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Biomedical subjects

G J Dennis

Publications and source records attributed to G J Dennis.

At least 19 recordsLinked to original sources

Rapid clinical progression to diagnosis among African-American men with systemic lupus erythematosus.

The initial clinical course of systemic lupus erythematosus (SLE) is variable, ranging from relatively minor manifestations progressing over years to rapid onset of fulminate disease. We sought to identify factors associated with the rapid manifestation of SLE. Chart review of military medical records was used to identify 130 patients who met the American College of Rheumatology classification criteria for SLE. Demographics, clinical criteria date of occurrence, and the date of SLE classification (at least four clinical criteria) met were documented. Prospectively stored serum samples prior to the diagnosis were evaluated for SLE autoantibodies. Median time from the first recorded criteria to diagnosis was significantly shorter in African-American (AA) males compared with AA females and European American (EA) females and males combined. AA males were more likely to have nephritis as their first clinical symptom. Also, less time transpired between the first clinical criterion and SLE diagnosis in AA males with nephritis than in other groups presenting with nephritis. Even when cases presenting with nephritis were excluded, a diagnosis of SLE was made more rapidly in AA males. African-American men progress from initial clinical manifestations to SLE diagnosis more rapidly than other ethnic or gender groups.

Black People↗

Spinal loads during individual and team lifting.

The aim of this experiment was to compare lumbar spinal loads during individual and team lifting tasks. Ten healthy male subjects performed individual lifts with a box mass of 15, 20 and 25 kg and two-person team lifts with a box mass of 30, 40 and 50 kg from the floor to standing knuckle height. Boxes instrumented with force transducers were used to measure vertical and horizontal hand forces, whilst sagittal plane segmental kinematics were determined using a video based motion measurement system. Dynamic L4/L5 torques were calculated and used in a single equivalent extensor force model of the lumbar spine to estimate L4/L5 compression and shear forces. A significant reduction in L4/L5 torque and compression force of approximately 20% was found during team lifts compared to individual lifts. Two main reasons for the reduced spinal loads in team lifting compared to individual lifting were identified: (1) the horizontal hand force (i.e. pulling force) was greater in team lifting, and (2) the horizontal position of the hands was closer to the lumbar spine during team lifts. The horizontal hand force and position of the hands had approximately equal contributions in reducing the spinal load during team lifting compared to individual lifting.

Adult↗

Juvenile dermatomyositis presenting with anasarca: A possible indicator of severe disease activity.

Juvenile dermatomyositis is a rare autoimmune disease characterized by inflammation of the muscle, skin, and other organs. Although localized edema is a common feature of juvenile dermatomyositis, generalized edema has been reported infrequently. We describe a patient with juvenile dermatomyositis presenting with anasarca and note that generalized edema has been associated with severe disease activity.

Child↗

Prevalence of pulmonary disorders in patients with newly diagnosed rheumatoid arthritis.

Our objective was to determine the prevalence of airway hyperreactivity (AHR) in patients with newly diagnosed rheumatoid arthritis (RA) who had received no disease-modifying antirheumatic drugs (DMARDs) and to characterise the spectrum of lung diseases identifiable in these patients at the time of presentation. Eighteen consecutive patients with newly diagnosed RA referred to our medical centre's rheumatology clinic over 2 years underwent pulmonary evaluation with arterial blood gas analysis, chest radiographs, spirometry before and after bronchodilator medication, and body plethysmography. They returned on subsequent days in random order for methacholine inhalation challenge (MIC) and eucapnic voluntary hyperventilation (EVH) as bronchoprovocation techniques. One patient had severe obstructive disease at presentation and therefore did not undergo bronchoprovocation. We found a wide variety of pulmonary abnormalities, including two patients with hypoxia (12%), two with obstruction (12%), three with restriction (18%) and four with AHR (23%). The data also suggest a strong association between pulmonary diseases in RA and cigarette smoking. Although no single characteristic lung disease such as AHR was identified in patients presenting with RA, the association between lung disease and cigarette smoking is striking and underscores the need to emphasise smoking cessation in this patient population.

Adult↗

Multivalent cross-linking of membrane Ig sensitizes murine B cells to a broader spectrum of CpG-containing oligodeoxynucleotide motifs, including their methylated counterparts, for stimulation of proliferation and Ig secretion.

We have previously reported that B cells that are activated by multivalent but not bivalent membrane Ig cross-linking ligands synergize with various B cell activators culminating in enhanced B cell proliferation. In this study we asked whether B cells that are activated by a multivalent mIg cross-linking agonist could respond to oligodeoxynucleotides (ODN) containing non-stimulatory motifs. Earlier reports have shown that ODN containing a CpG motif in which the cytosine is unmethylated and is flanked by two 5' purines and two 3' pyrimidines induce high levels of B cell activation, while ODN whose CpG are methylated or flanked by sequences other than the optimal two 5' purines and two 3' pyrimidines were non-stimulatory. In this manuscript we show that when B cells are stimulated in vitro with dextran-conjugated anti-IgD antibodies (anti-IgD-dex), as the multivalent mIg ligand, their proliferation is enhanced and they can be induced to secrete Ig in response to ODN containing various non-optimal motifs, both methylated and non-methylated. Furthermore we could induce synergistic levels of proliferation with concentrations of anti-IgD-dex that were in the picomolar concentration range and with concentrations of ODN that were 10- to 100-fold less than previously reported to be necessary for mitogenic activity. These data provided a model to explain how low concentrations of a multi-epitope-expressing microorganism in the context of mammalian (methylated) or microorganism (non-methylated) DNA can lead to dysregulated B cell proliferation and Ig secretion.

Animals↗

The use of Western blotting as the confirmatory test for syphilis in patients with rheumatic disease.

OBJECTIVE: As a direct or indirect result of antiphospholipid antibody production, subjective laboratory interpretation, and false positive results, the common serologic tests for syphilis have been inherently inaccurate diagnostic tests in patients with systemic lupus erythematosus (SLE) and other autoimmune diseases. We assessed the diagnostic accuracy of syphilis testing in patients with SLE and other autoimmune diseases using the treponemal Western blot (TWB) as the gold standard. METHODS: A prospective cohort study carried out at a tertiary care medical center. We studied 107 patients with autoimmune disease, 50 with at least one positive serologic test for syphilis and 57 disease matched controls. Prior to enrollment all eligible patients underwent a clinical assessment performed by at least 2 rheumatologists to confirm a diagnosis of rheumatic disease. All subjects underwent serologic testing, in blinded fashion, for syphilis using the rapid plasma reagin test (RPR), Venereal Disease Research Laboratory test (VDRL), fluorescent treponemal antibody absorption test (FTA-ABS), and the TWB. RESULTS: Eighty-seven percent of the patients studied were female, the mean age was 46.5 years, and the most common diagnosis at the time of enrollment was SLE. Using the TWB as the gold standard diagnostic test for syphilis, the sensitivity, specificity, and positive predictive values for each syphilis test were calculated. The sensitivity and specificity for the RPR in patients with rheumatic disease was 62.5% (95% confidence interval 24.5 to 91.5%) and 91.9% (95% CI 84.2 to 96.2%), respectively. The sensitivity and specificity for the VDRL were 37.5% (95% CI 8.5 to 75.5%) and 89.9% (95% CI 81.8 to 94.8%), respectively. Confirmatory syphilis testing using the FTA-ABS showed a sensitivity of 100% (95% CI 68.6 to 100%) and a specificity of 67.7% (95% CI 57.4 to 76.5%). Eight patients tested positive for syphilis by Western blotting. For the FTA-ABS test, there was a significantly higher number of false positive results (n = 32) compared to false negative results (n = 0), p < 0.0005. CONCLUSION: The FTA-ABS is not an accurate confirmatory test for syphilis in patients with SLE and other autoimmune diseases. While a negative FTA-ABS may exclude syphilis infection in the majority of cases, a positive FTA-ABS test result cannot assuredly confirm syphilis infection in this population. Western blotting is an accurate confirmatory test for syphilis and may be necessary to unequivocally discern the immunological response of syphilis from that of an underlying autoimmune disease.

Blotting, Western↗

The value of screening for psychiatric disorders in rheumatology referrals.

BACKGROUND: Musculoskeletal complaints are common and often unexplained and often lead to rheumatology referrals. The prevalence of psychiatric disease in patients with musculoskeletal complaints is unknown. OBJECTIVES: To determine the prevalence of common psychiatric disorders among patients referred to a rheumatology clinic and the likelihood of establishing a rheumatic diagnosis if a psychiatric disorder is present. DESIGN: Prospective diagnostic survey. SETTING: Two hospital-based rheumatology clinics and a general medicine clinic. PARTICIPANTS: A consecutive sample of newly referred patients (n = 185) and their rheumatologists (n = 9). INTERVENTION: Before their visit, all patients filled out a self-administered version of PRIME-MD (Primary Care Evaluation of Mental Disorders), a questionnaire that makes Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition: Primary Care Version, diagnoses of depressive, anxiety, and somatoform disorders. After the visit, the study rheumatologists, who were unaware of the PRIME-MD results, completed a questionnaire regarding their diagnostic assessment. These patients were compared with 210 patients with musculoskeletal complaints who were cared for in a general medicine clinic. MAIN OUTCOME MEASURES: Psychiatric and rheumatic disorders. RESULTS: Compared with patients with musculoskeletal complaints in a general medicine clinic, patients referred to a rheumatology clinic had a higher prevalence of psychiatric disease (40% vs 29%; P = .008), had an almost 2-fold higher prevalence of anxiety disorders, and were more likely to have multiple psychiatric disorders (odds ratio = 2.70, 95% confidence interval = 1.50-5.00). The likelihood of a psychiatric disorder differed among patients with connective tissue disease, nonsystemic articular or periarticular disorders, and nonarticular disorders (27%, 38%, 55%, respectively; P = .006). In a best-fitting logistic regression model, psychiatric disorders markedly decreased the likelihood of a connective tissue disease (odds ratio = 0.24, 95% confidence interval = 0.09-0.62). CONCLUSIONS: Forty percent of patients referred to a rheumatology clinic in this study had a psychiatric disorder, and its presence predicted a lower likelihood of a connective tissue disease. Prospective studies are needed to determine if screening for psychiatric disease before referring patients with unexplained musculoskeletal complaints would reduce costs or improve recognition of potentially treatable psychiatric disorders.

Adolescent↗

Altered pattern of TCR/CD3-mediated protein-tyrosyl phosphorylation in T cells from patients with systemic lupus erythematosus. Deficient expression of the T cell receptor zeta chain.

Cellular immunity aberrations in patients with SLE are underscored by the abnormal early Ag receptor-mediated lymphocyte signal transduction pathway. To further characterize the T cell receptor (TCR)/CD3-initiated signaling defects, we studied 22 patients with SLE, 12 patients with other systemic rheumatic diseases, and 14 normal donors. The early (1 min) TCR/CD3-mediated tyrosine phosphorylation of cellular proteins with a molecular size between 36 and 64 kD was increased in 15 of 21 SLE patients, compared to normal or disease control subjects. The deficiency or absence of a band with a molecular size of approximately 16 kD in the immunoblots of SLE patients led us to investigate the expression of the TCRzeta chain. In immunoblots using anti-zeta antibodies we found that 10 of 22 lupus patients tested lacked the expression of TCRzeta, which was always present in control subjects (P < 0.001). Flow cytometric studies using permeabilized cells confirmed the deficiency or absence of the TCRzeta chain in lupus T cells. Using Northern blots we found that for eight patients tested, the TCRzeta mRNA was missing in three, decreased in three, and apparently normal in two patients (P < 0.003), but was always present in control subjects. Reverse transcriptase-PCR verified Northern blot results. We conclude that TCRzeta chain expression is either decreased or absent in the majority of patients with SLE, but not in patients with other systemic rheumatic diseases, regardless of disease activity, treatment status, or clinical manifestations. The previously described increases in TCR-initiated Ca2+ responses and the herein described increases in TCR-induced protein tyrosine phosphorylation and deficient TCRzeta expression may represent intrinsic defects modulating lupus T cell function.

Adult↗

Dermatomyositis and malignant melanoma.

Patients with dermatomyositis may face an increased risk of malignancy. Malignant melanoma has been linked to dermatomyositis. We present a case of concomitant dermatoyositis and metastatic malignant melanoma and review the English literature concerning this topic. Analysis revealed that the development of dermatomyositis in patients with malignant melanoma heralds the diagnosis of metastatic disease. These patients face dismal prognoses.

Adult↗

Increased expression of functional Fas-ligand in activated T cells from patients with systemic lupus erythematosus.

The Fas ligand induces apoptosis upon binding to Fas/APO-1 (CD95) bearing target cells. Activation induced cell death (AICD) in T cells is mediated by upregulation of Fas ligand on the cell surface membrane upon crosslinking of the TCR. AICD is considered to be essential for the elimination of autoreactive T cells in the peripheral blood. To elucidate possible abnormalities in the process of AICD in human SLE, we studied the expression and function of Fas ligand in polyclonal T cell lines from patients with SLE, patients with other rheumatic diseases and normal controls. SLE T cells expressed on their surface significantly higher amounts of Fas ligand compared to the two control groups. Stimulation of the cells with anti-CD3 mAb lead to further increase in surface membrane Fas ligand expression in all three groups with SLE expressing the highest amounts. The percentage of increase was though lower in SLE T cells than in normal T cells or disease control cells. The T cells were examined for Fas ligand-mediated cytotoxicity in a 51Cr release assay using Fas-expressing normal T cells as target cells. There was no difference in SLE and control T cells with regard to specific 51Cr lysis, indicating that the Fas ligand expressed by the SLE T cells is functional. Our data show that activated T cells from patients with SLE express high amounts of functional Fas ligand with intact TCR-mediated upregulation. This could account for the high apoptotic rates that have been observed in lymphocytes from patients with SLE.

Adult↗

Focal myositis.

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Adult↗

Pyogenic arthritis complicating varicella infection.

Arthritis has not previously been reported as a complication in adult patients with chickenpox. In pediatric patients, the arthritis that complicates chickenpox is most commonly aseptic but does rarely result from bacterial infection. We report the case of a 21-year-old man who developed acute monoarticular septic arthritis due to Lancefield Group A beta-hemolytic streptococci. Despite the more common viral cause of arthritis in pediatric patients, physicians should not attribute arthritis associated with varicella in adults to a viral cause without diagnostic arthrocentesis.

Adult↗

Corticosteroid induction of Ig+Ia- B cells in vitro is mediated via interaction with the glucocorticoid cytoplasmic receptor.

Flow microfluorometry was used to examine the effect of dexamethasone on the expression of surface Ia (sIa) on resting and activated murine B cells. Although dexamethasone resulted in a 50% reduction in sIa expression 12 h after injection, it was significantly less suppressive when injected together with B cell activators. In vitro dexamethasone, but not other related steroid hormones, induced a population of cells that were sIg+sIa-. A 20% reduction in the expression of sIa was noted by 4 h of culture with 10 nM dexamethasone, but maximal inhibition of 70% was not reached until 12 h of culture, and this degree of suppression persisted as long as dexamethasone remained in culture. When the dexamethasone was washed out after 8 h of culture, the maximal reduction was still noted at 12 h, but by 24 h there was re-expression of sIa toward base line levels, indicating it did not induce irreversible lethal alterations in the B cell. The inhibition of sIa expression correlated with a specific reduction in the quantity of messenger RNA for sIa as measured by Northern blot analysis, indicating that this is mediated at least in part by suppression of the steady state levels of Ia mRNA. The corticosteroid receptor antagonist RU486 was able to reverse the suppressive effects of dexamethasone on sIa expression, thus demonstrating that its effect is mediated specifically by binding to its intracellular receptor. Furthermore, when protein synthesis was inhibited during the short period of time that cells were preincubated with dexamethasone, minimal suppression of Ia expression was noted, suggesting that the dexamethasone may be stimulating a protein that has suppressive effects on MHC class II expression. The suppressive effects of dexamethasone in vitro were substantially reduced when B cells were simultaneously activated by stimuli that increase the expression of sIa. These data indicate that the suppressive effects of corticosteroids on immune response Ag are corticosteroid specific; are greater in resting than in activated B cells; are induced via the classical steroid mechanism of action, which is receptor mediated; and may result from the induction of an inhibitory protein that suppresses Ia mRNA.

Animals↗

Comparison of the calcium requirement for the induction and maintenance of B cell class II molecule expression and for B cell proliferation stimulated by mitogens and purified growth factors.

As an important intracellular second-messenger, the concentration of calcium in the cytosol [Ca+2]i influences diverse cellular activities. To investigate the calcium requirement for distinct phases of B cell activation, we studied the effect of altering the quantity of extracellular calcium on the induction of increased B cell MHC class II molecule (Ia) expression and DNA synthesis by different B cell mitogens. During short-term cultures (less than 24 hr), the induction of class II molecules by anti-immunoglobulin (anti-Ig) and calcium ionophore were dependent on the presence of extracellular calcium, whereas activation induced by B cell stimulation factor-1 (BSF-1) was minimally dependent on extracellular calcium, and that induced by LPS was independent of it. During longer-term cultures (i.e., greater than 24 hr), the heightened class II molecule expression that was induced by all of the B cell mitogens used was significantly compromised by depletion of extracellular free calcium. Although the anti-Ig-stimulated increase in expression of Ia could be restored by the addition of calcium to the medium at 12 hr, it could not be restored when the addition of calcium was delayed to 24 hr after the onset of culture. This was in marked contrast to the finding that BSF-1-stimulated B cell responses which were suppressed after 24 hr of culture in the presence of EGTA could be restored by the addition of calcium. Activation of B cells along the pathway leading to DNA synthesis demonstrated a requirement for extracellular calcium which was greater than that required for induction of MHC class II molecule expression. Thus, LPS-stimulated size increases of B cells after 12 hr of culture was dependent on extracellular calcium while its induction of MHC class II molecule expression was independent of extracellular calcium at this early time point. These observations indicate that the extracellular calcium requirement for B cell activation is dependent both on the activation pathway utilized by the mitogenic signal and on the duration of cell activation. Furthermore, they demonstrate that B cell stimuli that can initiate B cell activation in the relative absence of extracellular calcium may require extracellular calcium for maintenance of this activational state.

Animals↗