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Biomedical subjects

S J Liu

Publications and source records attributed to S J Liu.

At least 109 records · Page 6Linked to original sources
PubMed1983

Regeneration of re-covered bark in Eucommia ulmoides.

The girdled trunk of Eucommia ulmoides, sometimes could not regenerate a new bark due to ringed surface necrosis. But, if an extension of 10cm of the bark on each end of the necrotic part was removed in time and re-covered with new bark taken from another tree, the re-covered bark and the newly girdled part could heal together one week after. Opposite to the necrotic surface the loose part of the re-covered bark regenerated callus from the phloem ray cells. If the re-covered part was very close to the necrotic surface, no callus was regenerated. However, many scattered tracheid-like elements derived from phloem were found. And then groups of cells including several tracheid-like elements were discernible. There was a ring of meristematic cells around that group of cells. Finally these meristems gradually became normal and had usual activities of vascular cambium.

Medicine, Chinese Traditional↗
PubMed1976

Effects of desipramine treatment on the biliary, fecal and urinary excretion of methadone in the rat.

The effects of desipramine (DMI) given i.p. 1 hour before administration of 14C-methadone (5 mg/kg s.c.) on the excretion of methadone in bile, feces and urine were studied. Rats with cannulated bile ducts excreted 52% of administered 14C into bile within 4 hours, 60% of the excretion as 2-ethylidine-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) and 30% as water-soluble metabolite (WSM). The percentages of 14C excreted within 48 hours into the feces and urine of rats without biliary fistula were 60.6 and 17.4%, respectively. The excretion of 14C in feces consisted mostly of EDDP. Urinary excretion consisted of unchanged methadone, EDDP and WSM in the first 12 hours and consisted mostly of WSM thereafter. DMI treatment increased biliary flow but decreased the biliary excretion of 14C, mainly by a decrease in WSM. The fecal output was greatly decreased by DMI, thus decreasing fecal excretion of 14C in the first 12 hours. DMI treatment markedly decreased urinary volume but did not change the urine pH. The decreased urinary excretion of WSM in DMI-treated rats during the first 12-hour urine sample accounted for most of the decreased elimination of 14C. It is suggested that DMI-induced inhibition of methadone metabolism in the liver is a major factor responsible for the observed decreases in the biliary and urinary excretion of WSM...

Animals↗
PubMed1975

Interactions of tricyclic antidepressants and barbiturates in barbiturate-tolerant and nontolerant rats.

Pretreatment of rats with tricyclic antidepressants, imipramine, desipramine, amitriptyline and nortriptyline, at two doses (5 and 25 mg/kg) 20 minutes before administration of barbiturate markedly reduced the latent period of the response to barbital and prolonged the sleeping time induced by pentobarbital (PB) and barbital. The effects were dose-dependent. The prolonged sleeping time produced by PB was associated with decreases in the rates of disappearance of PB from the brain and plasma. The effect of tricyclic antidepressants on PB hypnosis in PB-tolerant and nontolerant rats was apparently not related to change in central nervous system (CNS) sensitivity to PB, since at the time of awakening there were no significant differences in the concentrations of unmetabolized PB in either the plasma or brain of tricyclic antidepressant-treated animals as compared to controls. As barbital is not metabolized, potentiation of barbital hypnosis by tricyclic antidepressants must be attributable to a direct effect on CNS rather than on liver microsomal enzymes. Direct evidence was provided by the findings that amitriptyline accelerated the brain uptake of barbital and that amitriptyline-treated animals lost and recovered the righting reflex at brain barbital levels lower than those of controls. Rats made tolerant to the hypnotic effect of barbital also became tolerant, in varying degrees, to the hyposis-prolonging properties of tricyclic antidepressants. It is concluded that tricyclic antidepressants prolong PB sleeping time in PB-tolerant and nontolerant rats by inhibiting its biotransformation in the liver. The action of tricyclic antidepressants to prolong the hypnotic action of barbital in normal rats is related to their direct effects on CNS sensitivity to barbital, but such effects are makedly diminished after animals become tolerant to barbital.

Amitriptyline↗
PubMed1975

Increased analgesia and alterations in distribution and metabolism of methadone by desipramine in the rat.

Treatment of rats with desipramine (DMI) 1 hour before the subcutaneous administration of methadone increased the intensity and prolonged the duration of methadone analgesia, as determined by the hot plate method. DMI significantly reduced the analgesic ED50 of methadone from a control value of 3.4 to 1.6 or 0.5 mg/kg in rats treated with 20 or 30 mg/kg of DMI, respectively. DMI treatment also significantly reduced the LD50 of methadone. DMI (20 mg/kg i.p.) was given 1 hour prior to administration of 14C-methadone (5 mg/kg s.c.) and the distribution of total 14C, unchanged methadone and methadone metabolites in various tissues was studied. DMI treatment greatly increased the brain uptake of 14C and the methadone brain/plasma concentration ratios for up to 3 hours. The concentrations of 14C and unchanged methadone were higher in kidneys and lower in lungs of DMI-treated rats as compared to controls. However, the ratios of unchanged methadone to its metabolites in kidneys and lungs were not changed significantly by DMI treatment. The level of unchanged methadone in liver was markedly elevated by DMI treatment at 45 and 90 minutes (190 and 183% of controls, respectively). The level of a water-soluble glucuronide metabolite of methadone was significantly decreased at 45-, 90- and 180-minute intervals (37, 36 and 54% of controls, respectively.) However, the total 14C in liver and the concentrations of two N-demethylated metabolites of methadone were not changed significantly. In vitro addition of DMI to liver microsomal incubations resulted in inhibition of the N-demethylation of methadone. It is suggested that DMI potentiated and prolonged methadone analgesia by increasing the brain concentration of methadone and by inhibiting metabolism of methadone in the liver.

Analgesia↗