Evidence for the bacterial origin of Acholeplasma laidlawii A.

L-forms from a Corynebacterium were induced in hyperosmolar media and gradually adapted to normal osmolarity over a period of two years. During this adaptation several morphologic L-form variants derived from the L-form cultures and were serologically identified as Acholeplasma laidlawii A. The possibility that the bacterial and L-form cultures were contaminated with acholeplasmas was carefully investigated; this was determined not to be the case. Membrane protein gel electrophoresis patterns of these L-form variants were identical to the ATCC A. laidlawii strain PG-8. Acholeplasma phage MVL-1 displayed no affinity for these L-form variants. Phage MVL-2 showed low affinity, but after virus enhancement in the specific host, high plaquing efficiency ensued. DNA hybridization experiments showed a high level of nucleotide sequence homology (greater than 90%) between the L-form-derived variants and PG-8. The homology between the diphtheroid L-forms and the PG-8 strain was 16.4% with te50 values of 86%; this indicates strong base pairing homology. These findings suggest that the L-form variants are acholeplasmas and that they are biologically and genetically related to the Corynebacterium L-forms.

Chemoimmunotherapy of a murine fibrosarcoma: critical factors for success of combined modality therapy.

Thiabendazole (TBZ), a new nonspecific immunopotentiator, was evaluated in combination with Cytoxan in the therapy of a syngeneic murine fibrosarcoma. The reduction of tumor burden by chemotherapy was critical in achieving an optimal response from immunotherapy. Eighty-eight percent of the mice that responded to Cytoxan had sustained regression of tumor with TBZ treatment. The response to TBZ was markedly diminished, both in duration and magnitude, in the mice considered to be Cytoxan nonresponders. Timing of immunotherapy was also important. If Cytoxan and TBZ were given simultaneously, growth kinetics similar to those observed with Cytoxan alone were observed. However, if TBZ was given 4 days after Cytozan administration, prolonged regression of tumor was seen. Alone, TBZ was most effective at a dose of 20 mg/kg. However, in combination with Cytoxan the most effective dose was 0.2 mg/kg. The implications of this finding are discussed.

Intraoperative localization of a renal calculus using ultrasound.

Ultrasound is gaining widespread application in the area of diagnostic urology. We wish to describe its use in the intraoperative localization of a caliceal diverticulum and stone when more conventional techniques would not have been adequate.