Ned D. Heindel

DETERMINATION OF DEGREE OF SUBSTITUTION OF FORMYL GROUPS IN POLYALDEHYDE DEXTRAN BY THE HYDROXYLAMINE HYDROCHLORIDE METHOD

Colorimetric or potentiometric titration of the aldehyde residues in polyaldehyde dextran by the hydroxylamine hydrochloride/sodium hydroxide method has been found to be a convenient and accurate method to determine formyl content. Nitrogen combustion analyses on the isolated oximes confirmed the titrametric results.

Mechanisms Mediating the Vesicant Actions of Sulfur Mustard after Cutaneous Exposure

Sulfur mustard (SM), a chemical weapon first employed during World War I, targets the skin, eyes, and lung. It remains a significant military and civilian threat. The characteristic response of human skin to SM involves erythema of delayed onset, followed by edema with inflammatory cell infiltration, the appearance of large blisters in the affected area, and a prolonged healing period. Several in vivo and in vitro models have been established to understand the pathology and investigate the mechanism of action of this vesicating agent in the skin. SM is a bifunctional alkylating agent which reacts with many targets including lipids, proteins, and DNA, forming both intra- and intermolecular cross-links. Despite the relatively nonselective chemical reactivity of this agent, basal keratinocytes are more sensitive, and blistering involves detachment of these cells from their basement membrane adherence zones. The sequence and manner in which these cells die and detach is still unresolved. Much has been discovered over the past two decades with respect to the mechanisms of SM-induced cytotoxicity and the intracellular and extracellular targets of this vesicant. In this review, the effects of SM exposure on the skin are described, as well as potential mechanisms mediating its actions. Successful therapy for SM poisoning will depend on following new mechanistic leads to develop drugs that target one or more of its sites of action.

Oxidants and antioxidants in sulfur mustard–induced injury

Sulfur mustard (SM) is a chemical weapon that targets the skin, eyes, and lung. It was first employed during World War I and it remains a significant military and civilian threat. As a bifunctional alkylating agent, SM reacts with a variety of macromolecules in target tissues including nucleic acids, proteins and lipids, as well as small molecular weight metabolites such as glutathione. By alkylating subcellular components, SM disrupts metabolism, a process that can lead to oxidative stress. Evidence for oxidative stress in tissues exposed to SM or its analogs include increased formation of reactive oxygen species, the presence of lipid peroxidation products and oxidized proteins, and increases in antioxidant enzymes such as superoxide dismutase, catalase, and glutathione‐S‐transferase. Inhibition of antioxidant enzymes including thioredoxin reductase by SM can also disrupt cellular redox homeostasis. Consistent with these findings, SM‐induced toxicity has been shown to be reduced by antioxidants in both in vitro and in vivo models. These data indicate that drugs that target oxidative stress pathways may represent important candidates for reducing SM‐induced tissue injury.

Orally active vasopressin V1a receptor antagonist, SRX251, selectively blocks aggressive behavior

Arginine vasopressin functions as a neurochemical signal in the brain to affect social behavior. There is an expanding literature from animal and human studies showing that vasopressin, through the vasopressin 1A receptor (V1A), can stimulate aggressive behavior. Using a novel monocylic beta lactam platform, a series of orally active vasopressin V1a antagonists was developed with high affinity for the human receptor. SRX251 was chosen from this series of V1a antagonists to screen for effects on serenic activity in a resident-intruder model of offensive aggression. Resident, male Syrian golden hamsters were given oral doses of SRX251 or intraperitoneal Manning compound, a selective V1a receptor antagonist with reduced brain penetrance, at doses of 0.2 microg, 20 microg, 2 mg/kg or vehicle. When tested 90-120 min later, SRX251, but not Manning compound, caused a significant dose-dependent reduction in offensive aggression toward intruders as measured by latency to bite and number of bites. The reduction in aggression persisted for over 6 h and was no longer present 12 h post treatment. SRX251 did not alter the amount of time the resident investigated the intruder, olfactory communication, general motor activity, or sexual motivation. These data corroborate previous studies showing a role for vasopressin neurotransmission in aggression and suggest that V1a receptor antagonists may be used to treat interpersonal violence co-occurring with such illness as ADHD, autism, bipolar disorder, and substance abuse.

Vasopressin antagonists as anxiolytics and antidepressants: recent developments.

A compelling case for the potential utility of vasopressin (AVP) antagonists as a novel therapeutic class for the treatment of stress-related affective illness has emerged based on observations in depressed individuals, findings in animal models of anxiety and depression, and an understanding of changes in hypothalamic-pituitary-adrenal (HPA) axis regulation under chronic stress. The scientific bases for vasopressin antagonists as a pharmacotherapy for anxiety and depression include: 1) the neuroadaptation and dysregulation of HPA function that accompanies chronic stress in affected humans and in animal models of anxiety and depression, 2) recognition that AVP, not corticotrophin releasing factor (CRF), drives HPA function associated with chronic psychological stress, 3) the CNS localization of vasopressin V1a and V1b receptors in limbic system regions involved in HPA regulation and control of social behaviors, and 4) preclinical data showing efficacy in animal models employed as screens for anxiolytic and antidepressant activity. The public health need for new pharmaceutical treatments for stress-related affective illness is well documented. In the United States alone, anxiety and depression affect some 40 million people each year and carry a conservatively estimated annual total economic burden of at least

Doxycycline Hydrogels as a Potential Therapy for Ocular Vesicant Injury

125 billion. Existing pharmacotherapies for both indications are not uniformly effective and frequently have undesirable side effects. These limitations demonstrate that a new treatment approach through vasopressin receptor antagonism in the CNS may offer significant opportunities for improved outcomes. In this review, the development of compounds in this class since 2005 is considered. The most advanced clinical candidates and newer compounds described in recent patents are presented.

A condition variation study for radioiodination via triazene intermediates

PURPOSE The goals of this study were (1) to compare the injury at the basement membrane zone (BMZ) of rabbit corneal organ cultures exposed to half mustard (2 chloroethyl ethyl sulfide, CEES) and nitrogen mustard with that of in vivo rabbit eyes exposed to sulfur mustard (SM); (2) to test the efficacy of 4 tetracycline derivatives in attenuating vesicant-induced BMZ disruption in the 24-h period postexposure; and (3) to use the most effective tetracycline derivative to compare the improvement of injury when the drug is delivered as drops or hydrogels to eyes exposed in vivo to SM. METHODS Histological analysis of hematoxylin and eosin–stained sections was performed; the ultrastructure of the corneal BMZ was evaluated by transmission electron microscopy; matrix metalloproteinase-9 was assessed by immunofluorescence; doxycycline as drops or a hydrogel was applied daily for 28 days to eyes exposed in vivo to SM. Corneal edema was assessed by pachymetry and the extent of neovascularization was graded by length of longest vessel in each quadrant. RESULTS Injury to the BMZ was highly similar with all vesicants, but varied in degree of severity. The effectiveness of the 4 drugs in retaining BMZ integrity did not correlate with their ability to attenuate matrix metalloproteinase-9 expression at the epithelial–stromal border. Doxycycline was most effective on organ cultures; therefore, it was applied as drops or a hydrogel to rabbit corneas exposed in vivo to SM. Eyes were examined at 1, 3, 7, and 28 days after exposure. At 7 and 28 days after SM exposure, eyes treated with doxycycline were greatly improved over those that received no therapy. Corneal thickness decreased somewhat faster using doxycycline drops, whereas the hydrogel formulation decreased the incidence of neovascularization. CONCLUSIONS Corneal cultures exposed to 2-chloroethyl ethyl sulfide and nitrogen mustard were effective models to simulate in vivo SM exposures. Doxycycline as drops and hydrogels ameliorated vesicant injury. With in vivo exposed animals, the drops reduced edema faster than the hydrogels, but use of the hydrogels significantly reduced neovascularization. The data provide proof of principle that a hydrogel formulation of doxycycline as a daily therapy for ocular vesicant injury should be further investigated.

Photoénolisation—VIII: Stéréospécificitéet régiospécificitéde la réaction de diels-alder avec les photodiénols issus de la benzyl-2 et de l'éthyl-2 benz

Pyrrolidyl triazenes prepared by interception of the diazonium transient in the Sandmeyer reaction of amines can serve as useful intermediates in the iodination and radioiodination of aryl rings. Decomposition of such triazenes in the presence of iodide is acid-catalyzed and is sensitive to choice of solvent, acid, and triazene structure. A condition variation study by HPLC of four different solvent systems and two non-nucleophilic acids was carried out on the123I iodination of the triazenes of p-nitroaniline, p-anisidine and p-toluidine. This method has proven useful in radiolabeling of two pharmaceutical analogs which were not amenable to labeling through the classic Sandmeyer method.

Peripheral site acetylcholinesterase inhibitors targeting both inflammation and cholinergic dysfunction

Abstract 2-Methyl- and 2,4-dimethylbenzophenone were irradiated with the unsymetrical dienophiles methyl acrylate, acrylonitrile, methyl methacrylate and methyl propiolate. The dienols additions proceed regiospecifically yielding in each instance a single hydroxylic compound having the car☐ylate or the carbonitrile group in vicinal position. Syntheses of 1,2,3,4-tetrahydro- and 1,4-dihydronaphthols with various substituents were thus achieved. 3,4-Dihydronaphthalenes and naphthalenes were also obtained by dehydration. 2,4-dimethylbenzophenone was irradiated with acetylenedicarbonitrile yielding the dehydrated addition product 6-methyl 1-phenylnaphthalene-2,3-dicarbonitrile.

Investigation of anticholinergic and non-steroidal anti-inflammatory prodrugs which reduce chemically induced skin inflammation.

The design and study of two classes of noncompetitive acetylcholinesterase inhibitors (AChEIs) which also function as NSAID prodrugs are reported. The most potent AChEIs disclosed contain an aromatic alkyl-aryl linker between an NSAID and a lipophilic choline mimic and they inhibit acetylcholinesterase (AChE) in the submicromolar range. These agents have the therapeutic potential to dually target inflammation by releasing an NSAID in vivo and activating the cholinergic anti-inflammatory pathway via cholinergic up-regulation.