PubMed Health⌕ Search

Biomedical subjects

S Estrada-Parra

Publications and source records attributed to S Estrada-Parra.

At least 19 recordsLinked to original sources
PubMed1995

Identification and purification of armadillo (Dasypus novemcinctus) immunoglobulins: preparation of specific antisera to evaluate the immune response in these animals.

In this work we describe the purification and characterization of armadillo immunoglobulins. The IgM was precipitated using low-strength ionic solution and further purified by filtration through Sephadex G-200. The IgG was obtained in pure form by precipitation of serum with ammonium sulfate and DEAE-cellulose ion exchange chromatography. The purity of these immunoglobulins was evaluated by polyacrylamide gel electrophoresis. The results showed 28-kDa light chains and 55-kDa and 70-kDa heavy chains for IgG and IgM, respectively. The rabbit antibodies against these molecules were used to prepare fluorescein (FITC) and peroxidase conjugates. The FITC conjugate was used to quantify IgM-bearing lymphocytes. An average of 17% of peripheral blood lymphocytes were sIgM+ from 14 healthy animals. Additionally, in the same animals we quantified lymphocytes with the capacity to form rosettes with sheep red-blood cells; the average for this marker was 10%. Also, the production of crossreacting antibodies to BCG was evaluated in healthy and Mycobacterium leprae-inoculated animals using the peroxidase conjugates. All animals with active infection recognized BCG antigens.

Animals↗
PubMed1992

Use of synthetic peptides corresponding to sequences of Mycobacterium leprae proteins to study delayed-type hypersensitivity response in sensitized guinea pigs.

In this work we report the synthesis of 10 peptides (P1-P10) corresponding to one or several segments of the amino acid sequence of proteins from Mycobacterium leprae: 65 kDa, 28 kDa, 18 kDa, and 28 kDa superoxide dismutase, recently renamed antigens 2L, 9L, 12L, and 14L, respectively. They were assayed in the guinea pig model for the induction of a delayed-type hypersensitivity response in M. leprae and BCG-sensitized animals. To sensitize the animals two schemes were used: either a single dose of 5 x 10(9) irradiated or autoclaved whole bacilli, or four weekly intramuscular injections each containing 500 micrograms of soluble extract of M. leprae (MLSE) in incomplete Freund's adjuvant. Because the second scheme used far too much antigen, we decided to use the first scheme for the experiments we report here. DTH reactions of sensitized animals were induced after 30 days with intradermal injections of 5 micrograms of MLSE and with each of the 10 peptides at three different concentrations: 250 micrograms, 100 micrograms, and 0.05 micrograms. All M. leprae-sensitized guinea pigs gave indurations of 10 mm or more with MLSE, which indicates that the animals were sensitized. None of them gave DTH indurations with 250 micrograms or 100 micrograms, but some of them had positive DTH reactions with the 0.05 micrograms doses of the synthetic peptides. This is most likely due to the fact that we have used an outbred strain of guinea pigs. The peptides were also tested at 0.05 micrograms in animals sensitized with BCG. P7 and P10 seem to be nonspecific peptides; the remaining peptides only induced DTH in the M. leprae-sensitized guinea pigs. P3 (segments 65-85 of the 65-kDa protein) induced a positive DTH in 58% of the tested animals. In other experiments, guinea pigs were sensitized with a single injection (500 micrograms) of each of the synthetic peptides. All animals, except those sensitized with P4 and P8, had positive DTH responses when the homologous peptide was used. Those sensitized with P2, P4, P5, P7, and P8 were able to produce indurations when MLSE was used for the induction of the DTH reaction.

Amino Acid Sequence↗
PubMed1985

Biochemical alterations in the serum of armadillos (Dasypus novemcinctus) infected with Mycobacterium leprae. A preliminary report.

Armadillos (Dasypus novemcinctus) were inoculated with Mycobacterium leprae isolated from lepromas taken from untreated lepromatous patients or from the spleen of an armadillo previously infected with human M. leprae. The effect of the infection on the serum levels of lactic dehydrogenase (LDH), alkaline phosphatase (AlkP), glutamate-oxalacetate (GOT) and glutamate-pyruvate (GPT) transaminases was investigated. In general, there was a good correlation between positive evidences of infection and alterations in the levels of LDH, GOT, and GPT. Although elevations in LDH levels were more striking, elevations in GOT and GPT levels were more consistent with the disease. When an absolute increase in the total LDH activity was not observed in a M. leprae-infected animal, an increase in the level of LDH isozyme V was still clearly evident. Serum levels of alkaline phosphatase were not affected by the disease. The ratio GOT/GPT (greater than 1.0) in the infected animals reflected and supported the chronic nature of the disease and the liver involvement. The enzymatic alterations are not, however, specific for leprosy.

Alanine Transaminase↗
PubMed1982

Phagocytosis in leprosy. 5. The effect of the infection with Mycobacterium lepraemurium on the level of diverse hydrolytic lysosomal enzymes of murine peritoneal macrophages.

The effect of the infection with M. lepraemurium on the activity of several lysosomal enzymes of mouse peritoneal cells was studied. The enzymes studies were acid- and alkaline-phosphatases, acid (cathepsin D-type) proteinase, beta-glucuronidase, deoxyribonuclease, a nonspecific lipase, and lysozyme. Enzyme determinations were carried out four months and six months after the infection with 15.5 X 10(7) bacilli per mouse. Clear differences between M. lepraemurium-infected and normal animals were observed at four months of infection, with all of the mentioned enzyme activities well above the normal values. At six months of infection, a tendency to decrease to normal values of the enzyme activities was observed. It is suggested that this biochemical activation of mouse peritoneal cells reflects the effect of the cell-mediated immune response triggered by the infection with the murine leprosy bacillus. M. lepraemurium-infected mice possess macrophages in a high state of biochemical activation; yet, they are unable to get rid of the infecting microorganism.

Acid Phosphatase↗
PubMed1980

Phagocytosis in leprosy. III. Defective adhesive and endocytic abilities of circulating leukocytes in lepromatous leprosy.

Two aspects of the phagocytic process in normal and lepromatous polymorphonuclears (PMN) and monocytes (MN) were studied. These aspects were endocytosis and adherence to surfaces. These 2 phenomena are closely related to each other and to the whole phagocytic process as they depend on membrane activity. It was found that both lepromatous phagocytes (PMN and MN) show, on the average, a depressed ability to endocytose opsonized Mycobacterium lepraemurium when compared to normal phagocytes. This impairment, however, does not seem to be related to intrinsic defects in the phagocytic cells themselves but to the presence in lepromatous serum of factors that interfere with the endocytic function. This conclusion was drawn from the fact that lepromatous serum causes a similar diminution in the endocytic ability of normal phagocytes. On the other hand, lepromatous plasma but not indeterminate leprosy nor normal plasmas interfere with the capacity of PMN leukocytes to adhere in vitro to plastic surfaces. These impairments in the phagocytic function might help to better understand the depressed overall inflammatory responses observed in vivo in lepromatous patients with a long-lasting disease.

Adult↗
PubMed1976

Immunochemical characterization of the anti-RNA antibodies found in scleroderma and systemic lupus erythematosus. II. Reactivity with hsa-coupled, uridine-containing, monophosphoric ribodinucleotides.

Sera from patients with scleroderma have been found to have anti-RNA antibodies which react with human serum albumin (HSA)-coupled uridine and uridine monophosphate (UMP) and are inhibited by uracil, uridine and UMP. Scleroderma sera react uniformly with 5'-polyuridylic acid (poly(U)) and fail to react with polyadenylic, polyuridylic acid poly(A) - poly(U)) which is also indicative of their uracil specificity. Anti-RNA antibodies found in systemic lupus erythematosus (SLE) are immunochemically different from those found in scleroderma in that, instead of being uniformly specific to uracil, they are markedly heterogeneous and may react with uracil, uridine and/or UMP. SLE sera frequently react with poly(A) - poly(U), indicating also their ability to recognize the double helical structure of double-stranded RNA. Thirty-seven scleroderma and thirty-four SLE sera from as many patients with either of these conditions were tested against HSA-coupled, uridine-containing monophosphoric dinucleotides in an attempt to characterize further their anti-RNA antibodies. Scleroderma sera were found to react primarily with dinucleotides in which uridine was the base proximal to the carrier protein and, except for sera that also contained antibodies to adenosine which reacted with UpA, they failed to react with dinucleotides in which uridine was in a terminal position only. Reaction with dinucleotides in which uridine was proximal to the carrier protein could be inhibited by uracil but not by the corresponding terminal base. Some lupus sera were found to react with both dinucleotides that contain the same bases in opposite sequence, e.g. ApU and UpA, while others were found to react with only one of the sequences. They were also found to react more frequently with dinucleotides in which HSA was coupled to a base other than uridine, suggesting that the reaction is primarily due to anti-DNA antibodies. Because immunization with dinucleotides coupled to protein prepared by the same method we have used, yields higher specificity to the base attached to the carrier protein, our findings suggest that, in scleroderma, a single event, akin to that of immunization with a purified antigen, gives rise to the anti-RNA antibodies, whereas in systemic lupus erythematosus there is a considerably wider immunological aberration.

Adenosine↗
PubMed1975

Uracil-specific anti-R.N.A. antibodies in scleroderma.

Antibodies to single-stranded R.N.A. were found by counter immunoelectrophoresis in all of 40 sera from patients with scleroderma. These antibodies were specific to the uracil bases of R.N.A. Antibodies to R.N.A. were also found in 20 of 40 sera from patients with systemic lupus erythematosus (S.L.E.), but in none of forty controls. Antibodies to R.N.A. found in S.L.E. sera could be differentiated immunochemically from those found in scleroderma in that they were more heterogeneous and could react selectively with either uridine or uridine monophosphate. Antibodies ot D.N.A. were more frequent in S.L.E. than in scleroderma. That antibodies to D.N.A. are actually present in scleroderma and precipitin lines are not the result of cross reactivity with anti-R.N.A. antibodies is indicated by the finding that 10 of the 18 scleroderma sera which reacted with D.N.A. also reacted with thymidine, a base present in D.N.A. but not in R.N.A.

Adenosine↗
PubMed1975

The heterogeneity of anti-DNA antibodies in systemic lupus erythematosus and other diseases.

The antigenic specificities of antinucleic acid antibodies occurring in systemic lupus erythematosus (SLE), chronic active liver disease, and progressive systemic sclerosis (PSS) have been studied by means of haptenic nucleosides and nucleotides coupled to human serum albumin. SLE sera were also tested with dinucleotides. SLE and chronic active liver disease sera showed marked heterogeneity, producing precipitin lines with nucleosides or nucleotides, or both. The reaction might occur with a nucleoside and not with the corresponding nucleotide, or vice versa. The SLE sera reacted to dinucleotides with marked specificity, being able to recognize base sequences or to react with a dinucleotide despite the absence of a reaction with the individual bases. All sera from patients with PSS showed precipitins with RNA, uridine and UMP. PSS sera which reacted with a nucleoside also reacted with the corresponding nucleotide. Antibodies to DNA were found in a smaller proportion of PSS sera than in sera from SLE or chronic active liver disease. Their presence was confirmed by reactivity with thymidine and TMP.

Antibodies, Anti-Idiotypic↗