Search

Objectives: This study examines the practice of the regulation of Standards for Medical Exposure Quality Assurance (SMEQA) in Taiwan based on on-site quality audit for radiation therapy systems from 2016 to 2019. Methods: 81 radiation therapy departments, 141 linacs, 9 γ knife systems, 34 high dose rate brachytherapy systems, 20 Tomotherapys, and 6 Cyberknives were audited yearly. Data collection and analysis for each institute’s documents including QA procedure, ion chamber and electrometer calibration reports, and a questionnaire relating to machine type and staffing, were requested first and reviewed by auditors. On-site SMEQA core item measurements, including beam output, beam profile and energy constancy for external beam therapy systems, and the source strength, positioning, and timer accuracy for brachytherapy systems were audited second. More than 300 photon beams and more than 400 electron beams were measured each year. Results: There were approximately 8.9 radiotherapy units per million population, and 1.2 medical physicists per unit in Taiwan. For the output measurements, more than 78 and 75% of the photon beams and electron beams, respectively, from linacs were with deviations within ±1.0%. Photon beams have lower beam quality measurement deviations than electron beams. Including in-plane and cross-plane measurements, more than 90 and 85% photon and electron beams, respectively, were with flatness consistency within 1.0%. All audit measurements were within the SMEQA acceptance criteria. Conclusions: According to SMEQA regulations on-site QA audits were successfully carried out from 2016 to 2019 for all Taiwan radiotherapy units. The measurement results showed high quality machine performance in Taiwan. Advances in knowledge: Dosimetry audits with directly acquired measurement readings have lower uncertainties; allow immediate feedback, discussion, and adjustment in a timely manner. In addition to regulation system establishment and education and training implementation, the machine quality is closely related to machine maintenance implementation.

Purpose: This study examines the practice of the regulation of Standards for Medical Exposure Quality Assurance (SMEQA) in Taiwan based on on-site quality audit for radiation therapy systems from 2016 to 2019. Methods and Materials: about 81 radiation therapy departments, 141 medical linear accelerators, 9 gamma knifes, 34 high dose rate brachytherapy systems, 20 Tomotherapys and 6 Cyberknives were audited yearly. The inspection was implemented in two stages. Data collection and analysis for each institute’s documents including QA operating procedure, ion chamber and electrometer calibration reports, and a questionnaire relating to machine type and staffing, were requested first and reviewed by specially trained auditors. On-site measurements of SMEQA core items, including beam output, beam profile and energy constancy for external beam therapy systems, and the source strength, positioning and timer accuracy for brachytherapy systems were audited second. More than 300 photon beams were measured from linacs, Gamma knives, Cyberknives and Tomotherapys, and more than 400 electron beams from linacs each year.Results: The radiation treatment resource is about 8.9 therapy machines or 7.5 MV/MeV/ion beam therapy machines per million population, respectively, and there are on average about 1.20 medical physicists per radiation therapy unit in Taiwan. There were more than 78% and 75% of photon and electron beams respectively from linacs with deviations measured to the stated reference-point dose within 1.0%. Photon beams have lower beam quality measurement deviations than electron beams, and more than 90% of photon beams from linacs were within 1.0%. Including in-plane and cross-plane measurements, more than 90% and 85% of photon and electron beams respectively with flatness consistency within 1.0%. Beam symmetry as an absolute value has more than 75% of measurements within 1.0%. All audit measurements in this study were within the SMEQA acceptance criteria.Conclusions: On-site machine QA audits have been implemented from 2016 to 2019 for all radiation therapy units each year. The measurement results have shown a high quality machine performance in Taiwan.

The present study investigated the neuroprotective effect of minocycline, a microglial inhibitor, against the retinal ischemia–reperfusion (IR) injury in the rat. The retinal IR injury was induced in Sprague–Dawley (SD) rats by infusing normal saline into anterior chamber of eye to create a higher intraocular pressure (IOP) than blood pressure for 45 min. Minocycline (45 and 90 mg/kg/day) was administered intraperitoneally to rats receiving IR injury. The neuroprotective effects were evaluated by morphometrical histology analysis 7 days after ischemia. The data was compared with the groups treated with saline and methylprenisolone (MP, 30 mg/kg, IV). The results showed that the retinal inner plexiform layer/outer nuclear layer (IPL/ONL) ratio was reduced following IR damage compared with that in the normal control. The IPL/ONL ratio was reduced to 43.5% in the IR-control group, 93.3% and 93.6% in the Mino-45 and Mino-90 group. The IPL/ONL ratio was preserved to 95.7% in the MP group. These results suggest that minocycline and methylprednisolone showed significantly good neuroprotective effects demonstrated in retinal histology of the rats under retinal IR injury.

Both mycelium and fruiting body of Antrodia camphorate, a traditional medicinal fungus of the family Polyporaceae in Taiwan, have been suggested to possess multiple biological functions. However, there is little information on the anticancer components and actions of mycelium of Antrodia camphorate. In the present study, the anticancer potential of synthesized maleimide derivatives, which have been isolated from mycelium of Antrodia camphorate, is examined. Comparing the cytotoxicity of two synthesized maleimide derivatives in four human cancer cell lines, camphorataimide B displayed potent efficacy. Then we investigated the impact of camphorataimide B on cell survival and cell cycle progression in vitro, and tumor growth in vivo in MDA-MB-231 breast cancer cells. Camphorataimide B decreased the cell viability and foci formation of MDA-MB-231 breast cancer cells. Further, camphorataimide B triggered apoptosis and blocked cell cycle progression of MDA-MB-231 breast cancer cells. Using immunoblotting analysis, camphorataimide B decrease the expression of cyclin-A and cyclin-B1. Moreover, we demonstrated for the first time that camphorataimide B inhibited cyclooxygenase-2 (COX-2) activity and protein expression in MDA-MB-231 cells. In nude mice study, camphorataimide B administration retarded the xenograft tumor growth of MDA-MB-231 cells. By immunohistochemical analysis, camphorataimide B decreased the expression of Ki-67 in xenograft tumor in vivo. It implied that camphorataimide B blocked cell cycle progression. Consistent with the cell culture investigation, camphorataimide B also reduced the expression of cyclin-A, cyclin-B1 and COX-2 in xenograft tumor. Thus, camphorataimide B may play a crucial role in prevention and therapy of malignant breast cancer.

Retinal ischemia is a common cause of visual impairment for humans and animals. The neuroprotective effects of lidocaine (LDC) and methylprednisolone (MP) upon retinal ischemic injury were investigated in a rat model. Sprague-Dawley rats were divided into 3 groups, the IR control, LDC and MP. A very high intraocular pressure (HIOP) and retinal ischemia were induced. In LDC group, LDC bolus (1.5 mg/kg) was i.v. injected 30 min before ischemia and then a constant rate infusion (CRI) with 2 mg/kg/hr was given until 60 min after reperfusion. In MP group, MP bolus (30 mg/kg) was i.v. administered twice at 2 min before and immediately after ischemia, respectively. The HIOP damage to retina was evaluated by electroretinogram (ERG) and morphometrical histology. The functional analysis of the retina by ERG revealed a 35.2% reduction of a-wave in the IR group, 49.7% reduction in the LDC group but no significant change in the MP group compared to normal controls. An 81.0% reduction of b-wave was observed in the IR group, 80.7% reduction in the LDC group and 17.6% reduction in the MP group. In the morphometrical histology, the retinal inner plexiform layer/outer nuclear layer (IPL/ONL) ratio was reduced to 48.8% in the IR group, 80.1% in the LDC group and 96.2% in MP group. In conclusion, the MP showed significantly good neuroprotective effects on retinal IR injury, and the LDC showed moderate neuroprotective effects demonstrated in retinal structure but not in retinal function.

Maxillary bone epithelial cyst is rare in dogs. A 5-year-old, spayed female miniature schnauzer developed a swelling below the nasal canthus of left eye. Plain radiograph demonstrated a 1.5 cm diameter of radiolucent lesion on the maxillary bone anteroventral to the eye, and contrast dacryocystorhinography confirmed an obstructed nasolarcrimal duct. The swelling showed poor response to antibiotic treatment but responded well to oral prednisolone. Exploratory surgery revealed a cyst-like structure filled with brown serous fluid. Histopathological examination of the removed cyst revealed a double cuboidal epithelial cyst. The dog recovered rapidly after surgery, and the swelling had not recurred for a 36-month follow-up. It is the first case of periorbital bone epithelial cyst reported in an adult miniature schnauzer.

Ocimum gratissimum is used as a traditional folk medicine in many countries. The objective of this study was to evaluate the antioxidant activities of an aqueous O. gratissimum extract (OGE) and to evaluate its cytoprotective activity against hydrogen peroxide-induced toxicity in human HepG2 cells. The results revealed that the total phenolic content of the OGE reached 20%. In the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, the OGE reduced up to 80% of the free radicals at a plateau concentration of 66.7 μg/mL. This indicates that OGE contains considerable free radical scavenging activity. In a dose-dependent manner, OGE pretreatment counteracted the decrease in cell viability in H2O2-treated HepG2 cells (p