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Biomedical subjects

C Levy

Publications and source records attributed to C Levy.

At least 127 records · Page 7Linked to original sources
PubMed1981

Early inhibition by progesterone of oestrogen-induced ornithine decarboxylase activity in the chick oviduct and rat uterus.

The oestradiol-induced increase of ornithine decarboxylase (ODC) activity in the 'withdrawn' chick oviduct was found to be inhibited by progesterone. In vitro (2 h at 37 degrees C), progesterone (1 mumol/l) abolished the effect of oestradiol (20 nmol/l), progesterone alone having no effect. In vivo, progesterone (3 mg/kg) inhibited approximately 70% of the augmentation of ODC activity induced in the oviduct within 2 to 6 h of treatment with oestradiol benzoate (1.5 mg/kg). Administration of progesterone alone in vivo caused an increase in the ODC activity, the maximum level measured after 6 h being similar to that obtained when the chicks were given both oestrogen and progesterone. In the rat uterus in vivo progesterone also inhibited the rise of ODC activity caused by oestradiol, approximately % inhibition being observed between 2 and 6 h after treatment. Progesterone alone had no effect on uterine ODC activity during this period.

Animals↗
PubMed1980

Assay of nuclear estradiol receptor by exchange on glass fiber filters.

A glass fiber filter exchange assay for nuclear estradiol receptor in human endometrium has been developed. It permits both exchange and measurement of bound radioactivity to be performed without any transfer of the nuclear preparations. Suspensions of nuclei containing estradiol-receptor complexes are adsorbed onto glass fiber filters. Receptor sites, both empty and occupied by endogenous hormone, are labelled by incubation with 20 nM [3H]estradiol without (total binding) or with 2 microM radioinert estradiol (nonspecific binding). Buffer containing unbound radioactive estradiol is then drained, the filters washed, transferred into vials and counted in toluene-based scintillator. Following removal from the scintillator, DNA content of the filters can be measured by the Burton procedure. This exchange technique is easy and specific, with accuracy and precision similar to those of the technique of Bayard et al. (Bayard, F., Damilano, S., Robel, P. and Baulieu, E.E. (1978) J.Clin. Endocrinol. Metab. 46, 635-648). It offers the advantage of increased sensitivity, allowing receptor determinations on nuclear samples containing more than 10 microgram DNA. Approximately 20 measurements can be made from 50 mg tissue (wet weight).

Cell Nucleus↗
PubMed1980

Estradiol and progesterone receptors in human endometrium: normal and abnormal menstrual cycles and early pregnancy.

Estradiol and progesterone receptor sites (empty or filled with endogenous hormone)have been measured in the cytoplasm and nuclei of human endometrium. Receptor changes have been observed throughout the normal menstrual cycle. During the preovulatory phase the cytoplasmic estradiol receptor sites do not change while the nuclear receptor sites more than double. Cytoplasmic estradiol receptor sites decrease very early in the secretory phase, whereas the decrease in nuclear sites occurs later. Cytoplasmic progesterone receptor sites more than double during the preovulatory phase and show a large decrease immediately after ovulation, when the concentration of nuclear receptor is at its highest. Thus the total cellular concentrations of both estradiol and progesterone receptors are lowest in the late secretory phase. It was found that they are positively correlated with the concentration of plasma estradiol only during the proliferative phase. The concentration of cytoplasmic progesterone receptor is negatively correlated with 17 beta-hydroxysteroid oxidoreductase activity during the secretory phase. In anovulatory cycles the concentrations of estradiol and progesterone receptors are high, similar to those of the late proliferative phase. "luteal insufficiency" is characterized by a very low concentration of estradiol receptor. Early pregnancy endometrium (8 to 10 weeks' gestation) is characterized by a large concentration of progesterone receptor, exceeding those of any period of the menstrual cycle.

Anovulation↗
PubMed1979

Serious infections from Bacillus sp.

Serious infections caused by organisms of the genus Bacillus developed in seven patients. Five drug abusers had either endocarditis or osteomyelitis, one leukemic patient had necrotizing fasciitis, and one patient had a ventriculoatrial shunt infection with recurrent bacteremia. All patients recovered. Experience with these cases reemphasizes the importance of not dismissing Bacillus organisms as culture contaminants, especially when isolated from blood, body fluids, or closed-space infections.

Adolescent↗
PubMed1975

Evidence for successful acceptance of irradiated free gingival allografts in dogs.

Free graft samples were excised via split thickness dissection from two mongrel dogs, washed in lactated Ringer's solution, immersed into tubes containing glycerol and distilled water, and frozen to -55 degrees C. Subsequently the grafts were exposed to 2.5 x 10-6 rads of 60-Co gamma-radiation. The irradiated allogeneic grafts were later reconstituted and surgically transferred to four recipient subjects. Three autogenous nonirradiated grafts were also placed as controls. The animals were killed so as to furnish healing data at 0, 3, 7, 10, and 40 days postoperatively. Fourteen allografts were evaluated. They were judged to be nonantigenic, immunologically incompetent and nonviable. However, retention of an essentially unaltered connective tissue corium may have been instrumental in supporting subsequent epithelial regeneration from adjacent host tissue, while being passively incorporated into a very dynamic receptor zone. The graft thus served as a scaffolding for connective tissue deposition and attachment. It appears that the experimental regime obviated the immunologic interference usually encountered in allografting procedures. Thus, high intensity irradiation of the graft tissue may have rendered the tissue to be immunologically tolerable. Further studies are required to ascertain the duration of the host's immunologic unresponsiveness to the alien tissue, as well as ultimate structural and biologic fate of the transplanted tissues. Experiments are now in progress which have been designed to test the extent of immunologic sensitization induced by the grafted tissue.

Animals↗