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Biomedical subjects

C Y Su

Publications and source records attributed to C Y Su.

103 records · Page 6Linked to original sources
PubMed1979

Serotoninergic mechanisms of beta-endorphin-induced hypothermia in rats.

The effects of intraventricular administration of beta-endorphin on thermoregulatory responses of unanesthetized rats to different ambient temperatures (Ta) of 8, 22 and 30 degrees C were assessed. Administration of beta-endorphin produced a fall in rectal temperature at both Ta 8 and 22 degrees C. The hypothermia in response to beta-endorphin was brought about by both cutaneous vasodilation (as indicated by an increase in both the tail and the foot skin temperatures) and decreases in metabolic heat production. However, at Ta 30 degrees C, administration of beta-endorphin produced no change in rectal temperature or other thermoregulatory responses. Furthermore, the hypothermic effect induced by beta-endorphin was greatly attenuated by either the depletion of brain serotonin levels (with 5,6-dihydroxytryptamine and p-chlorophenylanine) or the blockade of opiate receptors (with naloxone). The data indicate that beta-endorphin leads to hypothermia in rats by increasing sensible heat loss and decreasing metabolic heat production, probably via the release of endogenous serotonin within brain.

Animals↗
PubMed1979

Metabolic, respiratory, vasomotor and body temperature responses to beta-endorphin and morphine in rabbits.

1. The effects of beta-endorphin and morphine on thermoregulatory responses of unanaesthetized rabbits to different ambient temperatures (Ta) of 2, 22 and 32 degrees C were assessed. 2. Intraventricular administration of either beta-endorphin or morphine produced dose-dependent hypothermia at 2 and 22 degrees C Ta. At 2 degrees C Ta the hypothermia was brought about solely by a decrease in metabolic heat production. At 22 degrees C Ta the hypothermia was due to a decrease in metabolism and an increase in peripheral blood flow. However, at 32 degrees C Ta, there were no changes in rectal temperature in response to either beta-endorphin or morphine application. 3. Hypothermic effects of the administration of beta-endorphin or morphine were greatly antagonized by pretreatment of animals with either an opiate antagonist naloxone or a serotonin depletor 5,6-dihydroxytryptamine. 4. These findings indicate that the hypothermic responses to beta-endorphin or morphine in rabbits may be mediated through central serotonergic mechanisms. The hypothermia was due to a decrease in heat production and/or an increase in heat loss.

5,6-Dihydroxytryptamine↗
PubMedDate not supplied

Molecular aspects of persistent woodchuck hepatitis virus and hepatitis B virus infection and hepatocellular carcinoma.

It seems evident that the development of fully malignant HCC is a multistage process with many variables. One possible mechanism by which many of these variables may interact is as follows. During chronic active hepatitis, viral DNA integration occurs randomly and at a low frequency in hepatocytes. Integration may be stimulated by the increased rate of hepatocyte cell division resulting from liver necrosis and regeneration during chronic disease. The presence of viral integrations in the cellular genome provides focal points for the generation of chromosomal aberrations. One pathway by which these aberrations may be generated involves rearrangement of integrated viral and cellular sequences following viral DNA integration. The rearrangements which occur may include deletion, translocation, transposition or amplification of specific viral and cellular DNA sequences. We and others have directly demonstrated that all of these events are associated with different HBV integrations. The presence of viral integrations in chromosomes may also, by some unknown mechanism, destabilize those chromosomes such that whole chromosomes fail to segregate and are lost from particular cells. Preliminary studies we have conducted using restriction fragment length polymorphisms have revealed the loss of Chromosome 11 alleles in several HCC, indicating that chromosome loss may be a common occurrence in HCC. Our studies with restriction fragment length polymorphisms support such a mechanism involving Chromosome 11 in HCC. Specific chromosomal aberrations associated with all HCCs have not yet been identified.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Combined use of an amniotic membrane and tissue adhesive in treating corneal perforation: a case report.

We report a new method combining the use of an amniotic membrane and cyanocrylate tissue adhesive to seal a corneal perforation. A 47-year-old male suffered from an alkali injury complicated with corneal melting and perforation in the left eye. We placed an amniotic membrane of optimal size in the anterior chamber directly under the corneal perforation lesion. The cyanocrylate tissue adhesive was then applied over the perforation site and sealed successfully. Three weeks later, the tissue adhesive had dislodged. The amniotic membrane had sealed the perforated lesion and was well adhered to the surrounding corneal tissue with complete epithelial covering. Vision was 20/25 six months after the operation. The combined use of an amniotic membrane and tissue adhesive is a promising method in the treatment of corneal perforation.

Amnion↗