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Biomedical subjects

T S Bocanegra

Publications and source records attributed to T S Bocanegra.

At least 37 records · Page 2Linked to original sources
PubMed1982

Vascular changes in psoriatic synovium. A light and electron microscopic study.

Light and electron microscopic studies were performed on the synovial membranes from the large joints of 12 patients with psoriatic arthritis. The most significant histopathologic findings were vascular changes that were characterized by endothelial cell swelling accompanied by inflammatory cell infiltration and marked thickening of the vessel wall. Fibrosis of the subsynoviocyte tissue was also prominent, especially in patients with chronic disease. Villi were not prominent, and the lining layer was not thickened. Both type A and B cells were seen; none had significant abnormalities. No electrondense deposits were observed. These findings lend further support to the theory that microvascular changes play a significant role in the pathogenesis of psoriasis and its related arthritis.

Adult↗
PubMed1982

In vitro cytotoxicity of human endothelial cells in polymyalgia rheumatica and giant cell arteritis.

We studied sera from 20 patients with polymyalgia rheumatica (PMR)/giant cell arteritis (GCA), 15 patients with systemic lupus erythematosus (SLE), 15 patients with the CREST syndrome (calcinosis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly, and telangietasia) and 33 age and sex matched controls for cytotoxicity against human endothelial cells using a 51Cr release assay. We observed increased levels of endothelial cytotoxic activity in the PMR/GCA sera compared with controls (P less than 0.001). This cytotoxicity was predominantly found in the GCA group, where 7 out of 10 patients (70%) demonstrated significant cytotoxicity. Sequential studies showed that the cytotoxic activity returned to normal when the disease was under control. Although 7 SLE and 3 CREST sera had significant cytotoxic activity, as a group they did not differ from controls (P less than 0.05). Pre-incubation with soybean trypsin inhibitor suppressed the cytotoxic activity in the positive sera suggesting the cytotoxicity is mediated via a protease mechanism. Our results demonstrate the presence of a cytotoxic factor in the serum of patients with PMR/GCA which may play an important role in the pathogenesis of the vascular lesions observed in these disorders.

Aged↗
PubMed1982

Articular involvement in human brucellosis: a retrospective analysis of 304 cases.

Brucellosis is a zoonosis which in humans is caused by one of four species of the Brucella genus: B. melitensis, B. abortus, B. suis and B. canis. B. abortus is the species prevalent in North America and Europe and B. melitensis in most developing countries. Differences in disease manifestations may be accounted for either by differences in the species or by differences in the host. Articular involvement in brucellosis, although recognized since 1904, has been variably emphasized. Three hundred and four cases of human Brucellosis caused by B. melitensis, the prevalent species in Perú, were seen during a 12-yr period in one Lima hospital. Fever, malaise and hepatomegaly were the most frequent findings. Diagnosis was greatly improved when cultures were done in the biphasic Ruiz-Castañeda medium, rather than in trypticase soy broth. Serologic diagnosis is still important, and it should include standard tube testing, detection of IgG blocking antibodies and fractionation with 2-ME in chronic cases. The disease may take one of three courses: acute, (< 8 wk), chronic (> 8 wk) or undulant (periods of remissions and exacerbations). Four syndromes were recognized in a total of 33.8% of patients with Brucellosis. The most frequent pattern (in approximately 46.6% of patients with arthritis) was sacroiliitis, usually non-destructive and either uni- or bilateral. The second most frequent articular syndrome was peripheral arthritis (38.8%), manifested either as a single large lower extremity joint or as an asymmetric pauciarthritis. Rarely patients presented with a rheumatoid-like arthritis. Mixed arthritis (7.8%) was a combination of the first two. The above forms occurred in patients with an acute or undulant course. Spondylitis was the least common form of arthritis (6.8%), and differed significantly from the other forms of arthritis in the duration of symptoms (chronic course), age of patients (older individuals) and the paucity of fever and malaise. It also tended to be destructive. The arthritis usually resolved with the combined regimen of tetracycline (2 g p.o. for 21 days) and streptomycin (1 g i.m. for 21 days) without sequelae. Illustrative cases of these syndromes are presented. The relatively benign nature of most of the patients with bruccellar arthritis lead us to postulate that they are for the most part reactive arthritides. Host factors are thought to be important in determining the response to the infection, but they are yet to be identified. Our own genetic studies have failed to identify an increased frequency of B27 or CREG antigens in the patients with sacroiliitis.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1981

Reactive arthritis induced by parasitic infestation.

Arthritis developed in two patients during the course of parasite infestation with Strongyloides stercoralis and Taenia saginata, respectively. The joint involvement was polyarticular and symmetrical but seronegative and nonerosive radiologically. We found evidence of abnormal humoral immunity to the parasites, immune complexes in serum and synovial fluid, and immunoglobulin deposits in the synovia. Nonsteroidal anti-inflammatory agents proved ineffective but specific antiparasitic treatment resulted in resolution of the symptoms and immunologic abnormalities. Our findings provide further documentation of the interaction between the body's immune system and parasites and suggest that arthritis induced by parasitic infestation may be mediated by immune complex formation in susceptible hosts.

Adult↗
PubMedDate not supplied

The efficacy, tolerability, and safety of 1200 mg/d of oxaprozin and 1500 mg/d of nabumetone in the treatment of patients with osteoarthritis of the knee.

This 6-week, multicenter, double-masked, placebo-controlled study compared the efficacy, tolerability, and safety of the recommended starting dose of oxaprozin (1200 mg/d) and a 1500-mg/d dose of nabumetone in the treatment of patients with moderate-to-severe osteoarthritis (OA) of the knee. A total of 347 patients with a mean age of 61.1 years were randomized to receive oxaprozin (116 patients), nabumetone (115 patients), or placebo (116 patients). Adults of either sex who were older than 18 years of age were eligible for entry into the study, if they had had OA of the knee for at least 6 months. Efficacy variables included knee pain on weight bearing, knee pain on motion, patients' and physicians' global assessments of OA, pain intensity as measured on a visual analog scale, and time to walk 50 feet as quickly as possible. Efficacy variables were assessed at baseline and at weeks 1, 2, 4, and 6. Between-group differences in efficacy variables were evident by week 1. Mean improvements were significantly greater with oxaprozin than with placebo for all efficacy variables at all time periods, except knee pain on motion at weeks 2 and 4 and time to walk 50 feet at weeks 1, 2, and 4. Mean improvements were significantly greater with nabumetone than with placebo for all efficacy variables at all time periods, except the following: knee pain on weight bearing at weeks 2, 4 and 6; knee pain on motion at weeks 2 and 4; patients' global assessment at week 4; and pain intensity as measured on a visual analog scale at weeks 2 and 4. There were, however, no significant differences between oxaprozin and nabumetone in any of these efficacy variables. Adverse events were reported by 83 (71.6%) patients who took oxaprozin, by 80 (69.6%) patients who took nabumetone, and by 57 (49.1%) patients who took placebo. Adverse events were reported for significantly more patients taking oxaprozin or nabumetone than placebo. However, adverse events tended to be mild or moderate and rarely resulted in patients withdrawing from the study. Combined with the results of an earlier study, the results of this study showed that a 1500-mg/d dose of nabumetone, which is higher than the recommended starting dose of 1000 mg/d, is required for efficacy equivalent to that of the recommended starting dose of oxaprozin, 1200 mg/d, in relieving the symptoms of OA. Thus nabumetone may require dosage titration from the recommended starting dose. Oxaprozin and nabumetone were found to have similar tolerability profiles, as shown by adverse-event monitoring and withdrawal rates, as well as clinically similar safety profiles, as demonstrated by physical examinations, hematologic and biochemical laboratory testing, hemoccult testing, and adverse-event monitoring and symptom assessment.

Adult↗
PubMedDate not supplied

Humoral immune abnormalities in human brucellosis.

Humoral immune responses were evaluated in a group of patients with acute brucellosis due to Brucella melitensis biotype I. Levels of immunoglobulins, C3 and C4, and the presence of antinuclear antibodies, rheumatoid factor and circulating immune complexes were sequentially studied in all brucellosis patients during the acute phase of the disease and following specific therapy. Elevated levels of all immunoglobulin classes, IgG, IgM and IgA and C3, C4, were found in the majority of patients. Antinuclear antibodies, rheumatoid factor and circulating immune complexes were found in circulation, particularly during the active stages. These findings provide support for the participation of the humoral immune system in the pathogenesis of human brucellosis.

Adolescent↗
PubMedDate not supplied

Polymyalgia rheumatica and giant cell arteritis: circulating immune complexes.

Circulating immune complexes (CIC) were detected in a large population of patients with polymyalgia rheumatica (PMR) alone, PMR-giant cell arteritis (GCA), and GCA alone. CIC were found in the majority of patients studied. A direct correlation was observed between levels of CIC material and the erythrocyte sedimentation rate. The presence of immune complexes in the sera of patients with these disorders do not have diagnostic significance but may play an important role in their pathogenesis.

Aged↗
PubMedDate not supplied

The major histocompatibility complex.

The major histocompatibility complex on the sixth chromosome controls expression of a complex series of cell surface antigens which comprise the human leukocyte antigen (HLA) system. These markers, beyond their importance in human organ transplantation, have been demonstrated to occur with an increased prevalence in certain disease states. The group of conditions showing the closest association with specific HLA antigens are the "spondyloarthropathies." These include ankylosing spondylitis (AS), Reiter's syndrome (RS), psoriatic arthritis (PsA), and the arthritis of inflammatory bowel disease (AIBD). Clinical and radiographic studies were made of 310 unrelated caucasoid patients with seronegative arthritis. HLA-A, B, C, and DR typing were performed using the microdroplet lymphocyte cytotoxicity test. Statistically increased prevalences of A26, B27, and Bw38 were observed, while B27 was associated with spinal involvement regardless of diagnosis (90 percent in AS p less than 0.0001). Experiments found A26 (23 percent p less than 0.001) and Bw38 (38 percent p less than 0.0001) in patients with PsA. Spondyloarthritis patients with spinal involvement who lacked B27 frequently had B7. The HLA DR typing for seven specificities was carried out in 196 patients. It was found that DRw4 (52 percent p less than 0.03) and DRw7 (39 percent p less than 0.04) were increased in the PsA patients. This study further confirms the close association of HLA antigens and the spondylarthropathies.

Arthritis↗
PubMedDate not supplied

Reactive arthritis associated with brucellosis: HLA studies.

HLA typing studies were performed on a group of 16 patients with acute Brucella-induced reactive arthritis and results were compared to those obtained in 16 patients with acute brucellosis but without arthritis and to 55 normal control subjects. No increased prevalence of any HLA antigen was noted between patients and control groups. HLA-B27 frequency was diminished in the Peruvian population studied. The most interesting finding was the presence of a statistically significant low frequency of HLA-A2 in the disease group suggesting that this antigen may play a protective role for the development of brucellosis.

Adolescent↗