Biomedical subjects

X C Huang

Publications and source records attributed to X C Huang.

5 recordsLinked to original sources

PubMed1992

DNA sequencing using capillary array electrophoresis.

A DNA sequencing method is presented that utilizes capillary array electrophoresis, two-color fluorescence detection, and a two-dye labeling protocol. Sanger DNA sequencing fragments are separated on an array of capillaries and detected on-column using a two-color, laser-excited, confocal-fluorescence scanner. The four sets of DNA sequencing fragments are separated in a single capillary and then distinguished by using a binary coding scheme where each fragment set is labeled with a characteristic ratio of two dye-labeled primers. Since only two dye-labeled primers are required, it is possible to select dyes that have identical mobility shifts. It is also shown that the ratio of the signal in the two detection channels provides a reliable identification of the sequencing fragment. DNA sequencing results on a 25-capillary array are presented.

Base Sequence↗

PubMed1992

Capillary gel electrophoresis of single-stranded DNA fragments with UV detection.

Capillary gel electrophoresis has proven to be a powerful tool in biomedical research. We report our investigation of some of the critical parameters affecting separations of single-stranded DNA fragments as monitored by ultraviolet (UV) absorbance detection. Although not as sensitive as laser-induced fluorescence (LIF), UV absorbance detection allows one to calculate quite accurately, and inexpensively, the molarity of each separated DNA fragment and, moreover, the signal "fading" effect normally observed with LIF detection can be, in many cases, substituted for fluorescence to detect the many different single-stranded DNAs, as well as for detection of sequencing reactions.

Coliphages↗

PubMed1990

[A study of DNA content in relation to histological type, ER and CEA in primary breast carcinoma].

The immunohistochemical technique (ABC and PAP methods) and microspectrophotometry were used separately to localize estrogen receptor (ER) and carcinoembryonic antigen (CEA) and to measure the DNA content in 44 cases of primary breast carcinoma. The results showed that (1) there was significant statistical difference in DNA content among most histological types of breast carcinoma (P less than 0.05); (2) the DNA content was inversely correlated with ER status (P less than 0.05) and positively with CEA (P less than 0.05) in breast cancer; (3) the mean values of DNA content and nuclear area were higher in patients survived more than 5 years than in those survived less than 5 years. It is suggested that the DNA content was roughly consistent with the grades of malignancy of the histological types of carcinoma, and the changes of DNA content not only affected the expression of ER and CEA but are also correlated with the refractoriness to hormone therapy in some patients with ER positive tumor.

Adenocarcinoma, Scirrhous↗

PubMed1989

Conditions for uniqueness of limit cycles in general predator-prey systems.

Using a transformation to a generalized Lienard system, theorems are presented that give conditions under which unique limit cycles for generalized ecological systems, including those of predator-prey form, exist. The generalized systems contain those studied by Rosenzweig and MacArthur (1963); Hsu, Hubbell, and Waltman (1978); Kazarinnoff and van den Driessche (1978); Cheng (1981); Liou and Cheng (1987); and Kuang and Freedman (1988). Although very similar in approach to the result presented by Kuang and Freedman, the conditions presented here are of simpler form and in terms of the original (untransformed) functions. The results also apply to more general growth terms for the prey as shown in the examples provided. In particular, an immigration term is allowable.

Animals↗

PubMedDate not supplied

Comparison of TRH and its analog (NS-3) in thermoregulatory and cardiovascular effects.

The effects of TRH and its metabolically stable analog NS-3 [(3R,6R)-6-methyl-5-oxo-3-thiomorpholinylcarbonyl-L-histidyl-L-pro linamide tetrahydrate] on thermoregulation and circulatory control have been investigated. Both NS-3 (1-100 ng/kg ICV) and TRH (0.1-10 micrograms/kg ICV) increased rectal temperature and metabolic rate with a transient cutaneous vasoconstriction in conscious rabbits. They also increased arterial blood pressure, heart rate, respiratory rate, and renal sympathetic nerve activity (RSNA) in urethane-anesthetized rabbits. Ten ng/kg of NS-3 and 10 micrograms/kg of TRH had comparable hyperthermic, pressor, and tachycardic activities, while the relative potency of NS-3 to increase RSNA was greater and that to increase metabolic rate was smaller than the other effects. In conclusion, NS-3 was more potent than TRH in all of the effects measured, but there was a dissociation in the relative potency of NS-3 in the different autonomic effects.

Animals↗