 (95% CI 0.72 to 0.87) for the mean TCP over the study period.

CONCLUSIONS

The estimates of chlorpyrifos exposure based on job classifications and industrial hygiene measurements were significantly related to urinary TCP excretion, indicating that the ambient estimates are useful for providing exposure estimates among chlorpyrifos manufacturing workers.

Tetrahydrobenzothiophene inhibitors of hepatitis C virus NS5B polymerase

A novel series of selective HCV NS5B RNA dependent RNA polymerase inhibitors has been disclosed. These compounds contain an appropriately substituted tetrahydrobenzothiophene scaffold. This communication will detail the SAR and activities of this series.

Interdependence of steroidogenesis and shape changes in Y1 adrenocortical cells: studies with inhibitors of phosphoprotein phosphatases

Y1 adrenocortical cells respond to activators of the cyclic AMP-dependent protein kinase (PKA) signalling pathway not only with increases in steroid secretion but also with a characteristic change in cell morphology from flat and adherent to round and loosely attached. This change of shape, which may facilitate cholesterol transport to the mitochondrion, requires tyrosine dephosphorylation of the focal adhesion protein, paxillin, and can be blocked by inhibitors of phosphotyrosine phosphatase (PTP) activity. In a previous study we demonstrated that inhibition of phosphoserine/threonine phosphatase 1 and 2A (PP1/2A) activities caused a similar morphological response to PKA activation whilst opposing the effects on steroid production. We have now investigated the responses to PKA activation and inhibition of PP1/2A and used PTP inhibitors to examine the relationship between the morphological changes and enhanced steroid production. Both forskolin (FSK) and the PP1/2A inhibitor, calyculin A (CA), caused rapid and extensive rounding of Y1 cells. FSK-induced cell rounding was reversible and accompanied by a reduction in the tyrosine phosphorylation of paxillin. Rounding was prevented by the PTP inhibitors pervanadate (PV) and calpeptin (CP) and was associated with the maintained tyrosine phosphorylation of paxillin. In contrast, CA-induced cell rounding was not reversible over a 2-h period and was not affected by the presence of PTP inhibitors, and CA had no effect on the tyrosine phosphorylation of paxillin. Although neither CA nor FSK produced any gross changes in cell viability as judged by Trypan Blue exclusion or mitochondrial activity, CA-treated cells showed a marked reduction in total protein synthesis assessed by (35)S-incorporation. The effects of FSK and the PTP inhibitors on cell rounding were reflected in their effects on steroid production since PV and CP also inhibited FSK-stimulated steroid production. These results suggest that the mechanism through which inhibition of PP1/2A activities induces morphological changes in Y1 cells is fundamentally different from that seen in response to activation of PKA. They are consistent with PKA-induced shape changes in adrenocortical cells being mediated through increased PTP activity and the dephosphorylation of paxillin, and support the view that the morphological and functional responses to PKA activation in steroidogenic cells are intimately linked.

Reaction of the uranyl(VI) ion (UO(2)(2+)) with a triamidoamine ligand: preparation and structural characterization of a mixed-valent uranium(V/VI) oxo-imido dimer

The synthesis and structural characterization of a mixed-valent uranium(V/VI) oxo-imido complex are reported. Reaction of the uranyl chloride complex [K(18-crown-6)](2)[UO(2)Cl(4)] (1) with the triamidoamine ligand Li(3)[N(CH(2)CH(2)NSiBu(t)Me(2))(3)] yields oxo-imido [K(18-crown-6)(Et(2)O)][UO(mu(2)-NuCH(2)CH(2)N(CH(2)CH(2)NSiBu(t)Me(2))(2))](2) (2) as the major isolated uranium product in moderate yield. The reaction that forms 2 involves activation of both the triamidoamine ligand and the uranyl dioxo unit of 1. An X-ray crystal structure determination of 2 reveals a dimeric complex in which the coordination geometry at each uranium center is that of a capped trigonal bipyramid. The multidentate triamidoamine ligand coordinates to uranium through the capping amine and two of the three pendant amido ligands, while the third pendant amido donor has been activated to generate a bridging imido ligand by loss of the silyl substituent. One of the uranyl oxo groups is retained as a terminal ligand to complete the coordination sphere for each uranium center. The oxo and imido nitrogen may be regarded as the axial ligands of the trigonal bipyramid, while the two amido ligands and the other imido donor occupy equatorial coordination sites. The central amine of the tripodal set serves as the capping ligand. Distortion of the axial O-U-N angle from 180 degrees emanates from the proximity of the capping amine and the bridging interaction to the other uranium center. The structure and bonding in 2 are assessed in the context of metal-ligand multiple bonding in high-valent actinide complexes. The possibility of valence averaging [5.5/5.5 vs 5.0/6.0] via delocalization or rapid intramolecular electron-transfer dynamics of the unpaired electron is also discussed in the context of crystallographic, spectroscopic (NMR, IR, Raman, and EPR), and electrochemical data. Crystal data for 2: triclinic space group P1 macro, a = 12.1144(6) A, b = 12.6084(6) A, c = 14.5072(7) A, alpha = 101.374(1) degrees, beta = 103.757(1) degrees, gamma = 109.340(1) degrees, z = 1, R1 = 0.0523, wR2 = 0.1359.

A longitudinal study of respiratory health of toluene diisocyanate production workers

A longitudinal comparison of 305 toluene diisocyanate (TDI) and 581 hydrocarbons workers employed at a Texas chemical manufacturing facility from 1971 through 1997 tested whether workplace exposure to TDI was associated with changes in any of the respiratory measures collected by the company's health surveillance program. Mean TDI exposures measured 96.9 ppb-months, or 2.3 ppb per job. At the end of the study, there were no differences in self-reported symptoms between the groups. Longitudinal analyses of symptoms and pulmonary function showed no correlation with TDI exposure, yielding an average annual decrease in forced expiratory volume at 1 second of 30 mL per year. We concluded that exposure to TDI at workplace concentrations was not associated with respiratory illnesses in this cohort, and consistent with other recent research, it seemed not to accelerate the normal age-related decline in pulmonary function.

ERKs regulate cyclic AMP-induced steroid synthesis through transcription of the steroidogenic acute regulatory (StAR) gene

Cyclic AMP-dependent expression of the steroidogenic acute regulatory (StAR) protein is thought to be the controlling step for steroid production, but the mechanisms through which external signals are translated into increased transcription of the StAR gene are unknown. We demonstrate that cyclic AMP-induced steroid synthesis is dependent upon the phosphorylation and activation of ERKs and that ERK activation results in enhanced phosphorylation of SF-1 and increased steroid production through increased transcription of the StAR gene. Adenylate cyclase activation with forskolin (FSK) caused a time-dependent increase in ERK activity and translocation from cytoplasm to nucleus, which correlated with an increase in StAR mRNA levels, StAR protein accumulation, and steroidogenesis. Similarly, ERK inhibition led to a reduction in the levels of FSK-stimulated StAR mRNA, StAR protein, and steroid secretion. These effects were attributed to the finding that ERK activity is required for SF-1 phosphorylation, a transcription factor required for the regulation of StAR gene transcription. This conclusion was supported by our demonstration of an ERK-dependent increase in the binding of SF-1 from FSK-treated Y1 nuclei to three consensus double-stranded DNA sequences from the StAR promoter region. These observations suggest that the activation of ERK2/1 by increasing cAMP is an obligatory and regulated stage in the stimulation of steroid synthesis by cyclic AMP-generating stimuli.

Solution- and Solid-Phase Synthesis of Components for Tethered Bilayer Membranes

The synthesis of the novel compound PhCH(2)SS(C(24)H(44)N(4)O(10))(C(20)H(41)) (5) for the preparation of tethered bilayer membranes is described. The compound is the all-amide analogue of the previously reported ester-containing membrane-forming material PhCH(2)SS(C(24)H(40)O(14))(C(20)H(41)) (1). The advanced intermediate (C(20)H(41)) C(16)H(28)N(3)O(8) (17) was prepared from the same starting materials using both solution-phase (13% yield) and solid-phase (81% yield) techniques. Monolayers on gold derived from 5 have been analyzed by ellipsometry and FTIR. The monolayers exhibit thicknesses similar to monolayers derived from 1 and possess H-bonded amide functionality.

Approaching zero discharge in uranium reprocessing: photochemical reduction of uranyl

We have studied the photochemical reduction of uranyl to generate UO2 without hydrogen reduction. Formate and oxalate were examined as potential reductants that only lead to CO2 production as a side product. Despite the similar nature of the two reductants, the mechanism for quenching the uranyl excited-state changes drastically and leads to dramatically different chemistry at low pH. Oxalate quenches by unimolecular electron transfer and formate quenches by H-atom abstraction. Because of the change in mechanism, photochemical reduction of uranyl with formate works with high efficiency at low pH while photolysis in the presence of oxalate leads to the generation of CO and no net uranyl reduction. Photochemical reduction of uranyl with formate at low pH leads to U(IV) in solution that can then be precipitated as UO2 by simply raising the pH with yields as high as 99.992%.

Mortality in chemical workers potentially exposed to 2,4-dichlorophenoxyacetic acid (2,4-D) 1945-94: an update

OBJECTIVE

To update and add to a previously identified cohort of employees potentially exposed to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). The putative association between 2,4-D and non-Hodgkin's lymphoma has been debated for more than a decade.

METHODS

Cohort members were male employees of The Dow Chemical Company who manufactured or formulated 2,4-D any time from 1945 to the end of 1994. Their mortality experience was compared with national rates and with more than 40 000 other company employees who worked at the same location.

RESULTS

330 Deaths were observed among 1517 people compared with 365 expected (standardised mortality ratio (SMR)=0.90, 95% confidence interval (95% CI) 0.81 to 1.01). There were no significantly increased SMRs for any of the causes of death analyzed. When compared with the United States rates, the SMR for non-Hodgkin's lymphoma (NHL) was 1.00 (95% CI 0.21 to 2.92). The internal comparison with other Dow employees showed a non-significant relative risk of 2.63, (95% CI 0.85 to 8.33). Death was attributed to amyotrophic lateral sclerosis (ALS) for three cohort members. Compared with the other company employees, the relative risk was 3.45 (95% CI 1.10 to 11.11). The cases were employed in the manufacture or formulation of 2,4-D at different periods (1947-9, 1950-1, and 1968-86), and for varying durations of time (1.3, 1.8, and 12.5 years).

CONCLUSION

There was no evidence of a causal association between exposure to 2,4-D and mortality due to all causes and total malignant neoplasms. No significant risk due to NHL was found. Although not an initial hypothesis, an increased relative risk of ALS was noted. This finding is unsupported by other animal and human studies.

A trigonal bipyramidal uranyl amido complex: synthesis and structural characterization of [Na(THF)2][UO2(N(SiMe3)2)3]

The synthesis and structural characterization of a rare example of a uranyl complex possessing three equatorial ligands, [M(THF)2][UO2(N(SiMe3)2)3] (3a, M = Na; 3b, M = K), are described. The sodium salt 3a is prepared by protonolysis of [Na(THF)2]2[UO2(N(SiMe3)2)4], whereas the potassium salt 3b is obtained via a metathesis reaction of uranyl chloride UO2Cl2(THF)2 (4) with 3 equiv of K[N(SiMe3)2]. A single-crystal X-ray diffraction study of 3a revealed a trigonal-bipyramidal geometry about uranium, formed by two axial oxo and three equatorial amido ligands, with average U=O and U-N bond distances of 1.796(5) and 2.310(4) A, respectively. One of the oxo ligands is also coordinated to the sodium counterion. 1H NMR spectroscopic studies indicate that THF adds reversibly as a ligand to 3 to expand the trigonal bipyramidal geometry. The degree to which the coordination sphere in 3 is electronically satisfied with only three amido donors is suggested by (1) the reversible THF coordination, (2) a modest elongation in the bond distances for a five-coordinate U(VI) complex, and (3) the basicity of the oxo ligands as evidenced in the contact to Na. The vibrational spectra of the series of uranyl amido complexes [UO2(N(SiMe3)2)n]2-n (n = 2-4) are compared, to evaluate the effects on the axial U=O bonding as a function of increased electron density donated from the equatorial region. Raman spectroscopic measurements of the nu 1 symmetric O=U=O stretch show progressive axial bond weakening as the number of amido donors is increased. Crystal data for [Na(THF)2][UO2(N(SiMe3)2)3]: orthorhombic space group Pna2(1), a = 22.945(1) A, b = 15.2830(7) A, c = 12.6787(6) A, z = 4, R1 = 0.0309, wR2 = 0.0524.

Basicity of uranyl oxo ligands upon coordination of alkoxides

Uranium(VI) alkoxide complexes are prepared via metathesis reactions of [UO2Cl2(THF)2]2 with potassium alkoxides in nonaqueous media. The dark red compound U[OCH2C(CH3)3]6, 1, results from redistributive exchange of oxo and neopentoxide ligands between more than one uranium species. Single-crystal X-ray diffraction analysis of 1 reveals a monomer in which the uranium is coordinated in a pseudooctahedral fashion by six neopentoxide ligands. Imposition of steric congestion at the metal center prevents oxo-alkoxide ligand exchange in the reactions using more sterically demanding alkoxides. Simple metathesis between uranyl chloride and alkoxide ligands occurs in the synthesis of golden yellow-orange UO2(OCHPh2)2(THF)2, 2, and yellow UO2[OCH(tBu)Ph]2(THF)2, 3. Single-crystal X-ray diffraction analysis of 2 reveals a monomer in which the uranium is coordinated in a pseudooctahedral fashion by two apical oxo ligands, two diphenylmethoxide ligands occupying trans positions, and two tetrahydrofuran ligands. Coordination of diisopropylmethoxide allows for synthesis of a more complex binary alkoxide system. Single-crystal X-ray diffraction analysis of watermelon red [UO2(OCH(iPr)2)2]4, 4, reveals a tetramer in which each uranium is coordinated in a pseudooctahedral fashion by two apical oxo ligands, one terminal alkoxide, two bridging alkoxide ligands, and one bridging oxo ligand from a neighboring uranyl group. These compounds are characterized by elemental analysis, 1H NMR, infrared spectroscopy, and, for 1, 2, and 4, single-crystal X-ray diffraction analysis. Luminescence spectroscopy is employed to evaluate the extent of aggregation of compounds 2-4 in various solvents. Vibrational spectroscopic measurements of 2-4 imply that, in contrast to the case of uranyl complexes prepared in aqueous environments, coordination of relatively strongly donating alkoxide ligands allows for enhancement of electron density on the uranyl groups such that the uranyl U=O bonds are weakened. Crystal data are as follows. 1: monoclinic space group C2/m, a = 10.6192(8) A, b = 18.36(1) A, c = 10.6151(8) A, beta = 109.637(1) degrees, V = 1949.1(3) A3, Z = 2, dcalc = 1.297 g cm-3. Refinement of 2065 reflections gave R1 = 0.045. 2: monoclinic space group P2(1)/c, a = 6.1796(4) A, b = 15.669(1) A, c = 16.169(1) A, beta = 95.380(1) degrees, V = 1558.7(2) A3, Z = 2, dcalc = 1.664 g cm-3. Refinement of 3048 reflections gave R1 = 0.036. 4: tetragonal space group I4, a = 17.8570(6) A, b = 17.8570(6) A, c = 11.4489(6) A, V = 3650.7(3) A3, Z = 2, dcalc = 1.821 g cm-3. Refinement of 1981 reflections gave R1 = 0.020.

Inhibition of protein tyrosine phosphatase activity blocks shape change & steroidogenesis in Y1 cells

Y1 adrenocortical cells respond to forskolin stimulation with increases in steroid secretion and change of shape. The rapid rounding of flat, adherent cells which occurs is known to involve dephosphorylation of the focal adhesion protein, paxillin. We have investigated the effects of a tyrosine phosphatase inhibitor, calpeptin (CP) on steroidogenesis and shape change in Y1 cells. Forskolin treatment (FSK, 2 microM) caused marked rounding of Y1 cells (FSK = 76.3 +/- 1.5% cells rounded after 30 minutes, untreated = 2.9 +/- 0.7 % rounded); calpeptin pretreatment (CP; 100 ug/ml) had little effect on shape (9.6 +/- 2.4% rounded) but blocked the rounding response to FSK (32.1 +/- 2.1% rounded. Calpetin also eliminated the steroidogenic response to FSK ( FSK = 242 +/- 14% control ; FSK + CP = 113 +/- 18% control ) without affecting production of steroid from membrane permeant 22R-OH-cholesterol. The results support the view that dephosphorylation of paxillin is important in the rounding response and provide evidence for the involvement of tyrosine-phosphatase activity in cyclic AMP-stimulated steroidogenesis in Y1 cells.

Solid-phase synthesis of an arylsulfone hydroxamate library

Synthesis of an arylsulfone hydroxamate lead optimization library is presented. Biological activity of representative examples is given to demonstrate the value of this approach for lead optimization.

Phosphoprotein phosphatases regulate steroidogenesis by influencing StAR gene transcription

The rate-limiting step in steroidogenesis is the transport of cholesterol into the mitochondria, and this is controlled by the steroidogenic acute regulatory (StAR) protein. We have previously shown that inhibition of phosphoprotein phosphatase 1 and 2A (PP1/2A) activities with the PP1/2A inhibitor calyculin A selectively reduces StAR protein expression and thus inhibits the synthesis of steroid hormones. The aim of this study was to determine whether this inhibition of StAR protein expression occurs at the level of transcription of StAR mRNA. We have used a competitive reverse transcription-polymerase chain reaction (RT-PCR) technique to determine whether inhibition of PP1/2A activities has any effect on the levels of StAR mRNA. Exposure of Y1 cells to forskolin significantly increased the expression of StAR mRNA and this forskolin-induced increase was reduced after exposure to Cal A at levels similar to those seen in the controls. These results suggest that cyclic AMP-induced increases in StAR mRNA levels are dependent upon phosphoprotein phosphatase activities.

Cyclic AMP-induced expression of steroidogenic acute regulatory protein is dependent upon phosphoprotein phosphatase activities

In addition to the well-documented role of protein kinases in the regulation of steroid production, phosphoprotein phosphatase (PP) activity is required for steroidogenesis. In the present study, we have used the mouse Y1 adrenocortical cell line to identify the site of action of PPs on steroid production by measuring the effects of PP inhibition on the expression of the steroidogenic acute regulatory (StAR) protein and on steroid production. Forskolin-induced activation of cyclic AMP-dependent protein kinase (PKA) enhanced steroidogenesis and this was accompanied by an increased expression of StAR protein. Both steroidogenesis and StAR protein expression were inhibited by two structurally dissimilar inhibitors of PP1 and PP2A activities, okadaic acid and calyculin A. These results suggest that inhibition of PP1 and PP2A inhibits steroid production by preventing the expression of the StAR protein, implicating PP1/2A dephosphorylation reactions as important regulators of stimulus-dependent StAR protein expression, and thus of steroidogenesis.

Signaling through the p38 and p42/44 mitogen-activated families of protein kinases in pancreatic beta-cell proliferation

The present study has focused on the role of the 42- and 44-kDa mitogen-activated protein kinases (p42/44 MAPKs) and the 38-kDa mitogen-activated protein kinase (p38 MAPK) in the proliferation of the pancreatic beta-cell line MIN6. MIN6 beta-cell proliferation was assessed by measuring 5-bromo-2'-deoxyuridine (BrdU) incorporation into cellular DNA. Inhibition of both the p42/44 MAPK pathway using the MEK inhibitor PD098059 (PD) and the p38 MAPK pathway using the p38 inhibitor SB203580 (SB) caused a marked, concentration-dependent reduction in the BrdU immunostaining observed in the presence of 15% FCS when assessed using fluorescence immunocytochemistry. These data provide direct evidence of a role for p42/44 MAPKs in the mitogenic response of MIN6 beta-cells to FCS. Furthermore, these data also suggest a novel role for the p38 MAPK pathway in MIN6 beta-cell proliferation.

High-resolution functional labeling of vertebrate and invertebrate olfactory receptor neurons using agmatine, a channel-permeant cation

Methods are described for odor-stimulated labeling of olfactory receptor neurons (ORNs) of the freshwater zebrafish Danio rerio and the marine spiny lobster Panulirus argus. Permeation of a cationic molecule, 1-amino-4-guanidobutane ( = agmatine, AGB), through ion channels following odor stimulation, and its detection by an anti-AGB antibody, allow labeling of odor-stimulated ORNs. Parameters adjusted to optimize activity-dependent labeling included labeling medium ionic composition, stimulation times, and AGB concentration. For lobsters, 7% of ORNs were labeled by a complex odor, oyster mixture, under optimal conditions, which was stimulation for 5 s per min for 60 min with 20 mM AGB in artificial seawater with reduced sodium and calcium concentrations. AGB was a weak odorant for lobsters; it elicited only a small electrophysiological response from ORNs and labeled < 1% of the ORNs during stimulation with AGB in the absence of odors. For the zebrafish, stimulation for 10 s per min for 10 min with 5 mM AGB plus odorant (L-glutamine) in fish Ringer's solution was the optimal labeling condition, resulting in labeling of 17% of the olfactory epithelial area. Approximately 6% of the olfactory epithelium was labeled during stimulation with a control stimulus, AGB alone. This labeling by AGB alone suggests it is an olfactory stimulus for zebrafish; a conclusion supported by electrophysiological recordings. We used electrophysiological assays and channel blockers to examine, for each species, potential ion channels for entry of AGB into ORNs. These results show that AGB can be used as an activity-dependent label for chemoreceptor neurons of diverse phyla living in a range of environmental conditions.

The p38 mitogen-activated protein kinase cascade is not required for the stimulation of insulin secretion from rat islets of Langerhans

The expression of the p38 subfamily of mitogen-activated protein kinases (MAPKs) was examined in rat islets of Langerhans and pancreatic beta-cell lines, and its involvement in the regulation of insulin secretion was investigated. Rat islets and several rodent beta-cell lines were shown to express p38 MAPK by Western blotting. The cellular stress agents sodium arsenite and hyperosmotic sorbitol significantly stimulated p38 MAPK activity, as did the tyrosine phosphatase inhibitor sodium pervanadate and the serine/threonine phosphatase inhibitor okadaic acid. Increases in p38 MAPK activity were not consistently correlated with increases in insulin secretion, and the dissociation between p38 MAPK activity and the regulation of insulin secretion was further demonstrated in studies using the specific p38 MAPK inhibitor SB203580, which was without significant effect on the stimulation of insulin secretion by glucose, 4beta phorbol myristate acetate and forskolin. These studies indicate that although p38 MAPK is expressed in pancreatic beta-cells and can be activated pharmacologically, its activity can be dissociated from the exocytotic release of insulin from rat islets of Langerhans.

Tyrosine kinases play a permissive role in glucose-induced insulin secretion from adult rat islets

The role(s) played by protein tyrosine kinases (PTKs) in the regulation of insulin secretion from pancreatic beta cells is not clear. We have examined the effects of glucose, the major physiological insulin secretagogue, on the tyrosine phosphorylation state of islet proteins, and assessed beta cell insulin secretory responses in the presence of PTK inhibitors. Under basal conditions islets contained many proteins phosphorylated on tyrosine residues, and glucose (20 mM; 5-15 min) was without demonstrable effect on the pattern of tyrosine phosphorylation, in either the absence or presence of the protein tyrosine phosphatase (PTP) inhibitor, sodium pervanadate (PV). PV alone (100 microM) increased tyrosine phosphorylation of several islet proteins. The PTK inhibitors genistein (GS) and tyrphostin A47 (TA47) inhibited islet tyrosine kinase activities and glucose-, 4alpha ketoisocaproic acid (KIC)- and sulphonylurea-stimulated insulin release, without affecting glucose metabolism. GS and TA47 also inhibited protein serine/threonine kinase activities to a limited extent, but had no effect on Ca2+, cyclic AMP- or phorbol myristate acetate (PMA)-induced insulin secretion from electrically permeabilised islets. These results suggest that PTK inhibitors exert their inhibitory effects on insulin secretion proximal to Ca2+ entry and it is proposed that they act at the site of the voltage-dependent Ca2+ channel which regulates Ca2+ influx into beta cells following nutrient- and sulphonylurea-induced depolarisation.

Mortality experience for Louisiana chemical workers

A previous mortality study for Louisiana workers of The Dow Chemical Company identified greater than expected deaths due to leukemia and aleukemia and cancer of the brain and central nervous system. The current study updated the mortality experience through 1992. No new deaths due to leukemia and aleukemia and only one new death due to cancer of the brain and central nervous system were observed. No causes of death were statistically significantly elevated. The number of observed deaths was statistically significantly less than expected for a number of disease categories. Mortality rates were not shown to be higher among Louisiana chemical employees when compared to the United States, state, and regional populations.

Update of the morbidity experience of employees potentially exposed to chlorpyrifos

OBJECTIVES

Chlorpyrifos, an organophosphate ingredient of several important insecticides, has been manufactured at The Dow Chemical Company for 25 years. A previous morbidity study among employees of The Dow Chemical Company found no increased prevalence of illness or symptoms among employees potentially exposed to chlorpyrifos from 1977 to 1985 compared with matched controls. The purpose of the current study was to update the original study to 1994, thereby increasing the statistical power.

METHODS

In the present study, 496 potentially exposed subjects were identified and matched for age, race, sex, pay, and year of hire to 911 control subjects. Morbidity data were abstracted from company medical records.

RESULTS

The prevalence of peripheral neuropathy was not significantly increased among this group of employees potentially exposed to chlorpyrifos. Significantly increased prevalence odds ratios were identified for five diagnostic categories: diseases of the ear and mastoid process; acute respiratory infections; other diseases of the respiratory system; general symptoms, signs, and ill defined conditions; and symptoms, signs, and ill defined conditions involving the digestive system. There was a strong association of diagnosis with duration of observation period, indicating that the exposed workers were more likely than unexposed workers to have a diagnosis abstracted from the company medical records due to their longer mean period of follow up. Analyses by exposure classification and mean plasma cholinesterase activity did not show a dose response.

CONCLUSIONS

These data do not support a cause and effect relation of the diagnoses mentioned and exposure to chlorpyrifos.

Glucose-stimulated insulin secretion from rat islets of Langerhans is independent of mitogen-activated protein kinase activation

The role played by mitogen-activated protein kinases (MAPKs) in the regulation of insulin secretion from adult rat islets of Langerhans was investigated by examining the effects of glucose, forskolin and 4beta phorbol myristate acetate (PMA) on islet MAPK activity and by measuring insulin secretion from islets in response to these agonists after inhibition of MAPK by PD 098059 (PD). Glucose (20mM) had a small (<2-fold) stimulatory effect on MAPK activity in isolated islets, and this was potentiated by forskolin (10 microM) and PMA (500nM), which also significantly stimulated MAPK activity at 2mM glucose. Pretreatment of islets with 50 microM PD inhibited MAPK activity, but had no effect on secretory responses to glucose, forskolin and PMA. These results suggest that although MAPK may be activated by insulin secretagogues in adult rodent islets, this can be dissociated from the exocytotic release of insulin.

Racial differences in scleroderma among women in Michigan

OBJECTIVE

To examine racial differences in disease onset, extent, manifestations, and survival among women with scleroderma.

METHODS

A retrospective cohort study of women with scleroderma, diagnosed in Michigan between 1980 and 1991, was conducted. Clinical, laboratory, and demographic data were abstracted from the patients' medical records.

RESULTS

A total of 514 women with scleroderma were identified: 117 (23%) were black and 397 (77%) were white. Among black women, the mean age at diagnosis was lower (44.5 years versus 51.5 years; P < 0.001) and diffuse disease was more common (49.6% versus 24.9%; P < 0.001) than among white women. The overall incidence of scleroderma was 14.1 per million per year: 22.5 per million per year in black women versus 12.8 per million per year in white women (P < 0.001). Pericarditis (P = 0.009), pulmonary hypertension (P < 0.001), pleural effusions (P = 0.01), myositis (P = 0.02), and an erythrocyte sedimentation rate >40 mm/hour (P < 0.001) were more frequent among black women, while white women were more likely to have digital infarctions (P < 0.001). Survival at 7 years from diagnosis was 72.5% among black women and 77.6% among white women. Age-adjusted survival was significantly reduced among black women (P = 0.033), most likely because of increased diffuse involvement. Survival among those with renal or pulmonary involvement was also significantly reduced.

CONCLUSION

Black women with scleroderma were significantly more likely than white women to develop diffuse disease, be diagnosed at a younger age, have a higher incidence of inflammatory features, and have a worse age-adjusted survival rate.

Liver enzyme activity and body mass index

Obesity has been identified as a risk factor for liver disease in a number of cross-sectional studies. We investigated the association of biochemical livers tests (BLTs) among male employees of The Dow Chemical Company who had participated in two consecutive health surveillance examinations. The activity of three liver enzymes-alanine aminotransferase, aspartate aminotransferase, and gamma glutamyl transferase were used as measures of liver injury. Body mass index was strongly associated with increased enzyme activity in both examinations. Alcohol consumption was similarly associated with higher BLT results. Body mass index remained significantly associated with each BLT after controlling for alcohol consumption, race, and age. When changes in BLTs were investigated over time, the employees who gained weight showed a significant increase in alanine aminotransferase activity compared with those who did not gain weight.

The epidemiology of scleroderma among women: assessment of risk from exposure to silicone and silica

OBJECTIVE

To investigate the relationship between exposure to silicone (including breast implants) and silica and the development of scleroderma (systemic sclerosis, SSc) among women.

METHODS

A population based case-control study was conducted among women in Michigan. 274 confirmed cases of SSc diagnosed between 1985 and 1991 were identified by contacting rheumatologists, hospitals, and a scleroderma support group. These cases and 1184 controls were interviewed by telephone to ascertain past exposures to silicone or silica.

RESULTS

Silicone in the form of breast implants was not associated with significantly increased risk of SSc (adjusted odds ratio, 1.30; 95% confidence interval, 0.27 to 6.23). Among 20 other potential silicone exposure surveyed, self-reported exposure to silicone based glues, sealants, and caulks, manufacture or repair of windows or windshields, repairing or frequently using photocopy machines, consumption of simethicone-containing antacids, and implanted medication delivery pumps were significantly associated with SSc. However, blinded assessment of all job and hobby descriptions in terms of their potential for silicone exposure failed to support the first 3 associations, antacid consumption may have been confounded by esophageal dysmotility before the diagnosis of SSc, and other silicone containing device categories (pacemakers, central nervous system shunts, other shunts and catheters) were not significantly associated with SSc. Surgically implanted metallic fixation devices were associated with significantly reduced risk for SSc. No association was detected between SSc and silica dust exposure.

CONCLUSION

Consistent with other studies, we found no increased risk of SSc among women with silicone breast implants, equivocal evidence of risk from other silicone exposures, and no evidence of risk from silica exposure.

Characterization of the bisphosphonate recognition site on hydroxyapatite using radioligand binding techniques with [14C]citric acid

The present studies characterize the binding of [14C]citric acid to synthetic hydroxyapatite (HA) crystals. [14C]Citric acid specifically bound to HA and was dependent upon the concentration of HA in the assay. The binding of [14C] citric acid to HA reached equilibrium within 20 min and remained stable for at least 90 min. Dissociation of bound [14C]citric acid was biphasic in nature since both rapid and more slowly reversible binding components were detected. Saturation experiments also indicated that [14C]citric acid labeled two recognition sites with different affinity (KdH = 42 nM and KdL = 24,000 nM) and density (BmaxH = 161 fmol/micrograms HA and BmaxL = 8.8 pmol/micrograms HA). Ligand competition experiments revealed that compounds that are known to readily bind bone (e.g., sodium pyrophosphate, methylene diphosphonic acid, etidronate) potently inhibited the binding of [14C]citric acid to HA, whereas compounds known to have poorer affinity for bone (e.g., oxalic acid and GABA) did not. Computer analysis of these inhibition curves revealed specific ligand interactions at two different affinity recognition sites. The present results indicate that [14C]citric acid binds discrete sites on synthetic HA in a fashion consistent with a specific labeling of the bisphosphonate recognition site. Analysis of the binding of [14C]citric acid to HA provides a useful method to further explore the structure activity relationships of novel compounds that have binding affinity for bone.

Pigments of Fungi. XXIII. Approaches Towards (±)-Austrocortirubin From 3-Methyl-1-trimethylsilyloxybuta-1,3-diene

The products (5) and (21) of cycloaddition between 3-methyl-1-trimethylsilyloxybuta-1,3-diene (3) and naphthazarin (4), and between (3) and the naphthopurpurin acetal (2), respectively, are converted into the tetrahydroanthraquinones (16)-(18), (26) and (27) via a series of intermediate epoxy alcohols. Stereochemical assignments are corroborated by a single-crystal X-ray structure analysis of the bromohydrin (16). The tetrahydroanthraquinones (27) and (18), advanced intermediates in a proposed synthesis of the fungus pigment austrocortirubin (1) and its 6-demethoxy analogue (20), respectively, are resistant to efficient dehalogenation.

Pigments of Fungi. XXI. Synthesis of (±)-6-Demethoxyaustrocortirubin

6-Demethoxyaustrocortirubin (6) is synthesized via the epoxide (21) which is available in 73% yield over four steps from naphthazarin (10). Hydrolysis of the epoxide (21) yields the diol (25) which on hydrogenolysis affords 6-demethoxy-1-deoxyaustrocortirubin (7). Stereoselective benzylic hydroxylation of (7) gives (6). Cleavage of the epoxide (21) with sodium acetate in acetic acid affords a mixture of the esters (22)-(24), while methanolysis yields the isomeric ethers (29) and (30). Hydrogenolysis of (22), (23) and (29) gives high yields of (7). Potentially more direct routes to the alcohol (7) involving oxymercuration, epoxidation and bromohydrin formation from the alkene (8) are not viable.

Pigments of Fungi. XXIV. New Trihydroxylated Tetrahydroanthraquinones From an Australian Fungus Belonging to the Genus Dermocybe

The pigments (9)-(11), the first trihydroxylated tetrahydroanthraquinones from Basidiomycetes, are isolated from an Australian toadstool belonging to the genus Dermocybe and the structure and relative stereochemistry of each one is established by spectroscopy. The absolute stereochemistry of each pigment is determined by synthesis from dihydroxylated tetrahydroanthraquinones of known absolute configuration.

Pigments of Fungi. XXII. Synthesis of (±)-Austrocortirubin and Related Tetrahydroanthraquinones

The fungal tetrahydroanthraquinones austrocortirubin (1) and austrocortilutein (3) and their deoxy derivatives (2) and (4), respectively, are synthesized in racemic form from naphthopurpurin (6).