Intraluminal Research Articles

Bimodal nuclear estrogen receptor binding: synchrony in athymic mouse uterus and human breast tumor xenografts.

Human MCF-7 tumors were transplanted into ovariectomized female athymic nude mice supplemented with estradiol pellets. Ten days after hormone pellet removal, the animals were treated with 10 micrograms/kg estradiol, and the nuclear estrogen receptor (ERn) profile was assessed by the exchange assay. The pattern in the tumors was qualitatively similar to that in the uterus. A bimodal pattern of ERn was seen, with peaks at 1 and 8 h. Further biochemical analysis of uterine samples showed that both peaks were comprised of similar levels of salt-resistant ERn forms. Scatchard plot analysis of estradiol binding demonstrated high affinity receptors (Kd = 0.73-0.86 nM) as components of both peaks. In the ovariectomized adult rat there was also a bimodal pattern of ERn 1 and 13-14 h after the injection of 20 micrograms/kg estradiol. Direct hormone stimulation of the uterus was achieved with intraluminal (IL) injection of estradiol. IL injections of estradiol (100-800 pg/horn) stimulated uterine DNA synthesis compared to IL saline injections in the contralateral horn. IL injection of 200 pg/horn estradiol resulted in a bimodal pattern of ERn at 3 and 9 h. These data indicate that a bimodal pattern of ERn is present in estrogen target tissues exhibiting a growth response.

PROTECTION AGAINST INTESTINAL REPERFUSION INJURY BY DEXAMETHASONE (DM)

Studies have implicated oxygen radicals in the etiology of necrotizing enterocolitis (NEC). DM, a membrane stabilizer, may protect against oxidant injury of cells. We assessed the role of DM in gut ischemia and reperfusion, which produces experimental NEC. Laparotomy under anesthesia was performed in 16 rabbits. In each, 4 intestinal loops, 5 cm long, were prepared. Only 2 of these loops were rendered ischemic for 5 min., the other 2 loops serving as non-ischemic controls. 8 rabbits were pre-treated with IV DM (0.1 mg/kg); in the other 8, Intraluminal (IL) DM (1 mg) was injected into 2 loops while the other 2 were injected with saline (S). The animals were sacrificed 4 hrs. after surgery. All ileal loops were fixed and examined histologically by a single pathologist unaware of group assignment. Histological changes were graded. The non-ischemic loops were normal. DM (IV & IL) was fully protective against reperfusion injury, with two exceptions. These dramatic results suggest that DM may prevent experimental intestinal necrosis.

Evaluation of the 4cases of dissecting aneurysms which underwent surgical treatment with an int raluminal ringed graft

Evaluation of the 4cases of dissecting aneurysms which underwent surgical treatment with an int raluminal ringed graft

Displacement of estradiol-17-beta from the uterus by estradiol-17-alpha: effect on template capacity of uterine chromatin.

Administration of 6,7-3H-estradiol- 17β to mature ovariectomized rats results in the labeling of 2 pools of estradiol-17β in the uterus. Half-lives of the 2 pools are 0.7 and 5 hr. Intraluminal (IL) uterine application of 10 μg of estradiol-17α 6 hr after administration of 3Hestradiol- 17β is capable of enhancing the rate of displacement of the previously bound active estrogen from the uterus. By the 12th hr the uterine levels are 30-50% less than in saline treated controls. The reduced estradiol-17β content is reflected in the relative labeling of uterine chromatin prepared from the 2 groups. When assayedassayed for its capacity to serve as a template for DNA-dependent RNA polymerase, it was found that treatment with estradiol-17α prevented the additional increase in template capacity of uterine chromatin normally observed to occur between the 6th and 12th hr after treatment with estradiol-17β. These results suggest that estradiol- 17α and perhaps other estrogenic compounds with subdued biological activity may well able to inhibit certain estrogen induced uterine responses which are in progress at the time treatment. (Endocrinology83: 585, 1968)

EFFECT OF HISTAMINE AND ESTROGEN ON THE GLYCOGEN CONTENT OF THE RAT UTERUS.

Intraluminal (IL) histamine and control saline solutions were administered to spayed rats to ascertain whether histamine could reproduce the uterine H2O and glycogen effects elicited by estrogen in 24 hr. Intramuscular (im) or IL injections of estrogen caused a 2–3% increase in H2O. This response was accompanied by a 3-fold increase in uterine glycogen. IL administration of histamine did not reproduce the water and glycogen responses evoked by estrogen. Free histamine produced no H2O imbibition, and the glycogen increase was only ⅓ of that effected by estrogen, while histamine dihydrochloride elicited neither a water nor glycogen response. Tissue sections showed that histamine-treated uteri had an increase in leukocyte content accompanying the small glycogen increase, while sections from estrogen-treated animals showed no leukocytic increase. Operational control procedures associated with the IL injections accounted for a 2% increase in H2O as well as a 20% increase in glycogen. Since, 24 hr after adminis...