[Influence of blue light from visual display terminals on human ocular surface].

Objective: To investigate the influence of blue light from visual display terminals (VDTs) on human ocular surface. Methods: Prospective intervention test Thirty volunteers were recruited to watch videos on the same VDT in a dark environment, about 40 cm from the screen. Volunteers were supposed to watch videos in the night shift mode that reduces the amount of blue light for 1 hour. At the same time of the second day, they watched the same videos on the VDT in the normal mode for 1 hour. Tear film break-up time (BUT), corneal fluorescein staining scores, lipid layer thickness (LLT), times of blinking in 19.1 seconds and the ratio of partial blinking in 19.1 seconds were measured before and after each watching. Meanwhile, volunteers were asked to complete a questionnaire about their subjective experience after watching. Results: BUT, corneal fluorescein staining scores and LLT showed no significant decreases in the volunteers after they watched videos on the VDT in the night shift mode [BUT before watching: (8.08±3.15)s, BUT after watching in the night shift mode: (5.31±2.49)s, t=-0.52, P>0.05], but there were significant decreases after they watched videos in the normal mode [BUT after watching in the normal mode: (3.35±1.95) s, t=2.40, P<0.05]. At the same time, there was a significant difference between night shift mode and normal mode[BUT after watching in the night shift mode (5.31±2.49)s, BUT after watching in the normal mode: (3.35±1.95)s, t=3.67, P<0.05). Times of blinking and the ratio of partial blinking in 19.1 seconds were increased modestly after watching in 2 different modes, but there was no significant difference(times of blinking after watching in the night shift mode were 5.55±3.27, times of blinking after watching in the normal mode were 5.93±3.59, t=-0.92, P>0.05). The questionnaire results showed that 70.0%(21) of the volunteers reported mild discomfort including eye dryness, itching, pain, foreign body sensation, redness and asthenopia, 46.7%(14) reported no difference between the 2 modes, 36.7%(11) preferred the night shift mode, 16.6%(5) felt better with the normal mode, and 80.0%(24) would like to try the night shift mode in their daily life. Conclusions: Use of VDTs for a short period of time can lower the stability of tear film. The night shift mode may cause less damage to the ocular surface than the normal mode. High-energy blue light from VDTs can be a risk factor in the ocular surface damage, but the damage is reversible. (Chin J Ophthalmol, 2018, 54: 426-431).

Increase in intracellular free/bound NAD[P]H as a cause of Cd-induced oxidative stress in the HepG(2) cells.

The present study shows the use of confocal autofluorescence spectroscopy coupled with the time-resolved fluorescence decay analysis to measure changes in FAD/NAD[P]H and free/bound NAD[P]H in HepG(2) cells at 0.5, 1.5, 3 and 4.5h after exposure to cadmium chloride (Cd). These changes were compared to changes in GSSG/GSH and production of reactive oxygen radicals (ROS) production. The results demonstrated that both FAD/NAD[P]H and GSSG/GSH increased significantly upon exposure to Cd. The change in GSSG/GSH occurred as early as 1.5h after treatment while the change in FAD/NAD[P]H did not occur until 3h after exposure. Production of ROS was also increased at 1.5h. The ratio of free/bound NAD[P]H was studied. It was demonstrated that free/bound NAD[P]H increased significantly as early as 0.5h and remained elevated until 4.5h after treatment with Cd. The present study provides novel data to show that changes in NAD[P]H metabolism precedes the increase in ROS production and cellular oxidative stress (increase GSSG/GSH, FAD/NAD[P]H). It is suggested that Cd causes a release of NAD[P]H, an important cofactor for electron transfer, from its normal protein binding sites. This may result in a disruption of the activity of the enzyme and proteins, and may lead to the subsequent toxic events.

A GIS-based prediction and assessment system of off-site accident consequence for Guangdong nuclear power plant.

GNARD (Guangdong Nuclear Accident Real-time Decision support system) is a decision support system for off-site emergency management in the event of an accidental release from the nuclear power plants located in Guangdong province, China. The system is capable of calculating wind field, concentrations of radionuclide in environmental media and radiation doses. It can also estimate the size of the area where protective actions should be taken and provide other information about population distribution and emergency facilities available in the area. Furthermore, the system can simulate and evaluate the effectiveness of countermeasures assumed and calculate averted doses by protective actions. All of the results can be shown and analysed on the platform of a geographical information system (GIS).

Preliminary study of in vivo autofluorescence of nasopharyngeal carcinoma and normal tissue.

BACKGROUND AND OBJECTIVE: In nasopharyngeal cancer, conventional white light endoscopy does not provide adequate information to detect the flat/small lesion and identify the margin of observable tumor. In the present study, we evaluate the potential of light-induced fluorescence spectroscopic imaging for the localization of cancerous nasopharyngeal tissue. STUDY DESIGN/MATERIALS AND METHODS: We built a multiple channel spectrometer specifically for the investigation of fluorescence collected by a conventional endoscopic system. Nasopharyngeal fluorescence were measured in vivo from 27 subjects during the routine endoscopy. The biopsy specimens for histologic analysis were taken from the tissue sites where the fluorescence were measured. RESULTS: Two algorithms to discriminate the nasopharyngeal carcinoma from normal tissue were created based on the good correlation between the tissue autofluorescence and histologic diagnosis. For the two-wavelength algorithm, carcinoma can be differentiated from normal tissue with a sensitivity and specificity of 93% and 92%, respectively. For the three-wavelength algorithm with compensation of variation of blood content in tissue, a sensitivity of 98% and specificity of 95% were achieved. CONCLUSION: Fluorescence endoscopic imaging used with the algorithms developed in this report is an efficient method for detecting the nasopharyngeal carcinoma.

Excitation-and-collection geometry insensitive fluorescence imaging of tissue-simulating turbid media.

We present an imaging technique for the correction of geometrical effects in fluorescence measurement of optically thick, turbid media such as human tissue. Specifically, we use the cross-polarization method to reject specular reflection and enhance the diffusive backscattering of polarized fluorescence excitation light from the turbid media. We correct the nonuniformity of the image field caused by the excitation-and-collection geometry of a fluorescence imaging system by normalizing the fluorescence image to the cross-polarized reflection image. The ratio image provides a map of relative fluorescence yield, defined as the ratio of emerging fluorescence power to incident excitation, over the surface of an imaged homogeneous turbid medium when fluorescence excitation-and-collection geometries vary in a wide range. We investigate the mechanism of ratio imaging by using Monte Carlo modeling. Our findings show that this technique could have a potential use in the detection of early cancer, which usually starts from a superficial layer of tissue, based on the contrast in the tissue fluorescence of an early lesion and of the surrounding normal tissue.

Concentration measurements of multiple analytes in human sera by near-infrared laser Raman spectroscopy.

Our primary goal in this study is to demonstrate that near-infrared Raman spectroscopy is feasible as a rapid and reagentless analytic method for clinical diagnostics. Raman spectra were collected on human sera by use of a 785-nm excitation laser and a single-stage holographic spectrometer. A partial-least-squares method was used to predict the analyte concentrations of interest. The prediction errors of total protein, albumin, triglyceride, and glucose in human sera ranged from 1.0% to 10%, which are highly acceptable for clinical diagnosis, of their mean physiological levels. For investigating the potential application of near-infrared Raman spectroscopy in screening of therapeutical drugs and substances of abuse the concentrations of acetaminophen, ethanol, and codeine in water solution were measured in the same fashion. The errors of the Raman tests for acetaminophen and ethanol are lower than their toxic levels in human serum, and the sensitivity for detection of codeine fails to reach its toxic level.

Lymph node metastasis and retroperitoneal lymphadenectomy in ovarian cancer.

While clinicians are devoting themselves to the study of the behaviour of ovarian cancer as well as to the search for more effective therapeutic modalities, little attention has been paid to an important route of metastasis in this group of diseases: retroperitoneal spread through the lymphatic pathway. The purpose of this report is to present a 5-year experience of a prospective study on lymph node metastasis in patients with ovarian cancer through retroperitoneal lymphadenectomy at the Peking Union Medical College Hospital. From June 1982 through May 1987, retroperitoneal lymph node dissection was performed in 105 cases of ovarian cancer. Seventy-seven (73.3%) were histologically diagnosed as cancer of epithelial origin, and 28 (26.7%) as germ-cell tumours. The overall incidence of retroperitoneal positive nodes was 54.3% (57/105). The incidence of positive pelvic nodes was 46.7% (49/105), and that of positive para-aortic nodes was 37.5% (30/80). In 69 patients who underwent systemic lymphadenectomy, 39 were found to have glandular involvement; in these 39 patients both aortic and pelvic nodes were positive in 19 cases (48.7%), aortic nodes were positive and pelvic nodes negative in 7 cases (18.0%), and pelvic nodes were positive and aortic nodes negative in 13 cases (33.3%). Preoperative lymphography was performed in 30 cases. The positive and negative correspondence rates with the pathological findings were both 83.3%. In 38 cases in which the primary cancer originated in the left ovary, 17 (44.7%) were found to have positive pelvic nodes, whereas in 25 cases with primary cancer arising in the right ovary only 2 (8%) had metastasis of the ipsilateral pelvic nodes. The lymph nodes obtained from 22 patients with positive nodes and sufficient preoperative chemotherapy were carefully examined under the microscope for the effects of the drugs. Some cellular degeneration of the lymph node metastasis was observed in only one of the 15 cases of epithelial cancer, and no response at all was noted in three cases of immature teratoma. Cellular degeneration accompanied by extensive necrosis was demonstrated in the metastatic tumours of the lymph nodes in all four cases of endodermal sinus tumour. Seventy-two patients were followed-up for at least 2 1/2 years. The rate of complete remission was 46.7% (14/30) in patients with negative nodes, but only 33.3% (14/42) in those with positive nodes. However, the difference was not statistically significant.

[Hemihepatectomy under hepato-portal interruption at normal temperature for liver malignancies--a report of 20 patients].

From July 1984 to December 1985, hemihepatectomy was done in 20 liver cancer patients under normothermic interruption of porta hepatis. There were 19 primary and 1 secondary liver carcinomas. Of the former, 17 (89%) were associated with mild or moderate cirrhosis. The peak age ranged 36-60 years. Right hemihepatectomy was performed in 18 and left hemihepatectomy in 2 with an operative mortality of 0%. Hepatic failure or secondary bleeding was not found. In the specimens resected, the largest weight was 2,500 gm. The normothermic interruption of porta hepatis usually lasted 15-25 minutes, a time long enough for hemihepatectomy. This procedure, being simple in manipulation and less detrimental to physiologic and biochemical balance in the human body, is relatively practical and beneficial to hepatectomy.

Lymph node metastasis of ovarian cancer: a preliminary survey of 74 cases of lymphadenectomy.

Retroperitoneal lymph node dissection was performed in 74 cases of various types of ovarian malignancies. Fifty-three (71.6%) were histologically confirmed as cancer of epithelial origin and 19 (25.7%) as germ cell tumors. The results indicate that lymphatic metastasis is an exceedingly important route of spreading of this group of malignant diseases. The overall incidence of retroperitoneal positive nodes was 56.8% (42/74). In 49 cases undergoing systemic lymphadenectomy 32 were found to have glandular involvement, of which both aortic and pelvic nodes were positive in 17 cases (53.1%), aortic nodes positive but pelvic negative in six (18.8%), and pelvic nodes positive but aortic negative in nine (28.1%). In 32 cases with primary cancer that originated from the left ovary, 17 (53.1%) were found to have positive pelvic nodes, whereas in 19 cases with cancer arising from the right ovary, only one (5.3%) had metastasis of ipsilateral pelvic nodes. The routes of lymphatic spreading and the significance of lymphadenectomy in ovarian cancer are discussed.

Peripheral nerve conduction velocity in workers occupational exposed to lead.

The peripheral nerve conduction velocity between the wrist and elbow of the right upper limb and the relationship between this parameter and biochemical parameters for workers occupationally exposed to lead were studied. The results showed that nerve conduction velocity could be altered by lead exposure. The nerve conduction velocity was decreased when the exposure level was 0.0652 mg/m3 (time-weighed average), and it slowed further in proportion to increasing exposure levels. There was a negative correlation between the nerve conduction velocity and the length of exposure. A decrease in the nerve conduction velocity was noted after less than three years of exposure to lead. There was a close relationship between the nerve conduction velocity and the level of lead in the blood; the nerve conduction velocity decreased proportionally with increasing blood lead levels. The blood lead level associated with a change in the nerve conduction velocity was less than 40 micrograms/100 ml (less than 1.9 mumol/l). No correlation between the nerve conduction velocity and the amount of metabolites of porphyrin was found. The measurement of nerve conduction velocity can be used as one of the sensitive criteria for the early detection of the toxic effects of lead.

Laparoscopy in the diagnosis and management of ovarian cancer.

Ninety-two laparoscopies were performed for diagnosis and follow-up on 83 patients with clinical diagnoses of ovarian cancer from May 1979 to May 1981. With laparoscopy about 10% of the cases were disproven; of suspicious cases only 53% were confirmed. Laparoscopy was very helpful in clarifying the clinical diagnosis of ovarian carcinoma. Laparoscopy for follow-up evaluation of treatment was done on 44 patients. Very early recurrence, which is very difficult to detect on clinical examination, was found with second-look laparoscopy. If few adhesions are present, laparoscopy can replace second-look exploration in the majority of cases of complete remission.