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Biomedical subjects

P Hasselbacher

Publications and source records attributed to P Hasselbacher.

At least 19 recordsLinked to original sources
PubMed1988

Serum amylase and macroamylase in patients with systemic lupus erythematosus.

We measured serum amylase and macroamylase activity in 25 patients with systemic lupus erythematosus (SLE) and 15 controls. The mean (+/- SD) for SLE was greater than for the controls (161 +/- 71.8 versus 116 +/- 38.8 units/dl). Five patients (20%) had elevated amylase and 6 (25%) had a macroamylase present. None of the controls had amylase elevation or macroamylase. None of the patients had abdominal pain and there was no observable correlation of amylase activity with disease activity, drugs, or renal function. Elevation of serum amylase in SLE without pancreatitis is frequent, as is the presence of macroamylase. Autoantibodies to this serum enzyme may be frequent in SLE.

Amylases↗
PubMed1987

Variation in synovial fluid analysis by hospital laboratories.

A survey of 42 hospitals revealed that the frequency of synovial fluid analysis was low (mean 3.9 per month). The mean was skewed upward by a higher frequency in 3 teaching hospitals, such that the overall median was 1.5 per month, with 15 hospitals studying 1 or less per month. There did not appear to be any consensus regarding what constitutes a routine synovial fluid analysis. Technical errors occurred, including dilution with acetic acid for cell counts and inappropriate use of automated cell counters. Twenty-six laboratories studied 4 "unknown" fluids for crystals. In 50 opportunities to detect each crystal type, calcium pyrophosphate was detected only 6 times, and sodium urate was detected 39 times. The white blood cell count reported for a single fluid ranged from 2,467-12,000/mm3 (mean +/- SD 6,683 +/- 1,992). The proportion of neutrophils identified varied from 0-30% (mean +/- SD 13.8 +/- 8.6). The majority of respondents believed that training and reference materials related to synovial fluid analysis should be improved.

Diagnostic Tests, Routine↗
PubMed1982

Stimulation of synovial fibroblasts by calcium oxalate and monosodium urate monohydrate. A mechanism of connective tissue degradation in oxalosis and gout.

The responses of cultured rabbit synovial fibroblasts to amorphous and microcrystalline calcium oxalate were compared with responses to MSUM. Like urate crystals, crystalline calcium oxalate (but not amorphous oxalate) caused marked stimulation of secretion of latent collagenase and PGE2 after 3 days of culture without significant change in cell protein or gross cellular morphology. Collagenase rose from undetectable levels in control cultures to 32.4 +/- 6.0 and 27.4 +/- 7.9 U/mg of cell protein for crystalline calcium oxalate and MSUM, respectively. PGE2 rose from a control level of 0.24 +/- 0.14 to 19.47 +/- 5.15 and 23 +/- 4.84 micrograms/mg of cell protein for crystalline calcium oxalate and sodium urate compared to 1.22 +/- 0.48 microgram for amorphous calcium oxalate. Although the crystalline species studied caused LDH in the media to increase threefold, this was minimal. Cell stimulation by amorphous oxalate and the crystals did not correlate with membranolytic potential as measured with an erythrocyte lysis assay. Stimulation of resident synovial cells by crystalline calcium oxalate and sodium urate may contribute to the chronic inflammation and destruction of joint tissues that occurs in oxalosis and gout.

Animals↗
PubMed1980

Activation of the alternative pathway of complement by microcrystalline cholesterol.

Microcrystalline cholesterol in either the anhydrous or monohydrate form was a potent activator of the alternative pathway of complement as measured by the electrophoretic conversion (crossed immunoelectrophoresis) of C3 and properdin factor B. Chelation with 0.01 M ethylene-diaminetetraacetate (EDTA) completely eliminated conversion, but 0.01 M ethyleneglycol tetraacetate (EGTA) had little or no effect. The magnitude of activation by cholesterol crystals was similar to that by zymosan, heat-aggregated IgG, or crystals of monosodium urate monohydrate. The microcrystalline forms of the acetate, linoleate, or oleate esters of cholesterol did not activate more complement than did saline controls. Cholestanol retained full C3 activating potency, but cholestane had none. Binding of IgG by cholesterol monohydrate is very small compared to that by sodium urate.

Adsorption↗
PubMed1980

In vitro effects of radiographic contrast media on the complement system.

The effect of several radiographic contrast media on the complement system in vitro was examined using quantitative crossed immunoelectrophoresis. Diatrizoate, iothalamate, metrizoate, and methiodal did not cause electrophoretic conversion of C3 or properdin factor B. In fact, the small degree of spontaneous conversion occurring when serum is incubated in polypropylene tubes was inhibited by these contrast media or by hypertonic sodium chloride. Metrizamide caused enhanced conversion of C3 and factor B that was only partially inhibited by ethylene glycol tetracetic acid (EGTA) but completely inhibited by ethylenediaminetetraacetic acid (EDTA). Iodipamide caused a unique electrophoretic alteration of C3 that was not affected by EDTA or several other inhibitors and that was not identical with the usual products of C3 activation. Iodipamide in very low concentrations inhibited complement activation through the classical pathway.

Citrates↗
PubMed1979

Immunoelectrophoretic assay for synovial fluid C3 with correction for synovial fluid globulin.

Synovial fluid C3 was measured by electroimmunoassay. When C3 was expressed as mg/ml, the amounts found in Reiter's disease, psoriatic arthritis, gout, and systemic lupus erythematosus were significantly different from degenerative arthritis. When C3 was corrected for total protein, the levels for rheumatoid arthritis, Reiter's disease, psoriatic arthritis, and systemic lupus were significantly different from degenerative arthritis. When C3 was corrected for synovial fluid globulin, only rheumatoid arthritis and systemic lupus were significantly different from degenerative arthritis. Correction of C3 for globulin increases the difference between rheumatoid arthritis and degenerative arthritis. A proportion of gouty fluids with a relative decrease in C3 is demonstrated. It is argued that correction of C3 for globulin is more meaningful than correction for total protein. While many nonrheumatoid inflammatory effusions demonstrate split products of C3, the majority of fluids from patients with systemic lupus have none.

Arthritis↗
PubMed1979

C3 activation by monosodium urate monohydrate and other crystalline material.

Monosodium urate monohydrate (MSUM) is a potent activator of the complement system as measured by electrophoretic conversion of beta1C to beta1A. Activation of C3 in human serum by MSUM is both time- and dose-dependent. The sensitivity of the assay allows detection of C3 activation by as little as 0.2 mg/ml of MSUM. It was observed that C3 activation is calcium dependent and elimination by both EDTA and EGTA, a finding that demonstrated the major role of the classic pathway of complement activation. Excess calcium or magnesium alone inhibited C3 activation by MSUM in accord with the inhibitory effect of these cations on sensitized sheep cell hemolysis by complement. Heating of MSUM at 200 degrees C for 2 hours removes the water of crystallization such that heated crystals may no longer be considered MSUM. Such treatment has a variable effect on C3 activation. Of the crystals and other material studied, only zymosan was more potent than MSUM in activating C3. Calcium prophosphate dihydrate and hydroxyapatite activated significant amounts of C3. Asbestos, glass wool, or a variety of microcrystalline steroids activated little or no C3.

Calcium↗
PubMed1979

Binding of immunoglobulin and activation of complement by asbestos fibers.

Asbestos fibers adsorbed IgG from whole human serum in amounts comparable to that taken up by crystals of calcium pyrophosphate or hydroxyapatite, but less than that adsorbed by crystals of monosodium urate monohydrate. Chrysotile asbestos was much more active in binding IgG than was amphibole asbestos. The electrophoretic mobility of adsorbed IgG was a function of the surface charge of the crystal studied. Negatively charged fibers adsorbed cationic IgG, and positively charged fibers adsorbed anionic IgG. Complement activation by asbestos, as judged by electrophoretic conversion of C3, was similar for all fiber types tested. Properdin factor B was also activated in the presence of asbestos. Activation of both properdin factor B and C3 was only partially inhibited by ethylene glycol tetraacetic acid, demonstrating that activation was occurring through both the classical and alternative pathways.

Adsorption↗
PubMed1979

Binding of IgG and complement protein by monosodium urate monohydrate and other crystals.

IgG adsorbed to negatively charged crystals of monosodium urate monohydrate was restricted to cationic species of immunoglobulin. Similar binding of smaller amounts of IgG was observed with crystals other than monosodium urate monohydrate. Heated monosodium urate monohydrate and amorphous sodium urate adsorbed greater amounts of IgG and other proteins. Complement activation as measured by electrophoretic conversion of C3, was not related to the amount of IgG adsorbed by the crystals studied. C1q was also adsorbed to some degree by all crystals studied but did not correlate with complement activation.

Complement Activation↗
PubMed1978

Immunoglobulin in tophi and on the surface of monosodium urate crystals.

By means of immunohistologic techniques IgG, IgM, and to a lesser degree, IgA were found in the intercrystalline matrix of gouty tophi. Smaller amounts of IgG and IgM were inconstantly found in association with tissue deposits of calcium pyrophosphate. When a technique of immune agglutination was used, the affinity of all three major classes of immunoglobulin to the surface of monosodium urate (MSU) crystals was demonstrated. Immunoglobulin and fibrin were found on MSU aspirated from large tophi.

Agglutination↗