Molecular Dynamics Simulations of p97 Including Covalent, Allosteric and ATP-competitive Inhibitors

Binary (nucleotide-protein dimer and hexamer complexes) and ternary (nucleotide-protein-inhibitor complexes) p97 complexes were subjected to molecular dynamics simulations in an attempt to further our understanding of the p97 protein oligomer domain stability and, more importantly, of the recently reported diverse molecular mechanisms of inhibition including allosteric, ATP-competitive and covalent inhibitors. Analysis of stable states following equilibration phases indicated a higher intrinsic stability of the homohexamer as opposed to the dimer, and of N-D1 domains as opposed to the D2 domain. The molecular dynamics of the proposed allosteric binding model reproduced important molecular interactions identified experimentally with high frequency throughout the trajectory. Observed conformational changes occurring in the D2 nucleotide binding site provided a novel bind-rearrange-react hypothesis of stepwise molecular events involved in the specific covalent inhibitor mode of action.

Abstract 5163: Characterization of NMS-E194, a selective and potent PERK inhibitor with efficacy in the KMS-11 multiple myeloma

PERK (PKR-like endoplasmic reticulum kinase) is a serine-threonine kinase associated to endoplasmic reticulum membrane. Together with ATF6 and IRE1, PERK is a key effector of the Unfolded Protein Response (UPR), a network of signaling pathways that ensures protein homeostasis in the endoplasmic reticulum. Multiple Myeloma (MM) and other protein-secreting tumors are highly dependent on UPR for survival, and inhibition of PERK may be an effective strategy to inhibit growth of these tumors. Here we describe the in vitro and in vivo properties of NMS-E194, a novel potent and selective ATP-competitive PERK inhibitor belonging to the arylsulfonamide chemical class. NMS-E194 inhibits PERK kinase with a Ki of ca 1.5 nM in biochemical assay and possesses high selectivity towards a panel of 54 kinases. When tested in cell proliferation assays, NMS-E194 is preferentially active on multiple myeloma (MM) and diffuse large B cell lymphoma cell lines. In mechanism of action studies, NMS-E194 shows a bi-phasic behaviour: at low nanomolar doses it activates PERK, causing ATF4 accumulation, while at >200 nM it inhibits PERK and downstream pathway, inducing apoptosis. NMS-E194 possesses a favourable in vitro ADME profile and has promising PK properties in the mouse. NMS-E194 demonstrated strong anti-tumor activity following oral administration at 25 mg/kg daily to mice harbouring luciferized KMS-11 cells in a disseminated growth model of MM, with no overt toxicity. Overall, the data available so far warrant further development of NMS-E194 and support PERK inhibition as a novel therapeutic approach in MM and other PERK-dependent tumors.

Citation Format: Claudia Perrera, Maurizio Pulici, Davide Carenzi, Ilaria Motto, Marina Fasolini, Elena Casale, Stefania Re Depaolini, Simona Rizzi, Daniela Asa, Fulvia Roletto, Simona Bindi, Daniele Casero, Patrizia Banfi, Elena Ardini, Nadia Amboldi, Dario Ballinari, Fabio Gasparri, Sabrina Cribioli, Laura Mancini, Marina Ciomei, Daniele Donati, Eduard Felder, Arturo Galvani, Antonella Isacchi, Barbara Valsasina. Characterization of NMS-E194, a selective and potent PERK inhibitor with efficacy in the KMS-11 multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5163. doi:10.1158/1538-7445.AM2017-5163

Abstract 2082: NMS-E668, a potent and selective RET kinase inhibitor characterized by specificity towards VEGFR2 and high antitumor efficacy against RET-driven models

RET, a receptor tyrosine kinase (RTK) expressed mainly in neural crest-derived tissues, plays a role in cell growth and differentiation and its physiological activation depends upon binding to the GDNF family. Genetic aberrations leading to constitutive RET activation are well-established as oncogenic events. Activating point mutations of RET, for example, are present in ca. 70% of medullary thyroid carcinoma patients including all hereditary cases, while RET gene rearrangements resulting in production of activated RET fusion proteins occur in approximately 10% of sporadic papillary thyroid carcinomas. More recently, recurring RET gene rearrangements have also been found in 1-2 % of lung adenocarcinomas and subsets of other solid tumors including colorectal and salivary gland carcinomas. Thus RET kinase represents an actionable therapeutic target in multiple clinical settings with high medical need. Consequently several small-molecule inhibitors targeting this kinase have been explored in clinical settings. A common feature of most advanced agents is their lack of selectivity and in particular their potent cross-reactivity against VEGFR2, an RTK whose inhibition is associated with serious, dose-limiting cardiovascular toxicity. Indeed, the high homology between the two kinases renders identification of ATP competitive compounds that selectively inhibit RET over VEGFR2 a highly challenging task. Here we describe the preclinical activity of NMS-E668, a potent and selective ATP-competitive RET inhibitor characterized by favorable activity, selectivity and ADME profiles. Biochemically, NMS-E668 has an excellent selectivity profile against a panel of >50 kinases, notably including >10-fold selectivity over VEGFR2. Selectivity of NMS-E668 for RET vs. VEGFR2 was confirmed in NIH-3T3 cells engineered to express activated forms of these kinases. NMS-E668 potently (IC50 circa 50 nM) and selectively inhibited proliferation of RET-dependent tumor cells, including TT medullary carcinoma cells harboring a RET C634W activating point mutation and LC2/ad lung carcinoma cells bearing the oncogenic fusion protein CCDC6-RET. NMS-E668 also potently inhibited IL3-independent growth of Ba/F3 cells expressing KIF5B-RET, the RET rearrangement that is most commonly found in lung adenocarcinomas. Cellular mechanism studies confirmed that NMS-E668 inhibits RET autophosphorylation and downstream signaling at doses consistent with antiproliferative activity. Tested in vivo against KIF5B-RET-driven Ba/F3 tumors, NMS-E668 displayed >90% tumor growth inhibition accompanied by target modulation following oral administration at 10 and 20 mg/kg, with prolonged tumor regressions observed at the higher dose. Thus NMS-E668, a potent and VEGFR2-sparing RET inhibitor is an innovative and highly promising candidate for further development.

Citation Format: Elena Ardini, Patrizia Banfi, Nilla Avanzi, Marina Ciomei, Paolo Polucci, Alessandra Cirla, Antonella Ermoli, Ilaria Motto, Elena Casale, Giulia Canevari, Cinzia Cristiani, Sonia Troiani, Federico Riccardi Sirtori, Nadia Amboldi, Dario Ballinari, Francesco Caprera, Eduard Felder, Arturo Galvani, Daniele Donati, Antonella Isacchi, Maria Menichincheri. NMS-E668, a potent and selective RET kinase inhibitor characterized by specificity towards VEGFR2 and high antitumor efficacy against RET-driven models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2082. doi:10.1158/1538-7445.AM2017-2082

Abstract 1223: NMS-P293, a novel potent and selective PARP-1 inhibitor with high antitumor efficacy and tolerability

Poly(ADP-ribose) polymerase-1 (PARP-1) has a well-established role in the signaling and repair of DNA and is a prominent target in oncology. Inhibition of PARP-1 is synthetically lethal with loss of function of the BRCA1 and BRCA2 tumor suppressor genes, as well with additional DNA repair defects. Tumor cells harboring defects in DNA repair pathways can thus be selectively targeted with PARP-1 inhibitors, and several such compounds are at different stages of clinical investigation in diverse tumor types, either as single agents or in combination regimens. However none of these agents selectively inhibits PARP-1 within the PARP family of enzymes: all drugs currently in clinical development, as well as the vast majority of preclinical compounds described to date potently cross-inhibit PARP-2, due to the high sequence homology between the two enzymes. Although PARP-2 is reported to be involved in DNA single-strand break repair, its contribution to total cellular levels of DNA damage-induced PARP activity is minimal (5-10%). Gene ablation studies show that loss of both PARP-1 and -2 function is incompatible with normal embryonic development, while PARP-2 single knockout mice show a variety of defects, including impaired erythropoiesis, thymopoiesis adipogenesis and spermatogenesis, increased neuronal loss after ischemic damage and higher risk of pancreatitis following chemical insult. We therefore reasoned that a potent and highly selective PARP-1 inhibitor might represent a significant advancement over currently available agents targeting both PARP-1 and -2, since sparing of PARP-2 inhibition potentially limits on target side-effects and offers greater opportunity for combination with other chemotherapeutic agents.

Here we describe the preclinical characterization of NMS-P293, a novel highly potent PARP-1 inhibitor possessing >200-fold selectivity versus PARP-2. In cells, NMS-P293 inhibits hydrogen peroxide induced poly ADP-ribose (PAR) synthesis with an IC50 in the single digit nanomolar range, confirming expected mechanism of action in cells.

NMS-P293 is selectively active on tumor cell lines defective in the HR repair pathway, such as pTEN and BRCA mutated lines, while sparing DNA repair proficient cells and normal myelocytes. NMS-P293 possesses favorable ADME properties including a low efflux ratio, high cross-species metabolic stability, low clearance and nearly complete oral bioavailability in rodents and non rodents. Oral administration to mice bearing BRCA mutated breast cancer xenografts resulted in complete tumor regressions and cures.

The highly favorable preclinical characteristics of NMS-P293 make this compound a promising candidate for further development.

Citation Format: Alessia Montagnoli, Sonia Rainoldi, Antonella Ciavolella, Dario Ballinari, Francesco Caprera, Lucio Ceriani, Rosita Lupi, Marina Ciomei, Eduard Felder, Antonella Isacchi, Daniele Donati, Arturo Galvani, Gianluca Papeo. NMS-P293, a novel potent and selective PARP-1 inhibitor with high antitumor efficacy and tolerability. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1223.

Discovery of Entrectinib: A New 3-Aminoindazole As a Potent Anaplastic Lymphoma Kinase (ALK), c-ros Oncogene 1 Kinase (ROS1), and Pan-Tropomyosin Receptor Kinases (Pan-TRKs) inhibitor

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase responsible for the development of different tumor types. Despite the remarkable clinical activity of crizotinib (Xalkori), the first ALK inhibitor approved in 2011, the emergence of resistance mutations and of brain metastases frequently causes relapse in patients. Within our ALK drug discovery program, we identified compound 1, a novel 3-aminoindazole active on ALK in biochemical and in cellular assays. Its optimization led to compound 2 (entrectinib), a potent orally available ALK inhibitor active on ALK-dependent cell lines, efficiently penetrant the blood-brain barrier (BBB) in different animal species and highly efficacious in in vivo xenograft models. Moreover, entrectinib resulted to be strictly potent on the closely related tyrosine kinases ROS1 and TRKs recently found constitutively activated in several tumor types. Entrectinib is currently undergoing phase I/II clinical trial for the treatment of patients affected by ALK-, ROS1-, and TRK-positive tumors.

Entrectinib, a Pan-TRK, ROS1, and ALK Inhibitor with Activity in Multiple Molecularly Defined Cancer Indications

Activated ALK and ROS1 tyrosine kinases, resulting from chromosomal rearrangements, occur in a subset of non-small cell lung cancers (NSCLC) as well as other tumor types and their oncogenic relevance as actionable targets has been demonstrated by the efficacy of selective kinase inhibitors such as crizotinib, ceritinib, and alectinib. More recently, low-frequency rearrangements of TRK kinases have been described in NSCLC, colorectal carcinoma, glioblastoma, and Spitzoid melanoma. Entrectinib, whose discovery and preclinical characterization are reported herein, is a novel, potent inhibitor of ALK, ROS1, and, importantly, of TRK family kinases, which shows promise for therapy of tumors bearing oncogenic forms of these proteins. Proliferation profiling against over 200 human tumor cell lines revealed that entrectinib is exquisitely potent in vitro against lines that are dependent on the drug's pharmacologic targets. Oral administration of entrectinib to tumor-bearing mice induced regression in relevant human xenograft tumors, including the TRKA-dependent colorectal carcinoma KM12, ROS1-driven tumors, and several ALK-dependent models of different tissue origins, including a model of brain-localized lung cancer metastasis. Entrectinib is currently showing great promise in phase I/II clinical trials, including the first documented objective responses to a TRK inhibitor in colorectal carcinoma and in NSCLC. The drug is, thus, potentially suited to the therapy of several molecularly defined cancer settings, especially that of TRK-dependent tumors, for which no approved drugs are currently available. Mol Cancer Ther; 15(4); 628-39. ©2016 AACR.

Introducing e-learning/teaching in a physiology course for medical students: acceptance by students and subjective effect on learning

Retrieval of information has substantially changed within the last two decades. Naturally, this has also affected learning/teaching techniques, and methods that are commonly referred to as "e-learning" have become an important part in modern education. Institutions have to decide if (and how) to implement this new form of teaching but face the problem that little subject-specific research has been published for different teaching modes and methods. The present study compares a course module of the physiology laboratory course for medical students in the preclinical phase before and after the introduction of computer-aided course instructions (CACI). Students were provided with an online questionnaire containing Likert items evaluating workspace redesign, acceptance of course instructions, incentive to actively participate in the course, and subjective gain of knowledge. CACI was clearly preferred over the previously used paper workbook. However, the questionnaire also revealed that the gain in knowledge, as subjectively perceived by the students, had not improved, which is in agreement with several studies that neglected a beneficial effect of e-learning on learning success. We conclude that the CACI meet today's student's expectations and that introducing this system seems justified from this perspective.

Abstract 1775: Characterization of new highly selective and potent PARP-1 inhibitors

Poly (ADP-ribose) polymerase 1 (PARP-1) is a key nuclear enzyme that is activated by DNA-strand breaks; activation of PARP-1 protects DNA breaks and chromatin structure and recruits DNA repair and checkpoint proteins to the sites of damage, by modification with poly(ADP-ribose) (PAR) polymers. PARP-2, another nuclear member of the PARP family with largely unknown functions, shares homology with PARP-1 and is also activated by DNA breaks. Embryonic knock out of either PARP-1 or PARP-2 is well tolerated; however, double knockout is embryonic lethal suggesting that inhibiting both PARPs could enhance toxicity. PARP inhibitors in clinical development generally inhibit more than one PARP isoforms. These compounds are synthetic lethal with defects in homologous recombination (HR), and are currently being tested in combination as well as in monotherapy for hereditable cancers deficient in the BRCA1 or BRCA2 genes. Here we describe the in vitro and in vivo properties of a novel class of potent and selective PARP-1 small molecule inhibitors. Starting from a series of derivatives that were found to be active against PARP-1 and PARP-2, an expansion and optimization program was undertaken. This led to the identification of inhibitors with single digit nM affinity for PARP-1 and negligible crossreactivity against PARP-2. Members of this sub-series display single agent cytotoxicity with IC50s below 1 μM in cell lines harboring BRCA mutations, or in cells stably transfected with BRCA-1 short harpin RNA, and more than 100 times selectivity against BRCA wild-type tumor cell lines. Furthermore, these compounds are highly active in other repair deficient backgrounds such as ATM and Mre11 mutated acute leukemias and lymphomas and they compared favorably with reference PARP inhibitors which are in clinical development. Expected mechanism of action was confirmed by observed modulation of PAR induction, in vitro and in vivo. These compounds show high oral bioavailability, good ADME properties and high tolerability. Selection of the candidate most suitable for further development is underway.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1775. doi:1538-7445.AM2012-1775

NMS-P937, an orally available, specific small-molecule polo-like kinase 1 inhibitor with antitumor activity in solid and hematologic malignancies

Polo-like kinase 1 (PLK1) is a serine/threonine protein kinase considered to be the master player of cell-cycle regulation during mitosis. It is indeed involved in centrosome maturation, bipolar spindle formation, chromosome separation, and cytokinesis. PLK1 is overexpressed in a variety of human tumors and its overexpression often correlates with poor prognosis. Although five different PLKs are described in humans, depletion or inhibition of kinase activity of PLK1 is sufficient to induce cell-cycle arrest and apoptosis in cancer cell lines and in xenograft tumor models. NMS-P937 is a novel, orally available PLK1-specific inhibitor. The compound shows high potency in proliferation assays having low nanomolar activity on a large number of cell lines, both from solid and hematologic tumors. NMS-P937 potently causes a mitotic cell-cycle arrest followed by apoptosis in cancer cell lines and inhibits xenograft tumor growth with clear PLK1-related mechanism of action at well-tolerated doses in mice after oral administration. In addition, NMS-P937 shows potential for combination in clinical settings with approved cytotoxic drugs, causing tumor regression in HT29 human colon adenocarcinoma xenografts upon combination with irinotecan and prolonged survival of animals in a disseminated model of acute myelogenous leukemia in combination with cytarabine. NMS-P937, with its favorable pharmacologic parameters, good oral bioavailability in rodent and nonrodent species, and proven antitumor activity in different preclinical models using a variety of dosing regimens, potentially provides a high degree of flexibility in dosing schedules and warrants investigation in clinical settings.

Abstract A213: Potent anticancer activity in vitro and in vivo by NMS-E973, a novel synthetic inhibitor of HSP90

The molecular chaperone heat shock protein 90 (HSP90) is essential for the conformational maturation and stability of a variety of proteins, including kinases, transcription factors, telomerase, and other key proteins implicated in cancer development and progression. The simultaneous block of multiple signaling pathways that is induced by Hsp90 inhibition makes this approach potentially attractive in a broad range of cancer types.

Prototype geldanamicyn-derivative HSP90 inhibitors have already shown efficacy in different types of tumors, but possess liabilities inherent to the class which may ultimately limit their development. Here we describe the in vitro and in vivo characterisation of NMS-E973, representative of a novel class of non-ansamycin Hsp90 inhibitors. NMS-E973 binds HSP90 with picomolar affinity, as revealed by Surface Plasmon Resonance analysis, whereas selectivity screening showed no significant activity against a broad panel of kinases, as well as other ATPases. NMS-E973, when profiled against a panel of 91 tumor cell lines of various tissue origins, showed widespread antiproliferative activity. On-target mechanism was confirmed in multiple cell lines by observation of dose and time dependent degradation of specific oncogenes, parallel blockade of the PI3K and RAF/MEK/ERK pathways, and upregulation of HSP70, a well-known feedback response to HSP90 inhibition. In vivo, NMS-E973 had a favourable pharmacokinetic profile, good tolerability, selective retention in tumors, and induced tumor shrinkage in multiple human xenograft models in nude mice. In the B-RAF V600E driven A375 melanoma model, for which a multi-cycle regimen was adopted, shrinkage was observed both during the first treatment cycle, as well as after successive re-challenge of larger, regrown tumor masses. In conclusion, NMS-E973 is a novel, potent non-ansamycin like inhibitor of HSP90, with efficacy and pharmacokinetic properties compatible with clinical development.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A213.

A prospective observational study of the efficacy of a novel hydroactive impregnated dressing

OBJECTIVE

To assess the clinical efficacy, tolerance and acceptance of a novel, hydroactive-impregnated dressing (Hydrotul) in the local treatment of acute and chronic wounds.

METHOD

In a prospective observational study 24 centres in France, Belgium, Germany and Austria recruited 74 patients. At each dressing change the investigators evaluated the condition of the wound, perilesional skin and patient-reported pain. Overall, five dressing changes were documented, or until complete healing occurred. The hydroactive properties of the dressing were assessed in laboratory tests by measuring fluid absorption capacity and kinetics.

RESULTS

Patients were treated for an average of 17 days. The wound condition improved markedly during the observation period. The wound area covered with fibrinous slough decreased from 29% to 14%, epithelialisation increased from 19% to 54% and 22 wounds were completely healed by the end of the study. The number of patients reporting severe and moderate wound pain decreased from 35% to 19% and the proportion of patients without wound pain doubled from 27% to 60%. In laboratory tests, Hydrotul absorbed two to three times the amount of fluid compared with other impregnated wound dressings and the kinetics of absorption was much faster.

CONCLUSION

The novel hydroactive impregnated dressing supports the healing process in patients with acute and chronic wounds and reduces wound pain. The dressing absorbs excess wound exudate while keeping the wound surface moist and protecting perilesional skin.

Percolation and the colossal magnetoresistance of Eu-based hexaboride

Upon substituting Ca for Eu in the local-moment ferromagnet EuB6, the Curie temperature T(C) decreases substantially with increasing dilution of the magnetic sublattice and is completely suppressed for x<or=0.3. The Ca substitution leads to significant changes of the electronic properties across the EuxCa1-xB6 series. Electron microscopy data for x approximately 0.27 indicate a phase separation into Eu- and Ca-rich clusters of 5 to 10 nm diameter, leading to percolation-type phenomena in the electrical transport properties. The related critical concentration x(p) is approximately 0.3. For x approximately 0.27, we observe colossal negative magnetoresistance effects at low temperatures, similar in magnitude as those reported for manganese oxides.

Selective aspects of human pathology in high-tone hearing loss of the aging inner ear

Accompanied with aging, the thresholds for high frequency sounds may elevate and result in a progressive hearing loss described as presbycusis. Based on correlations between audiometric measures of aged patients and histologic findings garnered from postmortem examinations, four types of presbycusis have been characterized: sensory-neural, neural, strial, and conductive [Schuknecht, H.F., Gacek, M.R., 1993. Ann. Otol. Rhinol. Laryngol. 102, 1--16]. Otopathologic changes to the inner ear as a direct function of age, however, remain controversial. The focus of this investigation involves the pathological impact on remaining sensory structures in patients having sensory--neural degeneration. The current study presents seven human temporal bones extracted from patients aged 53--67 years with high-tone hearing loss and with no known history of extraordinary environmental events involving head or noise trauma, acoustic overstimulation, or ototoxicity. In previously published findings of these specimens, all but one temporal bone failed to demonstrate a meaningful correlation between audiometric measurements and loss of functional hair cell populations with secondary retrograde degeneration of nerve fibers. Using the block surface method, electron microscopic micrographs demonstrate ultrastructural changes in the cuticular plate, stereocilia, pillar cells, stria vascularis, and the spiral ligament. In all pathological specimens, the greatest incidence of degeneration was seen at the cuticular plate. Conclusively, our findings present three implications in the aging human cochlea: firstly, audiometric measures that represent a high-tone hearing loss may take various forms with respect to ultrastructural patterns of degeneration and surviving structures; secondly, the incidence of lipofuscin and lysosome granules does not correlate with the degree of hearing loss and; thirdly, as shown only in guinea pigs [Anniko, M., 1988. Scanning Microsc. 2, 1035--1041], high-tone hearing loss can be associated with deformation of the cuticular plate.

Merged screening for human immunodeficiency virus Tat and Rev inhibitors

In addition to "conventional" drug discovery targets used in modern strategies, mainly focusing on proteins, recent insights into gene regulation as a novel drug concept have begun to invite the targeting of biomolecular interactions between proteins and RNA. Because two protein-RNA interactions (Tat and trans-activation-responsive element, Rev and Rev-responsive element) are essential for any productive replication of human immunodeficiency virus, this important human pathogen was used as a model system for our studies. The design of a fluorescence-based high throughput assay, in which both targets were presented in the same vessel, enabled us to simultaneously interrogate two characteristics of a potential inhibitor: potency of interference and selectivity toward each of the interactions. Although related systems have been reported for several DNA binders, an extension into interference with transcription events would open a new dimension of cellular regulation. Here we describe the setup of the screening assay for over 110,000 compounds as well as a primary characterization of identified hits. The assay's characteristics demonstrate that a microwell-based dual screening system for RNA binders may add a powerful tool to modern drug discovery.

Quantitative evaluation of cochlear neurons and computer-aided three-dimensional reconstruction of spiral ganglion cells in humans with a peripheral loss of nerve fibres

Quantitative data on human cochlear neuronal elements were collected from various regions in five patients with high-tone hearing loss due to presbycusis and in two patients with normal hearing. The number of nerve fibers was assessed in the spiral lamina and in the inner acoustic meatus together with counts of spiral ganglion cells. The results show that the number of neurons decreased peripherally, i.e., with increasing distance from the central nervous system in patients with high-tone hearing loss due to presbycusis. In two patients with normal hearing no significant difference in the number of neurons was found in the lamina spiralis as compared to the inner acoustic canal. Computer-aided 3-dimensional reconstruction of the human spiral ganglion displayed large bipolar neurons (type I cells), but also large ganglion cells with one missing axon. The results may indicate that a slow retrograde degeneration occurs from the periphery towards the spiral ganglion in presbycusis. Transmission electron microscopy analysis of freshly fixed human spiral ganglions displayed interneural connections. It is speculated whether a trophic supply from other neurons at the level of the spiral ganglion can prevent or delay further degeneration of the central axon.

Quantitative evaluation of myelinated nerve fibres and hair cells in cochleae of humans with age-related high-tone hearing loss

In this study 9 human temporal bones from 8 individuals were fixed with Karnovsky solution by perilymphatic perfusion within 1-3 h after death and examined using the "block-surface method' (Spoendlin and Brun, 1974; Spoendlin and Schrott, 1987) and the "micro-dissection method' (Johnsson and Hawkins, 1967). The audiogram of 7 individuals showed high-tone hearing loss, typical for sensory-neural presbycusis. The inner (IHC) and outer hair cells (OHC) and the myelinated nerve fibers in the osseous spiral lamina were counted to correlate audiometric curves with hair-cell and nerve-fibre densities. The "block-surface' method allows accurate hair-cell and myelinated nerve-fibre enumeration with maximal preservation of cochlear structures. The most significant change in the cochlea was not the expected loss of hair cells but an evident loss of nerve fibres in the spiral lamina along the entire length of the cochlea. This loss of nerve fibres was found to be age-related. Reductions up to 30-40% in comparison to normal-hearing middle-aged persons were found in cochleae from persons older than 60 years. In 2 cases only 13% of the fibres remained in some regions of the cochlea. The hair-cell counts showed a reduction of approximately 80% of the OHCs, mainly in the apical parts of the cochlea, and only little differences in the number of IHCs as compared with a group of normal-hearing middle-aged persons. We conclude that neither loss of hair cells nor primary degeneration of nerve fibres alone can fully explain the high-tone loss. Probably injuries of hair cells or neuronal elements at the cellular level can cause threshold elevation.

Integrating cultural diversity theoretical concepts into the educational preparation of the advanced practice nurse: the Cultural Diversity Practice Model

Educational preparation of the Advanced Practice Nurse (APN) for the challenging role of providing available and accessible health care to ethnic diverse populations requires that cultural diversity be included in the expanded education. The Cultural Diversity Practice Model is offered for that purpose.

Modulation of human prorenin gene expression by antisense oligonucleotides in transfected CHO cells

Four phosphorothioate oligonucleotides whose sequences are complementary to the 5' untranslated region, the initiation codon or the coding region of human prorenin mRNA, were studied for their capacity to inhibit gene expression in stably transfected Chinese hamster ovary (CHO) cells constitutively producing human prorenin. In contrast to oligomers complementary to the initiation codon and the coding region, antisense oligomers directed towards the 5' untranslated region have no inhibitory effects. The intracellular delivery of a biotinylated phosphorothioate oligonucleotide (biotin-CATCCATGCTTCCCTC) was monitored in immunofluorescence studies. In the absence of a cationic liposome preparation, Lipofectin, the oligomer failed to penetrate the cells. In the presence of Lipofectin, the 35S-labelled oligomer entered the cells and was distributed in proportions of 54% to the nuclei and 35% to the cytosol. The effects of regular oligonucleotides and of 3'-end and/or 5'-end-modified phosphodiester oligonucleotides on prorenin production were tested. Terminal modification by biotinylation at the 5'-end and/or 3'-dodecyl esterification stabilized oligonucleotides towards exonucleases, but did not translate into a significant inhibition of prorenin production and did not improve the intracellular delivery and or stability of the oligomers. We have shown that it is possible to inhibit prorenin production intracellularly using specific antisense oligonucleotides. Stability and delivery are crucial factors in the design of potent and specific compounds directed at prorenin mRNA.

Gd-BOPTA/Dimeg: experimental disease imaging

The novel tissue-specific contrast agent, Gd-BOPTA/Dimeg, was tested in MR imaging of experimental focal liver disease and of acute myocardial ischemia in rats. Directly implanted liver tumors and blood-borne metastases were used as models for focal liver disease and occlusion of the lower anterior descending coronary artery as model for acute ischemia. The studies with implanted tumors, at a dose level of 250 mumol/kg, showed a very high (370%) and persistent (greater than 2 h) increase in the tumor-liver contrast-to-noise ratio (CNR), owing to selective enhancement of normal liver parenchyma signal intensity. While all blood-borne metastases showed a similar late CNR enhancement, some of them experienced early contrast loss due to transient signal intensity enhancement. In myocardial imaging, Gd-BOPTA/Dimeg produced a signal intensity enhancement in normal myocardium and an injured area-normal area CNR enhancement which were both much stronger and more persistent than those produced by Gd-DTPA/Dimeg.

Comparison of Gd-BOPTA with Gd-DTPA in MR imaging of rat liver

A new lipophilic compound, gadolinium benzyloxypropionictetraacetate (BOPTA), with a high rate of biliary excretion was assessed as a magnetic resonance (MR) hepatospecific contrast-enhancing agent and compared with Gd-DTPA (diethylenetriaminepentaacetic acid) in MR imaging of normal rats. T1-weighted spin-echo images obtained before and after administration of each contrast agent at doses of 0.25, 0.5, and 1.0 mmol/kg showed greater enhancement of the liver with Gd-BOPTA than with Gd-DTPA, with the advantage more evident at lower doses. Images obtained with an inversion recovery sequence at the null value of rat liver parenchyma after injection of 0.1- and 0.5-mmol/kg doses of the contrast agent provided better evidence of the greater and longer-lasting hepatic enhancement due to Gd-BOPTA when compared with that of Gd-DTPA. Gd-BOPTA is a potentially good contrast agent for obtaining prolonged enhancement of the liver, permitting studies during the long time needed to acquire conventional T1-weighted images.

Baccalaureate and Associate Degree Student Nurses' Cultural Knowledge of and Attitudes Toward Black American Clients

The purpose of this study was to investigate the effect of cultural diversity education in nursing on baccalaureate and associate degree students' cultural knowledge of and attitudes toward black American clients. Cultural diversity education in nursing information processing, and attitude concepts (Fishbein & Ajzen, 1975) provided the conceptual framework. The sample consisted of 110 baccalaureate and associate degree senior and freshmen students from National League for Nursing accredited schools of nursing. Each school's dean confirmed that cultural diversity educational experiences were included in the curricula. The findings indicated that the group of associate degree students, which included a large number of various ethnic students, had higher cultural knowledge of black American clients then the baccalaureate degree students, who had less ethnic variance. However, adjustment for the ethnic variable was not significant (F(1,1) = 12.5, p less than .001). There were no differences in the attitudes toward black American clients between the two groups of students. The score ratings for cultural knowledge of (m = 66.90 on a scale of 0 to 100), and attitude toward (m = 35.40 on a scale of 7 to 56 points) black American clients were low in each group of students. Implications are for increased and improved cultural content in nursing education and alternative methods of teaching black American cultural content.

[A comparative study between Gd-BOPTA, a biliary excretion contrast medium, and Gd-DTPA in the magnetic resonance imaging of the rat liver]

A new lipophilic compound, Gd-BOPTA, presenting a high rate (38.6%) of biliary excretion was tested as an hepato-specific MR contrast agent. Its adequacy was compared to that of Gd-DTPA in laboratory animals. T1-weighted spin-echo sequences (TR 220 ms, TE 20 ms) both before and after the administration of the 2 contrast agents (doses: 0.25, 0.5, and 1.0 mmol/kg) showed better liver enhancement with Gd-BOPTA than with Gd-DTPA. Gd-BOPTA superiority was more evident at lower doses, while at 1.0 mmol/kg a comparable enhancement was achieved. Inversion recovery sequence at the T-null of liver parenchyma before contrast (TR 800 ms, TE 30 ms, TI 100 ms) was performed after the injection of 0.1 and 0.5 mmol/kg of Gd-DTPA and Gd-BOPTA. This sequence allowed the good and long-lasting liver enhancement achieved with Gd-BOPTA to be even better demonstrated, while Gd-DTPA provided only a slight and early enhancement with 0.1 mmol/kg and returned to baseline values 60' after the injection of the highest dose (0.5 mmol/kg). Gd-BOPTA proved to be a good contrast agent to obtain prolonged liver enhancement, thus providing the radiologist with the long time needed to acquire conventional T1-weighted pulse sequences.

Self-care agency and blood pressure control

This research examined whether blood pressure measurement relates to an individual Self-Care Agency's (SCA) capabilities (self-concept, knowledge, and initiative) to exercise self-care. A sample of 110 hypertensive high-risk urban black Americans (61 males and 49 females) with a mean age of 46 years (range 18-75), was administered the 43 item 'Exercise of Self-Care Agency' scale and a demographic/health questionnaire. The blood pressure (BP) of each participant was measured at the time of the survey. A large number of subjects (72%) had normal BP and 80% low SCA capability scores. Twenty-eight percent had abnormal BP and 21% had high SCA scores. Blood pressure did not relate to self-care agency. The SCA subconstruct, 'Initiative' was significantly related to normal BP (r = 0.3354, P = 0.006). Self-care agency was inversely associated with obesity, cigarette smoking and excessive salt use. These findings suggest a deficit relationship between SCA and therapeutic self-care demand among urban black Americans who are at high risk for hypertension.