Bacillus stearothermophilus Disc Assay for Detection of Inhibitors in Milk: Collaborative Study

A 2-part (A and B) collaborative study was conducted on a Bacillus stearothermophilus paper disc (12.7 mm) method to detect residual inhibitors in milk. The 18 participating collaborators assayed raw milk samples spiked with a beta-lactam (penicillin G). Of the 18 collaborators, 14 participated in part A and 16 in part B. Part A demonstrated that either Antibiotic Medium No. 4 or PM Indicator Agar is suitable for use in the assay. The lowest concentration detectable, not significantly different from 100% at the α = 0.05 level, was 0.008 unit/mL with either medium. Part B demonstrated that the sensitivity of the method is equal to that of the current AOAC method (16.131- 16.136). The concentration of beta-lactam detected by 50% of the analysts was 0.003-0.005 unit/mL in this study, compared with 0.005 unit/mL reported in an earlier collaborative study on the current AOAC method. No false positive results were reported in part A or part B. All samples found positive by the confirmatory test in part B were correctly identified as a beta-lactam with commercial Penase discs. The lowest concentration detectable by the method, not significantly different from 100% at the α = 0.05 level, was 0.008 unit/mL. The method was adopted official first action.

Immunodeficiency in patients with non-Hodgkin lymphomas

Seventy-one previously untreated patients with non-Hodgkin lymphomas were studied with several readilyvailable tests of immune function: number of peripheral blood lymphocytes, serum immunoglobulins, and delayed hypersensitivity to six recall antigens. The results were correlated to histology (Rappaport classification), stage (Ann Arbor classification), the presence of symptoms, and survival. As a group, 38 patients with diffuse lymphomas exhibited marked impairment in reactivity to five of six antigens (p less than 0.03 to p less than 0.001). In addition, lymphopenia and reduced levels of serum IgA were found in association with diffuse histiocytic lymphoma. Among patients with diffuse lymphoma, lymphocyte number and skin test reactivity tended to be greater in those with localized disease or without constitutional symptoms, and survival was superior for patients free of symptoms (p less than 0.01). As a group, 33 patients with nodular lymphoma had normal numbers of lymphocytes, lower levels of serum IgG and IgA, and significant impairment of reactivity to two antigens (streptokinase-streptodornase and mumps; p less than 0.01); reactivity to three other antigens (Candida albicans, coccidiodin, and tuberculin) was normal. Survival for patients with nodular lymphoma was superior (p less than 0.01) compared to those with diffuse lymphomas. In summary, severe immunodeficiency was found in patients with diffuse lymphoma (particularly diffuse histiocytic lymphoma), and definite but much less severe immunodeficiency was characteristic of patients with nodular lymphoma.