Espectro clínico de tuberculosis cutánea / Clinic spectrum of cutaneous tuberculosis

La Tuberculosis (TBC) es producida por el Mycobacterium tuberculosis o bacilo de Koch, y se ha observado en las últimas décadas, una reemergencia de casos pulmonares y extrapulmonares. La TBC cutánea es infrecuente, y presenta un amplio espectro clínico dependiendo del interjuego existente entre el agente, el huésped y el ambiente. TBC cutánea, ilustrándola con casos clínicos de pacientes que concurrieron a nuestro servicio.

Tuberculosis (TBC) is caused by Mycobacterium tuberculosis or Koch's bacillus, and there was a re-emergence of pulmonary and extrapulmonary cases in the last decades. Cutaneous TBC is uncommon, there is a broad clinical spectrum and an interrelationship between the agent, the guest and the environment. A description of each form of cutaneous TBC was made, illustrating it with clinical cases of patients who were attended in our service.

A new rational hypothesis for the pharmacophore of the active metabolite of leflunomide, a potent immunosuppressive drug.

Leflunomide is one of the most promising disease-modifying antirheumatic drug now in clinical trials for the treatment of rheumatoid arthritis. Metabolic studies have indicated that leflunomide is rapidly processed in vivo to an active metabolite, A771726 (2). To identify the chemical characteristics necessary for the immunosuppressive activity of 2, configurational and conformational studies were carried out on the latter and its inactive analogues (ethyl 3-hydroxy-2-((4-(trifluoromethyl)phenyl)carbamoyl)but-2-enoate, 3a, and 3-hydroxy-2-nitro-N-(4-(trifluoromethyl)phenyl)but-2-enamide, 3b). These studies suggested that the pharmacophore responsible for the immunosuppressive activity of 2 is a beta-keto amide with the enolic hydroxy group cis to the amidic moiety. To verify this hypothesis, a new class of immunosuppressive agents was designed and synthesized. Their testing in vitro and in vivo identified compounds which were more potent than both leflunomide and 2 and above all confirmed our hypothesis as to the key structural and chemical determinants for the immunosuppressive properties of 2 and our compounds.

Use of type I and type IV hypersensitivity responses to define the immunopharmacological profile of drugs.

Administration of antigen suspended in incomplete Freund's adjuvant supplemented with either heat-killed Mycobacterium tuberculosis (complete Freund's adjuvant, CFA) or Bordetella pertussis toxin sensitizes animals so that subsequent antigen challenge leads to delayed-type (DTH) or immediate type hypersensitivity (ITH) responses, named type IV and type I, respectively. Appropriate timing of administration of drugs with respect to immunization or antigen challenge allowed to detect predominantly immunosuppressive, antiinflammatory or antianaphylactic activities. Among the reference drugs tested, only cyclosporin A (CsA) and dexamethasone (Dex) markedly inhibited DTH reaction, due to their immunosuppressive and antiinflammatory activities, respectively, whereas leflunomide and indomethacin resulted less potent. On the other hand, only dexchlorpheniramine, a histamine-receptor antagonist, afforded significant protection against anaphylactic shock, a form of ITH. Two new chemical entities were studied according to this protocol: ITF 1697, a chemically stabilized C-reactive protein-derived tetrapeptide, and ITF 2018, a leflunomide analogue. Data obtained with these new compounds showed that ITF 1697 has antianaphylactic activity, while ITF 2018 is endowed, mainly, with antiinflammatory activity. These results show that, through appropriate timing of administration, established in vivo models of immunologically mediated disease states allow an accurate profiling of the effects of pharmacologically active molecules and the detection of unsuspected activities for new drugs.

Androstane derivative devoid of anabolic-virilizing effects and endowed with an antiglucocorticoid activity.

2-Carbodecyloxy-17 alpha-methylandrosta-1,4-dien-11 beta,17 beta-dihydroxy-3-one (decylroxibolone, BR 917) is a new androstane derivative, esterified with decyl alcohol, carrying a methyl group in the 17 position, a hydroxyl group in the 11 beta position and a carboxyl group in position 2. Unlike norandrostenolone decanoate, decylroxibolone did not cause any weight increase of the levator ani muscle and of the seminal vesicles in castrated rats, nevertheless exerting a marked antiglucocorticoid activity. This new steroid agent can consequently act positively on the nitrogen metabolism, being concurrently devoid of undesired virilizing anabolic effect.

Novel pyrimidine and 1,3,5-triazine hypolipidemic agents.

New compounds were synthesized by changing the substituents of a trisubstituted pyrimidine, i.e., [[4-chloro-6-[(2,3-dimethylphenyl)amino]-2-pyrimidinyl]thio] acetic acid, a potent hypolipidemic agent, impaired, however, by a marked hepatomegaly-inducing effect. The structural variations led to the subsidence (14b, i.e., 4-chloro-2-(dimethylamino)-6-[(2,3-dimethylphenyl)amino]pyrimidine) or to the reduction (18b, [[4-chloro-6-[(2,3-dimethylphenyl)amino]-2-pyrimidinyl]amino] acetic acid) of said untoward effect but still maintained the hypolipidemic effect that, although markedly decreased, still proves significant for serum cholesterol and triglycerides (18b) or for serum triglycerides only (14b).

Clofibrate, pirinixil (BR 931) and WY-14,643 do not affect body cholesterol in Sprague-Dawley rats.

Cholesterol levels in plasma and different tissues were determined in Sprague-Dawley male rats, on standard and cholesterol-cholic acid enriched diets, after short term treatment with the absorbable hypolipidemic agents, clofibrate, WY-14,643 and Pirinixil (BR 931). The objective of the study was to evaluate the mode of action of these drugs in decreasing plasma cholesterol, be it by increased tissue mobilization, or by redistribution from plasma to tissues. After one or two weeks on a standard diet, none of the three agents significantly affected total body cholesterol stores. In spite of the liver enlargement induced by all three, in no case was total liver cholesterol significantly raised. Only clofibrate significantly increased colonic cholesterol concentrations. On a cholesterol-cholic acid regimen, some cholesterol mobilization was noted with all three drugs. However, only Pirinixil significantly reduced total liver cholesterol as well as the estimated total body cholesterol. A parallel effect of diet and drugs on plasma and body cholesterol pools is not constantly observed. In the examined rat model, clofibrate and two chemically unrelated compounds with a probably similar mechanism of action, markedly reduce plasma cholesterol levels while not affecting or decreasing total body cholesterol stores.

Pharmacological profile of BR-931, a new hypolipidemic agent that increases high-density lipoproteins.

BR-931 [4-chloro-6-(2,3-xylidino)-2-pyrimidinylthio-(N-beta-hydroxyethyl)-acetamide], a new hypolipidemic agent of low toxicity, was evaluated in several tests of lipolysis and hyperlipidemia in rats, and in the cholesterol-induced atherosclerosis in rabbits. Significant hypolipidemic activity was observed in rats with doses of the agent at 12.5--50 mg/kg. In the Triton-induced hyperlipidemia, 50 mg BR-931 per kg was equieffective as 200 mg of clofibrate (CPIB) per kg. In contrast with CPIB, BR-931 exerted a powerful antilipolytic activity against epinephrine, ACTH, nicotine and cold exposure. BR-931 was particularly effective in diet-induced hyperlipidemias. Ethanol lipemia was totally prevented by the agent at 100 mg/kg. With Nath's diet, doses as low as 25 mg/kg significantly reduced hypercholesterolemia and hypertriglyceridemia. In these last two tests, the distribution of lipoprotein cholesterol was also determined. CPIB did not affect HDL cholesterol levels that had been decreased by the diets; in contrast, BR-931, already at doses of 50 mg/kg, brought the HDL/total cholesterol ratio back toward normal. A significant HDL cholesterol increase, together with some reduction of atheromatosis, was also observed in cholesterol-fed rabbits. BR-931, a potent inducer of liver peroxisones and of mitochondrial carmitine acetyltransferase, appears to be a hypolipidemic agent of high efficacy and low toxicity for the clinical treatment of hyperlipidemias and atherosclerosis.

Urinary metabolites of 2-formyl-17 alpha-methylandrosta-1,4-diene-11alpha, 17beta-dihydroxy-3-one in the rat.

The principal urinary metabolites of 2-formyl-17alpha-methylandrosta-1,4-diene-11alpha,17beta-dihydroxy-3-one (for myldienolone) are 2-carboxy- and 2-hydroxymethyl-17 alpha-methylandrosta-11alpha,17beta-dihydroxy-3-one, whose structures were confirmed by comparing them with synthesized samples.