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Biomedical subjects

C Lee

Publications and source records attributed to C Lee.

At least 1,081 records · Page 60Linked to original sources
PubMed1975

Effect of crosslinking on mitochondrial structure and function.

Rat liver mitochondria were treated with ethylacetimidate and methylbutyrimidate, monofunctional imidates, and with dimethylsuberimidate, a bifunctional imidate, and the effects on structure and function studied. Mitochondria treated with 5 mM dimethylsuberimidate or greater did not respond osmotically when placed in deionized water. Sodium dodecylsulfate-polyacrylamide gel electrophoresis revealed that at concentrations greater than 5 mM dimethylsuberimidate nearly all mitochondrial polypeptides failed to enter 6% gels, indicating crosslinking of both membrane and soluble proteins. Extensive amidination by ethylacetimidate and methylbutyrimidate had little effect on ascorbate-tetramethylphenylenediamine oxidase while extensive inhibition resulted from dimethylsuberimidate treatment. The possible involvement of molecular motion in electron transport is discussed.

Alkylating Agents↗
PubMed1975

Dose relationships of phase II, tachyphylaxis and train-of-four fade in suxamethonium-induced dual neuromuscular block in man.

In man under halothane-nitrous oxide-oxygen anaesthesia, suxamethonium-induced neuromuscular block can be divided into two phases using the train-of-four ratio: the first phase of minimal train-of-four fade and the second phase of marked train-of-four fade. The second phase is characterized by a low train-of-four ratio, 0.3 or less, and resembles tubocurarine-block) in many details. It corresponds to Phase II (dual block in the literature. Contrary to the prevailing belief, Phase II block has a rather abrupt onset. In this study of seven patients, Phase I covered up to a total of 1--3 mg/kg of suxamethonium, while 3--5 mg/kg established Phase II block, with a transitional zone of only 2 mg/kg. Establishment of Phase II also coincided with onset of unequivocal tachyphylaxis. The possibility of a causal relationship between tachyphylaxis and Phase II block is suggested.

Adult↗
PubMed1975

Catecholamine-binding brain protein in mice exposed to perinatal malnutrition and neonatal infection.

The formation and specific activity of a catecholamine-binding brain protein were studied in mice exposed to perinatal malnutrition and neonatal infection. In the malnourished group, the total norepinephrine (NE)-binding protein was less than in the control group (malnourished 7.1-10.0 mg; control 13.0-14.0 mg), but the dopamine (DM)-binding protein was not significantly affected. In the infected group, the quantity of NE-binding protein was also decreased (infected 6.4-8.0 mg), but the DM-binding protein was higher than in the control group. The specific and total binding activity of [3H]NE to brain protein was greatly reduced in the infected group (infected 22.6 pmol/mg protein; control 88.4 pmol/mg protein), and decreased also in the guanidine-HCl eluate of the malnourished group (56.5 pmol/mg protein). The binding activity of [14C]DM was decreased markedly in the infected group (infected 131 pmol/mg protein; control 330 pmol/mg protein), but its specific binding activity was not as severely affected in the malnourished as in the infected group. The molecular weights of the catecholamine-binding protein were 75,000 in the control, 70,000 in the malnourished and 65,000 in the infected groups. There were no marked differences between the malnourished and control groups with regard to the amino acid composition of the NE-binding protein. The DM-binding protein in these animals had decreased amino acid content. The infected group exhibited remarkable changes in NE- and DM-binding brain protein.

Amino Acids↗
PubMed1975

In vitro interaction of estrogen and prolactin on hormone-dependent rat mammory tumors (38511).

Hormone-dependent, regressing mammary tumors in rats were incubated in a chemically defined culture medium containing tritium labeled leucine at 37 degrees for 2 hr. The rate of tritium incorporation into the protein fraction by these tissues was measured with and without the addition of 17beta-estradiol and/or ovine prolactin into the medium. Tumor tissue responded to either estrogen or porlactin by a 6-7% increase in the rate of 3-H-leucine incorporation. When the incubation medium contained both the hormones, the increase in the rate of 3-H leucine incorporation was 19% which was significantly greater than the sum of the effect of each single hormone measured independelntly. These results demonstrate a synergistic effect between estrogen and prolactin on rat mammary tumors.

Animals↗
PubMed1971

Estrogen receptor in the rabbit corpus luteum.

The rabbit corpus luteum contains a cytoplasmic estrogen receptor substance in concentrations comparable to those found in the uterus. Receptor in corpora lutea of nonpregnant rabbits was highest at midluteal phase and decreased before physical regression of corpora was evident. These results support the view that the corpus luteum in this species is an estrogen-responsive tissue.

Animals↗