New latex reagent using monoclonal antibodies to capsular polysaccharide for reliable identification of both oxacillin-susceptible and oxacillin-resistant Staphylococcus aureus.

A new latex agglutination test (Pastorex Staph-Plus, Sanofi Diagnostics Pasteur), consisting of a mixture of latex particles coated with fibrinogen and immunoglobulin G for the detection of clumping factor and protein A and latex particles sensitized with monoclonal antibodies directed to Staphylococcus aureus serotype 5 and 8 capsular polysaccharides, was compared with three commercially available rapid agglutination methods for the identification of 220 isolates of S. aureus (61 oxacillin resistant) and 128 isolates of coagulase-negative staphylococci. The sensitivity for identification of S. aureus was high with the Pastorex Staph-Plus test (98.6%) compared with those of the other tests, which ranged from 91.8 to 84.5%. Test sensitivities for the identification of oxacillin-resistant S. aureus were as follows: Pastorex Staph-Plus, 95.1%; Pastorex Staph, 73.8%; Staphyslide, 72.1%; and StaphAurex, 49.2%.     

Anti-tumor effects of antibody-alkaline phosphatase conjugates in combination with etoposide phosphate.

Two anti-tumor monoclonal antibodies, L6 (anticarcinoma) and 1F5 (anti-B lymphoma), were covalently linked to alkaline phosphatase (AP), forming conjugates that could bind to the surface of antigen-positive tumor cells. The conjugates were capable of converting a relatively noncytotoxic prodrug, etoposide phosphate (EP), into etoposide--a drug with significant antitumor activity. In vitro studies with a human colon carcinoma cell line, H3347, demonstrated that while EP was less toxic than etoposide by a factor of greater than 100, it was equally toxic when the cells were pretreated with L6-AP, a conjugate that bound to the surface of H3347 cells. The L6-AP conjugate localized in H3347 tumor xenografts in nude mice and histological evaluation indicated that the targeted enzyme (AP) was distributed throughout the tumor mass. A strong antitumor response was observed in H3347-bearing mice that were treated with L6-AP followed 18-24 hr later by EP. This response, which included the rejection of established tumors, was superior to that of EP (P less than 0.005) or etoposide (P less than 0.001) given alone. The IF5-AP conjugate did not bind to H3347 cells and did not enhance the toxicity of EP on these cells in vitro. In addition, IF5-AP did not localize to H3347 tumors in nude mice and did not demonstrate enhanced antitumor activity in combination with the prodrug.     

Dosimetric Characteristics of the Siemens IGRT Carbon Fiber Tabletop

In this work, the dosimetric characteristics of a new commercial carbon fiber treatment table are investigated. The photon beam attenuation properties of the Siemens image-guided radiation therapy (IGRT) tabletop were studied in detail. Two sets of dosimetric measurements were performed. In the first experiment a polystyrene slab phantom was used: the central axis attenuation and the skin-sparing detriment were investigated. In the second experiment, the off-axis treatment table transmission was investigated using a polystyrene cylindrical phantom. Measurements were taken at the isocenter for a 360° rotation of the radiation beam. Our results show that the photon beam attenuation of the Siemens IGRT carbon fiber tabletop varies from a minimum of 2.1% (central axis) to a maximum of 4.6% (120° and 240° beam incidence). The beam entrance dose increases from 82% to 97% of the dose at the depth of maximum for a clinical 6-MV radiation field. The depth of maximum also decreases by 0.4 cm. Despite the wedge cross section of the table the beam attenuation properties of the IGRT tabletop remain constant along the longitudinal direction. American Association of Medical Dosimetrists.     

Aerobic exercise performance correlates with post-ischemic flow-mediated dilation of the brachial artery in young healthy men

In older healthy men, aerobic exercise capacity is related to postischemic flow-mediated dilation of the brachial artery (FMD), but corresponding data in a younger population is not available. In addition, whether submaximal aerobic exercise performance also correlates with this kind of vasomotor reactivity is not known. Therefore, in 15 nonsmoking young healthy men [age 27 (5) years; body mass index: 24 (2) kg/m²; mean (SD)] with different levels of ordinary physical activity, but not performing upper-extremity training, we measured FMD at 1 min after reactive hyperemia, and pulmonary oxygen uptake (O₂) at ventilatory anaerobic threshold (O₂AT) and at peak effort (peak O₂) during an incremental exercise on a treadmill. In our participants, FMD was 9.1 (3.4)%, O₂AT was 40.72 (5.92) ml/kg per min, and peak O₂ was 52.95 (8.13) ml/kg per min. Using bivariate Pearsons correlation, and in separate multivariate regression analyses, O₂AT and peak VO₂ showed a significant and reasonably good correlation with FMD (r=0.84, P<0.001 and r=0.77, P=0.001, respectively), independent of age, body mass index and serum total cholesterol (=0.77, P<0.001, R² of the overall model=0.79 and =0.70, P<0.005, R² of the overall model=0.69, respectively). Our data provide evidence suggesting that in young healthy men a higher submaximal and maximal aerobic exercise performance is associated with a greater FMD of peripheral conduit arteries.     

p27(Kip1) expression and grading of breast cancer diagnosed on cytological samples

The progressive reduction in p27(Kip1) (p27) protein immunohistochemical staining with increasing histological grading is a well-established finding occurring in breast cancer, and its role as diagnostic complement and prognostic marker has been thoroughly evaluated. To clarify whether this test may be applied to breast cytopathology, we performed p27 immunostaining on fresh fine-needle cytology (FNC) samples from 10 benign and 40 malignant breast lesions. On average, p27 immunostaining was significantly lower in carcinomas than in benign lesions (P < 0.005). In particular, among carcinomas, p27 immunostaining progressively reduced from well-to poorly differentiated lesions (G1 vs. G2, P < 0.05; G1 vs. G3, P < 0.001; G2 vs. G3; P < 0.001). A similar trend was noted in a subgroup of 20 matched FNCs and histological samples of breast carcinomas, when p27 immunostaining on FNCs was stratified according to the histological grading (G1 vs. G2, P = 0.18; G1 vs. G3, P < 0.05; G2 vs. G3, P < 0.05). In addition, p27 immunostaining on FNCs showed a good positive correlation with that on histology (Spearman R = 0.58; P < 0.01), with a diagnostic concordance between samples of 85%, by using the standard 50% positive cell cutoff. Taken in concert, our data suggest that p27 immunostaining is a reliable marker of tumor cell differentiation in breast cytopathology as well as in histopathology. Accordingly, staining FNCs for p27 may be an useful complement in addition to cytological grading in the preoperative assessment of breast cancer.