Synthesis, in vitro binding profile, and central nervous system penetrability of the highly potent 5-HT3 receptor antagonist [3H]-4-(2-methoxyphenyl)-2-[4(5)-methyl-5(4)-imidazolylmethyl]thiazole

4-(2-Methoxyphenyl)-2-[4(5)-methyl-5(4)-imidazolylmethyl]thiazole (5) is a highly potent member of a structurally novel series of selective serotonin-3 receptor antagonists. The synthesis of tritiated 5 and its binding profile in neuroblastoma-glioma 108-15 cells are described. Furthermore, in vivo studies in rat with this radioligand indicate that it effectively penetrates the blood-brain barrier upon peripheral administration. Thus, 5 should be a useful pharmacological tool for both in vitro and in vivo studies of this class of compounds.

An initial three-component pharmacophore for specific serotonin-3 receptor ligands

With computer modeling, an initial three-component pharmacophore for specific 5-HT3 receptor ligands ICS-205-930 (1), ondansetron (2), zacopride (3), and 3-[2-(guanidinylmethyl)-4-thiazolyl]indol (4) has been identified. Two parts represent electrostatic interactions, one as a hydrogen-bond-donating interaction and the other as a hydrogen-bond-accepting interaction. The third part is represented by a plane in which the lipophilic aromatic groups align. The generation of the pharmacophore relies on the interactions of these ligands with probe atoms representative of a possible hydrogen-bond donor or hydrogen-bond acceptor within the receptor. A carboxylate oxygen was used as a hydrogen-bond-accepting probe and a serine-like hydroxyl was utilized as a hydrogen-bond-donating probe.

Thiazole as a carbonyl bioisostere. A novel class of highly potent and selective 5-HT3 receptor antagonists

A novel structural class of highly potent and selective 5-HT3 receptor antagonists is described. The compounds in this new series contain a thiazole moiety linking an aromatic group and a nitrogen-containing basic region; the thiazole group appears to be acting as a carbonyl bioisostere in this system. An optimized member of this series, 4-(2-methoxyphenyl)-2-[[4(5)-methyl-5(4)-imidazolyl]methyl]thiazole (5), exhibits oral activity in the Bezold-Jarisch reflex paradigm comparable to or better than the standard agents ondansetron (1) and ICS-205-930 (2). Several of the structure-activity relationships are rationalized in terms of a computer pharmacophore model for 5-HT3 receptor binding.

Hodgkin's disease presenting in the skin: case report and review of the literature

Cutaneous manifestations of Hodgkin's disease are relatively uncommon. We present a case of Hodgkin's disease with widespread skin involvement and review the literature on the subject.

Caterpillar dermatitis

Lepidopterism is the term used to describe the aggregate adverse medical effects resulting from contact with adult or larval forms of butterflies and moths. Histamine, histamine-releasing substances, kinin activators, and other as yet undefined proteins are responsible for cutaneous, cardiovascular, neurologic, and constitutional signs and symptoms of lepidopterism. Insect venom is likely injected into the skin through specialized caterpillar hairs when contact occurs with the insect (or vegetation laden with insect debris). Mild cases of lepidopterism will resolve spontaneously; systemic corticosteroids may aid in the treatment of more serious cases.

Cutaneous cryptococcosis simulating Kaposi's sarcoma in the acquired immunodeficiency syndrome

A forty-one-year-old homosexual man with acquired immunodeficiency syndrome (AIDS) and biopsy proven Kaposi's sarcoma of the oral cavity presented to our clinic with a several month history of violaceous papules and plaques on his trunk and extremities. Although the patient already carried a clinical diagnosis of Kaposi's sarcoma, several biopsies of skin lesions were performed. Tissue specimens demonstrated cutaneous infection with Cryptococcus neoformans. As patients with AIDS have an increased incidence of both Kaposi's sarcoma and opportunistic infections, all progressing lesions should be biopsied in order to avoid missing a treatable life-threatening disease.

The fluoroquinolone antibacterial agents

In summary, the last decade has been a highly fertile and productive period in quinolone medicinal chemistry, resulting in major improvements in potency, antibacterial spectra, oral absorption and pharmacokinetic properties as well as an increased knowledge of the molecular features important to conferring these various properties. Very recent discoveries concerning replacements for the 3-carboxylic acid moiety, previously thought to be uniquely essential for activity, to give highly potent antibacterials such as (83) illustrate the potential for new breakthroughs in this field. Among the major goals for future research remains the understanding of the potential cartilage toxicity associated with this class of agents, such that an agent useful for pediatric indications may be developed. Future studies can also be expected to further enhance and refine the level of current insight into the manner by which these agents inhibit the target enzyme on a molecular level.

Acute radiodermatitis from occupational exposure to iridium 192

Industrial radiography using the man-made radioisotope iridium 129 is commonplace in the southern states. Despite established procedures and safeguards, accidental exposure may result in typical acute radiodermatitis. We have presented a clinical example of this phenomenon.

Carcinoembryonic antigen in basal cell neoplasms in black patients: an immunohistochemical study

The development of skin cancer in black persons is rare, and basal cell epitheliomas are the most uncommon. Eight tumors were evaluated by routine histochemistry examination and immunoperoxidase staining for carcinoembryonic antigen (CEA). Our results demonstrate that half these tumors showed a positive reaction to this antigen, supporting the adnexal origin/differentiation of these lesions. Sixteen (16/18) similar tumors from white patients failed to show equivalent features. In addition, some of these CEA-positive tumors seem to demonstrate less aggressive behavior.

Pityriasis folliculorum revisited

Six cases of facial erythema with follicular plugging are described. These cases correspond with characteristics of the disorder pityriasis folliculorum, a presumed demodicidosis. Treatment modalities included topical tretinoin, gamma benzene hexachloride (lindane) lotion, and 1% permethrin cream rinse.

Mechanism of inhibition of DNA gyrase by quinolone antibacterials: a cooperative drug--DNA binding model

We have proposed a cooperative quinolone-DNA binding model for the inhibition of DNA gyrase. The essential feature of the model is that bound gyrase induces a specific quinolone binding site in the relaxed DNA substrate in the presence of ATP. The binding affinity and specificity are derived from two unique and equally important functional features: the specific conformation of the proposed single-stranded DNA pocket induced by the enzyme and the unique self-association phenomenon (from which the cooperativity is derived) of the drug molecules to fit the binding pocket with a high degree of flexibility. Supporting evidence for and implications of this model are provided.

Aromatic dienoyl tetramic acids. Novel antibacterial agents with activity against anaerobes and staphylococci

Streptolydigin (1) and tirandamycin A (2) are typical members of the naturally occurring class of 3-dienoyl tetramic acids. These compounds, which possess potent antibacterial activity particularly against anaerobes, have been shown to inhibit bacterial RNA polymerase. In contrast, tenuazonic acid (5), which lacks a complex dioxabicyclononane moiety and diene chromophore present in 1 and 2, exhibits essentially no antimicrobial activity and has no effect on bacterial RNA polymerase, suggesting that one or both of these structural features may be critical for antibacterial activity. In this paper, we report on a novel series of synthetic dienoyl tetramic acids that lack a complex dioxabicyclononane unit. Several of these compounds, particularly 8T-W, exhibit potent antimicrobial activity against Gram-positive and Gram-negative anaerobes as well as staphylococci. We will discuss the structure-activity relationship for this series of compounds which, in contrast to their natural counterparts, do not inhibit significantly RNA polymerase. We will also discuss preliminary results on the biochemical and microbiological properties of this series of compounds, several of which moderately inhibit supercoiling by DNA gyrase isolated from E. coli H560, although this enzyme has not been established as their target in whole cells. Compound 8W, which is not cross-resistant with DNA gyrase subunit A or B inhibitors or tirandamycin, has also been demonstrated to be rapidly bactericidal.

Papulonodular demodicidosis associated with acquired immunodeficiency syndrome

We describe a papulonodular variant of demodicidosis seen in two patients with acquired immunodeficiency syndrome and its successful treatment with 1% gamma benzene hexachloride and 1% permethrin cream rinse. Alterations in T cell function may allow otherwise commensal organisms to proliferate to the point of causing disease.

Vesicular Jarisch-Herxheimer reaction

The Jarisch-Herxheimer reaction is a self-limited, febrile episode that may occur following antibiotic therapy for syphilis. We report four cases of a heretofore unrecognized vesicular variant of the Jarisch-Herxheimer reaction. It is important to distinguish this phenomenon from an allergic drug eruption.

Nail discoloration due to mahogany

A patient is described in whom orange-brown discoloration occurred following occupational exposure to mahogany wood. Mahogany-induced dermatitis is reviewed.

Radiation port dermatophytosis

We report two cases in which dermatophytic infection developed almost entirely within a radiation field mimicking an acute radiation effect. Radiotherapists and dermatologists should be aware of this possibility and be able to differentiate it from radiation dermatitis. Topical antifungal agents are the recommended treatment after diagnosis is established.

Design, synthesis, and properties of (4S)-7-(4-amino-2-substituted-pyrrolidin-1-yl)quinolone-3-carboxylic acids

The quinolonecarboxylic acids constitute a class of extremely potent and orally active broad-spectrum antibacterial agents. These compounds have been shown to inhibit DNA gyrase, a key enzyme in bacterial DNA replication. The 7-(3-aminopyrrolidinyl)quinolone A-60969 (1) is a particularly potent member of this class and is currently undergoing clinical evaluation. We have studied a series of enantiomerically homogeneous (4S)-7-(4-amino-2-substituted-pyrrolidinyl)quinolones in an effort to utilize the 2-position of the pyrrolidine moiety to improve upon the solubility and pharmacokinetic properties of this class of compounds while still maintaining potent antibacterial activity. We have found that the absolute stereochemistry at the 2-position of the pyrrolidine ring is critical to the maintenance of such activity. In this paper, we report the full details of the asymmetric synthesis and the in vitro and in vivo structure-activity relationships of this series of compounds as well as the physiochemical properties, such as water solubility and log P, associated with the structural modifications. We also discuss the pharmacokinetic properties of several of these compounds in mice and the pharmacokinetics of 59, which has the best overall properties of agents in this study, in dog.

Vibrio vulnificus septicemia

We report a case of Vibrio vulnificus infection in a middle-aged alcoholic man with Laennec's cirrhosis. The patient had recently received a puncture wound from the shell of a shrimp while fishing in the Gulf of Mexico. He presented with acrally distributed urticarial plaques, purpura, and bullae, as well as signs and symptoms of septic shock. Vibrio vulnificus was isolated from the blood, and histologic examination of the skin biopsy specimen demonstrated a devitalized, inflammatory, cell-poor superficial dermis and an acute cellulitis of the subcutis, with extensive tissue destruction. In addition, a necrotizing vasculitis, with a relative paucity of inflammatory cells but numerous bacilli around dermal vessels, was noted.