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This document describes the activities of ASTM Committee E-31 in the area of standards for computer systems in medical applications. Some of these efforts have already culminated in published standards, some are well along in the development process, and some are just getting started.
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PURPOSE: To determine whether the presence of prostate-derived cells in the peripheral blood circulation is a marker of prostate cancer and to define the clinical impact of the test. MATERIALS AND METHODS: We tested the peripheral blood of 99 patients with prostate adenocarcinoma (PAC), 79 of them undergoing radical prostatectomy, and 92 controls (31 healthy volunteers, 50 patients with adenoma and 11 with prostatitis) using a highly controlled procedure including reverse-transcriptase polymerase chain reaction (RT-PCR) targeted to prostate-specific antigen (PSA) mRNA. Patients were followed for 26 +/- 12 (range: 4 to 49) months. Forty tumor tissues were analyzed by immunohistochemistry for expression of p53 and E-cadherin antigens. RESULTS: Thirty three (33%) patients with PAC and 2 (2%) controls scored positive (p <0.0001) for the test. Detection of circulating prostatic cells was associated with development of metastases (p <0. 001), with relapse (p <0.001) and with a serum PSA level at diagnosis higher than 15 ng./ml. (p = 0.009). The rate of development of metastases according to time was significantly higher in patients who scored positive for the test (p <0.04). In a multivariate analysis, only the RT-PCR test was an independent risk factor associated with relapse (RR: 6.7). Finally, E-cadherin expression was significantly lower in the tumor tissues of positive patients as compared with those who scored negative for the test (p <0.01). CONCLUSIONS: This RT-PCR procedure, performed at diagnosis and with appropriate controls, is a clinically useful assay in evaluating the risk of tumor recurrence after radical prostatectomy in patients with PAC.
BACKGROUND AND AIM OF THE STUDY: Porcine bioprosthetic valves have excellent hemodynamics and do not require anticoagulation, but have limited durability. Cusp tearing is a major cause of bioprosthetic valve failure. It has been suggested that the mechanism of bioprosthetic valve failure is stiffening by calcification, which leads to elevated stresses and secondary collagen fiber damage and leaflet tearing. This thesis was tested in explanted porcine bioprostheses. METHODS: A total of 60 explanted porcine bioprosthetic valves was tested mechanically, and 15 explanted valves were examined grossly and histologically. Circumferentially and radially oriented samples of cusp tissue were tested uniaxially in a materials testing machine and compared with five controls. RESULTS: Mean (+/-SD) duration of implantation was 10.9+/-5.6 years. Circumferential specimens from explants were less extensible than controls (11.0+/-5.5% versus 24.5+/-2.8% strain, p <0.001), and failed at lower tensions (973+/-733 versus 3075+/-911 N/m, p = 0.001) and at lower strains (21.2+/-8.1% versus 47.3+/-7.1% strain, p <0.001). Radial specimens from explants were less extensible (28.7+/-6.8% versus 39.2+/-5.9% strain, p = 0.002) and failed at lower strains (60.3+/-17.3% versus 112.2+/-24.9% strain, p <0.001) than the controls. The stiffness of the explants was unchanged from controls in both circumferential and radial samples. There were no differences between explants and controls in radial and circumferential stiffness, and in radial failure strength. Calcification was mild and diffuse in most of the tested samples. Tears were found in areas without calcific deposits, along with breaks in collagen fiber bundles. CONCLUSION: These results do not support the thesis that calcification stiffens glutaraldehyde-fixed porcine bioprostheses, except when the entire cusp is transformed into a solid mass of mineral. Rather, leaflet tears may develop as a result of accumulated mechanical damage that is independent of calcification.
OBJECTIVE: The purpose of this study was to investigate the shear bond strength of resin-modified glass ionomer used for orthodontic bracket bonding. METHODS: 30 extracted premolars were evenly divided into two groups. Edgewise brackets (Orsu) were bonded with resin-modified glass ionomer (Advance) in group one and with composite resin (DM) in group two. The shear bond strengths of two materials were tested by material testing machine after 24 hours. The adhesive remnant index was scored after debonding. RESULTS: The shear bong strengths of resin-modified glass ionomer and composite resin were (6.862 +/- 2.142) MPa and (7.183 +/- 3.205) MPa respectively. There were no statistically significant differences between two groups. CONCLUSIONS: In vitro bond strength of resin-modified glass ionomer had reached the same level of composite resin. It had the prospect of clinic use.
OBJECTIVE: To assess the effect of Danshen-9403 (DS-9403, an effective fraction of Radix Salviae Miltiorrhizae) on healing of bone fracture. METHODS: Standardized radial fracture was performed in 120 Wistar rats. The model animals were randomized into four groups: group A was fed with DS-9403, group B injected with Staphylococcus Aureus, group C with normal saline, and group D with Salviae injection. The treatment began at the first day of fracture. The rats were sacrificed on the 25th, 39th and 50th day separately in batches and their intact radii were removed by dissection for detecting load and stress of three-point bending test with autograph universal material testing machine (Shimazu, Japan). RESULTS: The parameters of load in DS-9403 treated groups on the 39th day and that of stress at 25th, 39th and 50th day were (6.20 +/- 1.32) N, (5.71 +/- 3.58) N/mm2, (8.27 +/- 2.42) N/mm2 and (66.25 +/- 26.21) N/mm2 respectively, which were significantly higher than those in other groups, P < 0.05. CONCLUSION: DS-9403 has the action of increasing the strength of fracture healing site.
This article is intended to inform professionals in the fields of rehabilitation medicine and biomedical engineering of some of the more significant properities of Temper Foam, a new foam for support of the physically handicapped. The unique properties of this foam are explained in terms of its microstructure, illustrated by scanning electron micrographs and by mechanical tests using an Instron Materials Testing machine. Fourteen non-ambulatory patients with Duchenne muscular dystrophy are using this foam in custom-fitted contoured support systems. Normally, these children show increasing signs of discomfort and skin breakdown due to their inability to alternate areas of weight bearing and high local pressure such as the ischial tuberosities. In our support systems lined with Temper Foam these problems have completely dissappeared. We find that Temper Foam types T-36, T-38 and -41 are ideally suited for patients weighing up to 35 kg. T-41 may be used for patients weighing up to 70 kg.
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AIM: To detect endogenic intoxication syndrome (EIS) and to assess its severity depending on clinical manifestations of rheumatoid arthritis (RA) using laboratory tests. MATERIAL AND METHODS: Laboratory tests including analysis of synovial fluid, blood count with estimation of leucocytic intoxication index, urinalysis, total protein and protein fractions, seromucoid, syalic acids, peroxide-antioxidant balance, metabolism of proteoglycanes, immunological tests were made in 162 patients with documented RA and 86 healthy controls. Content of middle mass molecules served as an integral biochemical EIS marker. RESULTS: Inflammatory destructive processes in the affected tissues of RA patients lead to marked systemic metabolic and immune disorders accompanied with EIS. Severe EIS are associated with severe metabolic disorders. A significantl rise (p < 0.05) in content of middle mass molecules in the serum was found in all RA patients including in the disease onset and in minimal activity of inflammation and presence of only mono-olygoarthritis of the knee joints. CONCLUSION: RA patients develop EIS the severity of which depends on the activity and distribution of the inflammatory process but not on the disease stage. Metabolic disorders in RA patients can be assessed with an effective method--blood serum middle mass molecule assay.
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