Inhibitory action of gossypol on enzymes and growth of Trypanosoma cruzi

Gossypol, a phenolic compound isolated from the cotton plant, is a powerful inhibitor of nicotinamide adenine dinucleotide-linked enzymes (alpha-hydroxyacid dehydrogenase and malate dehydrogenase) of Trypanosoma cruzi, the parasite that causes Chagas' disease. Parasites at the epimastigote stage that were incubated for 5 minutes with 100 micromolar gossypol were completely immobilized. Concentrations of gossypol as low as 0.01 micromolar markedly reduced the growth rate of T. cruzi in culture.

Properties of the testicular lactate dehydrogenase isoenzyme

1. Studies were carried out with pure lactate dehydrogenase isoenzymes C4 (LDH isoenzyme X), B4, (LDH isoenzyme 1) and A4 (LDH isoenzyme 5) isolated from mouse testis, heart and muscle tissue respectively; with LDH isoenzyme X purified from pigeon testes and with crude lysates of spermatozoa from man, bull and rabbit. 2. LDH isoenzyme X from all species showed greater ability than the other isoenzymes to catalyse the NAD+-linked interconversions of 2-oxobutanoate into 2-hydroxybutanoate and of 2-oxopentanoate into 2-hydroxypentanoate. 3. Mouse LDH isoenzyme X presented the broadest spectrum of substrate specificity. It exhibited very similar Km values for a variety of 2-oxo acids: 2-oxopropanoate (pyruvate), 2-oxobutanoate, 2-oxo-3-methylbutanoate, 2-oxopentanoate, 2-oxo-3-methylpentanoate, 2-oxo-4-methylpentanoate, 2-oxohexanoate and 2-oxo-3-phenylpropanoate (phenylpyruvate). The corresponding 2-hydroxy acids were also readily utilized in the reverse reaction. A strong inhibition by substrate and product was demonstrated for the direct reaction. 4. Intracellular distribution of LDH isoenzyme X was investigated in mouse testes. LDH isoenzyme X activity was located in the fraction of "heavy mitochondria" and in the soluble phase. 5. A possible functional role for LDH isoenzyme X is proposed: the redox couple-2-oxo acid-2-hydroxy acid could integrate a shuttle system transferring reducing equivalents from cytoplasm to mitochondria.

Detection of varicella-zoster virus DNA in the oropharynx and blood of patients with varicella

The polymerase chain reaction (PCR) was used to detect varicella-zoster virus (VZV) DNA in respiratory epithelial cells and in peripheral blood leukocytes from adults with varicella. VZV DNA was detected in oropharyngeal epithelium in 62% of patients early in the course of varicella; the amount of VZV DNA declined with time and was detectable in only 22% of patients for greater than 6 days. VZV DNA was also detected in peripheral blood leukocytes in 74% of patients early in disease and was detected in both polymorphonuclear and mononuclear leukocytes. PCR demonstrated the presence of VZV DNA in the oropharynx and blood of most patients during varicella, in contrast to the ability to detect VZV in these tissues by viral culture.

Intracellular localization of the testicular and sperm-specific lactate dehydrogenase isozyme C4 in mice

The proposed dual intracellular distribution of the sperm-specific lactate dehydrogenase (EC 1.1.1.27) isozyme C4 (LDH C4) has been based on indirect evidence. In order to obtain direct evidence on the localization of this LDH isozyme in mice, postembedding immunocytochemistry at ultrastructural level was performed on testes, epididymal spermatozoa, and isolated testicular mitochondria. The immunogold technique was applied to thin sections incubated first in partially purified specific anti-LDH C4 rabbit IgG, and immunoreactive sites were detected with colloidal gold adsorbed to anti-rabbit IgG. In the testis, immunostaining was found in the cytoplasm of spermatocytes and spermatids and in the principal and middle pieces of differentiating spermatozoa. Spermatozoa from epididymis also exhibited heavy labeling of colloidal gold in their middle and principal pieces, but the immunostaining was weak in the special type of mitochondria present in spermatocytes, spermatids, and spermatozoa (sperm-type mitochondria, STM). The isolation of STM produced several morphological changes in comparison with those in situ, including an enhancement of the LDH C4 labeling in the mitochondrial matrix. The other type of mitochondria (non-STM) from spermatocytes and nonspermatogenic cells were not immunostained and served as background control. The results presented here confirm previous findings, gathered by indirect methods, indicating a dual localization of LDH C4 in the cytosol of spermatocytes, spermatids, and spermatozoa, as well as in the matrix of sperm-type mitochondria.

The lactate/pyruvate shuttle in spermatozoa: operation in vitro

The operation of a shuttle for the transfer of reducing equivalents in the special mitochondria present in the middle piece of spermatozoa (sperm-type mitochondria, STM) was studied in reconstituted systems in vitro with mouse, rat, and rabbit STM. The redox couple lactate/pyruvate and the lactate dehydrogenase isozyme C4 are involved in the shuttle. It is active with rat and rabbit STM, while it does not work with mouse STM, probably because the influx of lactate into the mouse organelles is relatively poor. Ratios of consumption of pyruvate/lactate by STM were 21.6, 1.28, and 1.6 for mouse, rat, and rabbit organelles, respectively. The shuttle is inhibited by 0.6 mM mersalyl, a blocker of lactate transport. The operation of the shuttle would oxidize cytosolic NADH produced during aerobic glycolysis (or fructolysis) in spermatozoa of those species having an efficient lactate carrier in mitochondria.

The impact of skin diseases on quality of life: A multicenter study

INTRODUCTION

To date, no formal study has been published regarding how Colombian patients with skin disorders could be affected according to their perception of disease.

OBJECTIVE

To determine the impact in quality of life of skin diseases in a Colombian population.

METHODS

This multicenter study included patients with skin disease from almost the whole country. Individuals >18 years old; of any gender; with any skin disease and who signed informed consent, were included. We applied the Colombian validated version of the Skindex-29 instrument.

RESULTS

A total of 1896 questionnaires had sufficient information for the analyses. No significant differences in sociodemographic characteristics of patients who returned the questionnaire incomplete vs. complete, were found. Participants mean age was 41.5 years. There were no statistical differences in men vs. women regarding the global (p=0.37), symptoms (p=0.71) and emotions (p=0.32) domains, whereas statistical differences were found in the function domain (p=0.04; Mann-Whitney U test). Psoriasis, contact dermatitis, atopic dermatitis, urticaria, hair disorders, Hansen's disease, scars, hyperhidrosis and genital human papillomavirus disease scored the highest.

LIMITATIONS

Skindex-29 score variability as a result of differences in the location of the skin lesions, their inflammatory or non-inflammatory nature, and the start of therapy.

CONCLUSIONS

Even the most localized or asymptomatic skin lesion in our population leads to a disruption at some level of patient's wellness. This study adds well supported scientific data of the burden of skin diseases worldwide.

DNA sequence-specific reading by echinomycin: role of hydrogen bonding and stacking interactions

The binding of echinomycin to DNA hexamers of the form GpApXpZpTpC, where the central XpZ step can be CpG, TpA, GpC, or ApT, has been studied by molecular modeling and molecular mechanics techniques. Interaction energies have also been calculated for the complexation of echinomycin with sequences containing the preferred central CpG step and different flanking base pairs. Besides, two more sets of sequences incorporating either 2,6-diaminopurine (DAP) or hypoxanthine in place of adenine or guanine, respectively, have been examined. The aim of this work was to evaluate the relative importance of hydrogen-bonding and stacking interactions in the association of echinomycin with DNA and further rationalize the experimental evidence. The results of these calculations are in consonance with available data from footprinting experiments and appear to support our previous hypothesis that, in addition to the crucial intermolecular hydrogen bonds in the central region, the stacking interactions involving the quinoxaline-2-carboxamide chromophores of the drug and the DNA base pairs play an important role in modulating the binding specificity of this bisintercalating antitumor antibiotic. This is most clearly seen when sequences with similar minor-groove environments are compared (e.g. CpI vs TpA or CpG vs TpDAP). The dipole moment of N-methylquinoxaline-2-carboxamide has been measured (mu = 4.15 +/- 0.03 D) and compares very well with the calculated value (mu = 4.14 D). The fact that G:C, I:C, A:T, and DAP:T base pairs are shown to be endowed with distinct van der Waals and electrostatic stacking properties with respect to this heteroaromatic ring system could have important implications for the design of novel DNA mono- and bis-intercalating agents.

Inhibition by gossypol of oxidoreductases from Trypanosoma cruzi

The effects of gossypol, a polyphenolic compound isolated from the cotton plant upon six oxidoreductases from cultured epimastigotes of Typanosoma cruzi were studied. Gossypol was a powerful inhibitor of the alpha-hydroxyacid and malate dehydrogenases, NAD-linked enzymes, and of glutamate dehydrogenase, malic enzyme and glucose-6-phosphate dehydrogenase, NADP-dependent enzymes. The drug did not have an effect on succinate dehydrogenase, a flavoprotein. The Ki values with respect to substrate were 0.73, 0.3 and 3.5 microM for alpha-hydroxyacid, malate and glutamate dehydrogenases, respectively, and 1.1, 0.19 and 7.8 microM with respect to the coenzyme. Inhibition was noncompetitive with respect to substrate and uncompetitive in relation to the coenzyme.

Harvesting, routing, and anastomosing the left internal mammary artery graft

A technique to harvest, intrapleurally route, and anastomose the left internal mammary artery is described.

Catalytic properties of the sperm-specific lactate dehydrogenase (LDH X or C4) from different species

A comparative study of catalytic properties of the sperm-specific lactate dehydrogenase (EC 1.1.1.27) isozyme X or C4 from a variety of animals (boar, bull, goat, Guinea pig, man, mouse, pigeon, rabbit, and rat) is presented. Optimum concentration and Km values for pyruvate, inhibition by substrate, and activity against analog substrates (alpha-ketoacids with linear and branched chains from 4 to 6 carbon atoms) for isozyme X of different species showed significant differences. The observed properties are correlated with available evidence on the metabolic role of the enzyme.

In vitro inhibition by gossypol of oxidoreductases from human tissues

The effect of gossypol, a polyphenolic compound with antifertility action on human males, has been investigated on the following oxidoreductases purified from human tissues: lactate dehydrogenase (EC 1.1.1.27) isozymes 1 or B4 from heart, 5 or A4 from liver and X or C4 from spermatozoa; malate dehydrogenase (EC 1.1.1.37) mitochondrial and "soluble" isozymes from heart and NADP-glutamate dehydrogenase (EC 1.4.1.4) from liver. Gossypol proved to be a powerful inhibitor of the six enzymes studied. For all of them, inhibition was of the competitive type with respect to the coenzyme and non-competitive in relation to substrate. The lowest ki values were shown for lactate dehydrogenase isozyme 1 or B4 and for the two isozymes of malate dehydrogenase. Results did not show selectivity of gossypol for the sperm-specific isozyme X or C4 of lactate dehydrogenase.

Correlation of lactate dehydrogenase isoenzyme C4 activity with the count and motility of human spermatozoa

The activity of lactate dehydrogenase isoenzyme C4 was determined on 90 human semen samples. The correlation between the isoenzyme activity and sperm count and motility was good (r = 0.74 for values of U/ml semen against sperm count).

Properties of alpha-hydroxyacid dehydrogenase isozymes from Trypanosoma cruzi

Whole cell extracts of culture epimastigotes of Trypanosoma cruzi (Tulahuén strain) have alpha-hydroxyacid dehydrogenase activity which catalyzes the NAD-linked reaction alpha-ketoacid in equilibrium with alpha-hydroxyacid, with a variety of substrates. Two molecular forms of the enzyme have been separated by means of gel electrophoresis. These isozymes were partially purified by DEAE-cellulose chromatography and ammonium sulfate precipitation. Molecular weights were estimated and some catalytic properties were determined with purified isozymes. The faster migrating fraction (isozyme I) has a molecular weight of 85 500 and showed significant activity against linear 3-5 carbon chain substrates. The lowest Km value was obtained for pyruvate. Isozyme II (MW 60 500) utilizes linear and branched chain substrates with 4-6 carbon atoms. Its highest activity and lowest Km value were recorded with alpha-keto-isocarproate as substrate.

Diagnosis of cutaneous tuberculosis by polymerase chain reaction using a species-specific gene

BACKGROUND

Diagnosis of tuberculosis (TB), especially cutaneous TBC, by conventional microbiologic methods is still a very laborious process and the results are usually inconclusive. Our purpose was to identify M. tuberculosis bacilli in uncultured clinical samples from skin lesions by means of the rapid, specific, and sensitive polymerase chain reaction (PCR).

METHODS

The PCR, using a set of species-specific primers, was performed on biopsies and fluid secretions from lesions.

RESULTS

A positive amplification reaction was observed in three of the four samples studied. For one of the samples, the result was confirmed by a positive culture in Löwenstein-Jensen medium and for the other two, by molecular hybridization and the clinical course of the patients after treatment. Samples obtained from a patient with panniculitis of Christian-Weber and a normal skin biopsy were included as negative controls.

CONCLUSIONS

We propose the PCR method as a tool for the diagnosis of cutaneous TBC. The presence of the M. tuberculosis in an erythema induratum of Bazin suggests a revision of the concept of this disease as a tuberculide reaction.

Effect of L-malate on pyruvate dehydrogenase activity of spermatozoa

Presence of L-malate (from 0.5 to 4 mM concentrations) in the medium produces a marked increment of pyruvate consumption by the special type of mitochondria found in the middle piece of spermatozoa (sperm-type mitochondria, STM). Pyruvate uptake by liver mitochondria is not increased by malate. A comparative study on pyruvate dehydrogenase (PDH) of STM and liver mitochondria from mouse, rat, and rabbit showed that 2 mM L-malate does not modify significantly the activity of liver PDH, while it increases markedly that of spermatozoal PDH in the three species. The differential sensitivity to L-malate appears to be a peculiar regulatory property of the PDH complex in the gametes, which contains at least one component (E1, pyruvate decarboxylase, EC 1.2.4.1) known to be a sperm-specific isozyme.

Studies in vitro on shuttle systems of mouse spermatozoa

Observations on systems reconstituted in vitro with different starting substrates (2-hydroxy-acids, 2-oxo-acids or leucine) indicate that a branched-chain 2-hydroxy-acid/2-oxo-acid shuttle for the transfer of reducing equivalents from cytosol to mitochondria may be operational in mouse sperm. Evidence is presented suggesting that the 2-oxo-acids produced by intramitochondrial oxidation of 2-hydroxy-acids ingressed from the cytosol can recycle back into the external phase. Observations in vitro demonstrate that, in addition to the branched-chain 2-hydroxy-acid/2-oxo-acid shuttle, the malate/aspartate system is also active in mouse sperm. On the contrary, the lactate/pyruvate redox couple does not appear to function as part of a shuttle system in mouse sperm mitochondria. The glycerol 3-phosphate shuttle probably is not functionally significant in mouse spermatozoa, since the activity of the 'soluble' glycerol 3-phosphate dehydrogenase is very low.

Substrate specificity of the lactate dehydrogenase isoenzyme C4 from human spermatozoa and a possible selective assay

The activity of lactate dehydrogenase (EC 1.1.1.27) in normal human sperm lysates and in human heart and liver homogenates was determined by using a variety of 2-oxoacids as substrates. Sperm preparations were active with pyruvate, 2-oxobutanoate, 2-oxopentanoate and 2-oxohexanoate, while heart and liver extracts utilized only pyruvate and 2-oxobutanoate. Selective staining after gel electrophoresis indicated that the fraction corresponding to lactate dehydrogenase C4, the sperm-specific isoenzyme, was responsible for the utilization of substrates with a linear chain of 3 to 6 carbon atoms. The use of 5 mM 2-oxohexanoate allowed the selective determination of isoenzyme C4 in preparations containing different lactate dehydrogenase molecular forms.

Effects of clofibrate on the main regulatory enzymes of cholesterogenesis

The in vivo effect of clofibrate on the main regulatory enzymes of cholesterogenesis has been comparatively studied for the first time in chick liver and brain. 3-Hydroxy-3-methylglutaryl-CoA reductase and mevalonate 5-pyrophosphate decarboxylase from chick liver were significantly inhibited by this hypocholesterolenic drug, while mevalonate kinase and mevalonate 5-phosphate kinase were not affected. No enzyme from chick brain was significantly inhibited by the in vivo treatment. However, both liver and brain reductase activity was inhibited in vitro by clofibrate, inhibition that was progressive with increasing concentrations (1.25-5.00 mM) of drug.

Immunocytochemical study of Met-enkephalin-like cell bodies in the cat hypothalamus

The distribution of methionine-enkephalin-like cell bodies in the hypothalamus of the cat was studied using an indirect immunoperoxidase technique. Previously, intraventricular or intratissular injections of colchicine were carried out. Met-enkephalin-like neurons were located in all hypothalamic nuclei. The densest clusters of immunoreactive perikarya were observed in the nucleus arcuatus, median eminence, regio praeoptica and perifornical region, whereas the nucleus supraopticus and hypothalamus anterior had the lowest density. In other hypothalamic nuclei the density of methionine-enkephalin (Met-enkephalin) cell bodies was intermediate.

Joint analysis of additive, dominant and first-order epistatic effects of four genes (IGF2, MC4R, PRKAG3 and LEPR) with known effects on fat content and fat distribution in pigs

LEPR, MC4R, IGF2 and PRKAG3 are genes with known effects on fat content and distribution in pig carcass and pork. In a study performed with Duroc × Landrace/Large White pigs, we have found that IGF2 has strong additive effects on several carcass conformational traits and on fatty acid composition in several anatomical locations. MC4R shows additive effects on saturated fatty acid content in several muscles. On the other side, almost no additive effect has been found for PRKAG3 and very few for LEPR. In this work, no dominant effect has been found for any of the four genes. Using a Bayesian Lasso approach, we have been able now to find first-order epistatic (mainly dominant-additive) effects between LEPR and PRKAG3 for intramuscular fat content and for saturated fatty acid content in L. dorsii, B. femoralis, Ps. major and whole ham. The presence of interactions between genes in the shaping of traits of such importance as intramuscular fat content and composition highlights the complexity of heritable traits and the difficulty of gene-assisted selection for such traits.

Hypolipidemic activity of dipyridamole: effects on the main regulatory enzyme of cholesterogenesis

The in vivo dipyridamole treatment for 16 days produced a significant decrease in chick plasma cholesterol, mainly due to the esterified form. This effect was especially patent in the VLDL + LDL fraction. Similar results were observed in triglyceride content. To our knowledge, this is the first report on this hypolipidemic effects of dipyridamole. Total and esterified cholesterol increased after the same treatment in chick liver, while brain cholesterol content was not affected. Hepatic 3-hydroxy-3- methylglutaryl-CoA reductase activity was drastically reduced, while other secondary regulatory enzymes such as mevalonate kinase, mevalonate 5-phosphate kinase and mevalonate 5-pyrophosphate decarboxylase did not change significantly. No significant differences were found in cholesterol and lipidic phosphorus from liver microsomes, so that the effect of dipyridamole on reductase activity cannot be due to modifications in cholesterol/lipidic phosphorus molar ratio. Neither of these enzyme activities was affected in vitro by dipyridamole.

Long-term follow-up of tension-free Lichtenstein hernioplasty: application of a qualitative-and-quantitative measurement instrument

Real outcomes for the inguinal tension-free Lichtenstein hernioplasty are not reflected by the usual parameters by which they are measured and habitually reported. It is possible to measure these outcomes from the point of view of the surgeon, as well as from the patient's, using an instrument specifically designed for that purpose. The aim of this study was to analyze the outcomes of the tension-free hernioplasty in 236 patients. Based upon the concept of quality-of-life, we designed a structured questionnaire in the form of a qualitative-and-quantitative measurement instrument. The study had two phases. First, we analyzed retrospectively the clinical records. Second, we interviewed the patients applying the instrument. The score demonstrated that 83% of the patients feel that the outcomes of their surgery are excellent, 9.7% feel that they are very good, and 3.8% feel that they are bad or very bad. Outcomes of the Lichtenstein hernioplasty should not only reflect the technological progress of hernia surgery but also the more intimate aspects of the patient's experience. It is possible to measure the outcomes of this common surgical procedure in a more complete way using a simple measurement instrument.