Kiron M. Das

Clinical Pharmacokinetics of Sulphasalazine

SummarySulphasalazine consists of 5-aminosalicylic acid and sulphapyridine both linked together by an azo bond. Sulphasalazine is clearly useful in long-term management of ulcerative colitis and may be useful in Crohn’s disease. The absorption, metabolism and excretion of sulphasalazine is similar in volunteers and patients with ulcerative colitis or Crohn’s disease. Sulphasalazine serves as a vehicle to deliver its possible active components, 5-aminosalicylic acid and sulphapyridine, to the colon in higher concentrations than could be achieved by oral administration of either one alone. Sulphasalazine reaches the colon mostly unchanged and is split by gut bacteria at the azo linkage, releasing 5-aminosalicylic acid and sulphapyridine.5-Aminosalicylic acid may act locally and is not absorbed to any great extent. On the contrary, sulphapyridine is mostly absorbed from the colon and may act both locally, during mucosal absorption, and systemically. A positive correlation exists between serum total sulphapyridine concentration and both therapeutic efficacy and toxicity. Sulphapyridine metabolism is largely determined by inherited acetylator phenotype, either slow or fast. Slow acetylators have higher levels of free sulphapyridine and lower levels of acetylated sulphapyridine than fast acetylators, and are likely to have more toxic symptoms on equivalent doses of sulphasalazine. Therapeutic effects of sulphasalazine in ulcerative colitis and Crohn’s disease correlate with serum concentrations of total sulphapyridine (20 to 50μg/ml), and toxicity with total sulphapyridine concentrations > 50μg/ml. Side-effects are mostly observed among slow acetylators. In long-term therapy of ulcerative colitis doses of 2 to 3g/day of sulphasalazine are most likely to sustain remissions and avoid toxicity. During therapy with sulphasalazine, determination of acetylator phenotype and total sulphapyridine concentration can guide effective dosage and avoid side-effects. A single serum sample for free and acetylated sulphapyridine concentrations is sufficient for this purpose.

Acetylation polymorphism of sulfapyridine in patients with ulcerative colitis and Crohn's disease

Sulfapyridine (SP) is one of the main metabolites of salicylazosulfapyridine (sulfasalazine) that is used extensively in the management of inflammatory bowel disease. One hundred and twenty‐two patients with ulcerative colitis or Crohns disease were studied, including 21 new, untreated patients and 101 previously treated patients. Patients were studied for at least one year during active disease and remission. It was shown that sulfapyridine shares the same acetylation polymorphism as sulfadimidine. The acetylation capability of each patient as determined in serum and urine was constant irrespective of dose (2 to 8 gm/day) and state of disease. A single study of serum can determine acetylator phenotype in patients on sulJasalazine therapy without using any other drug for this purpose and may help ascertain dosage and assess side effects.

Desensitization of patients with inflammatory bowel disease to sulfasalazine

Seventeen patients with ulcerative colitis and three patients with Crohns disease exhibited different side effects during sulfasalazine therapy. Eighty percent of these patients belonged to slow acetylator phenotypes. All side effects except skin rash were associated with a mean serum total sulfapyridine concentration of 62.9 +/- 17.4 micrograms/ml and free sulfapyridine concentration of 42 +/- 9.5 micrograms/ml. All patients were successfully desensitized, which allowed them the benefit of continued sulfasalazine therapy for prevention of relapses.

Antibody-dependent cell-mediated cytotoxicity in serum samples from patients with ulcerative colitis: Relationship to disease activity and response to total colectomy

A group of six medically treated patients with ulcerative colitis were followed for up to 30 months along with eight additional patients who underwent proctocolectomy. Patients were examined frequently, and serum samples were collected for antibody-dependent cell-mediated cytotoxicity studies. Clinically active disease was substantiated by history, physical examination, laboratory investigations, proctoscopy and, when feasible, by rectal and/or colonic biopsy specimens. During active clinical disease, serum samples from patients with ulcerative colitis showed antibody-dependent cell-mediated cytotoxicity of 16.5 +/- 1.6 percent (range 8.2 to 25.8 percent). During remission of the disease, serum samples from the same patients demonstrated a mean antibody-dependent cell-mediated cytotoxicity value of 5.9 +/- 1.3 percent (range 0.4 to 11.1 percent) (p less than 0.01). In the eight patients who underwent proctocolectomy, mean preoperative antibody-dependent cell-mediated cytotoxicity value was 19.5 +/- 2.3 percent (range 4.1 to 38.6 percent). One month after proctocolectomy, antibody-dependent cell-mediated cytotoxic activity decreased by 72 +/- 11 percent of the preoperative value (p less than 0.001). These findings reveal a positive correlation between the antibody-dependent cell-mediated cytotoxicity with RPMI-4788 and clinical activity of ulcerative colitis, and support the hypothesis that the antibody being studied has direct relation to the presence of the ulcerative colitis colon in situ.

Salicylazosulfapyridine in inflammatory bowel disease.

Salicylazosulfapyridine (SASP) (Azulfidine, Pharmacia; SAS-500, Rowell Laboratories Inc.) has been available as a therapeutic compound since 1940 when Svartz (1) in collaboration with chemists from Pharmacia Company developed an agent by combining a sulfonamide with salicylic acid intended for the treatment of patients with rheumatoid arthritis. A combination of 5-aminosalicylic acid (5-ASA) and sulfapyridine (SP), through an azo link, was synthesized and used empirically for patients with ulcerative colitis. There were good results in the first 12 patients treated with SASP in 1942 (1). A later series of 124 s imi lar patients (2) confirmed the earlier results and indicated that SASP was superior to absorbable and nonabsorbable sulfonamides in the treatment of ulcerative colitis (3-6). Controlled trials established the value of SASP in active colitis (7-10) and its effectiveness in the prevention of relapses of ulcerative colitis during: long-term therapy (11-12), although in one series the prophylactic effect of SASP was found to be doubtful (13). The value of SASP in the management of Crohns disease, which has not yet been settled (14-19), is being studied in a multicenter controlled trial in North America. SASP has also been used with some success in patients with ulcerative postdysenteric colitis (20) and scleroderma (21).

The feasibility of studying drug‐induced acute hepatitis with use of Medicaid data

To determine the feasibility of the use of Medicaid data to study drug‐induced acute liver disease, we reviewed the medical records of 414 patients receiving Medicaid, age 20 or older, with an ICD‐9‐CM inpatient billing code consistent with acute hepatitis. Of the patients whose records were reviewed, 15.9% were alcoholics, 31.9% had acute hepatitis A or B, 13.5% were intravenous drug users, 8.2% had acute cholecystitis or choledocholithiasis, and 4.1% had received a blood transfusion within the previous 6 months. No diagnosis of liver disease was found in 10.6% of the patients, and 5.7% had chronic liver disease. Of the 169 patients with idiopathic acute liver disease identified, many had very mild liver disease and were hospitalized for reasons other than liver disease. We conclude that Medicaid billing data has high reliability and validity for the diagnosis of acute liver disease. However, primary medical records are essential for the study of drug‐induced hepatitis, to be able to exclude other causes of liver disease, and to obtain information not included in the computer data.

Isolation and characterization of Crohn's disease tissue-specific glycoproteins

Two Crohns disease tissue-specific proteins are identified and purified several thousand-fold from crude tissue extracts by different chromatographic procedures. The two proteins migrate in sodium dodecyl sulfate-polyacrylamide gel electrophoresis as 200-210-kilodalton and 150-160-kilodalton species. They are glycoproteins, as evidenced by their binding to concanavalin A-Sepharose 4B and positive staining with Schiffs reagent. Specific immunoreactivity of the two glycoproteins against Crohns disease sera was demonstrated by immunotransblot analysis. All but one of the operative specimens of colon or small intestine (or both) from 13 patients with Crohns disease contained either or both of the proteins; they were not detected in specimens of colon from 5 patients with ulcerative colitis, 1 patient with diverticulitis, 1 patient with ischemic colitis, from the normal bowel segments resected from 3 patients with colon cancer, and from two normal ileal tissue specimens. The two glycoproteins did not react with antihuman IgG, IgM, and IgA, suggesting that they are not immunoglobulins. The purified glycoproteins may provide important leads toward the understanding of the pathogenesis of Crohns disease.

Demonstration of an internal pancreatic fistula by computed tomography.

The computed tomographic demonstration of a mediastinal pseudocyst communicating with the pancreatic duct in a patient with severe acute pancreatitis is reported. An awareness of this communication was essential in planning the appropriate surgical management.

Immunofluorescence assay using crohn's disease tissue-injected athymic nude mouse lymph nodes in the diagnosis of inflammatory bowel diseases☆

Sometimes, even after extensive investigative efforts, the diagnosis of inflammatory bowel disease remains in doubt. The accurate diagnosis is important if appropriate therapy is to be instituted. A simple indirect immunofluorescence assay that tests the patients serum against lymphoid tissues from athymic nude (nu/nu) mice receiving injections of filtrates of Crohns disease tissue is proposed. Eighty percent of serum samples from patients with active, symptomatic Crohns disease give positive results of immunofluorescence when tested with these lymphoid tissues. The false-positive rate has been very low (less than 10 percent). Because this assay is fairly sensitive and least invasive, it was used for the clarification of many puzzling cases that were seen at the Albert Einstein College of Medicine over the past three years. Ten of these cases were selected for illustration and discussion and are presented in this report.

Demonstration of Crohn's disease tissue-specific proteins by enzyme-linked immunosorbent assay (ELISA)

Theories on the etiology of Crohns disease have included extrinsic agents and intrinsic bowel wall defects. We sought to determine the presence of immunoreactive antigens specific to Crohns disease tissue by modifying the enzyme-linked immunosorbent assay. Tissue proteins were extracted from four patients with Crohns disease and from four normal segments of colon from patients with colonic cancer. These tissue extracts were further purified on Con A Sepharose 4B affinity column. The glycoproteins eluted from this column were adsorbed by polystyrene plates as antigen and tested against 85 sera from patients with Crohns disease, ulcerative colitis, other diarrheal diseases, and normal subjects. Sera from 48 patients with Crohns disease showed significantly greater recognition of Crohns disease tissue glycoproteins than sera from 27 disease controls (P<0.0125) and 10 normal subjects. These Crohns disease sera also showed preferential recognition of glycoproteins extracted from Crohns disease tissue compared to glycoproteins from normal colonic tissue (P<0.0005). The nature of these immunoreactive proteins, whether extrinsic or intrinsic, is not yet known. The ELISA may help in further characterization of Crohns disease tissue-specific glycoprotein(s) and to develop a clinically useful serological test.