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Intravenously infusible nanoparticles to control bleeding have shown promise in rodents, but translation into preclinical models has been challenging as many of these nanoparticle approaches have resulted in infusion responses and adverse outcomes in large animal trauma models. We developed a hemostatic nanoparticle technology that was screened to avoid one component of the infusion response: complement activation. We administered these hemostatic nanoparticles, control nanoparticles, or saline volume controls in a porcine polytrauma model. While the hemostatic nanoparticles promoted clotting as marked by a decrease in prothrombin time and both the hemostatic nanoparticles and controls did not active complement, in a subset of the animals, hard thrombi were found in uninjured tissues in both the hemostatic and control nanoparticle groups. Using data science methods that allow one to work across heterogeneous data sets, we found that the presence of these thrombi correlated with changes in IL-6, INF-alpha, lymphocytes, and neutrophils. While these findings might suggest that this formulation would not be a safe one for translation for trauma, they provide guidance for developing screening tools to make nanoparticle formulations in the complex milieux of trauma as well as for therapeutic interventions more broadly. This is important as we look to translate intravenously administered nanoparticle formulations for therapies, particularly considering the vascular changes seen in a subset of patients following COVID-19. We need to understand adverse events like thrombi more completely and screen for these events early to make nanomaterials as safe and effective as possible.

Infections with enteric pathogens impose a heavy disease burden, especially among young children in low-income countries. Recent findings from randomized controlled trials of water, sanitation, and hygiene interventions have raised questions about current methods for assessing environmental exposure to enteric pathogens. Approaches for estimating sources and doses of exposure suffer from a number of shortcomings, including reliance on imperfect indicators of fecal contamination instead of actual pathogens and estimating exposure indirectly from imprecise measurements of pathogens in the environment and human interaction therewith. These shortcomings limit the potential for effective surveillance of exposures, identification of important sources and modes of transmission, and evaluation of the effectiveness of interventions. In this review, we summarize current and emerging approaches used to characterize enteric pathogen hazards in different environmental media as well as human interaction with those media (external measures of exposure), and review methods that measure human infection with enteric pathogens as a proxy for past exposure (internal measures of exposure). We draw from lessons learned in other areas of environmental health to highlight how external and internal measures of exposure can be used to more comprehensively assess exposure. We conclude by recommending strategies for advancing enteric pathogen exposure assessments.

Here, we describe a nanoscale reactor strategy with a topical application in the therapeutic decontamination of reactive organophosphates (OPs) as chemical threat agents. It involves functionalization of poly(amidoamine) dendrimer through a combination of its partial PEG shielding and exhaustive conjugation with an OP-reactive α-nucleophile moiety at its peripheral branches. We prepared a 16-member library composed of two α-nucleophile classes (oxime, hydroxamic acid), each varying in its reactor valency (43-176 reactive units per nanoparticle), and linker framework for α-nucleophile tethering. Their mechanism for OP inactivation occurred via nucleophilic catalysis as verified against P-O and P-S bonded OPs including paraoxon-ethyl (POX), malaoxon, and omethoate by 1 H NMR spectroscopy. Screening their reactivity for POX inactivation was performed under pH- and temperature-controlled conditions, which resulted in identifying 13 conjugates, each showing shorter POX half-life up to 2 times as compared to a reference Dekon 139 at pH 10.5, 37 °C. Of these, 10 conjugates were further confirmed for greater efficacy in POX decontamination experiments performed in two skin models, porcine skin and an artificial human microtissue. Finally, a few lead conjugates were selected and demonstrated for their biocompatibility in vitro as evident with lack of skin absorption, no inhibition of acetylcholinesterase (AChE), and no cytotoxicity in human neuroblastoma cells. In summary, this study presents a novel nanoreactor library, its screening methods, and identification of potent lead conjugates with potential for therapeutic OP decontamination.

Despite its importance in the design of photocaged molecules, less attention is focused on linker chemistry than the cage itself. Here, we describe unique uncaging properties displayed by two coumarin-caged thymidine compounds, each conjugated with ( 2 ) or without ( 1 ) an extended, self-immolative spacer. Photolysis of 1 using long-wavelength UVA (365 nm) or visible (420, 455 nm) light led to the release of free thymidine along with the competitive generation of a thymidine-bearing recombination product. The occurrence of this undesired side reaction, which is previously unreported, was not present with the photolysis of 2 , which released thymidine exclusively with higher quantum efficiency. We propose that the spatial separation between the cage and the substrate molecule conferred by the extended linker can play a critical role in circumventing this unproductive reaction. This report reinforces the importance of linker selection in the design of coumarin-caged oligonucleosides and other conjugates.

Multivalent ligand-receptor interaction provides the fundamental basis for the hypothetical notion that high binding avidity relates to the strong force of adhesion. Despite its increasing importance in the design of targeted nanoconjugates, an understanding of the physical forces underlying the multivalent interaction remains a subject of urgent investigation. In this study, we designed three vancomycin (Van)-conjugated dendrimers G5(Van) n ( n = mean valency = 0, 1, 4) for bacterial targeting with generation 5 (G5) poly(amidoamine) dendrimer as a multivalent scaffold and evaluated both their binding avidity and physical force of adhesion to a bacterial model surface by employing surface plasmon resonance (SPR) spectroscopy and atomic force microscopy. The SPR experiment for these conjugates was performed in a biosensor chip surface immobilized with a bacterial cell-wall peptide Lys-d-Ala-d-Ala. Of these, G5(Van) 4 bound most tightly with a K D of 0.34 nM, which represents an increase in avidity by 2 or 3 orders of magnitude relative to a monovalent conjugate G5(Van) 1 or free vancomycin, respectively. By single-molecule force spectroscopy, we measured the adhesion force between G5(Van) n and the same cell-wall peptide immobilized on the surface. The distribution of adhesion forces increased in proportion to vancomycin valency with the mean force of 134 pN at n = 4 greater than 96 pN at n = 1 at a loading rate of 5200 pN/s. In summary, our results are strongly supportive of the positive correlation between the avidity and adhesion force in the multivalent interaction of vancomycin nanoconjugates.

Despite its potent antibacterial activities against drug-resistant Gram-positive pathogens, oritavancin remains partially understood with respect to its primary mode of hydrogen bond interaction with a cell-wall peptide regarding the role of its lipophilic 4'-chlorobiphenyl moiety. Here we report a surface plasmon resonance (SPR) study performed in two cell-wall model surfaces, each prepared by immobilization with a vancomycin-susceptible Lys-d-Ala-d-Ala or vancomycin-resistant Lys-d-Ala-d-Lac peptide. Analysis of binding kinetics performed on the peptide surface showed that oritavancin bound ∼100-1000-fold more tightly than vancomycin on each model surface. Ligand competition experiments conducted by SPR and fluorescence spectroscopy provided evidence that such affinity enhancement can be attributed to its 4'-chlorobiphenyl moiety, possibly through a hydrophobic interaction that led to a gain of free energy with a contribution from enthalpy as suggested by a variable-temperature SPR experiment. On the basis of these findings, we propose a model for the bivalent motifs of interaction of oritavancin with cell-wall peptides, by which the drug molecule can retain a strong interaction even with the vancomycin-resistant peptide. In summary, this study advances our understanding of oritavancin and offers new insight into the significance of bivalent motifs in the design of glycopeptide antibiotics.

Despite their proven ability for precise and targeted release, nanoplatform systems for photocontrolled delivery often face formidable synthetic challenges, in part due to the paucity of advanced linker strategies. Here, we report on a novel linker strategy using a thioacetal ortho-nitrobenzaldehyde (TNB) cage, demonstrating its application for delivery of doxorubicin (Dox) in two nanoscale systems. This photocleavable linker, TNB(OH), which presents two identical arms, each terminated with a hydroxyl functionality, was prepared in a single step from 6-nitroveratraldehyde. TNB(OH) was used to cross-link Dox to a folate receptor (FAR)-targeting poly(amidoamine) dendrimer conjugate G5(FA) n=5.4 (Dox) m=5.1 , and also used to prepare an upconversion nanocrystal (UCN) conjugate, UCN-PPIX@(Dox)(G5FA), a larger core/shell nanostructure. In this core/shell nanostructure, the UCN core emits UV and visible light luminescence upon near-infrared (NIR) excitation, allowing for the photocleavage of the TNB linker as well as the photostimulation of protoporphyrin IX (PPIX) coupled as a cytotoxic photosensitizer. Drug-release experiments performed in aqueous solutions with long-wavelength ultraviolet A (UVA) light showed that Dox release occurred rapidly from its TNB linked form or from its dendrimer conjugated form with comparable decay kinetics. Cellular toxicity studies in FAR-overexpressing KB carcinoma cells demonstrated that each nanoconjugate lacked intrinsic cytotoxicity until exposed to UVA or NIR (980 nm) (for the UCN nanoconjugate), which resulted in induction of potent cytotoxicity. In summary, this new TNB strategy offers synthetic convenience in drug conjugation chemistry with the ability for the temporal control of drug activation at the delivery site.

The use of coumarin caged molecules has been well documented in numerous photocaging applications including for the spatiotemporal control of Cre-estrogen receptor (Cre-ERT2) recombinase activity. In this article, we report that 4-hydroxytamoxifen (4OHT) caged with coumarin via a conventional ether linkage led to an unexpected photo-Claisen rearrangement which significantly competed with the release of free 4OHT. The basis for this unwanted reaction appears to be related to the coumarin structure and its radical-based mechanism of uncaging, as it did not occur in ortho-nitrobenzyl (ONB) caged 4OHT that was otherwise linked in the same manner. In an effort to perform design optimization, we introduced a self-immolative linker longer than the ether linkage and identified an optimal linker which allowed rapid 4OHT release by both single-photon and two-photon absorption mechanisms. The ability of this construct to actively control Cre-ERT2 mediated gene modifications was investigated in mouse embryonic fibroblasts (MEFs) in which the expression of a green fluorescent protein (GFP) reporter dependent gene recombination was controlled by 4OHT release and measured by confocal fluorescence microscopy and flow cytometry. In summary, we report the implications of this photo-Claisen rearrangement in coumarin caged compounds and demonstrate a rational linker strategy for addressing this unwanted side reaction.

Post-translational modification of proteins by covalent attachment of ubiquitin or a polyubiquitin chain is involved in myriad of processes in eukaryotic cells. The particular outcome of ubiquitination is directed by the length of the ubiquitin conjugate and its linkage composition. Among seven possible isopeptide linkage sites in ubiquitin, K48 and K63 occur most commonly and act as distinct cellular signals. Strategies are reported here for analysis of linkage sites and complexity of K63-linked polyubiquitin chains, based on rapid chemical proteolysis at aspartate residues combined with immunoprecipitation and mass spectrometry. Rapid chemical proteolysis at aspartate residues results in K63-linked peptides with truncated branches, which enable identification and characterization of stretches of consecutive K63 linkages on generally available instruments. A characteristic cleavage pattern and a characteristic fragmentation pattern allow recognition of K63 oligomers in proteolytic mixtures. Engineered K63-linked polyubiquitin chains of defined lengths were used to evaluate and demonstrate the method. In-gel microwave-supported acid hydrolysis was used to observe peptides specific to K63-linked ubiquitin dimers and trimers. Acid hydrolysis in solution, used in conjunction with linkage-specific immunoprecipitation, allowed more complex K63-linked branches to be characterized. Finally, a substrate protein, UbcH5b, was conjugated to monoubiquitin and to polyubiquitin chains containing only K63 linkages, and the sites of conjugation and chain lengths were characterized.

Osmosis is fundamental to many processes, such as in the function of biological cells and in industrial desalination to obtain clean drinking water. The choice of solute in industrial applications of osmosis is highly important in maximizing efficiency and minimizing costs. The macroscale process of osmosis originates from the nanoscale properties of the solvent, and therefore an understanding of the mechanisms of how these properties determine osmotic strength can be highly useful. For this reason, we have undertaken molecular dynamics simulations to systematically study the influence of ion size and charge on the strength of osmosis of water through carbon nanotube membranes. Our results show that strong osmosis occurs under optimum conditions of ion placement near the region of high water density near the membrane wall and of maintenance of a strong water hydration shell around the ions. The results in turn allow greater insight into the origin of the strong osmotic strength of real ions such as NaCl. Finally, in terms of practical simulation, we highlight the importance of avoiding size effects that can occur if the simulation cell is too small.

This report demonstrates the application of a capillary LC-LTQ-orbitrap system to provide automated middle-down analysis of proteolytic peptides in the mass range 3000 to 10,000 Da. The novel workflow combines an underutilized method in the orbitrap-high resolution, mass-accurate product ion measurements-with software tailored to search such data (ProSightPC 2.0) and an Asp-selective chemical cleavage approach that generates peptides across an extended mass range. The strategy using high resolution mass measurements on both precursor and product ions is analogous to that widely used on FT-ICR analyzers. The approach is demonstrated in an analysis of the highly basic ribosomal proteome isolated from human MCF7 cancer cells.

Bisphenol A (BPA) is a common structural component in a wide variety of biomaterial monomers. The effects of BPA and the following derivatives: bisphenol A glycidyl methacrylate (BisGMA), bisphenol A glycidyl diacrylate (BAGDA), bisphenol A ethoxylate dimethacrylate (BAEDM), bisphenol A dimethacrylate (BADM), and bisphenol A diglycidyl ether (BADGE) on mixed function oxidases (MFOs) are reported in this study. The rate of formation of metabolites from isoform-specific substrates for the MFOs (or cytochromes) CYP 1A, 2A, 2C, 2E, 3A, and 4A in the absence (control) and presence of BPA and derivatives was used to assess inhibition or stimulation of human, rat (male and female) liver, and minipig liver microsomal MFO activity. For human preparations the strongest inhibition by BPA was observed for CYP 2C. The inhibition was most prominent when a lower dose of BPA was used on the complete post-mitochondrial fraction. BPA inhibited rat microsomal CYP 1A isoform-specific metabolite production to 29 +/- 3% of control levels (100%). Biomaterial monomers exhibited mixed effects. For example, BPA stimulated CYP 4A in pooled human S9 to 129 +/- 1% of control. Also, BADM and BAGDA stimulated CYP 4A to 141% and 142% of control values, respectively.

(R)- And (S)-11-hydroxy-10-methylaporphine 1 and 2 are, respectively, a potent, highly specific serotonergic (5-HT1A) agonist and antagonist. In an ongoing structure-activity study, racemates of the positional isomers 8-hydroxy-9-methyl- and 8-methyl-9-hydroxyaporphine were prepared by modifications of literature methods and were resolved. The methyl ethers of the target compounds were also evaluated pharmacologically. All of the free phenolic derivatives [(+)- and (-)-8 and 10] were inert in an assay for 5-HT1A receptor activity. All of the methyl ethers [(+)- and (-)-9 and 11] demonstrated quantitatively similar low potency stimulant effect at 5-HT1A receptors. The agonist or antagonist activity exhibited by 1 and 2 reflects the high degree of structural specificity required of aporphine derivatives for action at 5-HT1A receptors.

p-Dimethoxyaryl analogs of certain potent catechol-derived dopaminergic agonists show dopaminergic properties for which no structure-activity relationship has yet been defined. (S)-3-(3-Hydroxyphenyl)-N-n-propylpiperidine (1, S-"3-PPP") is a dopaminergic autoreceptor agonist, and at high doses it also exhibits postsynaptic antagonism. (R)-1 is a postsynaptic agonist. In a continuation of studies of effects of the p-dimethoxy moiety at dopamine receptors, synthesis and resolution of the 2,5-dimethoxy analog 3 of 3-PPP was undertaken. The two enantiomers and the racemic modification showed cardiovascular effects consistent with actions at DA-2 receptors. The potency of all three compounds was much lower than that of 3-PPP, although they displayed approximately the same duration of action. Absolute configuration does not seem to be a major determinant of these compounds' ability to interact with DA-2 receptors.

The subject compounds were prepared as a part of a continuing structure-activity study of the contrasting actions (agonism-antagonism) of (+)- and (-)-11-hydroxy-10-methylaporphine at serotonin (5-HT1A) receptors. None of the targeted nonoxygenated aporphine derivatives demonstrated significant activity in assays for any effects at serotonin 5-HT1A receptors. It is concluded that, in the aporphine series, serotonergic agonist or antagonism requires an alkyl group ortho to a phenolic OH group in the A ring.

Molecular modifications have been made on a highly potent, active antagonist to organophosphate-induced toxicity, 4,4'-bis[1,3-dioxan-2-ylmethyl)methylamino]acetyl]biphenyl dimethobromide (1). Stepwise removal of the oxygen atoms from the dioxane rings, as well as changing the position of attachment of substituents on the 1,3-dioxane rings and decreasing the ring size from six-membered to five-membered caused drastic or complete loss of pharmacological effect. Partial structures of 1 were all inactive. Thus, the structure of 1 seems to be remarkably specific. Additional pharmacological data are reported for 1.

The isomeric monomethyl ether derivatives of (RS)-9,10-dihydroxyaporphine ("isoapomorphine") were synthesized unequivocally as possible metabolites in catechol-O-methyltransferase (COMT) mediated O-methylation reactions. In vitro incubation studies revealed that isoapomorphine is not a substrate for the COMT using experimental conditions under which apomorphine (10,11-dihydroxyaporphine) is converted in high yield into its 10-methyl ether, apocodeine. The in vivo dopaminergic inactivity of isoapomorphine (as compared with that of apomorphine) seems to be due to factors other than metabolic inactivation by COMT.

In order to facilitate identification of possible metabolites arising from in vitro action of catechol-O-methyltransferase upon 7,8-dihydroxy- and 8,9-dihydroxy-4-n-propyl-1,2,3,4,4a,5,6,10b-octahydrobenzo[f]quinolines (11, 12), all four possible monomethyl ether derivatives have been synthesized. Incubation of 11 and 12 with the enzyme revealed that the 8,9-dihydroxy positional isomer 12 (which contains the dopamine moiety held in the beta conformation) but not the 7,8-dihydroxy isomer 11 (which holds the dopamine moiety in the alpha conformation) was a substrate for the enzyme. The sole detectable product of 12 was 8-hydroxy-9-methoxy derivative 15 in which the "meta" hydroxy group of the dopamine moiety is etherified.

A series of congeners of hemicholinium-3, in which the 1,4-oxazinium rings of hemicholinium are replaced by pyrrolidine, piperidine, 1,3-dioxane, or 1,4-oxazine rings, is described. Several of the target compounds produced blockade of neuromuscular transmission in the rabbit, and three heterocyclic derivatives, 10, 11, and 13, significantly antagonized paraoxon-induced lethality in mice. 1,3-Dioxane derivative 11 was an extremely potent antagonist of paraoxon-induced toxicity in mice, compared with prototypical protective agents physostigmine and pyridostigmine. Compound 11 exhibited a much more favorable therapeutic ratio than the reference drugs. The mechanism of action of 11 has not been elucidated, although it is concluded that it differs from that of hemicholinium-3 (inhibition of high-affinity, sodium-dependent uptake of choline into nerve terminals).

Two series of N-substituted 2-aminoindan systems have been prepared: 4,5-dihydroxy-2-aminoindan (1) has a hydroxylation pattern analogous to the alpha conformer of dopamine, and 5,6-dihydroxy-2-aminoindan (2) has a hydroxylation pattern of the beta conformer of dopamine. All members of both series demonstrated only extremely weak binding to calf caudate homogenate. Certain N-alkylated 4,5-dihydroxyindans were violent emetics in the dog and were potent in blockade of the effect of stimulation of the cardioaccelerator nerve of the cat. In contrast, the 5,6-dihydroxy series displayed low or no activity/potency in these assays. Conformational analysis of the 2-aminoindan system is described and discussed.

Three series of bicyclic, semirigid congeners of beta-phenethylamine have been prepared for evaluation of the effect of ring size (and of concomitant conformational variation) on biological activity in a variety of assays for adrenergic and dopaminergic actions. Pharmacologic activity was associated with 2-aminotetralin and 2-aminoindan derivateves, but was not found with 6-aminobenzocycloheptene derivatives. Noteworthy is the ability of several aminotetralins and aminoindans to increase the hot-plate reaction time without eliciting dopaminergic effects. This action was not blocked by pretreatment with naloxone.

The molecule 3',6'-bis(4-guanidinobenzoyloxy)-5-[N'-(4-carboxyphenyl)thioureido[spirop]isobenzofuran-1-(3H),9'-[9H]xanthen]-3-one, abbreviated FDE, was designed and synthesized as a fluorogenic active-site titrant for serine proteases. It is an analogue of p-nitrophenyl p-guanidino-benzoate (NPGB) in which a fluorescein derivative is substituted for p-nitrophenol. FDE and NPGB exhibit similar kinetic characteristics in an active-site titration of trypsin in phosphate-buffered saline, pH 7.2. The rate of acylation with FDE is extremely fast (k2 = 1.05 s-1) and the rate of deacylation extremely slow (k3 = 1.66 X 10(-5) s-1). The Ks is 3.06 X 10(-6) M, and the Km(app) is 4.85 X 10(-11) M. With two of the serine proteases involved in fibrinolysis, the rate of acylation with FDE is also fast, K2 = 0.112 s-1 for urokinase and 0.799 s-1 for plasmin, and the rate of deacylation is slow, k3 = 3.64 X 10(-4) s-1 for urokinase and 6.27 X 10(-6) s-1 for plasmin. The solubility limit of FDE in phosphate-buffered saline is 1.3 X 10(-5) M, and the first-order rate constant for spontaneous hydrolysis is 5.1 X 10(-6) s-1. The major difference between FDE and NPGB is the detectability of the product in an active-site titration. p-Nitrophenol can be detected at concentrations no lower than 10(-6) M whereas fluorescein can be detected at concentrations as low as 10(-12) M. Thus, FDE should be useful in quantitatively assaying serine proteases as very low concentrations.

In a study of conformational requirements for certain dopaminergic agonist molecules, a series of conformationally predictable dopamine congeners related to cis- and trans-octahydrobenzo[f]quinoline was prepared. The complexity and equivocal character of the reduction of variously substituted 4-methyl-1,2,3,4,5,6-hexahydrobenzo[f]quinolines were demonstrated and studied. It was shown that several literature methods for reduction of these systems were in error regarding the stereochemical nature of the product(s). It has been concluded that geometrically specific and predictable reductions of these hexahydrobenzo[f]quinolines seem unlikely to attain, and a plausible rationalization for this conclusion has been proposed. Pharmacologic data on the compounds prepared are consistent with our earlier proposals of a biologically significant conformation of dopamine for emesis, the pecking syndrome in pigeons, and other physiological effects.

The vinyl ethers of choline and of its alpha- and beta-methyl homologues were prepared to determine their cholinergic effects and to determine whether a separation of the dual physiologic activity (nicotinic and muscarinic) reported for the vinyl ether of choline could be achieved by this modification. A literature method of vinyl transetherification of amino alcohols has been studied and modified. The ethyl ethers of choline and of alpha- and beta-methylcholine were prepared for comparison with the vinyl ethers. Two independent, unequivocal syntheses of the ethyl ether of beta-methylcholine have been accomplished. This study showed that the two literature methods for synthesis of this compound are equivocal, and, hence, the biological data reported for this compound in the older literature may not be valid. Certain of the ethers showed marked nicotinic or muscarinic activities.

The title compound was proposed to be a biologically active metabolite of a dopaminergic agent, 4-[2-(di-n-propylamino)ethyl]indole. This proposed metabolite was synthesized by a multistep sequence beginning with methyl 3,5-dinitro o-toluate, and involving the Batcho-Leimgruber modification of the Reissert indole synthesis. The target compound exhibited high potency/activity in vivo in a cat cardioaccelerator nerve assay and in vitro in an isolated cat atrium assay. It manifested maximal pharmacological effect less than 5 min after intravenous administration in cats, as compared with a 20-min lag time following intravenous administration of the nonoxygenated congener. These pharmacological data are consistent with the proposal that the target compound is a metabolite of 4-[2-(di-n-propylamino)ethyl]indole.

Series of N-alkylated derivatives of 2-amino-4,6-dihydroxyindan 3 and 6-amino-1,3-dihydroxybenzocycloheptene 2 were prepared for pharmacological testing as congeners of 2-amino-5,7-dihydroxytetralin, which elicits dopaminergic effects in a variety of assays. All of the subject compounds demonstrated a lower order of dopamine-like activity than the tetralin derivatives. Some of the subject compounds showed weak interactions with alpha 1- and beta 1-adrenoceptors, but the major determinant of activity seemed to be the nature of the N-alkyl substituent rather than ring size.

A series of cis- and trans-dihydroxycotahydrobenzo[f]quinoline congeners of dopamine has been prepared, in which the N substitutent is H, ethyl, or n-propyl. The trans isomers include the dopamine moiety held rigidly in an antiperiplanar diposition which is believed to be necessary for certian central and peripheral dopaminergic effects. The cis isomers are flexible molecules; the dopamine moiety lacks conformational integrity and it can exist in a conformation which is believed not to favor dopaminergic activity. The trans series of compounds was shown to possess a high level of central and peripheral dopaminergic effects, whereas the cis series was of low activity or was inert. These data further support previous proposals concerning stereochemical requirements for certain dopaminergic agonist activity.

The title compounds have been synthesized and evaluated for emetic effects in the dog, actions on the cardioaccelerator nerve in the cat, pecking in pigeons, and for behavioral effects following both peripheral and direct intracerebral injection into the nucleus accumbens and caudate-putamen of the rat. Generally, in the series studied, the N,N-diethyl and N,N-di-n-propyl congeners of dopamine displayed notably high degrees of activity. However, the test compounds exerted differing effects on peripheral and central dopamine receptors and in the area postrema. Differentiations of the activities of the different homologues within the brain were also shown.

The title compounds were designed as flexible congeners of trans-octahydrobenz[h]isoquinoline, in which the dopamine moiety can exist in the alpha conformation. Extremely low dopamine-like effects in the title series in the cat cardioaccelerator nerve assay paralleled low activity in the trans-octahydrobenz[h]isoquinoline compounds and was consistent with a prior proposal of the presence of a bulky region on the dopamine receptor(s).

Secondary and tertiary amino homologs of the title compounds have been prepared, bearing an N-isopropyl group. In peripheral evaluation, certain members of the series exhibited beta-adrenergic agonist effects of lower activity than isoproterenol. N-Methyl-N-isopropyl-5,6-dihydroxytetralin exhibited marked properties consistent with its being an alpha agonist, and it is concluded that introduction of considerable bulk about the nitrogen of a catecholamine does not a priori destroy alpha-agonist effects. The compounds qualitatively paralleled the effects of dopamine in assays based upon direct intrastriatal administration in rats, although they were less potent than dopamine.

Replacement of the catechol 3,4-dihydroxylation pattern of certain adrenergic beta-phenethylamines by a resorcinol 3,5-dihydroxylation pattern has led to a greater selectivity of adrenergic agonist effects in certain molecules. This strategy has been applied to a series of dopaminergic agents derived from 2-aminotetralin, leading to a 5,7-dihydroxylation pattern. Traditional literature approaches to formation of a tetralin ring with this oxygenation pattern failed. A method was used which involved cyclization of 3,5-dimethoxybenzylsuccinic acid derivatives with pyridinium poly(HF) and subsequent modification of the tetralin ring. The resorcinol-derived 2-aminotetralins were less potent and less active dopaminergic agents than their catechol-derived isomers (5,6-dihydroxy and/or 6,7-dihydroxy). Certain of the subject compounds demonstrated alpha- and beta 1-adrenoceptor activating properties.

Series of N-alkylated derivatives of trans-octahydrobenzo[g]quinoline and of cis- and trans-octahydrobenzo[f]quinoline were prepared for pharmacological testing as congeners of 2-amino-5,7-dihydroxytetralin, which elicits dopaminergic effects in a variety of assays. Trans-fused compounds bearing N-ethyl or N-n-propyl displayed high potency/activity in inhibition of effect of stimulation of the cat cardioaccelerator nerve. Certain N-alkyl homologues in the octahydrobenzo[f]quinoline series showed high potency in binding studies in rat caudate homogenate.

Two synthetic paths have been investigated for the preparation of cis and trans 8,9-dioxygenated octahydrobenz[h]isoquinoline ring systems. A sequence involving intramolecular Diels--Alder cyclization of a ring-opened intermediate product of a benzocyclobutene derivative was more satisfactory. The trans-fused isomers of the title compounds are frozen congeners of the alpha conformer of dopamine, isomeric with certain other tricyclic heterocycles which elicit a high degree of dopamine agonist activity. However, the present series of compounds exhibited a very low potency in an assay for dopamine-like actions. A possible reason for this inactivity has been suggested.

The (+/-) title compound was prepared to evaluate prior observations that certain acetylcholine congeners derived from cyclobutane are devoid of muscarinic effects. It was prepared by a multistep sequence from trans-2-carbomethoxycyclobutyl methyl ketone. In a guinea pig ileum assay, it was 0.02 times as active as AcCh, and in a dog blood pressure assay, it was 0.09 times as active. In these assays, its (+/-)-cyclopropane congener and AcCh were equally active. This is the first cyclobutane-derived AcCh congener possessing significant muscarinic effect.

The ortho hydroxy/methyl, hydroxy/hydroxymethyl, hydroxy/formyl, and hydroxy/carboxy substitution patterns, some of which confer dopaminergic agonist effects upon 2-aminotetralin ring systems, have been incorporated into beta-phenethylamine, 2-aminoindan, and trans-octahydrobenzo[f]quinoline rings. Certain of the 2-aminoindan derivatives displayed pharmacologic properties consistent with their being dopaminergic agonists. The beta-phenethylamine derivative did not show any significant dopamine-like activity. The 7-hydroxy-8-methyloctahydrobenzo[f]quinoline derivative 4a was a moderately potent, short-acting DA2 receptor antagonist. All of the carboxylic acid derivatives were inert. Of the ortho hydroxy/methyl derivatives, only the 5-hydroxy-6-methyl-2-aminotetralin derivative displayed pharmacological properties consistent with its being a dopaminergic prodrug. It is concluded that 5-hydroxy-6-methyl-2-(di-n-propylamino)tetralin (1a) is structurally unique for a dopaminergic drug.

A series of variously N-substituted 2-aminotetralins having OH groups at 5 and 6 and at 6 and 7 positions, as well as nonoxygenated systems, has been evaluated for central dopaminergic effects. Stereotypical behavioral effects (sniffing, compulsive gnawing, and hyperactivity) produced by direct intracerebral administration of some of the agents were shown to differ strikingly from responses resulting from peripheral administration. The centrally mediated responses of hyperactivity and sterotypical gnawing-biting head and limb movements were shown to be separable in some test compounds. An improved route to 2-aminotetralin systems has been utilized for some of the compounds, which involves Pummerer rearrangement and cyclization of beta-keto sulfoxides and reductive amination of beta-tetralones with a NaBH4-carboxylic acid complex.

A synthetic precursor to a potent dopaminergic agonist, (RS)-4-hydroxy-2-(di-n-propylamino)indan, has been resolved by classical recrystallization procedures, and the absolute configurations of the enantiomers have been established by X-ray crystallographic analysis. The enantiomers were converted by literature procedures into (R)- and (S)-1. (R)-1 was approximately 100 times as potent as (S)-1 in an assay for dopamine agonist effect in the isolated cat atrium.

On the basis of the premise that the dopaminergic agonist profile of 2-(di-n-propylamino)-5-hydroxy-6-methyltetralin (1a) is due to in vivo oxidation of the 6-methyl moiety and that 1a may represent a novel prodrug strategy, the vicinal methyl-hydroxyl substitution pattern was incorporated into the 6- and 7-positions of 2-(di-n-propylamino)tetralin to give the 6-methyl-7-hydroxy and 6-hydroxy-7-methyl isomers 8 and 9, respectively. A multistep synthetic approach was devised which permitted preparation of target molecules 8 and 9. Pharmacological data revealed that both target compounds exhibit modest dopamine-like effects in the cardioaccelerator nerve assay in the cat, but neither appeared to be metabolically activated as was the case with 1a. The effects of 9 (but not of 8) were antagonized by pretreatment with haloperidol. Thus, the 5-hydroxy-6-methyl substitution pattern in the 2-aminotetralins remains unique as a dopaminergic agonist prodrug structure.

The title compounds were designed to provide semirigid congeners of m-tyramine in which the ring position ortho to the phenolic OH is blocked to metabolic hydroxylation. A sequence leading to a key synthetic intermediate, 5-methoxy-6-methyl-2-tetralone, has been developed. In animal test models for dopamine-like effects, the title compounds demonstrated qualitative and quantitative differences from the isomeric 5-methyl-6-hydroxy-2-aminotetralins and from 5,6-dihydroxy-2-aminotetralins. Two of the compounds were potent in a cat cardioaccelerator nerve assay, which involves dopamine receptors.

The N-n-propyl homologues of the title compounds were prepared for further assessment of the ability of the "p-dimethoxy" moiety to confer dopaminergic agonism upon a variety of ring systems. Both the angularly and the linearly annulated trans-benzoquinoline ring derivatives displayed prominent DA2 dopaminergic effects on the peripheral sympathetic nerve terminal and displayed postjunctional dopamine receptor agonist properties in the striatum. It is speculated that the angular octahydrobenzo[f]quinoline derivative (but not the linear octahydrobenzo[g]quinoline derivative) may owe its dopamine-like effects to metabolic activation phenomena. In contrast, the cis-fused isomer of the angularly annulated benzoquinoline was inactive, as was the simple benzene derivative N,N-di-n-propyl-beta-(2,6-dimethoxyphenyl)ethylamine.

Prompted by previous findings that a p-dimethoxy substitution pattern on an aromatic ring permits retention of dopaminergic agonist effects in certain ring systems, catechol derivatives of which are potent dopaminergic agonists, an 8,11-dimethoxy substitution pattern was introduced into the aporphine ring in place of the 10,11-dihydroxy moiety in apomorphine. Acid-catalyzed rearrangement of an appropriate morphine derivative provided the aporphine ring system with retention of the stereochemical integrity of the 6a asymmetric center. The hydroxyl group at position 10 was removed by catalytic hydrogenolysis of its phenyltetrazoyl ether. The methyl ether of the resulting 11-hydroxyaporphine was iodinated in high yield at position 8 with trifluoroacetyl hypiodite. This is the first account of synthesis of an iodinated aporphine derivative. The 8-iodo substituent was replaced with methoxyl by reaction with sodium methoxide and cuprous iodide. Neither the N-methyl target compound 7 nor the N-n-propyl derivative 8 demonstrated dopaminergic nor serotonergic agonism. However, 7 exhibited receptor-binding characteristics and other pharmacological properties suggesting that it may be a 5-HT1A receptor antagonist.

As a model for the transport of hemin across biological membranes, sonicated phosphatidylcholine liposomes with incorporated hemin were characterized. The interaction of the hemin liposomes with the heme binding proteins albumin, apomyoglobin, and hemopexin was examined as a function of liposome charge and cholesterol content. In all cases, there was an almost complete transfer of hemin from liposome to protein; a rapid phase and a slow phase were observed for the transfer. For negatively charged liposomes (with 11% dicetyl phosphate), the rapid and slow phases showed observed rates of transfer of ca. 2 and 0.01 s-1, respectively, for all three proteins. The presence of cholesterol in the liposomes decreased the observed rates by a factor of 2, and positively charged liposomes (with 11% stearylamine) showed about one-fifth the observed rates of negatively charged liposomes. The observed rates were independent of protein concentration, indicating that the rate-determining step is hemin efflux from the lipid bilayer. The hemin interaction with the phospholipid bilayer is suggested to be primarily hydrophobic with some electrostatic character. The two phases are suggested to arise from two different populations of hemin within the liposomes and are interpreted as arising from two different orientations of hemin within the bilayer.