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Biomedical subjects

L H Silveira

Publications and source records attributed to L H Silveira.

At least 19 recordsLinked to original sources
PubMed2006

Serological detection of antibodies against Paracoccidioides brasiliensis in dogs with leishmaniasis.

The aim of this study was to detect antibodies against Paracoccidioides brasiliensis in dogs seropositive and seronegative for leishmaniasis. Sera from 836 dogs (449 positive and 387 negative to leishmaniasis) were analysed by ELISA and the immunodiffusion test using gp43 and exoantigen, respectively. The analysis of the 836 serum samples by ELISA and the immunodiffusion test showed a positivity of 67.8 % and 7.3%, respectively, for P. brasiliensis infection. The dogs positive to leishmaniasis showed a higher reactivity to gp43 (79.9%) and exoantigen (12.7%) than the negative ones (54.0% and 1.0%, respectively). The higher reactivity to P. brasiliensis antigens may be due to cross-reactivity or a co-infection of dogs by Leishmania and P. brasiliensis. The lower correlation (0.187) observed between reactivity to gp43 and Leishmania antigen reinforces the latter hypothesis.

Animals↗
PubMed2002

Vascular endothelial growth factor plasma levels in patients with systemic lupus erythematosus and primary antiphospholipid syndrome.

The objective of this study was to assess the possible role of vascular endothelial growth factor (VEGF) in the pathogenesis of systemic lupus erythematosus (SLE) and primary antiphospholipid syndrome (PAPS). We studied 28 patients with SLE, 10 patients with PAPS, and 24 healthy controls. VEGF plasma levels were measured by ELISA. Immunolocalization of VEGF was done in renal tissue from SLE patients and cadaveric controls. Our results showed that VEGF plasma levels were increased in SLE patients compared with PAPS and controls. The correlation between clinical manifestations and VEGF levels revealed that SLE patients with renal failure had significantly increased plasma VEGF levels (134.1 + 91.0 pg/ml) compared with SLE patients with normal renal function (42.9 + 19.0 pg/ml), PAPS patients (41.9 + 26.6 pg/ml), and controls (36.2 + 27.0 pg/ml; P < 0.01). Immunostaining showed a strong expression of VEGF in SLE renal tissue samples. Our preliminary results indicate that VEGF is increased in plasma from patients with lupus nephritis and a moderate degree of renal failure and is overexpressed in renal tissue from these patients.

Adult↗
PubMed1999

Inhibition and uncoupling of oxidative phosphorylation by nonsteroidal anti-inflammatory drugs: study in mitochondria, submitochondrial particles, cells, and whole heart.

The effects of the anti-inflammatory drugs diclofenac, piroxicam, indomethacin, naproxen, nabumetone, nimesulide, and meloxicam on mitochondrial respiration, ATP synthesis, and membrane potential were determined. Except for nabumetone and naproxen, the other drugs stimulated basal and uncoupled respiration, inhibited ATP synthesis, and collapsed membrane potential in mitochondria incubated in the presence of either glutamate + malate or succinate. Plots of membrane potential versus ATP synthesis (or respiration) showed proportional variations in both parameters, induced by different concentrations of nimesulide, meloxicam, piroxicam, or indomethacin, but not by diclofenac. The activity of the adenine nucleotide translocase was blocked by diclofenac and nimesulide; diclofenac also slightly inhibited mitochondrial ATPase activity. Naproxen did not affect any of the mitochondrial parameters measured. Nabumetone inhibited respiration, ATP synthesis, and membrane potential in the presence of glutamate + malate, but not with succinate. NADH oxidation in submitochondrial particles also was inhibited by nabumetone. Nabumetone inhibited O2 uptake in intact cells and in whole heart, whereas the other five drugs stimulated respiration. These observations revealed that in situ mitochondria are an accessible target. Except for diclofenac, a negative inotropic effect on cardiac contractility was induced by the drugs. The data indicated that nimesulide, meloxicam, piroxicam, and indomethacin behaved as mitochondrial uncouplers, whereas nabumetone exerted a specific inhibition of site 1 of the respiratory chain. Diclofenac was an uncoupler too, but it also affected the adenine nucleotide translocase and the H+-ATPase.

Adenosine Triphosphate↗
PubMed1997

Absence of ANCA in Mexican patients with Takayasu's arteritis.

Antineutrophil cytoplasmic autoantibodies (ANCA) were sought in 43 sera from 39 Mexican patients with typical Takayasu's arteritis (TA), (5 with active and 34 with inactive disease), and in a comparative group comprising 50 sera. Results were negative in all cases. This suggests that ANCA are not a serologic feature in TA per se, even during its active stage. ANCA positivity in TA, when present, may be a non-related phenomenon and probably identifies a subset of patients with atypical forms of TA or a polyangiitis overlap syndrome.

Adult↗
PubMed1995

Familial anticardiolipin antibodies and C4 deficiency genotypes that coexist with MHC DQB1 risk factors.

OBJECTIVE: To investigate the familial basis of antiphospholipid antibodies by studying putative risk factors at the C4 and MHC class II loci. METHODS: Autoimmune diseases, anticardiolipin (aCL) and other autoantibodies were studied in 38 first and 2nd degree family members of 3 index cases selected for primary antiphospholipid syndrome (APS) and 33 controls. C4 protein phenotyping and restriction fragment length polymorphism analysis of C4 and MHC class II loci were performed. RESULTS: Nineteen family members (46%) had autoimmune diseases or autoantibodies; aCL were present in 10 family members, 4 of whom had primary APS. Each family had 2 or more subjects with aCL. Among 22 independent haplotypes in family members, there was a high frequency of C4A and C4B deficiency alleles (0.41 vs 0.18 in 66 controls, p = 0.03) and a strong trend toward an increase in MHC DQB1 putative risk factors that share the TRAELDT structural domain. This DQB1 structural domain was present in 4/5 different haplotypes that contained a C4B deficiency genotype; however, neither of 2 different haplotypes with a C4A deletion (one being a common ancestral haplotype) contained this DQB1 putative risk factor. Among the 10 family members who had aCL, 10/20 haplotypes contained a C4 deficiency genotype; moreover, the DQB1 putative risk factor was present in all 16 MHC haplotypes that did not contain a C4A deletion. CONCLUSION: In these families, expression of an autoimmunity trait as aCL antibody appears to be associated with the coexistence of C4 deficiency alleles with DQB1 alleles that contain the TRAELDT structural domain.

Adolescent↗
PubMed1995

Serum antinuclear antibodies in women with silicone breast implants.

OBJECTIVE: Recent evidence suggests that immunologic abnormalities are not uncommon in individuals with silicone breast implants. The purpose of our study was to evaluate in a consecutive manner, the prevalence of autoimmunity as assessed by the presence of antinuclear antibodies in a larger number of patients with silicone breast implants. METHODS: Antinuclear antibody (ANA) testing using an indirect immunofluorescence technique was performed on 813 individuals with silicone breast implants. All subjects except for 3 transsexual males, were female. The overwhelming majority, over 99%, were white. The average age of the subjects was 46.2, with a range of 17 to 72 years. RESULTS: ANA positivity was found in 244 of 813 individuals (30%) using a mouse kidney substrate; and in 470 of 813 (57.8%) using a HEp-2 cell line. The most common immunofluorescent pattern found using HEp-2 was speckled, present in 341 (72.5%) individuals, followed by homogeneous pattern in 113 (24%), nucleolar in 63 (13.4%), and 5 (1.06%) were anticentromere. Anti-dsDNA antibodies measured by an ELISA assay were found in 6 of 71 patients (8%). Rheumatoid factor and C-reactive protein were found above healthy controls in less than 10% of cases studied. The high prevalence of ANA found in patients with silicone breast implants agrees with similar observations by others. The finding of anticentromere and nucleolar patterns has great interest and relevance. These fairly distinct ANA patterns are most commonly seen in the idiopathic form of scleroderma and related conditions. CONCLUSION: These findings suggest that ANA positivity is relatively common in individuals with silicone breast implants, and may support the existence of autoimmune mechanisms in the pathogenesis of the clinical manifestations seen in this population.

Adolescent↗
PubMed1994

Eosinophilic hepatitis: a new feature of the clinical spectrum of the eosinophilia-myalgia syndrome.

The eosinophilia-myalgia syndrome associated with L-tryptophan-containing products is highlighted by eosinophilia, incapacitating myalgias, and diverse multisystemic manifestations. In addition to involvement of the skin, skeletal muscle, and peripheral nerves, visceral damage has been quite prominent, particularly affecting the lungs, the heart, and the liver. Hepatic involvement has been manifested by altered liver tests but is clinically silent. We report the unique case of a woman with this syndrome who developed abdominal pain, a clinical picture of hepatitis and chronically abnormal liver tests. Histologic examination of the liver disclosed eosinophilic hepatitis with piecemeal necrosis. The occurrence of clinically overt hepatic involvement has not been reported previously. Potential mechanisms of liver damage in eosinophilia-myalgia syndromes are discussed.

Adult↗
PubMed1994

Pneumatosis cystoides intestinalis in systemic lupus erythematosus with intestinal vasculitis: treatment with high dose prednisone.

Pneumatosis cystoides intestinalis (PCI) is an uncommon disorder usually associated with intestinal and pulmonary obstructive diseases, recent abdominal procedures and systemic illnesses. PCI has been reported in patients with systemic lupus erythematosus associated with intestinal vasculitis. We describe herein a patient with a month history of intermittent abdominal pain, diarrhoea, hyporexia, and weight loss who underwent intestinal resection for acute abdomen. Post-operatively she gave a three-month history of arthritis of the right knee, ankles and feet, arthralgia of the wrists, MCPs and shoulders. She also described weakness, weight loss, Raynaud's phenomenon, and a skin rash. Laboratory examination revealed an increased ESR, low haemoglobin and haematocrit, positive rheumatoid factor, a positive ANA with a speckled pattern, as well antibodies to DNA, SS-A and cardiolipin. The abdominal symptomatology especially pain, cramps and bouts of diarrhoea persisted after the surgery and became worse two months later. Abdominal X-ray showed distention of bowel with cyst formation in the wall of the entire colon. A diagnosis of PCI was made radiologically. The intestinal pathology was reviewed and vasculitis was identified. The patient received treatment with high dose prednisone with an excellent response; prednisone was progressively tapered and she has been asymptomatic without abdominal complaints or other symptoms for over a year.

Adult↗
PubMed1994

Recent developments in psoriatic arthritis.

Psoriatic arthritis affects 5% to 7% of patients with psoriasis. Genetic, immunologic, and environmental factors play a role in its pathogenesis. The role of inflammatory cytokines has been better defined, and recent immunohistochemical studies of the synovial membranes have shown important differences and similarities between psoriatic arthritis and rheumatoid arthritis. The association of psoriatic arthritis with infection, particularly HIV, remains an interesting observation. The most common clinical presentation appears to be peripheral polyarticular, and extra-articular manifestations including the SAPHO (synovitis, acne, pustulosis, hypertosis, and osteitis) syndrome are not common. Methotrexate and sulfasalazine therapy are effective in patients who do not respond to nonsteroidal anti-inflammatory drugs.

Arthritis, Psoriatic↗
PubMed1994

Hyperprolactinemia in Reiter's syndrome.

OBJECTIVE: Accumulated evidence suggests that certain immunoregulatory hormones including prolactin (PRL) may play a role in the pathogenesis and disease expression of certain autoimmune diseases. Our objective was to investigate the possible role of PRL in the pathogenesis and disease expression of the spondyloarthropathies, including Reiter's syndrome (RS). METHODS: Basal levels of PRL (serum) were determined by radioimmunoassay in patients with various types of spondyloarthropathies, patients with acute anterior uveitis (AAU), and healthy controls. Clinical manifestations at the time of serum collection were correlated with PRL levels. RESULTS: Hyperprolactinemia (PRL > 20 ng/ml) was found in 9 of 25 (36%) patients with RS. In contrast, only 1 of 34 (2.9%) (p < 0.001) patients with ankylosing spondylitis and none of the patients with psoriatic arthritis, AAU or healthy controls had hyperprolactinemia. The frequency of conjunctivitis, urethritis, dysentery, and uveitis was higher in hyper than in normoprolactinemic patients with RS. CONCLUSION: Our results suggest a possible role for this immunoregulatory hormone in the pathogenesis and disease expression of RS.

Acute Disease↗
PubMed1994

Fibroblast function in psoriatic arthritis. I. Alteration of cell kinetics and growth factor responses.

OBJECTIVE: To explore the potential role of fibroblasts in the pathogenesis of psoriasis and its related arthritis. Specifically, we analyzed the cell cycle of psoriatic fibroblasts obtained from skin and synovium by flow cytometry, and we also studied their response to several growth factors. METHODS: Fibroblast cultures were established from normal and psoriatic skin, uninvolved and involved, and synovium. NIH-3T3 cells were also used as indicator cells in some of the experiments. Fibroblasts DNA cell cycle analysis was performed by flow cytometry, and the data was analyzed by using the "Cytologic DNA applications software version 2." In addition, fibroblasts were stimulated with growth factors including epidermal growth factor, transforming growth factor-beta, and platelet derived growth factor. RESULTS: A significant increase of S and G2-M phase values in confluent cultures of psoriatic fibroblasts in both skin and synovium compared to normal fibroblasts was found. Psoriatic fibroblasts also exhibited a greater proliferative response to growth factors compared to normal fibroblasts. CONCLUSION: Data obtained clearly showed a significant intrinsic in vitro alteration in skin and synovium fibroblasts from patients with psoriasis.

3T3 Cells↗
PubMed1994

Fibroblast function in psoriatic arthritis. II. Increased expression of beta platelet derived growth factor receptors and increased production of growth factor and cytokines.

OBJECTIVE: The main objective was to investigate the expression of platelet derived growth factor (PDGF) receptors, and production of growth factors and cytokines from psoriatic skin and synovium derived fibroblasts. METHODS: Fibroblast cultures were established from normal and psoriatic skin and synovium. Confluent cultures of fibroblasts were used for a receptor binding assay for PDGF, and then extracts were run on Western blot. The amount of immunoreactive A and B chain peptides present was determined with specific A or B chain antisera. Production of interleukin 1 beta and PDGF-beta was accomplished by neutralization with the use of commercially available antisera. A functional assay was used to measure transforming growth factor-beta (TGF-beta). RESULTS: There was an increased expression of the beta PDGF receptor in the psoriatic fibroblasts. Interleukin 1 beta and PDGF-beta production by psoriatic fibroblasts was also increased. However, TGF-beta production was similar in normal and psoriatic fibroblasts. CONCLUSION: Our data demonstrate an increased expression of beta PDGF receptor, and production of IL-1 beta and PDGF by psoriatic fibroblasts. The findings provide further support for an active role of this cell line in the pathogenesis of psoriasis and psoriatic arthritis.

Adult↗
PubMed1993

Refractory nephrotic syndrome in lupus nephritis: favorable response to indomethacin therapy.

The effects of indomethacin on urinary protein excretion, levels of serum albumin and renal function were studied prospectively in six patients with systemic lupus erythematosus (SLE) and refractory nephrotic syndrome due to lupus nephritis. Two had membranoproliferative glomerulonephritis, two had diffuse proliferative glomerulonephritis, and one each had mesangioproliferative and membranous glomerulonephritis. All experienced a considerable reduction in urinary protein excretion and an increase in serum albumin. Indomethacin was discontinued in two patients because of side effects, and proteinuria recurred to pretreatment levels. The decrease of proteinuria continued during long-term treatment in three patients. Indomethacin did not cause a permanent decline in renal function. Our results suggest that therapy with indomethacin may be beneficial for the treatment of refractory nephrotic syndrome in selected SLE patients. However, because of potential side effects the administration of indomethacin should be monitored closely.

Adult↗
PubMed1993

Chlamydia-induced reactive arthritis.

Chlamydia trachomatis infection is now recognized as the most prevalent veneral disease in the Western World. The majority of cases of Reiter's syndrome, one type of reactive arthritis, are secondary to sexually transmitted infections. Evidence of urogenital C. trachomatis infection is found in 36% to 61% of cases of Reiter's syndrome. We investigated the prevalence of infection by this organism in a group of patients with spondyloarthropathies. Positive cultures were obtained in 39.4% of patients with Reiter's syndrome, as well as in 22.2% of patients with psoriatic arthritis and in 20% of patients with ankylosing spondylitis. An important percentage of patients also had positive serum antibodies against C. trachomatis (62.1% of patients with Reiter's syndrome), suggesting presence of infection at some point during the course of the disease. Our findings and those from other authors support the use of long-term antibiotic therapy in patients with reactive arthritis, mainly in those in whom positive culture for C. trachomatis has been obtained as well as in their sex partners.

Adolescent↗
PubMed1993

Candida arthritis.

Septic arthritis can be caused by Candida species. Its true incidence is unknown because only a few cases have been reported. Two clinical syndromes have been identified. The first is an isolated monarthritis caused by the direct intra-articular inoculation of fungi that inhabit the skin, by means of an injection, or during surgery. The second is the development of a mono- or polyarthritis as a complication of hematogenously disseminated candidiasis. The optimum treatment of this condition is not yet known, although the combination of medical and surgical treatment seems to be the most convenient therapeutic modality. Amphotericin-B continues to be the drug of choice.

Arthritis, Infectious↗
PubMed1993

Other fungal arthritides.

Fungi are not a common cause of musculoskeletal infection; however, reports of fungal bone and joint infections have lately surged and are expected to increase more. There is evidence of an increasing incidence of pathogenic and opportunistic fungal infections and emergence of new species of disease-causing fungi, particularly in immunosuppressed patients. Distribution is worldwide, signs of infection can be mild, and chronic evolution as well as delayed diagnosis are common.

Arthritis, Infectious↗