Choice of antibiotic in nonelective cesarean section.

The use of antibiotics for prophylaxis against infection among women undergoing nonelective cesarean section has become the standard of care in the United States. Many different antibiotics have been used successfully. Single-dose regimens administered after the cord is clamped have proven just as effective as multiple-dose regimens. Although the most frequently used class of antibiotics is the cephalosporin family, the single best agent has not been determined. This study was a double-blind, randomized trial in which we compared a narrow-spectrum cephalosporin (cefazolin; n = 63) with an expanded-spectrum cephamycin (cefoxitin; n = 66) and with a broad-spectrum cephalosporin (cefotaxime; n = 60) used as a single-dose prophylaxis in patients undergoing a nonelective cesarean section. Of the 194 patients enrolled in the study, 189 were evaluable. There was no significant difference between the groups in mean age, gravidity, parity, duration of labor, duration of ruptured membranes, number of vaginal examinations, or socioeconomic status (socioeconomic status was defined by third-party coverage). There was no significant difference among the antibiotics in the incidence of immediate or delayed postoperative infections. These data indicate that a less expensive, narrow-spectrum cephalosporin is as effective as more expensive, broader-spectrum cephamycins and cephalosporins as prophylaxis for patients undergoing nonelective cesarean section.

Effect of mismatches for major histocompatibility complex and minor antigens on corneal graft rejection.

The importance of minor histocompatibility genes in corneal graft rejection was investigated using a model that simulates the major histocompatibility complex (MHC) and minor mismatches of the human allograft more accurately than previous animal models. DA(RT1a) x LEW(RT1(1]F1 hybrid rats were backcrossed to LEW, and the backcross generation were used as corneal graft recipients. Female DA(RT1a) strain animals were used as donors throughout. As in humans, the MHC disparity (a to 1) between each donor-recipient pair could be controlled; minor mismatches were variable and unknown. The MHC haplotype of each backcross individual (either homozygous l/l) or heterozygous a/l) was determined. Depending on this haplotype, the transplanted DA cornea was either matched or mismatched with the recipient for MHC antigens. The average proportion of minor disparate loci was 50%, although this was variable and unknown from recipient to recipient. Some animals of each MHC type were sensitized with three subcutaneous DA strain skin grafts at intervals of 2 weeks. Prior sensitization caused more rapid corneal graft rejection in both MHC mismatched (P less than 0.001) and matched (P less than 0.01) animals. All animals in the two MHC-mismatched groups (sensitized, 26; unsensitized, 17) and most in the MHC-matched groups (sensitized, 25 of 27; unsensitized, all 13) rejected their grafts. The MHC matching resulted in a greater range of survival times, although the difference in survival in unsensitized animals between matched and mismatched groups was not significant (unsensitized, P greater than 0.05; sensitized, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of biopsy-proven Pneumocystis carinii pneumonia in acquired immune deficiency syndrome patients and renal allograft recipients.

Pneumonia unresponsive to antibacterial agents in patients with acquired immune deficiency syndrome (AIDS) has become a new indication for lung biopsy. In 14 patients, transbronchial or open-lung biopsy demonstrated Pneumocystis carinii. An additional 12 patients, who were immunosuppressed after renal transplantation, were seen with P. carinii pneumonia. The diagnosis was established by transbronchial biopsy in the majority of patients. All patients were treated initially with trimethoprim plus sulfamethoxazole. Pentamidine was added after diagnosis if improvement did not occur. Both groups demonstrated reversal in the T cell helper: suppressor ratio. We compared these two groups of immunocompromised patients with respect to clinical presentation, lung pathology, response to therapy, and survival. Patients with AIDS were seen with a two- to three-week prodrome of fever, lymphadenopathy, weight loss, and malaise followed by hypoxia and leukopenia within 12 hours. Transplant patients became acutely ill with fever and hypoxia within 24 to 36 hours. In both groups, chest roentgenogram showed bilateral diffuse infiltrates; sputum cultures were generally negative; and lung biopsy demonstrated Gomori-Jones periodic acid-methenamine-silver-positive P. carinii. Mortality was substantially higher in patients with AIDS (50% versus 8%). This difference may be explained by the fact that the T cell defect in AIDS has an infectious cause, while the defect in the renal allograft recipient is pharmacologically mediated.