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Biomedical subjects

C Y Dong

Publications and source records attributed to C Y Dong.

6 recordsLinked to original sources
PubMed1998

New time-resolved techniques in two-photon microscopy.

Microscopy is traditionally a tool for determining biological structures. Many recent advances in optical microscopy involves the incorporation of spectroscopy techniques to monitor biochemical states of microscopic structures in living cells and tissues. By minimizing tissue photodamage, two-photon excitation microscopy provides a new opportunity to study the dynamics of biological systems on time scales from nanoseconds to hours. This review will focus on a number of these new methods: two-photon time-lapse microscopy, two-photon photoactivation, two-photon correlated spectroscopy, two-photon single particle tracking and two-photon lifetime microscopy.

Animals↗
PubMed1995

Fluorescence lifetime imaging by asynchronous pump-probe microscopy.

We report the development of a scanning lifetime fluorescence microscope using the asynchronous, pump-probe (stimulated emission) approach. There are two significant advantages of this technique. First, the cross-correlation signal produced by overlapping the pump and probe lasers results in i) an axial sectioning effect similar to that in confocal and two-photon excitation microscopy, and ii) improved spatial resolution compared to conventional one-photon fluorescence microscopy. Second, the low-frequency, cross-correlation signal generated allows lifetime-resolved imaging without using fast photodetectors. The data presented here include 1) determination of laser sources' threshold powers for linearity in the pump-probe signal; 2) characterization of the pump-probe intensity profile using 0.28 microns fluorescent latex spheres; 3) high frequency (up to 6.7 GHz) lifetime measurement of rhodamine B in water; and 4) lifetime-resolved images of fluorescent latex spheres, human erythrocytes and a mouse fibroblast cell stained by rhodamine DHPE, and a mouse fibroblast labeled with ethidium bromide and rhodamine DHPE.

Animals↗
PubMed1989

An analysis of prognostic factors in cirrhosis.

To develop a more comprehensive index for predicting the prognous of liver cirrhosis. 300 consecutive patients with cirrhosis were studied in terms of survival from 1975 to 1986. Median follow-up period was 5.3 years. A multivariable survival analysis (Cox's regression model) using clinical biochemical data obtained at admission disclosed eight factors of value in predicting prognosis: age, frequency of previous GI bleeding, ascites, hepatic encephalopathy, serum albumin, serum bilirubin, hemoglobin and prothrombin time. A prognostic index was constructed for the calculation of the estimated survival probability.

Adult↗
PubMed1983

Prevention of type 2 herpes simplex virus induced cervical carcinoma in mice by prior immunization with a vaccine prepared from type 1 herpes simplex virus.

Repeated intra-vaginal inoculation of mice with inactivated type 2 herpes simplex virus induced cervical carcinoma in approximately 50% of mice. Prior immunization with subunit vaccine Ac NFU1(S-) BHK reduced the frequency of cervical carcinoma to 19%. Inoculation of mice with a control preparation of uninfected cell extract never induced preinvasive or invasive cervical cancer. There was evidence of an antibody response in every vaccinated and/or innoculated animal. Mice developing cervical cancer had a significantly higher antibody titre to type 2 herpes virus than mice not developing cancer. These results are in general accord with sero-epidemiological studies of preinvasive and invasive cervical carcinoma in human subjects and suggests that this experimental model may be appropriate for further investigation of prevention of human cervical cancer by vaccination.

Animals↗