Functional differences in the hypothalamic-pituitary-gonadal axis are associated with alternative reproductive tactics based on an inversion polymorphism.

The evolution of social behavior depends on genetic changes, yet, how genomic variation manifests itself in behavioral diversity is still largely unresolved. Chromosomal inversions can play a pivotal role in producing distinct behavioral phenotypes, in particular, when inversion genes are functionally associated with hormone synthesis and signaling. Male ruffs exhibit alternative reproductive tactics (ARTs) with an autosomal inversion determining two alternative morphs with clear behavioral and hormonal differences from the ancestral morph. We investigated hormonal and transcriptomic differences in the pituitary and gonads. Using a GnRH challenge, we found that the ability to synthesize testosterone in inversion carriers is severely constrained, whereas the synthesis of androstenedione, a testosterone precursor, is not. Inversion morphs were able to produce a transient increase in androstenedione following the GnRH injection, supporting the view that pituitary sensitivity to GnRH is comparable to that of the ancestral morph. We then performed gene expression analyses in a second set of untreated birds and found no evidence of alterations to pituitary sensitivity, gonadotropin production or gonad sensitivity to luteinizing hormone or follicle-stimulating hormone across morphs. Inversion morphs also showed reduced progesterone receptor expression in the pituitary. Strikingly, in the gonads, inversion morphs over-expressed STAR, a gene that is located outside of the inversion and responsible for providing the cholesterol substrate required for the synthesis of sex hormones. In conclusion, our results suggest that the gonads determine morph-specific differences in hormonal regulation.

Paleoceanographic events and deep-sea ostracodes.

Eight recognized or theorized paleoceanographic events during the past 70 million years were tested against changes in the global deep-sea benthic ostracode fauna. Two events, the sudden Cretaceous-Tertiary boundary event at 66 million years ago and the more gradual 40-million-year event (formation of the psychrosphere), show up most dramatically. Before the 40-million-year event, ostracodes freely radiated into the deeper water regions but were provincial. The development of thermal stratification isolated these deep-water taxa, mostly the survivors of the Cretaceous-Tertiary boundary event, which adapted to a new, free-flowing but more frigid ecosystem and spread rapidly throughout the world.

Indomethacin in the treatment of lithium-induced nephrogenic diabetes insipidus.

Nephrogenic diabetes insipidus (NDI) is a frequent complication in patients receiving long-term lithium therapy. Both thiazide diuretics and amiloride may reduce the polyuria, but the use of each is associated with problems. We report the results of a clinical trial using the nonsteroidal anti-inflammatory drug indomethacin to treat a patient with well-documented lithium-induced NDI that persisted following cessation of lithium treatment. The administration of a single dose of indomethacin resulted in a dramatic decrease in urine volume and increase in urine osmolality that persisted for several hours, and was independent of renal hemodynamic changes. Subsequently, the patient experienced a sustained, favorable effect on her polyuria during long-term (3 months) indomethacin therapy without a deleterious effect on her renal function. Indomethacin may be a useful therapeutic tool for the amelioration of lithium-induced NDI.

Role of cigarette use in hyponatremia in schizophrenic patients.

Urine volume and osmolality were studied in two schizophrenic patients with hyponatremia and six normal subjects after they smoked or ingested cigarettes. The results suggest that cigarette use may contribute to the development of hyponatremia by impairing water excretion.

Gossypol: prototype of inhibitors targeted to dinucleotide folds.

Gossypol, a disesquiterpene from cottonseed, exhibits multiple biological properties, including male antifertility activity and anticancer activity. Gossypol also inhibits the growth of numerous parasitic organisms and shows antiviral activity against a number of enveloped viruses, including the AIDS virus. Derivatives of gossypol, in which the aldehyde functional groups that contribute to toxicity have been modified, retain or even show enhanced biological activity. Ring substituted 2,3-dihydroxy-1-naphthoic acids, which are structural analogs of gossypol, share with gossypol the ability to complex with dehydrogenases at the dinucleotide fold (Rossmann fold) with selectivity, suggesting that gossypol may be considered the prototype of a new class of drugs targeted to dehydrogenases. Most of the biological activities of gossypol and related compounds may result from inhibition of dehydrogenases.

Substrate and cofactor specificity and selective inhibition of lactate dehydrogenase from the malarial parasite P. falciparum.

Lactate dehydrogenase from the malarial parasite Plasmodium falciparum has many amino acid residues that are unique compared to any other known lactate dehydrogenase. This includes residues that define the substrate and cofactor binding sites. Nevertheless, parasite lactate dehydrogenase exhibits high specificity for pyruvic acid, even more restricted than the specificity of human lactate dehydrogenases M4 and H4. Parasite lactate dehydrogenase exhibits high catalytic efficiency in the reduction of pyruvate, kcat/Km = 9.0 x 10(8) min(-1) M(-1). Parasite lactate dehydrogenase also exhibits similar cofactor specificity to the human isoforms in the oxidation of L-lactate with NAD+ and with a series of NAD+ analogs, suggesting a similar cofactor binding environment in spite of the numerous amino acid differences. Parasite lactate dehydrogenase exhibits an enhanced kcat with the analog 3-acetylpyridine adenine dinucleotide (APAD+) whereas the human isoforms exhibit a lower kcat. This differential response to APAD+ provides the kinetic basis for the enzyme-based detection of malarial parasites. A series of inhibitors structurally related to the natural product gossypol were shown to be competitive inhibitors of the binding of NADH. Slight changes in structure produced marked changes in selectivity of inhibition of lactate dehydrogenase. 7-p-Trifluoromethylbenzyl-8-deoxyhemigossylic acid inhibited parasite lactate dehydrogenase, Ki = 0.2 microM, which was 65- and 400-fold tighter binding compared to the M4 and H4 isoforms of human lactate dehydrogenase. The results suggest that the cofactor site of parasite lactate dehydrogenase may be a potential target for structure-based drug design.

The kinetic properties and sensitivities to inhibitors of lactate dehydrogenases (LDH1 and LDH2) from Toxoplasma gondii: comparisons with pLDH from Plasmodium falciparum.

Toxoplasma gondii differentially expresses two forms of lactate dehydrogenase in tachyzoites and bradyzoites, respectively, designated LDH1 and LDH2. Previously it was demonstrated that LDH1 and LDH2 share a unique structural feature with LDH from the malarial parasite Plasmodium falciparum (pLDH), namely, the addition of a five-amino acid insert into the substrate specificity loops. pLDH exhibits a number of kinetic properties that previously were thought to be unique to pLDH. In the present study, kinetic properties of LDH1 and LDH2 were compared with those of pLDH. LDH1 and LDH2 exhibit broader substrate specificity than pLDH. For both LDH1 and LDH2, 3-phenylpyruvate is an excellent substrate. For LDH2, 3-phenylpyruvate is a better substrate even than pyruvate. By comparison, pLDH does not utilize 3-phenylpyruvate. Both LDH1 and LDH2 can utilize the NAD analog 3-acetylpyridine adenine dinucleotide (APAD) efficiently, similar to pLDH. LDH1 and LDH2 are inhibited competitively by a range of compounds that also inhibit pLDH, including gossypol and derivatives, dihydroxynaphthoic acids, and N-substituted oxamic acids. The lack of substrate inhibition observed with pLDH is also observed with LDH2. By comparison, LDH1 differs from LDH2 in exhibiting substrate inhibition in spite of an identical residue (M163) at a cofactor binding site that is thought to be critical for production of substrate inhibition. For gossypol and gossylic iminolactone, but not the other gossypol derivatives tested, the in vitro inhibition of T. gondii LDH activity correlated with specific inhibition of T. gondii tachyzoite growth in fibroblast cultures.

Gossypol and derivatives: a new class of aldose reductase inhibitors.

Gossypol and 17 derivatives were tested as inhibitors of aldose reductase from human placenta. Gossypol and a number of the derivatives were potent inhibitors. The order of inhibitory activity was interpreted in relation to the Kador-Sharpless pharmacophor model for the aldose reductase inhibitor site. The structural but not the electronic aspects of the model were found to apply to this series of compounds.

Biologically active derivatives of gossypol: synthesis and antimalarial activities of peri-acylated gossylic nitriles.

A series of peri-acylated gossylic nitriles were synthesized from gossypol dioxime by treatment of the dioxime with the appropriate acid anhydride and its salt. The reaction pathway was elucidated by isolation and characterization of intermediates. Peri-acylated gossylic nitriles (acyl = acetyl, propionyl, butyryl, and valeryl) were compared with gossypol for activity against both chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum. The gossylic nitriles all retain activity, with activity increasing with the length of the peri-acyl group. Gossylic nitrile 1,1'-divalerate shows antimalarial activity comparable to gossypol itself. The peri-acylated gossylic nitriles are strong inhibitors of parasite lactate dehydrogenase.

3-Alkyl-6-chloro-2-pyrones: selective inhibitors of pancreatic cholesterol esterase.

A series of 3-alkyl-6-chloro-2-pyrones with cyclohexane rings tethered to the 3-position was synthesized. The tether ranged from 0 to 4 methylene units. Inhibition of pancreatic cholesterol esterase by this series of pyrones was markedly dependent upon the length of the tether. Dissociation constants as low as 25 nM were observed for 6-chloro-3-(1-ethyl-2-cyclohexyl)-2-pyranone. This class of cholesterol esterase inhibitors functioned as simple competitive inhibitors of substrate binding rather than as suicide substrates or active site inactivators. Trypsin and chymotrypsin were not strongly inhibited by this class of pyrones. Selectivities for cholesterol esterase were greater than 10(3). This is in contrast to 3-aryl-6-chloro-2-pyrones which are nonselective, irreversible inactivators of serine hydrolases. Thus, replacement of the 3-aryl group by an appropriately tethered 3-alkyl ring can produce highly selective inhibitors of cholesterol esterase. A second series of halogen-containing esters was prepared in which cholesterol was esterified with alpha-haloacyl halides. These haloesters were simple substrates of cholesterol esterase with no evidence of irreversible inactivation.

Synthesis and anti-HIV activity of 1,1'-dideoxygossypol and related compounds.

1,1'-Dideoxygossypol (DDG), 1,1'-dideoxygossylic acid (DDGA), 8-deoxyhemigossypol (DHG), and 8-deoxyhemigossylic acid (DHGA) were synthesized and tested for their ability to inhibit the replication of HIV in vitro. The EC50 for DDGA was < 1 microM, and its threshold cytotoxicity was approximately 20 microM. DDG was less effective than DDGA against HIV and showed considerable toxicity at 5 microM. DHGA was ineffective against HIV and had very low cytotoxicity. DHG showed some anti-HIV activity, but the threshold cytotoxicity was 5 microM. The dissociation constants for the binding of the four compounds to human serum albumin were determined by fluorescence quenching titrations, and all four were found to have much lower affinities for albumin than the parent compound gossypol.

Selective inhibitors of human lactate dehydrogenases and lactate dehydrogenase from the malarial parasite Plasmodium falciparum.

Derivatives of the sesquiterpene 8-deoxyhemigossylic acid (2, 3-dihydroxy-6-methyl-4-(1-methylethyl)-1-naphthoic acid) were synthesized that contained altered alkyl groups in the 4-position and contained alkyl or aralkyl groups in the 7-position. These substituted dihydroxynaphthoic acids are selective inhibitors of human lactate dehydrogenase-H (LDH-H) and LDH-M and of lactate dehydrogenase from the malarial parasite Plasmodium falciparum (pLDH). All inhibitors are competitive with the binding of NADH. Selectivity for LDH-H, LDH-M, or pLDH is strongly dependent upon the groups that are in the 4- and 7-positions of the dihydroxynaphthoic acid backbone. Dissociation constants as low as 50 nM were observed, with selectivity as high as 400-fold.

Inactivation of glutathione reductase by 4-hydroxynonenal and other endogenous aldehydes.

4-Hydroxynonenal, a product of oxidative degradation of unsaturated lipids, is an endogenous reactive alpha,beta-unsaturated aldehyde with numerous biological activities. 4-Hydroxynonenal rapidly inactivated glutathione reductase in an NADPH-dependent reaction. Inactivation appears to involve the initial formation of an enzyme-inactivator complex, K(D) = 0.5 microM, followed by the inactivation reaction, k = 1.3 x 10(-2) min(-1). alpha,beta-Unsaturated aldehydes such as acrolein, crotonaldehyde, and cinnamaldehyde also inactivated glutathione reductase, although rates varied widely. Inactivation of glutathione reductase by alpha,beta-unsaturated aldehydes was followed by slower NADPH-independent reactions that led to formation of nonfluorescent cross-linked products, accompanied by loss of lysine and histidine residues. Other reactive endogenous aldehydes such as methylglyoxal, 3-deoxyglucosone, and xylosone inactivated glutathione reductase by an NADPH-independent mechanism, with methylglyoxal being the most reactive. However, 2-oxoaldehydes were much less effective than 4-hydroxynonenal. Inactivation of glutathione reductase by these 2-oxoaldehydes was followed by slower reactions that led to the formation of fluorescent cross-linked products over a period of several weeks. These changes were accompanied by loss of arginine residues. Thus, the sequence of events is different for inactivation and modification of glutathione reductase by alpha,beta-unsaturated aldehydes compared with 2-oxoaldehydes with respect to kinetics, NADPH requirements, fluorescence changes, and loss of amino acid residues. The ability of 4-hydroxynonenal at low concentrations to inactivate glutathione reductase, a central antioxidant enzyme, suggests that oxidative degradation of unsaturated lipids may initiate a positive feedback loop that enhances the potential for oxidative damage.

Selective active site inhibitors of human lactate dehydrogenases A4, B4, and C4.

Human lactate dehydrogenases (LDH-A4, -B4, and -C4) are highly homologous with 84-89% sequence similarities and 69-75% amino acid identities. Active site residues are especially conserved. Gossypol, a natural product from cotton seed, is a non-selective competitive inhibitor of NADH binding to LDH, with K(i) values of 1.9, 1.4, and 4.2 microM for LDH-A4, -B4, and -C4, respectively. However, derivatives of gossypol and structural analogs of gossypol in the substituted 2,3-dihydroxy-1-naphthoic acid family exhibited markedly greater selectivity and, in many cases, greater potency. For gossypol derivatives, greater than 35-fold selectivity was observed. For dihydroxynaphthoic acids with substituents at the 4- and 7-positions, greater than 200-fold selectivity was observed. Inhibition was consistently competitive with the binding of NADH, with dissociation constants as low as 30 nM. By comparison, a series of N-substituted oxamic acids, which are competitive inhibitors of the binding of pyruvate to LDH, exhibited very modest selectivity. These results suggest that substituted dihydroxynaphthoic acids are good lead compounds for the development of selective LDH inhibitors. Selective inhibitors of LDH-C4 targeted to the dinucleotide fold may hold promise as male antifertility drugs. Selective inhibitors of LDH-A4 and -B4 may be useful for studies of lactic acidemia associated with ischemic events. More broadly, the results raise the question of the general utility of drug design targeted at the dinucleotide binding sites of dehydrogenases/reductases.

Binding of gossypol derivatives to human serum albumin.

In light of our previous finding that gossypol competes effectively with bilirubin for the high affinity bilirubin binding site on human serum albumin, a study of the binding to albumin of four gossypol derivatives was undertaken. The derivatives are compounds in which the aldehyde groups of gossypol are converted to nitriles and the periphenolic groups are acylated with acetyl, propionyl, butyryl, or valeryl groups. These periacylated gossylic nitriles bind to the high affinity bilirubin binding site on human serum albumin, but with dissociation constants approximately 30 times greater than that of gossypol. The gossypol derivatives also bind to another site on albumin, but with dissociation constants approximately 6 times greater than those for the bilirubin site. This second site has been identified as the major drug binding site in domain III.

Paraquat poisoning.

The authors present a review of the toxicology, pathophysiology, and treatment of paraquat, a potent herbicide.

Prevalencia de depresión en pacientes adultos con enfermedad celíaca / Prevalence of depression in adult celiac disease patients

Introduction: Celiac disease (CD) is an autoimmune disorder that affects the gastrointestinal tract and other systems like the neuropsychiatric system, where depression is the most frequent disease. Objectives: To determine the prevalence of depression in adult celiac patients and relate these results with the adherence to a gluten-free diet. Materials and Methods: Descriptive cross-sectional study, with +18-year-old patients diagnosed with CD, confirmed with biopsy. 123 subjects from Fundación Convivir and from Instituto de Diagnóstico Gastroenterológico answered Beck Depression Inventory II (BDI-II) vía e-mail, which consists of 21 questions on personal aspects of their life; and also a survey on general aspects generales. A result of > 20 points was considered depression. Results: Average age was 38.9 years, 82.9 percent female. 17.1 percent (21 cases) present with depression according to BDI-II score. 62.6 percent adhere to the diet and 10.4 percent present depression; on the other hand, of 37.4 percent that are non-adherent, 28.3 percent present this disease. The association between both variables is statistically significant (p < 0.014). Discussion: High prevalence of depression was determined in CD patients compared to 9 percent, corresponding to the countries global figure. Most of them showed previous history of depressive disease. Adequate adherence to a gluten-free diet is associated to lower prevalence of depression.

Introducción: La enfermedad celíaca (EC) es una patología autoinmune que afecta al aparato gastrointestinal y a otros sistemas como el neuro-psiquátrico, área en la que la depresión es la patología más frecuente. Objetivos: Determinar la prevalencia de depresión en pacientes adultos con EC y relacionar resultados con la adherencia o no a una dieta libre de gluten. Materiales y Métodos: Estudio descriptivo de corte transversal que incluyó a pacientes de 18 años o más, con diagnóstico de EC confirmado por biopsia. Se aplicó vía correo electrónico el Inventario de Depresión de Beck II (BDI-II) que consta de 21 preguntas sobre aspectos de su vida personal; y una encuesta de antecedentes generales a 123 sujetos provenientes de la Fundación Convivir y del Instituto de Diagnóstico Gastroenterológico. Se consideró depresión si el puntaje es > 20 puntos. Resultados: La edad promedio fue de 38,9 años y el 82,9 por ciento eran mujeres. El 17,1 por ciento (21 casos) presentan depresión según la escala de BDI-II. El 62,6 por ciento son adherentes a la dieta y presentan depresión el 10,4 por ciento; en cambio del 37,4 por ciento que no son adherentes, el 28,3 por ciento presenta esta patología. La asociación entre ambas variables es estadísticamente significativa (p < 0,014). Discusión: Se determinó una alta prevalencia de depresión en pacientes con EC en comparación con 9 por ciento que corresponde a la cifra global del país. La mayoría de ellos presentaban antecedentes previos de enfermedad depresiva. Una adecuada adherencia a la dieta libre de gluten se asocia a una menor frecuencia de depresión.