Additive growth-inhibitory effects of DL-alpha-difluoromethylornithine and antiestrogens on MCF-7 breast cancer cell line

We studied the growth inhibitory effects of DL-alpha-difluoromethylornithine, and antiestrogens (tamoxifen, 4-hydroxytamoxifen, trioxifene, keoxifene, and LY117018) as single agents and in combinations on the proliferation of a breast cancer cell line, MCF-7. At 0.1 mM difluoromethylornithine, the proliferation of MCF-7 cells was inhibited to 75 +/- 6% of the controls. Treatment of the cells with 0.1 microM 4-hydroxytamoxifen reduced cell growth to 72 +/- 4%. Combination of 0.1 mM difluoromethylornithine and 0.1 microM 4-hydroxytamoxifen reduced cell growth to 38 +/- 5%, indicating additive growth inhibitory effects. Similar additive effects were observed with all 5 antiestrogens in combination with difluoromethylornithine.

Fibromatosis of the breast: a case report and literature review

Fibromatosis is an uncommon, relatively benign though locally infiltrating neoplasm consisting of well-differentiated fibroblasts surrounded by collagen bundles. The majority of the literature suggests that prevention of local recurrence mandates wide (en bloc) excision. Few more than a dozen cases of primary breast fibromatosis have been reported. Herein the clinical characteristics, diagnostic evaluation, and therapeutic options are presented. Management should be based upon principles utilized for extra-mammary primary disease-en bloc resection. This may require total mastectomy and removal of pectoralis major muscle. Breast reconstruction should be deferred for a minimum of 3 years, during which time the majority of recurrences will have become manifest.

Structural alterations and stabilization of rabbit uterine estrogen receptors by natural polyamines

Estrogenic regulation of gene expression involves interaction of the hormone with its receptors, which undergo structural and conformational changes to interact with specific DNA sequences. Putrescine, spermidine, and spermine, are ubiquitous cellular components. We studied the effects of these polyamines on rabbit uterine estrogen receptors by sucrose gradient centrifugation and ligand dissociation kinetics. The native 7S receptor converted to a 9S-10S form in the presence of 100 microM spermidine or spermine. Higher concentrations caused precipitation of the receptor. This precipitation was reduced by RNase treatment of the receptor. RNase-treated receptors sedimented at 4S and 7S regions of sucrose gradient. The dissociation rate constant (k) of the 4S receptor is 2.8 X 10(-3) min-1 in the presence of 1 mM spermidine, compared to a control value of 7.7 X 10(-3) min-1. Similar effects were observed with putrescine and spermine. The dissociation of the RNase-treated 7S receptor was biphasic, with about 50% of the receptors dissociating at a faster rate (k1 = 40 X 10(-3) min-1) than the other half (k2 = 7.4 X 10(-3) min-1). Spermidine (1 mM) caused a 2-fold reduction in k2, whereas k1 was not affected. This study shows that polyamines affect the structural organization and ligand dissociation kinetics of estrogen-receptor complexes.

Aldosterone and the mobilization of energy

Aldosterone diminishes the ability to endure starvation. Its exogenous administration to adrenalectomized rats advances the onset of hypothermia and death. The impairment seems to lie in an inability to mobilize energy stores fully: animals given the steroid are unable to lose weight at a normal rate. The findings help to establish the significance of mineralocorticoids in the regulation of energy exchange and solve some theoretical questions as to their general mode of action.

The selective role of endoscopic sclerotherapy in the management of bleeding esophageal varices

Twenty-one patients (62% Child's C) underwent endoscopic sclerotherapy (ES) to control hemorrhage from esophageal varices. Four patients exsanguinated; bleeding was controlled in the remaining 17 patients (81%). Of this latter group, 14 patients were discharged from the hospital and three patients died from causes other than hemorrhage. A protocol of continued ES was offered to those patients with estimated poor hepatic reserve and to those with excellent reserve who refused portasystemic shunt procedures. During a mean 13 month follow-up of the six patients in this group, rebleeding occurred in two patients (one of whom died). All three patients with excellent hepatic reserve who underwent elective portacaval shunt have suffered neither morbidity nor further hemorrhagic episodes. No significant morbidity related to ES was encountered. ES is recommended in the acute phase of managing all patients with unremittent variceal hemorrhage, and on a continued basis for those with poor hepatic reserve. Patients with excellent reserve should be offered elective portasystemic shunt, accepting the risk of surgical intervention as fair trade-off for its superiority over ES in controlling hemorrhage.

Ribonuclease-induced transformation of progesterone receptor from rabbit uterus

The effect of RNase on the transformation of progesterone receptor from rabbit uterus was studied by density-gradient centrifugation and DNA-cellulose binding assay. The 7S form of the receptor in crude cytosol was RNase sensitive, and converted to the 4S form after RNase treatment. This reaction was prevented by an RNase inhibitor and reversed by the addition of ribosomal RNA. RNase treatment also caused a two-fold increase in the DNA binding of cytosolic receptor, and reduced the time required for heat-induced transformation. However, sucrose-gradient-purified progesterone receptor (7S) did not undergo transformation by warming unless exogenous RNase was added, thereby suggesting that a cytosolic factor, which might be endogenous RNase, is necessary for the heat-induced transformation of progesterone receptor. Furthermore, degradation of the receptors which occurred after prolonged warming at 25 degrees C in the presence of RNase could be prevented by the addition of DNA-cellulose to the reaction mixture. These results indicate that RNA is associated with the 7S form of progesterone receptor, and that its hydrolysis by RNase might be involved in the transformation of this receptor.

Effect of ribonuclease on the physico-chemical properties of estrogen receptor

Estrogen receptors (ER) from rat and rabbit uterine cytosol were examined for their sensitivity to ribonuclease (RNase). After RNase treatment, a major part of rabbit uterine ER was converted from the 7S to 3-4S form, and its binding to DNA-cellulose was increased by 40%. Similar treatment on rat uterine ER showed a shift from 7S to 4.5S, and the DNA-cellulose binding was stimulated by 20%. Measurement of endogenous RNase levels showed that lower RNase concentration in rabbit uterine cytosol coincided with larger stimulation of DNA-cellulose binding by exogenous RNase. These results indicate that a major part of 7S ER is susceptible to RNase, and cleavage of bound RNA seems to uncover additional binding sites for DNA. In contrast to the general thinking that 4S to 5S transformation is essential for nuclear binding, we have observed that RNase-treated rat uterine ER did not undergo such a transformation by warming at 25 degrees C, while DNA-cellulose binding of the receptors increased. Thus, temperature activation could occur independent of 4S to 5S transformation.

Acute-phase response of plasma protein synthesis during experimental inflammation in neonatal rats

The pattern of plasma protein concentrations in neonatal rats differs characteristically from that in adult animals. Immediately after birth, the concentration of alpha 2-macroglobulin is about 200 times higher, that of major acute-phase alpha 1-protein the same, and that of alpha 1-acid glycoprotein, another acute phase protein, is considerably lower, compared with the values observed in healthy adults. The concentration of prealbumin, a negative acute-phase protein, remains low in the immediate postnatal period, but increases at a time when concentrations of both thyroxine and corticosterone increase. At this time, there is also a distinct increase in the concentration of alpha 1-acid glycoprotein. Despite the differences in concentration of plasma proteins in the adult rat and the neonate, the neonatal liver has the capability to respond to an acute inflammation with a coordinated change in the synthesis rates of plasma proteins similar to that observed in adult animals.

Characterization of nuclear estradiol receptors released by micrococcal nuclease and deoxyribonuclease I

Interaction of estradiol receptor with chromatin was probed by nuclease digestion of receptor-chromatin complex. The complex was formed by incubating partially purified receptor with chromatin. Micrococcal nuclease digestion of the complex released a 7S form of receptor which could be converted to 2.8S form by DNAase I. Digestion of the complex with DNAase I yielded different forms of receptors ranging from 7S to 2.8S depending on the digestion time. Receptor distribution was also examined by isolating nuclei form tissue pre-incubated with radioactive estradiol. Micrococcal nuclease digestion of receptor-filled nuclei released 7S, 5.5S and 3.5S forms of receptors. Collectively, these results indicate that the 7S nuclear receptor may have an associated chromatin fragment which is sensitive to DNAase I activity. The desirable features of receptor-chromatin method over conventional methods for studies relating to receptor interaction at the gene site are discussed.

Two classes of estrogen receptors which differ in their activation mechanisms

Studies on the mechanism of activation of estrogen receptor (ER) have led us to identify two classes of receptors. Effect of molybdate on the activation of ER was determined by their affinity for nuclei or DNA-cellulose. Molybdate caused inhibition of nuclear binding with rat uterine ER, but an increase in the binding was observed with rabbit uterine ER. Similar results were observed when DNA-cellulose was used instead of nuclei. To further test the diversity in ER activation, DNA-cellulose binding of ER from 10 primary breast cancer tissues was determined in the presence or absence of molybdate. ER from 8 tissues showed inhibition of binding, one showed an increase, and one was not affected by molybdate. These results indicate the presence of two classes of ER, one whose activation is inhibited by molybdate and another whose activation is either unaffected or stimulated by molybdate. Other differences between rat and rabbit uterine ER are also discussed.

The pathological basis and microanatomy of occlusive thrombus formation in human coronary arteries

Myocardial necrosis, usually called infarction, occurs in different patterns. A common form is necrosis of one segment of the left ventricle, i.e., anterior, septal, lateral or posterior. This regional infarction is consistently associated with an acute occlusive thrombosis of the artery supply that region. Diffuse necrosis involving the whole circumference, usually the subendocardial zone, of the ventricle is not consistently associated with thrombi. Occlusive thrombi identified in post-mortem coronary arterio-grams have been reconstructed in their entirety from serial sections at 150 micron intervals. Most occlusive thrombi were found to be associated with a dissection track into the intima at an atheromatous plaque. The break into the plaque usually extended over several millimeters, often in spirals, so that a mass of thrombus within the plaque compressed the original lumen. Previous accounts of plaque rupture or cracking greatly underestimated the magnitude of the dissection of blood into the intima.

Nucleotide sequence changes in polyoma virus A gene mutants

The mutational alterations in polyoma virus mutants ts-a and ts-25E which cause their large T-antigens to be thermolabile have been identified. In ts-a, a G leads to A transition at nucleotide 2193 causes the replacement of Ala (GCT) by Thr (ACT). In ts-25E, a G leads to T transversion at nucleotide 2883 causes the replacement of Gly (GGC) by Cys (TGC). Revertants of both mutants have been isolated and shown to have the original nucleotides restored at these positions.

Viable deletion mutant in the medium and large T-antigen-coding sequences of the polyoma virus genome

A polyoma virus mutant that maps in the early region between the known hr-t and ts-a mutants has been isolated. Its 66-base-pair deletion results in structural changes in both medium and large T-antigens but causes no substantial alterations in viral replication or cell transformation.

Management of hyperstimulation syndrome

A case of hyperstimulation syndrome secondary to Pergonal therapy is presented. Successful management was based principally on severe sodium and fluid restriction without the use of volume expanders. The rationale for this therapeutic approach is presented and discussed. Although this iatrogenic disease should be virtually eliminated with the monitoring of daily urinary estrogens, severe hyperstimulation may still occur as a result of laboratory error.

Biphasic effect of the alpha-adrenolytic phentolamine on hormone-stimulated formation of cyclic adenosine-3',5'-monophosphate in isolated fat cells of rats

Isolated fat cells from rat epididymal adipose tissue were incubated with various lipolytic hormones in the absence and presence of the alpha-adrenergic blocking agent phentolamine. Lipolysis, stimulated by noradrenaline, isoproterenol, or ACTH, was inhibited dose-dependently by phentolamine. At concentrations of phentolamine where lipolysis was already inhibited, phentolamine had a biphasic effect on hormone-stimulated formation of cAMP. Low concentrations of phentolamine enhanced cAMP formation, while high concentrations inhibited cAMP. The additional increase of cAMP formation by phentolamine was only seen with maximally effective concentrations of noradrenaline, isoproterenol, and ACTH. Half-maximally effective concentrations were invariably inhibited by phentolamine. The activity of noradrenaline-stimulated adenylate cyclase of fat-cell plasma membranes was inhibited by phentolamine, whereas cAMP phosphodiesterase activity was unaffected.

Disordered blood coagulation in burned children receiving high molecular weight dextran

Coagulation studies were performed on nine children with burns. Four of these children received treatment which included intravenous dextran; all four showed abnormalities of coagulation and two of them developed a bleeding state. No abnormalities of haemostasis were detected in the remaining five children who had comparable degrees of burns but whose treatment did not include intravenous dextran.