Aminoglycosides

Despite their nephrotoxic and ototoxic side effects, AG remain useful antibiotics because of their major, rapid, and dose-dependent bactericidal effects. Combination therapy with an AG appears particularly important in neutropenic and other high-risk patients to provide broad-spectrum bactericidal activity, synergism, and reduction of emergence of resistant pathogens. OD AG therapy is associated with high peak levels in serum that maintain efficacy and low-to-undetectable trough levels in serum that attenuate the risk of toxicity. Administration of short-term OD AG therapy to patients not at risk without renal impairment may not absolutely require dosing monitoring. This therapeutic strategy has been proved useful in clinical trials, now including febrile episodes in neutropenic patients, but it should be avoided during infections in which antimicrobial synergism is required, such as enterococcal endocarditis.

Malignant germ cell tumors of the ovary: a study of 20 cases

In a study of 20 patients diagnosed with malignant ovarian germ cell tumors between 1961 and 1993, clinical and pathologic findings were evaluated. Of the 20 patients, seven (35%) had dysgerminoma, two (10%) endodermal sinus tumor, three (15%) malignant teratoma, one (5%) malignant struma ovarii, one (5%) primary ovarian carcinoid, two (10%) benign teratoma with malignant transformation, and four (20%) combination germ cell tumor. Twelve patients (60%) had stage IA, five (25%) stage IC, and three (15%) stage IIIC. Twelve patients (60%) underwent conservative surgery and eight (40%) had at least bilateral salpingo-oophorectomy. At follow-up, 18 patients (90%) were alive free of disease, one (5%) had died of disease, and one (5%) had died of intercurrent disease. The actuarial 5-year survival rate was 93.3%. It is concluded that for young women who wish to preserve child-bearing capacity, regardless of the stage of the tumor, fertility-preserving surgery with complete surgical staging followed, if necessary by cisplatin-based combination chemotherapy is an appropriate and definitive treatment in the absence of involvement of the contralateral ovary and uterus. For patients in whom child-bearing capacity is not an issue, surgery should include total abdominal hysterectomy and bilateral salpingo-oophorectomy with complete staging, followed if necessary by chemotherapy.

[Treatment of urinary bladder cancer--a retrospective analysis]

Data on 482 stage A-0--D2 bladder cancer patients referred between 1975-86 were analyzed. Prognosticators of survival were stage, histologic subtype and differentiation. 143 patients with disease localized to the pelvis (stage A-0--D1) received definitive radiotherapy with 60 Gy or more, and 25 underwent preoperative irradiation and cystectomy. Later, a group of 56 selected patients with stage B--D1, referred between 1988-1991, received neo-adjuvant MCV chemotherapy (methotrexate, cisplatin and vinblastine) preceding either definitive radiotherapy or surgery. The 2-year overall actuarial survival rates were similar: 63% for radiotherapy only, 72% for cystectomy and 68% for neo-adjuvant chemotherapy; they were also similar when broken down by stage and grade.

The carboxyl-terminal region of the spinach PsaD subunit contains information for its specific assembly into plant thylakoids

The assembly of the multi-subunit membrane-protein Photosystem I (PS I) complex involves incorporation of peripheral proteins into the complex. Here we studied assembly of the PsaD subunit of the cyanobacterial and plant PS I into the thylakoid membranes. We generated partial and chimeric psaD genes from which labeled proteins were synthesized in vitro. Assembly of these proteins into the cyanobacterial or plant thylakoids was assayed. The deletion of leader sequence and N-terminal extension of spinach prePsaD did not inhibit its assembly into spinach or cyanobacterial thylakoids. Addition of these sequences to the cyanobacterial PsaD did not enable it to assemble into plant thylakoids. Moreover, these additions significantly decreased the ability of the chimeric proteins to assemble into cyanobacterial thylakoids. In contrast, when the carboxyl-terminal half of cyanobacterial PsaD was replaced by the corresponding region of the spinach PsaD, the chimeric protein could assemble into both spinach and cyanobacterial thylakoids. Therefore, information in the carboxyl-terminal region of spinach PsaD is crucial for its assembly into plant thylakoids.

Assembly of the chlorophyll-protein complexes

The biogenesis of photosynthetic complexes in plants and algae is a multi-step process that involves intricate coordination of steps in two intracellular compartments, the chloroplast and the cytoplasm. The process initiates with the transcription and translation of the various polypeptide subunits. The nuclear-encoded Chl-binding proteins are translated on cytoplasmic ribosomes as precursors that have a transit (leader) sequence at their amino-terminus. The precursors are post-translationally imported into the chloroplasts, proteolytically processed into their mature forms, inserted into the thylationally imported into the chloroplasts, proteolytically processed into their mature forms, inserted into the thylakoid membrane, and bound to their co-factors (and pigments) and with other subunits to form an active complex. The order and mechanisms by which these events occur, are currently being discovered. Electrostatic interactions, the 'positive inside rule', interhelix interactions, interactions with lipids and chaperone proteins affect the insertion and stabilization of the Chl-proteins in the thylakoids. This review describes the events occurring during the integration and organization of the Chl-proteins.

Mechanical ventilation with heated humidifiers or heat and moisture exchangers: effects on patient colonization and incidence of nosocomial pneumonia

The contribution of ventilator circuit bacterial contamination to the occurrence of ventilator-associated pneumonia remains controversial. In a previous study, we found that the incidence of pneumonia was identical with ventilator circuit changes every 48 h and with no ventilator circuit changes. The present study prospectively assessed whether keeping ventilator circuits clean with a heat and moisture exchanger exhibiting antimicrobial barrier properties affects patient colonization and the incidence of nosocomial pneumonia in patients receiving mechanical ventilation for more than 48 h. Consecutive patients were randomly allocated to humidification with either a heat and moisture exchanger (Group 1, n = 61) or a heated humidifier (Group 2, n = 70). In both groups, no circuit changes were performed throughout ventilatory support. Duration of mechanical ventilation was identical in both groups (10 +/- 8.6 d (range: 2 to 47) in Group 1 and 12.5 +/- 14.2 d [range: 2 to 85] in Group 2). The incidence of pneumonia (positive quantitative culture of protected brush specimen) was similar in both groups (6/61 and 8/70 in Groups 1 and 2, respectively; p = 0.8), as was duration of ventilation prior to pneumonia (9 +/- 5.9 versus 8.2 +/- 5.7 d; p = 0.8). Ventilator tubing contamination was considerably reduced with the use of a heat and moisture exchanger. In contrast, bacterial colonization of the pharynx and trachea was identical in both groups. These results suggest that circuit colonization plays little or no role in the occurrence of ventilator-associated pneumonia, provided usual maintenance precautions are applied.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of roxithromycin against Mycobacterium avium infections in human macrophages and C57BL/6 mice

The activity of roxithromycin against three clinical isolates of Mycobacterium avium was compared with that of clarithromycin both in a model of infection of human monocyte-derived macrophages and in a model of established infection of C57BL/6 mice. In the cell culture model, roxithromycin and clarithromycin were bactericidal for strains MO-1 and N-92159 and bacteriostatic for strain N-93043. For the three strains, the differences between the intracellular activities of roxithromycin and clarithromycin were not singificant after 7 days of treatment. Mice were infected with the MO-1 strain. Drugs were given by gavage at a dosage of 200 mg/kg of body weight 6 days per week for 16 weeks starting 5 weeks after infection. At the end of treatment, clarithromycin was more effective than roxithromycin in lungs; roxithromycin was as effective as clarithromycin in spleens. Thus, the activity of roxithromycin was comparable to that of clarithromycin both in vitro and in vivo.

Use of normal C57BL/6 mice with established Mycobacterium avium infections as an alternative model for evaluation of antibiotic activity

Several murine models have been used to evaluate the activities of antimicrobial agents against Mycobacterium avium infection. The main model used is the beige mouse model, but beige mice are expensive and not easily available. Thus, we developed a model of infection in wild C57BL/6 mice. The drugs that exhibited some activity in a previous model of early infection were evaluated in a new model of established infection. Sparfloxacin (50 mg/kg of body weight), ethambutol (50 mg/kg), minocycline (25 mg/kg), and the inhibitor of the cortisol receptors RU-40555 (100 mg/kg) were compared with clarithromycin (50 mg/kg). Treatments were started 5 weeks after the inoculation and were continued for 21 days. Sparfloxacin and RU-40555, which exhibited a moderate activity in the model of early infection, were not effective in this model of established infection. Clarithromycin and combinations with clarithromycin kept their activities against M. avium infection, both in the spleen and in lungs. The present model of established infection of normal C57BL/6 mice is more relevant than the model of early infection for a stringent evaluation of drugs.

CA 15-3, mucin-like carcinoma-associated antigen and tissue polypeptide-specific antigen: correlation to disease state and prognosis in breast cancer patients

Serum testing for the tumor markers CA 15-3 and mucin-like carcinoma-associated antigen (MCA) was performed in 144 patients with breast cancer. Of those patients, 127 were also tested for a third tumor marker, tissue polypeptide-specific antigen (TPS). At the time of testing, 73 patients (51%) were without evidence of disease and 71 patients (49%) had active disease. Mean follow-up time was 16 months. Positivity rates were: 29.8% for CA 15-3, 47.2% for MCA, and 58.3% for TPS. Mean value for patients with no evidence of disease as compared to patients with active disease was 21 U/ml and 117 U/ml for CA 15-3 (P = 0.001), 10.2 kU/l and 22.6 kU/l for MCA (P = 0.001), and 148 U/l and 310 U/l for TPS (P = 0.02). Two year actuarial survival, according to values below and above an established cutoff for CA 15-3 were 80% and 31% (P < 0.001), 75% and 45% for MCA (P < 0.01), and 82% and 50% for TPS (P < 0.01). We conclude that CA 15-3, MCA and TPS values reflect disease state and prognosis in breast cancer patients.

Allogeneic human liposomal melanoma vaccine with or without IL-2 in metastatic melanoma patients: clinical and immunobiological effects

The aim of this pilot study was to assess the clinical and immunological effects of human allogeneic liposomal melanoma vaccine alone or combined with Interleukin-2 (IL-2) in patients with metastatic melanoma. Four concurrent treatment arms were included: vaccine alone (A); vaccine combined with systemic IL-2 (B); vaccine combined with low-dose liposomal regional IL-2 (C); and low-dose regional IL-2 as in group C but without vaccine (D). Vaccine was prepared from semisynthetic phospholipids (dimyristol phosphatidylcholine and dimyristol phosphatidylglycerol) and membranes of six human melanoma cell lines. The latter were chosen as expressing MHC class I and II antigens and a "mosaic" of melanoma-associated antigens (MAAs) as detected by MoAbs R24, p97, CF21 and TA99. Nine of the 24 patients had objective clinical responses: of the ten patients treated with liposomal vaccine and low dose regional IL-2 (arm C), three had complete responses (CR) and three had partial responses (PR); of the five patients treated with liposomal, low-dose regional liposomal IL-2 only (arm D), three had PRs. No clinical responses were seen in patients treated by vaccine alone (A) nor in patients treated by vaccine and systemic IL-2 (B). Patients' in vivo and in vitro cellular immune responses were closely monitored. Conversion to positive cutaneous delayed type hypersensitivity (DTH) to membrane vaccine (without liposomes) was induced only in the six clinical responders of arm C. Positive DTH correlated with augmented in vitro proliferative lymphocyte responses stimulated by melanoma cell lines and membrane preparation and with the augmented cytolytic activity against melanoma cell lines.