Serum level of Selenium, Zinc, and Vitamin C and their relation to the clinical spectrum of leprosy.

INTRODUCTION: Leprosy is a chronic infectious disease with many risk factors including inadequate nutrient intake and nutritional deficiencies, which affect the immune system, and influence leprosy progression. OBJECTIVES: To elucidate the relation between the serum level of zinc, vitamin C, and selenium and the clinical spectrum of leprosy. METHODOLOGY: A case control study included 100 leprotic patients (50 multibacillary and 50 paucibacillary) and 100 age and sex matched controls. Vitamin C was measured by ELISA, zinc was measured by using centronic colorimetric spectrophotometry, and selenium was measured by Inductivity Coupled Plasma Optical Emission Spectroscopy technique. RESULTS: Zinc and Vitamin C levels were significantly lower in paucibacillary (mean ± SD = 89.86 ± 20.712 and 2.52 ± 1.27 respectively) and multibacillary (mean ± SD = 81.41 ± 18.61 and 1.98 ± 0.59 respectively) than in controls (mean ± SD = 107.34 ± 3.98 and 4.95 ± 2.45 respectively) (p value < 0.001) with no significant difference between paucibacillary and multibacillary patients (p value = 0.142 and = 0.066 respectively). Selenium level showed no significant difference between the three groups (p value > 0.05) (mean ± SD = 51.27 ± 42.61 in paucibacillary, 47.54 ± 30.21 in multibacillary, and 44.07 ± 46.58 in controls). CONCLUSIONS: Lower serum levels of zinc and vitamin C in leprosy patients may be a result of disease pathogenesis or related to the antioxidants based treatment. It might also present prior to the disease onset due to malnutrition that may have accelerated the development of leprosy.

Diet and nutrition: An important risk factor in leprosy.

Leprosy, once considered as poor man's disease may cause severe neurological complications and physical disabilities. Classification of leprosy depends upon the cell mediated and humoral immune responses of the host, from tuberculoid to lepromatous stage. Current therapy to prevent the disease is not only very lengthy but also consists of expensive multiple antibiotics in combination. Treatment and the duration depend on the bacillary loads, from six months in paucibacillary to a year in multibacillary leprosy. Although as per WHO recommendations, these antibiotics are freely available but still out of reach to patients of many rural areas of the world. In this review, we have focused on the nutritional aspect during the multi-drug therapy of leprosy along with the role of nutrition, particularly malnutrition, on susceptibility of Mycobacterium leprae and development of clinical symptoms. We further discussed the diet plan for the patients and how diet plans can affect the immune responses during the disease.

Toenail concentrations of zinc, selenium and nickel in patients with chronic recurrent warts: A pilot two-group comparative study.

BACKGROUND: Normal immune functioning requires sufficient levels of trace elements including zinc and selenium, while elements such as nickel can be immunotoxic. AIM: To assess long-term abnormalities in zinc, selenium and nickel levels in patients with chronic recurrent warts. METHODS: Toenail samples were taken from 28 patients with chronic recurrent warts and 30 apparently healthy matching controls were analysed. Toenail concentrations of zinc, selenium and nickel were measured using inductively-coupled plasma-optical emission spectroscopy. RESULTS: Selenium levels were significantly higher in patients than in controls (P = 0.03). Levels of trace elements did not correlate with the number or duration of warts. Toenail nickel levels in all subjects were higher than globally reported values. LIMITATIONS: A small sample size and the absence of regional reference ranges for concentrations of trace elements in toenails. CONCLUSION: Zinc does not seem to be involved in the chronicity of warts, and it is unclear if selenium has a protective role against warts. Our finding of high concentrations of nickel in both patients and controls raises concerns about environmental exposure.

Micronutrients influencing the immune response in leprosy / Micronutrientes que influyen en la respuesta immune en la lepra

La lepra es una enfermedad infecciosa crónica causada por el Mycobacterium leprae, un bacilo intracelular de transmisión aérea. La enfermedad afecta la piel y los nervios periféricos y causa secuelas neurológicas. El bacilo se multiplica lentamente en el hospedador y posiblemente la enfermedad ocurre por el mal funcionamiento de la respuesta inmunitaria del hospedador. Esta revisión aborda el papel de algunos micronutrientes específicos en la respuesta inmunitaria, tales como las vitaminas A, D, E, C, el cinc y el selenio, detallando sus mecanismos de acción en las enfermedades infecciosas y en la lepra. La respuesta inmunitaria a los patógenos libera sustancias nocivas que producen lesión tisular. Esta revisión también aborda cómo una menor cantidad de antioxidantes puede contribuir a un aumento del estrés oxidativo y a complicaciones de las enfermedades infecciosas y la lepra. Puesto que los micronutrientes poseen un efecto regulador de la respuesta inmunitaria innata y adaptativa, es importante un equilibrio perfecto de sus concentraciones para mejorar la respuesta inmunitaria frente a los patógenos (AU)

Leprosy is a chronic infectious disease caused by Mycobacterium leprae, an intracellular bacillus of airborne transmission. The disease affects the skin and peripheral nerves and can cause neurological sequelae. The bacillusmultiplies slowly in the host and the disease probably occurs due to malfunctioning in host immune response. This review addresses the role of some specific micronutrients in the immune response, such as Vitamins A, D, E, C, Zinc and Selenium, detailing their mechanisms of actions in infectious diseases, and in leprosy. The immune response to pathogens releases harmful substances, which lead to tissue damage. This review discusses how a decreased level of antioxidants may contribute to an increased oxidative stress and complications of infectious diseases and leprosy. As the nutrients have a regulatory effect in the innate and adaptative immune responses, a perfect balance in their concentrations is important to improve the immune response against the pathogens (AU)

The increase of immunity and disease resistance of the giant freshwater prawn, Macrobrachium rosenbergii by feeding with selenium enriched-diet.

The effects of inorganic selenium (Se) (sodium selenate, SSe) and organic selenium (seleno-l-methionine, MSe) supplementation on the immune response, antioxidant status, and disease resistance of the giant freshwater prawn, Macrobrachium rosenbergii, were studied. Five experimental diets, including a control diet (without Se enrichment), 0.5 mg (kg diet)(-1) of MSe, 1 mg (kg diet)(-1) of MSe, 0.5 mg (kg diet)(-1) of SSe, and 1 mg (kg diet)(-1) of SSe, were used. After 75 days of culture, prawn fed the Se-enriched diets had lower mortality compared to that of prawn fed the control diet after being challenged by the pathogen, Debaryomyces hansenii. No significant differences in the total hemocyte count, superoxide dismutase activity, or clearance efficiency of prawn were recorded among the control and treated groups. Significantly increased phenoloxidase and phagocytic activities in prawn fed the Se-enriched diets were found compared to the controls. Respiratory bursts of prawn fed both forms of 1 mg Se (kg diet)(-1) significantly increased compared to control prawns. For the antioxidant status analysis, glutathione peroxidase, glutathione reductase, and glutathione s-transferase of prawn fed the SSe-enriched diet at 1 mg (kg diet)(-1) were significantly increased. The results indicated that the cheaper selenium, SSe is recommended to be added in prawn feed at the concentration of 0.5 mg resulting in 1.5 mg SSe (kg diet)(-1) increased prawn immunity and disease resistance against the pathogen, D. hansenii.

Identification and cloning of a selenium dependent glutathione peroxidase from giant freshwater prawn, Macrobrachium rosenbergii.

A selenium dependent glutathione peroxidase (Se-GPx) cDNA was cloned from haemocyte by a reverse-transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA (RACE). The 913 bp cDNA contained an open reading frame (ORF) of 558 bp encoded a deduced amino acid sequence of 186 amino acids. The prawn Se-GPx sequence contains a selenocysteine (Sec) residue which is encoded by the unusual stop codon, (115)TGA(117). According to the molecular modeling analysis, the active site Sec residue, located in the loop between beta3 and alpha2 in a pocket on the protein surface, and hydrogen bonded to Gln(73) and Trp(141). A GPx signature motif 2, (63)LAFPCNQF(70) and active site motif, (151)WNFEKF(156), two arginine (R) residues, R(89) and R(167) contribute to the electrostatic architecture that directs the glutathione donor substrate, and two putative N-glycosylation site, (75)NNT(77) and (107)NGS(109) were observed in the prawn Se-GPx sequence. In addition, the eukaryotic selenocysteine insertion sequence element is conserved in the 3'-UTR. Comparison of amino acid sequences showed that prawn Se-GPx is more closely related to vertebrate GPx 1. The prawn Se-GPx was synthesized in haemocyte, hepatopancreas, muscle, stomach, gill, intestine, eyestalk, heart, epidermis, lymph organ, ventral nerve cord, testis and ovary. The increase of respiratory burst in haemocyte was observed in pathogen, Debaryomyces hansenii-injected prawn in order to kill the pathogen, and the up-regulation in SOD and GPx acitivity, and prawn Se-GPx mRNA transcription were involved with the protection against damage from oxidation.

[Selenium tolerance of yeasts]. / Selenoustoichivost' drozhzhei.

Selenium tolerance of yeasts widely varies: the growth of some yeasts can be inhibited by a selenium concentration as low as 10(-4) M, whereas others can grow in the presence of 10(-1) M selenium. Homogeneous yeast taxa are characterized by a certain level of selenium tolerance, and heterogeneous taxa show a variable level of tolerance to selenium. In general, ascomycetous yeasts are more tolerant to selenium than basidiomycetous yeasts. Among the ascomycetous yeasts, the genera Dekkera and Schizosaccharomyces exhibited the lowest and the species Candida maltosa, Hanseniaspora valbyensis, Kluyveromyces marxianus, and Yarrowia lipolytica the highest tolerance to selenium. Among the basidiomycetous yeasts, the genera Bullera, Cryptococcus, and Holtermannia showed the lowest and the species Cryptococcus curvatus, Cr. humicola, and Trichosporon spp. the highest tolerance to selenium. The selenium tolerance of yeasts depends on the composition of the growth medium, in particular, on the presence of sulfate, sulfur-containing amino acids, and glutamine in the medium.

Thioredoxin reductase as a pathophysiological factor and drug target.

Human cytosolic thioredoxin reductase (TrxR), a homodimeric protein containing 1 selenocysteine and 1 FAD per subunit of 55 kDa, catalyses the NADPH-dependent reduction of thioredoxin disulfide and of numerous other oxidized cell constituents. As a general reducing enzyme with little substrate specificity, it also contributes to redox homeostasis and is involved in prevention, intervention and repair of damage caused by H2O2-based oxidative stress. Being a selenite-reducing enzyme as well as a selenol-containing enzyme, human TrxR plays a central role in selenium (patho)physiology. Both dietary selenium deficiency and selenium oversupplementation, a lifestyle phenomenon of our time, appear to interfere with the activity of TrxR. Selenocysteine 496 of human TrxR is a major target of the anti-rheumatic gold-containing drug auranofin, the formal Ki for the stoichiometric inhibition being 4 nM. The hypothesis that TrxR and extracellular thioredoxin play a pathophysiologic role in chronic diseases such as rheumatoid arthritis, Sjögren's syndrom, AIDS, and certain malignancies, is substantiated by biochemical, virological, and clinical evidence. Reduced thioredoxin acts as an autocrine growth factor in various tumour diseases, as a chemoattractant, and it synergises with interleukins 1 and 2. The effects of anti-tumour drugs such as carmustine and cisplatin can be explained in part by the inhibition of TrxR. Consistently, high levels of the enzyme can support drug resistance. TrxRs from different organisms such as Escherichia coli, Mycobacterium leprae, Plasmodium falciparum, Drosophila melanogaster, and man show a surprising diversity in their chemical mechanism of thioredoxin reduction. This is the basis for attempts to develop specific TrxR inhibitors as drugs against bacterial infections like leprosy and parasitic diseases like amebiasis and malaria.

The validity of extrinsic stable isotopic labeling for mineral absorption studies in rats.

The use of extrinsic stable and radioisotopic labels (Fe, Zn, Cu and Se) was compared with the use of intrinsic labels by measuring label retention in rats. Saccharomyces cerevisiae (Hansen strain CBS 1171) was prepared intrinsically enriched with a stable isotope of iron, zinc, copper or selenium, and unenriched freeze-dried yeast was extrinsically labeled with the appropriate stable and/or radioisotope. Male Wistar rats, weighing 80-100 g and fed a purified diet, were given a test meal of one of the above labeled yeasts. Isotopic retention was determined by fecal monitoring. Retention of the stable isotopes was determined by thermal ionization quadruple mass spectrometry (TIQMS) and retention of the radioisotopes by counting feces in a whole-body counter. The results indicated that the behavior of the labels differed among the minerals, with copper as the only one in which the intrinsic and extrinsic stable isotopes were comparably retained. With zinc, retention of the extrinsic radiolabel and intrinsic label was similar, but retention of the extrinsic stable isotope label was higher. With iron, the intrinsic label had a significantly lower retention than the two extrinsic labels; with selenium, retention of all three labels was different, but these differences were not of a sufficient magnitude to conclude that extrinsic stable isotopic labelling is not valid. These results demonstrate that an extrinsic stable isotope label can be used for copper, selenium and inorganic iron, but that such a label is not valid for studies on zinc.

Oxidation of formate by mycobacteria of the scrofulaceum group.

Intact cells obtained from Mycobacterium scrofulaceum as well as from mycobacterial strains M.A6 and M.R56 isolated respectively from leprous tissues of armadillo and rat leproma and grown with glycerol as the oxidizable substrate catalyzed complete oxidation of formate. The stoichiometry of formate oxidase system yielded a value of 2 mol of CO2 produced per mole of O2 or per 2 moles of formate consumed. Cell-free preparations from these three strains of mycobacteria contained formate dehydrogenase which was associated exclusively in the particulate fraction. Formate oxidation was markedly stimulated by small amounts of selenite and molybdate added together. Formate-reduced minus oxidized difference spectra disclosed cytochromes of the b type while spectral evidence did not suggest the existence of cytochromes a or c components. The effect of 2-N-heptyl-4-hydroxyquinoline-N-oxide on the redox state of cytochromes indicated that formate oxidation was mediated by cytochrome b with absorption maximum of 556 nm and not of 562 nm.