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Biomedical subjects

A Zermeno

Publications and source records attributed to A Zermeno.

11 recordsLinked to original sources

Silver iontophoretic catheter: a prototype of a long-term antiinfective vascular access device.

A silver iontophoretic catheter (SIC) was developed consisting of two electrically charged parallel silver wires helically wrapped around the proximal segment of a vascular catheter. In vitro and in vivo activities of this catheter were compared with those of an aseptic catheter coated with chlorhexidine and silver sulfadiazine (CH/SS). The SIC demonstrated broad-spectrum in vitro inhibitory activity against bacteria and Candida albicans comparable to that of the CH/SS-coated catheter. The durability of activity was determined by incubating catheters in serum at 37 degrees C for various time intervals. After 30 days, the antimicrobial activity of the SIC did not change significantly, while that of the CH/SS-coated catheter was reduced to a suboptimal level. In a rabbit model, the SIC was safe and significantly more efficacious than the CH/SS-coated catheter in preventing colonization with Staphylococcus aureus (P < .05). The SIC has broad-spectrum inhibitory activity of long durability and is highly efficacious in preventing colonization in vivo.

Animals

Physical characteristics of the M.D. Anderson Hospital clinical neutron beam.

The physical characteristics of the M.D. Anderson Hospital (MDAH) clinical neutron beam are presented. The central-axis percent depth-dose values are intermediate between a 4 and 6 MV X-ray beam. The build-up curves reach a depth of maximum dose at 1.2 cm and have surface dose values of approximately 30%. Teflon flattening filters are employed to flatten the beam at the depth of the 75% dose level. Two wedges are available for shaping the beam; they are made of Teflon and produce wedge angles of 31 degrees and 45 degrees as defined by the ICRU. Output factors ranged from 0.88 for a 4 x 4 cm field to 1.12 for a 20 x 20 cm field. Tungsten blocks reduced the dose received at Dmax to 25% of the unblocked value but only 52% of the unblocked value at a depth of 22.8 cm.

Filtration

Lack of efficacy of thermography as a screening tool for minimal and stage I breast cancer.

In a study of thermograms of 42 patients with Stage 1 or smaller carcinomas of the breast, 44 confounding cases and 64 randomly selected subjects being screened, we found that the ability of expert thermographers to identify the patients with carcinoma correctly (true positive = 0.238) varied little from the ability of untrained readers (true positive = 0.301). Furthermore, in the expert group, the indexes of suspicion were so high (0.436) and the true-positive levels were so relatively low (0.238, P = 0.0005) that thermography may well have a very limited role as a screening or pre-screening modality for the detection of minimal or Stage 1 breast cancers.

Breast Neoplasms