Richard N. Greenberg

Observations using antiendotoxin antibody (E5) as adjuvant therapy in humans with suspected, serious, gram-negative sepsis.

Objective:To evaluate the safety and efficacy of E5 (Xomen™-E5), a murine monoclonal immunoglobulin M antibody, in reducing mortality in patients with serious Gram-negative infections. Phase II, single-site study. Design:Randomized, double-blind, placebo-controlled study. Setting:Surgical, neurosurgical and medical ICUs, comprising approximately 30 beds in a multidisciplinary university hospital. Patients:Patients with clinical evidence of serious infection admitted to the ICU for monitoring of vital signs and for intensive care nursing. Of the 39 patients enrolled in the study, 23 had documented Gram-negative infection. Methods:Patients suspected of having life-threatening Gram-negative infections received one of two doses of E5 or placebo. Safety and efficacy were assessed by survival on days 3, 7, and 21, appearance of adverse reactions, development of antimurine antibodies, and effects on BP, urine output, WBC count, and temperature. Measurements and Main Results:Mortality rate from Gram-negative infection 3 days after the last drug (or placebo) infusion was two (22%) of nine deaths in the placebo group compared with 0 of nine for E5 2.5 mg/kg and 0 of five for E5 7.5 mg/kg. At 21 days after therapy, three patients treated with E5 had died. Only one of these three deaths resulted from infection. Eight of 15 E5 patients tested had immunoglobulin G antimurine antibodies by 3 wks after therapy began, but all were asymptomatic. Conclusions:E5 was well tolerated and may have the potential to reduce early morbidity and the mortality rate in seriously ill patients with Gram-negative infections. Results from larger phase HI studies are needed to confirm these findings.

Aztreonam therapy for gram-negative pneumonia

Nineteen patients with community- or hospital-acquired gram-negative pneumonia were treated with aztreonam. Other gram-negative antibiotics were withheld. Thirteen patients (68 percent) had clinical cures and 15 (79 percent) had microbiologic cures with aztreonam. No adverse reactions or drug toxicity occurred in this population.

Preparative purification of Escherichia coli heat-stable enterotoxin

Heat-stable enterotoxin (STa) isolated from bovine Escherichia coli strains was purified to homogeneity by growing the bacterial strains in a chemically defined medium, desalting, and concentrating the culture filtrate by batch adsorption chromatography on Amberlite XAD-2 resin, batch adsorption chromatography on reversed-phase silica, and preparative reversed-phase high-performance liquid chromatography. This rapid preparative purification scheme gave high recovery yields of pure STa which exhibited biochemical homology to STa purified by more complicated procedures.

Purification of Escherichia coli heat-stable enterotoxin.

Publisher Summary The chapter describes the purification of enterotoxigenic Escherichia coli (ETEC) enterotoxin ST a , which is the heat-stable mouse-active enterotoxin. ETEC may induce clinically significant intestinal fluid secretion (i.e., diarrhea) in humans and animals by production of enterotoxins. Several types of ETEC enterotoxins are recognized, each with a unique structure and mechanism of action. ST a activates particulate guanylate cyclase in intestinal epithelial cells. A modification suckling mouse assay (SMA) is used for detection and quantitation of ST a throughout the purification steps. Sequence analysis of ST a peptides is performed by the manual microsequencing technique of Chang using the double-coupling method with dimethylaminoazobenze isothiocyanate/phenyl isothiocyanate. After each cycle of derivatization, the labeled amino-terminal amino acid is cleaved. For preparative purposes the described scheme can be scaled upward to produce larger amounts of ST a . The derivatized amino acids are identified by their retention times in comparison with amino acid standards derivatized and chromatographed under the same conditions.

Correction: Authors of Letters

Excerpt To the editor:I would like to include Horace M. Perry, MD, as a coauthor of the letter onStreptococcus pyogenesand bone resorption (1)....