PubMed Health⌕ Search

Biomedical subjects

P H Plotz

Publications and source records attributed to P H Plotz.

At least 19 recordsLinked to original sources
PubMed1992

Controlled trial of plasma exchange and leukapheresis in polymyositis and dermatomyositis.

BACKGROUND: The therapeutic options for patients with polymyositis or dermatomyositis that is resistant to corticosteroids are limited, unproved, and often toxic. Uncontrolled trials concluded that both plasma exchange and leukapheresis are beneficial, but despite the considerable use of these approaches, proof of their efficacy is lacking. METHODS: Thirty-nine patients with definite polymyositis or dermatomyositis were randomly assigned to receive plasma exchange (replacement of one volume of plasma with 5 percent albumin in saline), leukapheresis (removal of 5 x 10(9) to 10 x 10(9) lymphocytes), or sham apheresis in a double-blind manner, with 12 treatments given over a one-month period. Muscle strength, functional capacity, and serum levels of muscle-associated enzymes were measured before and after the 12 procedures. RESULTS: In each group 3 of 13 patients had improvements in strength and functional capacity. The condition of 3 patients treated with leukapheresis and 1 treated with plasma exchange deteriorated, and it was unchanged in the other 26 patients. Adverse effects of apheresis included the need for a central venous catheter (9 patients), major vasovagal episodes (3 patients), and severe citrate reactions (2 patients). Despite the occurrence of significant reductions in the serum levels of muscle enzymes with plasma exchange (P less than 0.001) and significant decreases in lymphocyte counts with leukapheresis (P = 0.002), there were no significant differences among the three treatment groups in the final muscle strength or functional capacity of the patients. CONCLUSIONS: As treatments for corticosteroid-resistant polymyositis or dermatomyositis, leukapheresis and plasma exchange are no more effective than sham apheresis.

Activities of Daily Living↗
PubMed1992

Viruses in idiopathic inflammatory myopathies: absence of candidate viral genomes in muscle.

There is indirect evidence that various viruses have aetiological roles in the idiopathic inflammatory myopathies. By means of a sensitive and specific method based on the polymerase chain reaction (PCR), we sought direct evidence for the presence in affected muscle of nucleic acid sequences from Coxsackie virus, mumps virus, encephalomyocarditis virus, adenovirus, human T-lymphotropic virus types I and II, and human immunodeficiency virus. RNA was extracted from muscle biopsy samples obtained from 44 patients with idiopathic inflammatory myopathies a mean of 45 (range 0-216) months after disease onset. All the subjects were older than 16 years at disease onset. The integrity of the mRNA extracted was confirmed by the successful PCR amplification of insulin receptor mRNA in all samples. The PCR method was able to detect between 1 and 20 molecules of added viral nucleic acid for the picornaviruses sought. No detectable virus sequences were found, however, in any of the patients' muscle samples or in samples from 13 controls. We tested for retroviral DNA in 22 samples (17 patients, 5 controls) that met our criterion for adequate DNA extraction (detectable beta-actin DNA by PCR); again no virus sequences were found. Persistence in muscle of these or closely related viruses is unlikely to be a continuing stimulus for disease in the idiopathic inflammatory myopathies.

Adenoviruses, Human↗
PubMed1979

Complement fixation by model immune complexes free in solution and bound onto cell surfaces.

Immunoglobin (IgG) molecules with anti-2,4-dinitrophenyl activity were covalently cross-linked by using three cross-linking reagents. The resulting oligomers were separated into monomer, dimer, trimer, and heavy fractions. These stable assemblages of IgG molecules were capable of fixing dilute whole guinea pig complement in solution. When oligomers were further aggregated noncovalently into larger complexes, all were able to fix complement. Radioiodinated oligomers were attached to 2,4,6,-trinitrophenylsulfonic acid treated sheep red blood cells (N3ph-SRBC), and the number of bound molecules was determined from the cell-associated radioactivity. Complement-mediated lysis of N3ph-SRBC was then assayed over a range of levels of bound protein and at increasing concentrations of complement. The lytic efficiencies of all oligomers increased with the number of bound molecules, with complement concentration, with hapten density on N3ph-SRBC, and with oligomer size. The results suggest that two adjacent IgG molecules may not serve as a unit signal for triggering the complement cascade, but instead, initiation occurs with increasing efficiency as the size of cell-bound IgG clusters increases.

Animals↗
PubMed1979

Defective reticuloendothelial system Fc-receptor function in systemic lupus erythematosus.

To determine whether reticuloendothelial-system immunospecific Fc-receptor function is abnormal in patients with systemic lupus erythematosus, we studied the clearance of IgG-sensitized 51Cr-labeled erythrocytes by these splenic macrophage membrane receptors in 15 untreated patients. Fc-specific clearance rates were strikingly abnormal in 13 of 15 patients (half-times ranging from 80 to 2256 minutes, P less than 0.001 as compared to controls). Abnormal clearances correlated with immune-complex levels (as measured by the C1q-binding assay) and with disease activity. C1q-binding activity and anti-DNA titers also correlated with disease activity. The correlations of C3, C4, CH50 and factor B with abnormal clearance and disease activity were weaker or nonexistent. The significant correlations among clearance, disease activity and C1q-binding activity suggest that the defect in Fc-receptor function may lead to the prolonged circulation of immune complexes, thereby contributing to tissue deposition and damage.

Adult↗
PubMed1979

Bladder complications in patients receiving cyclophosphamide for systemic lupus erythematosus or rheumatoid arthritis.

The bladder complications of 54 patients treated with oral cyclophosphamide for systemic lupus erythematosus (43) or rheumatoid arthritis (11) were reviewed. During an observation period of 241 patient years, we saw seven cases of acute hemorrhagic cystitis and two cases of transitional cell carcinoma of the bladder. Bladder carcinoma was identified 28 and 60 months after withdrawal of the drug and resulted in the death of one patient. The late-occurring serious toxicities of cyclophosphamide should limit the use of the drug in the treatment of nonmalignant inflammatory rheumatic conditions.

Administration, Oral↗
PubMed1979

NIH conference. Systemic lupus erythematosus: evolving concepts.

Systemic lupus erythematosus, a disease of unknown cause and protean manifestations, continues to excite substantial investigational interest. These papers bring together recent advances in concepts of its immunopathogenesis, evidence for a major genetic role in the causation of the process, developing systems for the morphologic assessment of its often fatal nephritis, and data from ongoing trials of cytotoxic drugs in its management.

Adolescent↗
PubMed1979

Studies of reticuloendothelial function in the mouse with model immune complexes. II. Serum clearance, tissue uptake, and reticuloendothelial saturation in NZB/W mice.

We have extended the findings in the accompanying paper by characterizing the serum clearance and tissue uptake of model soluble immune complexes and the saturation of the reticuloendothelial system (RES) by these complexes in normal mice and in mice with murine lupus (NZB/W F1 females). Adult NZB/W or young C3H mice were injected with radiolabeled stable site-specifically cross-linked mouse anti-DNP oligomers as model immune complexes to probe RES function. Blood clearance and uptake by liver, spleen, and kidney were unimpaired in NZB/W mice. To determine if the RES exhibits partial saturation in the NZB/W mice, we deliberately induced a state of RES blockade with heat-aggregated human gamma-glubulin (HAG). With increasing doses of HAG (1 to 4 mg/20 g body weight) both strains similarly showed a progressive increase in RES saturation as measured by reduced liver uptake of model oligomers. Recovery from saturation was complete by 120 min in both strains. At maximal liver saturation there was only a small increase in oligomer uptake by kidney or spleen, the majority of complexes remaining within the circulation. Thus, RES capacity for handling soluble model immune complexes appears unimpaired in NZB/W mice.

Animals↗
PubMed1978

Reduction of renal function by newer nonsteroidal anti-inflammatory drugs.

Because aspirin and indomethacin, two structurally dissimilar anti-inflammatory agents which reduce prostaglandin synthesis, both alter renal function, we studied the effect on renal function of three new nonsteroidal anti-inflammatory drugs which also reduce prostaglandin synthesis. We have shown that ibuprofen, naproxen, and fenoprofen are able to reduce renal function in patients with systemic lupus erythematosus and that such changes are associated with reduced excretion of urinary prostaglandin E (PGE)-like compounds. The changes may attenuate despite continued drug administration. These findings emphasize that renal function must be assessed with caution in patients taking these and perhaps other drugs which inhibit prostaglandin synthesis.

Adult↗
PubMed1978

Elevated urinary prostaglandins and the effects of aspirin on renal function in lupus erythematosus.

We studied the urinary excretion of immunoreactive prostaglandin E-like material (iPGE) and renal function in seven women with systemic lupus erythematosus to evaluate the relation between urinary iPGE and the increase in serum creatinine in patients taking aspirin. The mean pretreatment excretion of urinary iPGE in patients with lupus erythematosus, 42.7 +/- 6.4 ng/h, was significantly higher than the value of 29.0 +/- 1.9 ng/h for normal subjects (P less than 0.02). With aspirin, the urinary iPGE decreased an average of 45% (P less than 0.001). Increases in serum creatinine and blood urea nitrogen confirmed our previous clinical observations. The concomitant mean fall in creatinine clearance of 18% (P less than 0.001) was accompanied by a 14% decrease in inulin clearance (P less than 0.005); p-aminohippurate clearance fell 29% (P less than 0.005). The decline in urinary iPGE preceded the fall in creatinine clearance but was significantly correlated with it (r = 0.78; P less than 0.001). The observed changes reversed rapidly when aspirin was stopped. These data show that, in these patients with high urinary iPGE excretion, aspirin causes significant changes in renal function that may be mediated by the inhibition of prostaglandin synthesis.

Adult↗
PubMed1977

Aspirin-induced depression of renal function.

We observed elevation of serum creatinine and blood urea nitrogen and decrease in creatine clearance in patients taking anti-inflammatory doses of aspirin. In 13 of 23 patients with systemic lupus erythematosus increases in serum creatinine ranged from 27 to 163 per cent, and those in urea nitrogen from 42 to 270 per cent. Sequential creatinine-clearance studies, available in 11 of the 13 patients, demonstrated decreases up to 58 per cent. Patients with aspirin-induced changes in renal function were more likely to have active renal disease (P =0.035) or hypocomplementemia (P =0.030). Four of 22 patients with rheumatoid arthritis and two of three normal volunteers also demonstrated biochemical changes. The rate of aspirin-induced alterations was significantly higher in systemic lupus erythematosus (P =0.007) than in rheumatoid arthritis. Aspirin, and other nonsteroidal anti-inflammatory agents, can have a major reversible effect on renal function that may influence the interpretation of clinical data.

Adult↗