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Biomedical subjects

C M Brickman

Publications and source records attributed to C M Brickman.

9 recordsLinked to original sources
PubMed1992

Non-specific binding of normal human IgG, including F(ab')2 and Fc fragments, to embryonic rat brain neurons and human cortex synaptosomes.

Binding of normal human IgG to embryonic rat brain neurons was quantitated by flow cytometry. IgG binding was linear between 0.05 and 1.5 mg/ml; slight binding was detectable even at normal cerebrospinal fluid concentrations. Similar binding curves were obtained for purified Fc and F(ab')2 fragments from normal human IgG. Normal human IgG also bound to synaptosomes (resealed nerve terminals) from human cerebral cortex. However, competition assays utilizing 125I-IgG showed no evidence for specific binding. This study indicates that the specificity of putative anti-neuronal antibodies should be confirmed by competition assays as for other receptor-ligand binding.

Animals↗
PubMed1990

A new, simplified method for oxidation of human complement component C2.

Oxy C2 is a valuable immunologic reagent, particularly for investigators whose research or clinical assays require a stable classical pathway C3 and/or C5 convertase or a highly active plasma complement source. To date only one method for the conversion of serum C2 or purified C2 to their respective oxy C2 forms has been published. However, this method has several disadvantages. For example, handling and dissolving the iodine crystals required in this process are difficult and time consuming. Also, the enhancement procedure results in a significant dilution of the original C2 sample. We have, therefore, developed a new, simplified method for oxidation of plasma, serum, or pure C2 which circumvents the difficulties associated with the earlier method. Moreover, this method offers additional flexibility with regard to oxidative conditions (i.e., buffer pH, temperature, and C2 concentrations) and reagent handling and final C2 product stability.

Complement C2↗
PubMed1989

Abdominal pain in hereditary angioedema: the role of acid hypersecretion.

Hereditary angioedema is a familial disorder characterized by recurrent episodes of soft tissue swelling and abdominal pain. Whereas most patients are successfully treated with androgenic steroids, some have abdominal pain unresponsive to therapy. To determine whether acid-peptic disease could account for the abdominal pain unresponsive to androgen therapy, we performed upper gastrointestinal endoscopy and determined basal acid output in 21 consecutive patients with hereditary angioedema and abdominal pain. Mean basal acid output of this group was 6.0 +/- 5.9 mEq/h, with five patients having gastric acid hypersecretion (defined as a basal acid output of greater than 10.0 mEq/h). The abdominal pain in 18 responded to stanozolol, whereas the pain in three patients did not change. Acid-peptic mucosal disease (esophagitis or duodenal ulcer) was present in these three patients with abdominal pain unresponsive to androgen therapy, all of whom had gastric acid hypersecretion (basal acid outputs of 13.7, 19.1, and 21.5 mEq/h, respectively). These three patients were treated with ranitidine but required increased doses to control their gastric acid hypersecretion, and to promote complete relief of abdominal pain and healing of their esophagitis or ulcer disease. These results indicate that there is a subset of patients with hereditary angioedema whose abdominal pain may be secondary to acid-peptic disease and gastric acid hypersecretion. Such individuals may require increased therapeutic doses of antisecretory medication to promote complete healing of esophagitis or ulcer disease. Basal acid output and upper gastrointestinal endoscopy are important determinants when evaluating abdominal pain in patients with hereditary angioedema that fails to respond to standard therapy.

Abdomen↗
PubMed1988

Urine-histamine levels in patients with hereditary angioedema (HAE).

Hereditary angioedema (HAE) is defined clinically by recurrent, self-limited episodes of angioedema. The disease is defined biochemically by a deficiency in the functional activity of C1 esterase inhibitor. To date, the actual serum or tissue mediator(s) responsible for the angioedematous lesion remains controversial. Although antihistaminics have been clearly demonstrated to have no efficacy in the long-term treatment of this disorder, instances of elevated urine-histamine levels in patients with HAE raises the possibility of a role for histamine in the pathophysiology of this disease. Urine samples were collected from 28 asymptomatic and from 11 symptomatic patients with HAE. The urine-histamine levels were compared with levels of 41 normal control subjects. With the exception of one asymptomatic patient with HAE whose diagnoses also included rheumatoid arthritis and secondary Sjögren's syndrome, the urine-histamine levels from asymptomatic patients with HAE were similar to values obtained from normal control subjects. Except for data from two patients with HAE, urine-histamine levels from symptomatic patients with HAE were also indistinguishable from levels of normal volunteers. These data suggest that the vast majority of patients with HAE have normal urine-histamine levels both during and between attacks. Consequently, histamine is unlikely to play a pathophysiologic role in HAE.

Angioedema↗
PubMed1986

Immunoregulatory disorders associated with hereditary angioedema. I. Clinical manifestations of autoimmune disease.

Occasional reports have appeared linking hereditary angioedema (HAE) with autoimmune diseases. We have systematically evaluated 157 patients for manifestations of autoimmunity. Nineteen of these patients (12%) had clinical immunoregulatory diseases including glomerulonephritis (five patients), Sjögren's syndrome (three), inflammatory bowel disease (three), thyroiditis (two), systemic lupus erythematosus (one), drug-induced lupus (one), rheumatoid arthritis (one), juvenile rheumatoid arthritis with IgA deficiency (one), incipient pernicious anemia (one), and sicca syndrome (one). All eight patients with HAE who developed an autoimmune disease with a known human histocompatibility antigen association developed a disease associated with their histocompatibility antigen haplotype (p = 0.014). Although only four patients developed Sjögren's syndrome or sicca syndrome, an additional nine manifested part of the sicca complex. We also found patients with HAE with features suggestive of an immune-based abnormality. These features included idiopathic pancreatitis (three patients), Raynaud's disease (two), partial lipodystrophy (one), chronic chorioretinitis (one), and alopecia universalis (one).

Adolescent↗
PubMed1986

Immunoregulatory disorders associated with hereditary angioedema. II. Serologic and cellular abnormalities.

Hereditary angioedema is defined biochemically by a deficiency in the functional activity of the inhibitor of Cl, Cl esterase inhibitor (Cl INH). Deficiency of this regulator of the early classic pathway of complement results in chronic activation of this cascade with a resultant deficiency of C4 and C2. Ninety-seven patients with either complicated (associated with autoimmune disorders) or uncomplicated hereditary angioedema were evaluated for laboratory evidence of immunoregulatory defects. Specific cellular and humoral abnormalities were found and included increased mean total lymphocyte counts, increased mean Leu 4+ (total) and Leu 3+ (helper) T cells, an increased mean Leu 3/Leu 2 (helper/suppressor T cell) ratio, polyclonal B cell activation, and evidence of circulating immune complexes. C4 functional titers were negatively correlated with percent Leu 3+ cells and absolute Leu 3+ cell numbers. We failed to detect any evidence of immune deficiency in this population, and yet a statistically significant number of patients demonstrated elevated levels of antibodies to Epstein-Barr virus antigens when patients were compared to a control group. Thus, early classic complement pathway activation and/or partial complement component deficiency may effect T cell subpopulations and B cell activation. However, additional predisposing factors (e.g., genetic or viral) appear necessary for the development of a particular autoimmune disease in hypocomplementemic patients.

Adolescent↗
PubMed1985

Abnormal clearance of immune complexes from the circulation of patients with primary sclerosing cholangitis.

The ability of fixed macrophages of the reticuloendothelial system to clear circulating immune complexes was studied in 6 patients with primary sclerosing cholangitis, 5 patients with various other forms of chronic liver disease, and 12 normal control subjects. Autologous red cells were radiolabeled with 51Cr and sensitized with anti-Rh(D) immunoglobulin G in vitro. After intravenous infusion of the labeled antibody-coated red cells, the radioactivity content of timed blood specimens was measured. The time required by the reticuloendothelial system to clear one-half the labeled cells from the circulation (t1/2) was then determined. The t1/2 clearance times were significantly prolonged in all 6 patients with primary sclerosing cholangitis, whereas the clearance times in 4 of the 5 liver disease control patients were either normal or shortened. Serum immunoglobulin G and immunoglobulin M immune complex levels did not correlate with t1/2 clearance times. These results suggest that in primary sclerosing cholangitis there is a defect in the ability of fixed macrophages of the reticuloendothelial system to mediate clearance of circulating particles that have been opsonized with immunoglobulin G. This finding further supports recent data that incriminates the immune system in the pathogenesis of primary sclerosing cholangitis.

Adult↗