Discrimination following various conditions of nondifferential training

Thesis (Ph.D.)--Boston UniversityThe major purpose of the study was to investigate the influence of nondifferential preliminary training on the subsequent learning of a discrimination by: (a) utilizing different pretraining stimuli, (b) manipulating the amount of pretraining, and (c) employing a factorial design to determine the interaction between these variables. The experimential design design consisted of giving 3, 23, 63, and 103 reinforced trials: (a) to the stimulus which was used as the positive in a subsequent discrimination, (b) to the stimulus which was used as the negative in a subsequent discrimination, and (c) to two stimuli which were used as the positive and negative stimuli in a subsequent discrimination. A successive discrimination problem involving the differentiation of responses to two circle-size stimuli was employed to assess the effects of the varying conditions and amounts of pre-discrimination training. Ten male albino rats were assigned to each of the 12 experimental conditions. A number of different indices of discrimination behavior were used to ascertain the degree of differential responding displayed by the various groups during discrimination training. All pre-discrimination training treatments resulted in eventual discrimination learning as evidenced by a gradual decrease in latency of responses to the positive stimulus, and a corresponding increase in latency of responses to the negative stimulus. An. analysis of discrimination criterion scores, correct response learning curves, number of total errore, and the ratio of positive to negative response latencies, was used to determine the effect of the experimental treatments. This analysis indicated that the various conditions and amounts of pre-discrimination training resulted in marked differences in the learning of the subsequent discrimination. [TRUNCATED

Synthesis of Six-Membered Rings and Inhibitors of Protein Kinases

The six-membered rings have a priviledged presence in both natural products and synthetic compounds such as drug molecules. Multiple methods to prepare them in the laboratory have been developed. The Diels-Alder reaction provides several pathways toward the construction of substituted six-membered rings with a high degree of regio-, diastereo- and enantioselectivity. It can be considered to be the most important and powerful carbon-carbon bond-forming reaction of all, in synthetic organic chemistry. A practical synthetic method for the preparation of hexahydrocinnolines was developed here, as part of continuing research on polymer-supported pericyclic reactions in preparation of biologically interesting compounds. Some cinnoline derivatives from the literature were reported to show interesting biological properties, such as antimicrobial activity and inhibition of cancer cell lines. Hexahydro-1,2,4-triazolocinnoline-1,3-diones and related compounds were synthesized via aza Diels-Alder reaction on solid-phase. Protein kinases are key regulators of cell function that constitute one of the largest and most functionally diverse gene families. By adding phosphate groups to substrate proteins, kinase driven phosphorylation plays a significant role in a wide range of cellular processes. More than 500 protein kinase genes are present in the the human genome, constituting about 2% of all human genes. They regulate many cellular processes such as growth, differentiation, and proliferation. Protein kinases are seen as potential therapeutic targets since their mutation and dysregulation is causal in multiple human diseases, including metabolic, immunological disorders, and cancer. The consistent structure of the catalytic site among protein kinases sets limits for the development of protein kinase inhibitors. Some protein kinases, however, have regulatory domains as part of their structure, such as protein kinase C (PKC), whose regulatory (C1) domain is unique and is found only in a small number of kinases. This offers a selectivity advantage, thus making the C1-domain an attractive drug target. In fact, the utilization of the the X-ray crystal structure of the PKCδ C1b domain, with molecular modeling, led to the discovery, in this work, of novel C1 domain ligands, the tricyclic γ-amino alcohols. Synthesis of these compounds was achieved by the utilization of the Diels-Alder reactions. In the process of modifying a naturally occurring deep-blue colored hydrocarbon guaiazulene, a novel aminoguaiazulene derivative was synthesized. This novel derivative undergoes ring annulation reactions with 1,2-dicarbonyl reagents to yield tricyclic δ-lactams, types of benzo[cd]azulenes. Benzo[cd]azulenes derived from guaiazulene, are colorful synthetic carbocyclics with interesting chemical and biological properties. Some of the benzo[cd]azulenes synthesized in this study were recently characterized as selective Pim kinase inhibitors. Pim kinases have become intriguing targets for cancer therapy that possess unique structural features, among protein kinases, that offer a great potential in the design of selective Pim-inhibitors. Based on the promising Pim-kinase inhibition results from multiple cell-based assays, a further modification of the benzo[cd]azulenes was conducted, where some interesting findings in their chemical behavior were observed; new phenolic benzo[cd]azulene compounds were formed, with potent Pim-inhibitory activities. The benzo[cd]azulenes developed in this study were found to be useful research compounds, potential Pim-selective kinase inhibitors, and putative anti-cancer drug candidates. The new synthetic methods detailed in this study will be valuable tools in the further development of additional benzo[cd]azulenes and related systems in the future.Luonnossa esiintyvistä orgaanisista molekyyleistä valtaosalla on rengasrakenne. Näistä kuusirenkaisilla yhdisteillä on merkittävä asema. Luonnonaineiden lisäksi kuusirengasrakenne on yleinen monissa synteettisissä molekyyleissä kuten lääkeaineissa. Näiden valmistamiseksi laboratoriossa on kehitetty suuri joukko erilaisia menetelmiä. Yksi merkittävimmistä on Diels-Alder-reaktio, joka kuuluu laajempaan perisyklisten reaktioiden ryhmään. Yhtenäistä perisyklisille reaktioille on konjugoitu syklinen siirtymätila, jonka seurauksena reaktiotuote syntyy ilman välituotetta. Diels-Alder-reaktiolla voidaan valmistaa tehokkaasti kuusirenkaisisia yhdisteitä ja reaktio on usein stereo- ja regioselektiivinen. Reaktio ei rajoitu pelkästään hiiltä sisältävien renkaiden syntetisointiin, vaan erilaisia heteroatomeja kuten typpeä ja happea sisältäviäkin kuusirenkaita voidaan valmistaa. Diels-Alder-reaktion katsotaan olevan ehkäpä jopa tärkein ja tehokkain menetelmä uusien hiili-hiilisidosten muodostamiseksi synteettisessä orgaanisessa kemiassa. Reaktio ei rajoitu pelkästään laboratorioon, vaan myös luonnosta on löydetty entsyymejä jotka katalysoivat Diels-Alder-reaktiota. Tutkimusryhmässämme on valmistettu biologisesti mielenkiintoisia heterosyklisiä yhdisteitä kiinteäfaasitekniikalla, jossa reaktiot tapahtuvat kiintokantajan (polymeerin) pinnalla. Kiinteä-faasitekniikan etuina on mm. polymeeriin sidotun tuotteen helppo eristys ja puhdistus. Lisäksi suuria reagenssiylimääriä on mahdollista käyttää, sillä ne voidaan suodattaa helposti erilleen tuotteesta. Kirjallisuudessa esiintyvillä kinnoliinijohdannaisilla on havaittu mm. antibakteerisia ja syöpäsolujen kasvua estäviä vaikutuksia. Tutkimuksessa kehitettiin kiinteäfaasimenetelmä heksahydrokinnoliinirakenteen syntetisoimiseksi hetero-Diels-Alder-reaktiolla, jossa reaktiivinen typpi-typpikaksoissidos osallistuu dienofiilinä sykloadditioon polymeeriin sidotun dieenin kanssa. Reaktiotuotteiden irrotus kiintokantajista tapahtui happokäsittelyllä ja tämän jälkeen ne puhdistettiin pylväskromatografisin menetelmin. Lopuksi selvitettiin kinnoliiniyhdisteiden kyky estää 77 proteiinikinaasin aktiivisuutta. Proteiinikinaasit ovat kinaasientsyymejä, joiden substraatti on toinen proteiini. Liittämällä fosfaattiryhmän kohdeproteiiniinsa proteiinikinaaseilla on merkittävä rooli solunsisäisessä viestinnässä. Ihmisen genomi sisältää yli 500 proteiinikinaasigeeniä, joka käsittää noin 2 % koko ihmisen perimästä. Proteiinikinaasit säätelevät monia keskeisiä solun toimintaan vaikuttavia prosesseja, kuten kasvua, erilaistumista ja jakautumista. Proteiinikinaasit ovat potentiaalinen lääkevaikutuskohde, sillä näiden entsyymien mutaatiot ja säätelyhäiriöt ovat osallisena useissa ihmisen vakavissa sairauksissa kuten syövissä. Joillakin proteiinikinaaseilla, kuten proteiinikinaasi C:llä on erillinen regulatorinen C1b-domeeni osana proteiinirakennetta. Väitöstyössä käytettiin hyväksi tunnettua proteiinikinaasi C:n C1b:n kiderakennetta ja C1b-domeeniin sitoutuvan forboliesterin rakennetta, joiden avulla mallinnettiin C1b-domeeniin uudentyyppinen inhibiittoriyhdiste. Tämän kolmirengasrakenteisen, kuusi stereokeskusta sisältävän, γ-aminoalkoholin syntetisoinnissa käytettiin hyväksi peräkkäisiä Diels-Alder-reaktioita, joiden avulla yhdisteen molekyylirunko valmistettiin. Tutkimusryhmässämme on kehitetty menetelmiä luonnossa esiintyvän guajatsuleeni-hiilivedyn muokkaamiseksi. Tämän seskviterpeeneihin kuuluvan atsuleenin kemiallisesti muokatuilla johdoksilla on havaittu Pim-1 ja Pim-3-kinaasien toimintaa estävä vaikutus. Tutkimuksessa kehitettiin menetelmä aminoryhmän liittämiseksi guajatsuleenin rakenteeseen. Uusi aminoguajatsuleeni reagoi 1,2-dikarbonyyliyhdisteiden kanssa muodostaen δ-laktaamirakenteisia, typpiatomin sisältäviä, bentso[cd]azuleeneja. Tutkimuksessa muokattiin myös kemiallisesti jo aikaisemmin ryhmässämme syntetisoituja bentso[cd]atsuleenirakenteita, tarkoituksena valmistaa potentiaalisia ja selektiivisiä Pim-kinaasi-inhibiittoreita. Samalla havaittiin, että osalla näistä yhdisteitä on biologisten ominaisuuksien lisäksi myös ainutlaatuisia kemiallisia ominaisuuksia. Tässä tutkimuksessa valmistetut ja karakterisoidut bentso[cd]atsuleeniyhdisteet ovat osoittautuneet hyödyllisiksi tutkimuskäytössä ja voivat olla myös mahdollisia syöpälääkekandidaatteja tulevaisuudessa

The Natural Selection Game: Incorporating Active Learning in Evolution Curricula for General Biology

Teaching evolution in high school and in entry-level college courses can be challenging due to the inherent misinformation, misunderstanding, and biases with which students approach the topic. In this setting, it is critical to both teach the basic concepts and address common student misconceptions about evolution. We present two paired activities that allow students to (1) explore the processes of natural selection in a direct and experiential way and (2) address common misconceptions in evolutionary theory. The first activity, the “Natural Selection Game,” has students simulate a bird population and experience shifts in phenotype frequency as a result of selective pressures. Following the end of the game, students discuss the outcomes and connect them to real-life examples. The second activity encourages students to actively research common misconceptions with the use of personal technology in order to distinguish between scientifically supported data and poor information online. Both activities can be incorporated in high school and university-level general biology curricula. They will allow students to connect their firsthand experiences to lecture-based instruction and, as a result, develop a stronger understanding of the mechanisms of evolution

DESIGN, SYNTHESIS AND BIOLOGICAL EVALUATION OF BENZAZULENE-BASED COMPOUNDS

Peer reviewe

Differential Habitat Use by Common Watersnakes (Nerodia sipedon)

Understanding intraspecific variation in habitat use is important for the management of any species. In many studies of reptiles, habitat use by juveniles is poorly understood when compared to their adult conspecifics because of capture biases and logistical constraints. We compared habitat use between sexes and age classes of Common Watersnakes (Nerodia sipedon) at a reservoir in central Illinois. Juvenile N. sipedon occurred more frequently in habitat with high canopy cover, whereas adult N. sipedon, especially reproductive females, were found exclusively in habitat with no canopy cover. Adult males used both locations equally. We emphasize the need to investigate ontogenetic variation in habitat use to better understand how reptiles utilize diverse anthropogenically altered landscapes

Differential habitat use by Common Watersnakes (Nerodia sipedon)

Understanding intraspecific variation in habitat use is important for the management of any species. In many studies of reptiles, habitat use by juveniles is poorly understood when compared to their adult conspecifics because of capture biases and logistical constraints. We compared habitat use between sexes and age classes of Common Watersnakes (Nerodia sipedon) at a reservoir in central Illinois. Juvenile N. sipedon occurred more frequently in habitat with high conopy cover, whereas adults N. sipedon, especially reproductive females, were found exclusively in habitat with no canopy cover. Adult males used both locations equally. We emphasize the need to investigate ontogenetic variation in habitat use to better understand how reptiles utilize diverse anthropogenically altered landscapes

A covalent calmodulin inhibitor as a tool to study cellular mechanisms of K-Ras-driven stemness

This article is part of the Research Topic Ras and other GTPases in Cancer: From Basic to Applied Research https://doi.org/10.3389/978-2-88974-081-9Recently, the highly mutated oncoprotein K-Ras4B (hereafter K-Ras) was shown to drive cancer cell stemness in conjunction with calmodulin (CaM). We previously showed that the covalent CaM inhibitor ophiobolin A (OphA) can potently inhibit K-Ras stemness activity. However, OphA, a fungus-derived natural product, exhibits an unspecific, broad toxicity across all phyla. Here we identified a less toxic, functional analog of OphA that can efficiently inactivate CaM by covalent inhibition. We analyzed a small series of benzazulenones, which bear some structural similarity to OphA and can be synthesized in only six steps. We identified the formyl aminobenzazulenone 1, here named Calmirasone1, as a novel and potent covalent CaM inhibitor. Calmirasone1 has a 4-fold increased affinity for CaM as compared to OphA and was active against K-Ras in cells within minutes, as compared to hours required by OphA. Calmirasone1 displayed a 2.5-4.5-fold higher selectivity for KRAS over BRAF mutant 3D spheroid growth than OphA, suggesting improved relative on-target activity. Importantly, Calmirasone1 has a 40-260-fold lower unspecific toxic effect on HRAS mutant cells, while it reaches almost 50% of the activity of novel K-RasG12C specific inhibitors in 3D spheroid assays. Our results suggest that Calmirasone1 can serve as a new tool compound to further investigate the cancer cell biology of the K-Ras and CaM associated stemness activities.Peer reviewe

Novel Small Molecule Hsp90/Cdc37 Interface Inhibitors Indirectly Target K-Ras-Signaling

The ATP-competitive inhibitors of Hsp90 have been tested predominantly in kinase addicted cancers; however, they have had limited success. A mechanistic connection between Hsp90 and oncogenic K-Ras is not known. Here, we show that K-Ras selectivity is enabled by the loss of the K-Ras membrane nanocluster modulator galectin-3 downstream of the Hsp90 client HIF-1α. This mechanism suggests a higher drug sensitivity in the context of KRAS mutant, HIF-1α-high and/or Gal3-high cancer cells, such as those found, in particular, in pancreatic adenocarcinoma. The low toxicity of conglobatin further indicates a beneficial on-target toxicity profile for Hsp90/Cdc37 interface inhibitors. We therefore computationally screened >7 M compounds, and identified four novel small molecules with activities of 4 μM–44 μM in vitro. All of the compounds were K-Ras selective, and potently decreased the Hsp90 client protein levels without inducing the heat shock response. Moreover, they all inhibited the 2D proliferation of breast, pancreatic, and lung cancer cell lines. The most active compounds from each scaffold, furthermore, significantly blocked 3D spheroids and the growth of K-Ras-dependent microtumors. We foresee new opportunities for improved Hsp90/Cdc37 interface inhibitors in cancer and other aging-associated diseases

Novel Small Molecule Hsp90/Cdc37 Interface Inhibitors Indirectly Target K-Ras-Signaling

The ATP-competitive inhibitors of Hsp90 have been tested predominantly in kinase addicted cancers; however, they have had limited success. A mechanistic connection between Hsp90 and oncogenic K-Ras is not known. Here, we show that K-Ras selectivity is enabled by the loss of the K-Ras membrane nanocluster modulator galectin-3 downstream of the Hsp90 client HIF-1α. This mechanism suggests a higher drug sensitivity in the context of KRAS mutant, HIF-1α-high and/or Gal3-high cancer cells, such as those found, in particular, in pancreatic adenocarcinoma. The low toxicity of conglobatin further indicates a beneficial on-target toxicity profile for Hsp90/Cdc37 interface inhibitors. We therefore computationally screened >7 M compounds, and identified four novel small molecules with activities of 4 μM–44 μM in vitro. All of the compounds were K-Ras selective, and potently decreased the Hsp90 client protein levels without inducing the heat shock response. Moreover, they all inhibited the 2D proliferation of breast, pancreatic, and lung cancer cell lines. The most active compounds from each scaffold, furthermore, significantly blocked 3D spheroids and the growth of K-Ras-dependent microtumors. We foresee new opportunities for improved Hsp90/Cdc37 interface inhibitors in cancer and other aging-associated diseases

Carotid shunt provides cerebral protection during emergency coronary artery bypass grafting in a patient with bilateral high grade carotid stenosis: a case report

<p>Abstract</p> <p>Background</p> <p>Management of patients with co-existent coronary and carotid disease is a controversial and challenging issue. The risk for stroke after coronary artery bypass grafting (CABG) in patients with hemodynamically significant carotid stenosis is up to 30%. In these patients a common practice is to proceed first with the restoration of cerebral perfusion and then perform the coronary revascularization. The rationale is that this strategy will reduce perioperative neurological morbidity and mortality. However, what happens when the carotid procedure is acutely complicated by cardiac instability which necessitates the interruption of the carotid procedure?</p> <p>Case report</p> <p>We describe a case of a patient with unstable angina and high grade asymptomatic bilateral carotid stenosis who underwent emergency combined CABG and carotid endarterectomy (CEA). Due to hemodynamic instability, ST-T changes, hypotension and bradycardia, upon completion of endarterectomy we placed a carotid shunt and the patient was put on cardiopulmonary bypass through median sternotomy. After triple CABG (duration of 90 minutes) we concluded the interrupted CEA procedure with primary closure of the carotid arteriotomy with the shunt in place. The postoperative course was uneventful and the patient was discharged after a week. In extreme cases with bilateral severe carotid stenosis and coronary artery disease where the carotid procedure should be interrupted, we suggest the use of carotid shunt which can provide adequate cerebral perfusion giving time to cardiac surgeon to perform the life saving cardiac procedure first.</p