^125I放射微粒微创植入治疗前列腺癌

目的观察^125I放射微粒植入对前列腺癌的治疗效果。方法对26例临床确诊为前列腺癌患者经皮穿刺在癌组织植入^125I放射微粒，每例平均36粒，术后复查肛诊、B超、影像学及血生化指标。结果患者植入治疗经过顺利，2例少量出血，留置导尿后愈合，3个月后经肛诊、直肠B超示结节缩小，前列腺特异性抗原（PSA）降低，多普勒超声显示结节内动脉收缩期最大血流速度（VS）、阻力指数（RI）及动脉搏动指数（PI）均明显下降。结论^125I放射微粒植入对前列腺癌的治疗安全性好、效果可靠。     

Experimental investigation of the implementation of Fermi-Eyges-Hogstrom electron beam model of the Pinnacle3 system at extended SSDs.

A commercially available ADAC Pinnacle(3) radiation treatment planning system has been used to model electron beams from a Varian Clinac 2300C/D in the energy range of 6 to 22 MeV. Prior to clinical use, the dosimetric characteristics of the beams have to be modeled accurately. As a first step for beam modeling, a number of dose profile and depth dose measurements were taken at standard source-to-surface distance (SSD) of 100 cm. Dose profiles and depth dose measurements at extended SSDs up to 120 cm are important for ascertaining accuracy of the model, as well as their clinical usefulness in the treatment of some sites (e.g., head-and-neck tumors). Modeled and measured beam data were compared. Over 98% of comparison points (modeled vs. measured) at 100-cm SSD were within 2.5% or 2.5 mm. At 110 cm SSD, over 98% of compared points were within 4% or 4 mm, and at 120-cm SSD, over 98% of compared points were within 5% or 5 mm. Overall, more than 98% of compared points were within 4% or 4 mm. Better models were produced for lower energies (6 to 15 MeV) than higher energies (18 and 22 MeV). For 6, 9, 12, and 15 MeV, 89% of compared points were within 2% or 2 mm. For 18- and 22-MeV electron energies, 75% and 67%, respectively, were within 2% or 2 mm. These results are consistent with the recommendations of AAPM Task Group Report 53.     

Increase in levels of total free fatty acids in rat brain regions following 3-nitropropionic acid administration

Acute exposure to a neurotoxin, 3-nitropropionic acid (3-NPA), in rats results in an increase in total free fatty acid (FFA) concentration in selective brain regions. We investigated the effect of 3-NPA administration on the cerebral concentrations of FFA used as a marker of oxidative stress. Rats (n=3/group) were dosed subcutaneously (s.c.) either with a vehicle (phosphate buffer) or 3-NPA in phosphate buffer at 30 mg/kg body weight. Animals were sacrificed after 1, 2, 3, and 6 h of injection. Brains were then dissected into frontal cortex (FC), caudate nucleus (CN), and hippocampus (HIP). The concentration of total FFA increased from 130 to 300% within 1–2 h after 3-NPA injection in all brain regions when compared with the baseline level obtained from the control rats and taken as 100%. In CN, FFA returned to the baseline level within 3 h of treatment. However, in FC and HIP the concentration of FFA remained significantly elevated above the baseline until 6 h. The released FFA provide a substrate for free radicals formation. The results of this study suggest a role of oxidative stress in the mechanism of 3-NPA toxicity.     

Comparison of two-dimensional vs three-dimensional camera systems in laparoscopic surgery

Background: The lack of depth perception and spatial orientation in video vision are the drawbacks of laparoscopic surgery. The advent of a three-dimensional camera system enables surgeons to regain binocular vision and may be advantageous in complex laparoscopic procedures. Methods: We prospectively studied two groups of surgeons (with and without experiences in laparoscopic surgery) who performed a designated standardized laparoscopic task using a two-dimensional camera system (Olympus OTV-S4) vs a three-dimensional camera system (Baxter-V. Mueller VS7700) and compared their time performances. Results: The results suggested that only experience in laparoscopic surgery had significant effect on individual's performance. We could not demonstrate any superiority of the 3D system over the 2D system. However, two-thirds of the surgeons commented that the depth perception did improve. Conclusions: With further refinement of the technology, the 3D system may improve its potential in laparoscopic surgery.     

Reflex tear ascorbate in Hong Kong Chinese subjects: method comparison and biological variation.

BACKGROUND: Tear ascorbate is important for corneal health. A rapid and simple method for measurement of ascorbate in tears is needed, and adequate knowledge of physiological variation of tear ascorbate is important to facilitate comparative studies of the effect of, for example, contact lens wear and environmental conditions and stresses. However, there are currently no data on physiological variation of tear ascorbate. This study validated a simple and speedy method for tear ascorbate and investigated between-eye and between-day variation in tear ascorbate in healthy young adults. METHODS: Yawn-induced reflex tears were collected from 32 healthy Hong Kong Chinese subjects and measured by both high-performance liquid chromatography (HPLC) and by an enzyme-linked colorimetric method known as FRASC (total ferric reducing (antioxidant) activity and ascorbate concentration measurement). For between-eye variation, yawn reflex tears were collected from each eye of the same 32 healthy subjects, and ascorbate was measured using HPLC; in a separate experiment for between-day variation, tears were collected on two separate days from 14 subjects, and ascorbate was measured by FRASC. RESULTS: Both HPLC and FRASC showed high precision, and results obtained using FRASC were not statistically different from those using HPLC; mean +/- SD were, respectively, 18.5 +/- 4.4 microM and 18.5 +/- 4.8 microM for HPLC and FRASC methods (p = 0.943). No significant between-eye difference in tear ascorbate was found (p = 0.386), and no significant between-day variation was found overall: mean +/- SD ascorbate was 20.0 +/- 6.2 microM on day 1 and 19.3 +/- 6.8 microM on day 2 (p = 0.772). However, between-day variation was large in seven of 14 subjects. CONCLUSION: FRASC is an acceptable alternative to HPLC for measurement of tear ascorbate. Tears for ascorbate investigation can be collected from either eye or, if necessary, from both eyes and pooled. However, tear ascorbate may vary widely from day to day in the same individual. The reasons for this variation require further study but may relate to differences in ascorbate supply or demand within the precorneal tear layer.     

Renal function and urinary prostaglandins in rats given an adenine diet

The glomerular filtration rate (GFR), renal plasma flow (RPF) and renal blood flow (RBF) were all markedly decreased in rats given an adenine diet as the period of adenine administration lengthened. Concurrently, the urinary excretions of prostaglandin E2 (PGE2) and 6-keto-prostaglandin F1 alpha(6-keto-PGF1 alpha) decreased gradually in parallel with the renal function parameters, whereas the urinary excretion of thromboxane B2 (TXB2) increased markedly. These findings suggest the involvement of prostaglandin in the renal circulation.     

MR monitoring of MR-guided radiofrequency thermal ablation of normal liver in an animal model

The purpose of this study was to determine the suitability of MRI to accurately detect radiofrequency (RF) thermoablative lesions created under MR guidance. In vivo RF lesions were created in the livers of six New Zealand White rabbits using a 2-mm-diameter titanium alloy RF electrode with a 20-mm exposed tip and a 50-W RF generator. This was performed using a 0.2T clinical C-arm MR imager for guidance and monitoring. Each animal was sacrificed and gross evaluation was performed. Histologic correlation was performed on the first two animals. The MR-compatible RF electrode was easily identified on rapid gradient-echo images used to guide electrode placement. A single lesion was created in each rabbit liver. Lesions ranged from approximately 10 to 17 mm in diameter (mean, 13.5 mm). T2-weighted and short T1 inversion recovery (STIR) images demonstrated lesions ranging in diameter from 12 to 18 mm (mean, 14.6 mm). Lesion dimensions determined from images closely correlated with those determined at gross examination with the discrepancy never exceeding 2 mm, for an r² value of .87. MRI performed at the time of MR-guided RF ablation accurately demonstrated created lesions. This modality may provide a new option for the treatment of local and regional neoplastic disease.