Effect of levamisole on major histocompatibility complex class I expression in colorectal and breast carcinoma cell lines.

BACKGROUND: The antihelminthic drug levamisole (LMS) is used in conjunction with 5-fluorouracil (5-FU) as adjuvant therapy to reduce the incidence of colon cancer relapse following surgical resection. Clinical trials in patients with breast cancer have yielded conflicting results as to its efficacy in the treatment of this malignancy. LMS is thought to act as an immunostimulant, yet its precise mechanism remains unclear. In this study, the effect of LMS on major histocompatibility complex (MHC) class I (MHC I) and MHC class II (MHC II) expressions in human colorectal and breast carcinoma cell lines was examined. METHODS: The colon cancer cell line CaCo-2 and the breast cancer cell line MDA-MB-435 were cultured for 24-68 hours in the presence or absence of 10-microns LMS followed by staining with antibodies directed against either MHC I or MHC II: After staining, cells were visualized by fluorescent microscopy. RESULTS: When cultured in the presence of LMS, cells from both cell lines exhibited a decreased fluorescent intensity with antibodies directed against MHC I protein. The most significant difference from cells cultured without LMS was apparent after 48 hours of incubation. Neither cell line exhibited fluorescent intensities above background when stained with anti-MHC II antibody. CONCLUSIONS: LMS decreases the expression of MHC I on CaCo-2 and MDA-MB-435 tumor cell lines. Prior studies have indicated that natural killer (NK) cells are more efficient in attacking cells with lowered or no MHC I expression. An MHC I deficiency induced by LMS would augment NK-mediated immune surveillance. One mechanism contributing to levamisole's anti-tumor activity in vivo may be reduction of MHC I expression on tumor cells.

Premarket evaluation of Monofluor reagent for detecting Chlamydia trachomatis in adolescent outpatients.

A new direct fluorescent antibody reagent, Monofluor, was evaluated for detecting Chlamydia trachomatis in fresh specimens. Monofluor was compared with Micro Trak and with cultivation in McCoy cells. Both direct systems were slightly less sensitive than culture, but no significant differences in specificity or sensitivity were noted between culture, Monofluor, or Micro Trak results.

Postcesarean wound infection by Mycoplasma hominis in a patient with persistent postpartum fever.

Mycoplasma hominis was isolated in pure culture from a wound infection following delivery by cesarean section. The importance of recognizing this organism as a potential pathogen of the female genital tract is emphasized. Two commercially available isolation systems that allow the recovery of this organism are also described.

Comparative efficacy and safety of mezlocillin, cefoxitin, and clindamycin plus gentamicin in postpartum endometritis.

The efficacy of mezlocillin versus cefoxitin versus clindamycin plus gentamicin was evaluated in 152 patients with postpartum endometritis. There were no statistically significant differences in rate of cure among the three groups (87% with mezlocillin, 82% with cefoxitin, and 92% with clindamycin-gentamicin). There were no severe adverse reactions observed in any of the three treatment regimens. Mezlocillin is as safe and effective as cefoxitin and clindamycin-gentamicin for treatment of postpartum endometritis.

Isolation of Mycoplasma species and Ureaplasma urealyticum from obstetrical and gynecological patients by using commercially available medium formulations.

One hundred duplicate endocervical specimens from obstetrical and gynecological patients were cultured for Mycoplasma spp. and Ureaplasma urealyticum. Rates of recovery of these organisms from commercially prepared A7 medium and the Mycotrim-GU system were compared. We detected 14 (93%) of the total 15 isolates of Mycoplasma spp. on A7 plates and 11 (73%) in the Mycotrim-GU system. We detected 34 (89%) of the total 38 isolates of U. urealyticum on A7 plates and 32 (84%) in the Mycotrim-GU system. The times of detection for both types of organism were similar in the two systems. We conclude that cultivation on A7 medium as described is a more cost-effective method of recovery of Mycoplasma spp. and U. urealyticum than the Mycotrim-GU system.