Assessment of extent of breast cancer: comparison between digital breast tomosynthesis and full-field digital mammography.

AIM: To compare the accuracy of digital breast tomosynthesis (DBT) and full-field digital mammography (FFDM) in preoperative assessment of local extent of breast cancer. MATERIALS AND METHODS: Lesion sizes of breast cancers on DBT and FFDM images were independently evaluated by breast radiologists. Each lesion was flagged as either mis-sized or not depending on whether the assessment of size at imaging was within 1 cm of the lesion size at surgery. Additional analyses were made by mammographic parenchymal density and by lesion size, using 2 cm as the boundary to separate the two subgroups. Statistical comparisons were performed using a repeated measures linear model on the percent mis-sized. P-values < 0.05 were considered statistically significant. RESULTS: The dataset included 173 malignant breast lesions (mean size 23.8 mm, 43% of lesions were ≤2 cm in size) in 169 patients, two-thirds of which had heterogeneously or extremely dense breasts. Overall, the percentage of lesions mis-sized at DBT was significantly lower than at FFDM (19% versus 29%, p = 0.003). There was significantly less mis-sizing at DBT in both heterogeneously dense breasts (11.1% difference between DBT and FFDM, p = 0.016) and extremely dense breasts (15.8% difference, p = 0.024). DBT also had significantly less mis-sizing than FFDM in the subgroup of lesions that were ≤2 cm in size (14.7% difference, p = 0.005). CONCLUSION: DBT was significantly superior to FFDM for the evaluation of lesion size overall, and specifically for small lesions and for lesions in dense breasts. The superiority of DBT versus FFDM increased with parenchymal density.

Dual effect of N-methyl-N-(1-methyl-4-pyrolidino)-2-butyl)acetamide on release of (3H)-acetylcholine from the rat hippocampal slices.

The effect of muscarinic cholinergic drugs on (3H)-acetylcholine [3H)-Ach) release from slices of rat hippocampus was investigated either in the presence of eserine or hemicholinium-3 (HC-3), 10 microM each. BM-5 (N-methyl-N-(1-methyl-4-pyrolidino-2-butyl)acetamide) is a partial muscarinic cholinergic agonist. Like oxotremorine, BM-5 significantly (p less than 0.012) decreased the release of (3H)-Ach in the presence of HC-3. In the presence of eserine, (3H)-Ach release was significantly (p less than 0.001) enhanced both by atropine and BM-5. The decrease or increase in release of (3H)-Ach by BM-5, in the presence of HC-3 or eserine, respectively, may be due to its partial agonist effect on hippocampal muscarinic cholinergic receptors.

Inhibition of the 5-lipoxygenase pathway with piriprost (U-60,257) protects normal primates from ozone-induced methacholine hyperresponsive small airways.

Weekly exposure to ozone in seven normal Rhesus monkeys led to induction of methacholine hypersensitive airways (RL increases 242 +/- 60% and Cdyn decreases 68 +/- 13% of baseline methacholine responses). It took 19 weeks to establish this hyperresponse that persisted for greater than 15 weeks once ozone was stopped. A second exposure led to similar response peaks in 6 weeks. At the peak of the second response, weekly 1% piriprost exposure before ozone led to a return to baseline that was not different between placebo and piriprost treated animals (9.4 +/- 1.0 and 4.3 +/- 2.9 weeks, placebo and treated, respectively P = 0.09 NS). A statistical difference in the mecholyl response in placebo and piriprost treated groups while on ozone was shown only in the Cdyn measurement (Cdyn% change 68 +/- 13 vs 24 +/- 14, placebo and piriprost, respectively P = 0.03). Off ozone (or return to baseline), a statistical difference could be detected both in RL and Cdyn (RL% changed 151 +/- 41 vs 31.1 +/- 49, P = 0.03, and for Cdyn 62.7 +/- 8 vs 9 +/- 10, P = 0.0006, placebo and piriprost, respectively). We conclude tha the primate provides a chronic model of airways reactivity in which the role of lipoxygenase is implicated because of the beneficial role of piriprost, and further that the ozone lesion is primarily in the smaller airways (possibly and alveolitis).

Leukotriene B4 binding to human neutrophils.

[3H] Leukotriene B4 (LTB4) binds concentration dependently to intact human polymorphonuclear leukocytes (PMN's). The binding is saturable, reaches equilibrium in 10 min at 4 degrees C, and is readily reversible. Mathematical modeling analysis reveals biphasic binding of [3H] LTB4 indicating two discrete populations of binding sites. The high affinity binding sites have a dissociation constant of 0.46 X 10(-9)M and Bmax of 1.96 X 10(4) sites per neutrophil; the low affinity binding sites have a dissociation constant of 541 X 10(-9)M and a Bmax of 45.16 X 10(4) sites per neutrophil. Competitive binding experiments with structural analogues of LTB4 demonstrate that the interaction between LTB4 and the binding site is stereospecific, and correlates with the relative biological activity of the analogs. At 25 degrees C [3H] LTB4 is rapidly dissociated from the binding site and metabolized to 20-OH and 20-COOH-LTB4. Purification of neutrophils in the presence of 5-lipoxygenase inhibitors significantly increases specific [3H] LTB4 binding, suggesting that LTB4 is biosynthesized during the purification procedure. These data suggest that stereospecific binding and metabolism of LTB4 in neutrophils are tightly coupled processes.

Detergent solubilization of human neutrophil leukotriene B4 receptors.

Specific leukotriene B4 (LTB4) receptors in human neutrophils were solubilized by treatment of "receptor fraction" membranes with the zwitterionic detergent (3-[(3-cholamidopropyl)-dimethylammonio]1-propane sulfonate (CHAPS). The soluble receptors were assayed by polyethylene glycol (PEG) precipitation coupled with Millipore filtration. The solubilized receptors retained all of the characteristics of the receptor sites in intact neutrophils. The binding of LTB4 was rapid, reversible and stereospecific. Mathematical modeling analysis revealed biphasic binding of [3H] LTB4 indicating two classes of binding sites. The high affinity binding site had a dissociation constant of 1.93 nM and Bmax of 281 fmoles/mg protein; the low affinity binding site had a dissociation constant of 78.92 nM and Bmax of 2522 fmoles/mg protein. Competitive binding experiments with structural analogs of LTB4 demonstrate that the interaction between LTB4 and its binding site is stereospecific and correlates with the relative biological activity of the analogs. These data suggest that it may be possible to purify the LTB4 receptor from human neutrophil membranes.

Evidence for leukotriene B4 receptors in human neutrophils.

[3H]LTB4 binds concentration-dependently to intact human PMNs. The binding is saturable, reaches equilibrium in 10 min at 4 degrees C, and is readily reversible. Mathematical modeling analysis reveals biphasic binding of [3H]LTB4, indicating two discrete populations of binding sites. The high-affinity binding sites have a dissociation constant of 0.46 X 10(-9) M and a Bmax of 1.96 X 10(4) sites per neutrophil; the low-affinity binding sites have a dissociation constant of 541 X 10(-9) M and a Bmax of 45.16 X 10(4) sites per neutrophil. Competitive binding experiments with structural analogues of LTB4 demonstrate that the interaction between LTB4 and the binding site is stereospecific and correlates with the relative biological activity of the analogues. At 25 degrees C, [3H]LTB4 is rapidly dissociated from the binding site and metabolized to 20-OH- and 29-COOH-LTB4. Purification of neutrophils in the presence of 5-lipoxygenase inhibitors significantly increases specific [3H]LTB4 binding, suggesting that LTB4 is biosynthesized during the purification procedure. These data suggest that stereospecific binding and metabolism of LTB4 in neutrophils are tightly coupled processes.

Myeloid differentiated HL-60 cells display specific leukotriene B4 binding sites.

Exposure of HL-60 cells for 6 days to a combination of 1.25% (v/v) dimethyl sulfoxide (DMSO) and 10 microM dexamethasone (DEX) induces myeloid differentiation which results in a cell with many of the characteristics of a mature granulocyte. At 4 degrees C myeloid differentiated, but not undifferentiated, monocytic differentiated or eosinophilic differentiated HL-60 cells display marked specific leukotriene B4 binding. Leukotriene B4 binding at 4 degrees C reaches a maximum within 10 min, is readily reversed by unlabelled leukotriene B4, and is stereospecific. Only molecules with structural and biological similarity to leukotriene B4 can competitively inhibit leukotriene B4 binding. Scatchard analysis at 4 degrees C in differentiated cells shows two classes of binding sites. The high affinity sites have a Kd of 0.27 nM and a Bmax of 14.8 fmoles/10(7) cells; the low affinity sites have a Kd of 0.58 microM and a Bmax of 2453 fmoles/10(7) cells. The appearance of specific leukotriene B4 binding sites in the myeloid differentiated cells correlates with their ability to chemotax in response to leukotriene B4. Undifferentiated cells do not chemotax to leukotriene B4. At 37 degrees C leukotriene B4 is incorporated into phospholipid and triglyceride species in both undifferentiated and myeloid differentiated HL-60 cells making binding studies at 37 degrees C in intact cells impossible. Interestingly, incubation of the cells with cyclooxygenase inhibitors during differentiation enhances receptor density. No evidence of omega-hydroxylase activity was found in HL-60 cells. These data suggest that the HL-60 cell may be an excellent model system for the study of leukotriene B4 receptor binding, processing and gene expression.

Competitive irreversible inhibition of dopamine uptake by 6-hydroxydopamine.

We examined the effects of 6-hydroxydopamine (6-OHDA) treatment on the human neuroblastoma cell line SK-N-SH-SY5Y (SY5Y) and the rat pheochromocytoma cell line, PC12. Structural and metabolic integrity was tested by measuring the ability of cells to transport the non-metabolizable amino acid analogue [3H]-alpha-aminoisobutyric acid (AIB). We determined that treatment with 6-OHDA at concentrations of 49 microM and 62 microM inhibited 50% of the AIB uptake in SY5Y and PC12 cells, respectively. Inhibition of AIB uptake was prevented by the addition of catalase, but was not influenced by the addition of 1 mM dopamine. This indicated that cell damage resulted from the generation of H2O2 and was independent of the catecholamine uptake system. Effects directly on the catecholamine uptake system were observed by measuring the uptake of 3H-dopamine. In contrast to the effects on amino acid uptake, dopamine uptake was significantly inhibited by 6-OHDA treatment, and this inhibition was not prevented by the addition of catalase. The results indicate a Ki of 430 microM for inhibition of dopamine uptake by 6-OHDA treatment of PC12 cells. The results are consistent with a competitive irreversible inhibition of the dopamine uptake sites by 6-OHDA or one of its metabolites. Thus, the lack of a catecholamine uptake-dependent cellular toxicity appears to result from the direct inactivation of catecholamine uptake sites. Similarly, the inhibition of dopamine uptake in vivo by 6-OHDA may be explained, at least in part, by direct inactivation of dopamine uptake sites rather than exclusively by intracellular transport and action of 6-OHDA.

Intrinsic activity determinations at the dopamine D2 guanine nucleotide-binding protein-coupled receptor: utilization of receptor state binding affinities.

Guanine nucleotide-binding protein-coupled receptors have been shown to exist in both a high affinity agonist (HiAg) and a low affinity agonist (LowAg) state. The formation of the HiAg state is promoted by agonists, and the formation of this state of the receptor appears to be a critical factor in the generation of the effector-activating complex G alpha.GTP.Mg2+ and in the production of a stimulus. The magnitude of the difference in the affinity a compound has for the HiAg versus the LowAg state of the receptor has been related to the intrinsic activity of the compound. In this paper the HiAg and LowAg affinities (Ki) of full and partial dopamine agonists of varying levels of intrinsic activity were determined using membranes from Chinese hamster ovary cells stably transfected with the D2i receptor. The HiAg state was defined using the recently described dopamine agonist ligand [3H]U-86170, and the LowAg state was defined using [3H] raclopride plus 600 microM GTP. The LowAg/HiAg ratios for apomorphine (43), HW-165 (12.5), (-)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine [(-)-3-PPP] (4.5), terguride (1.6), SDZ-208-911 (1.2), and SDZ-208-912 (0.3) were found to correlate well with their electrophysiologically derived intrinsic activities (r = 0.92). Using this relationship, the intrinsic activity for compounds such as (+)-3-PPP (112%), quinpirole (104%), U-68553B (102%), and U-86170 (95%) was predicted to be high (greater than 90%); (-)-apomorphine (73%) was of high/moderate intrinsic activity, HW-165 (52%), (+)-apomorphine (51%), and (-)-3-PPP (34%) were in the intermediate range, and terguride (16.5%), SDZ-208-911 (11.7%), and SDZ-208-912 (-12%) were at the lower end of the intrinsic activity spectrum. The receptor state binding-determined intrinsic activity values for quinpirole (100%), U-86170F (94.8%), HW-165 (52.1%), (-)-3-PPP (34.3%), SDZ-208-911 (11.7%), and SDZ-208-912 (-12%) were found to correlate well (r = 0.908) with their maximum response (intrinsic activity), as determined using ATP-mediated increases in arachidonic acid release from CHO-D2i cells. In addition, the maximal effect of several of these compounds on rat striatal homovanillic acid (HVA) levels was determined. The drug-induced changes in tissue HVA levels were found to be consistent with the affinity-derived intrinsic activities of the drugs.(ABSTRACT TRUNCATED AT 400 WORDS)

Platelet-derived growth factor potentiates cellular responses of articular chondrocytes to interleukin-1.

Recombinant human interleukin-1 alpha (IL-1 alpha) induced a time-dependent (0-72 hours) and concentration-dependent (0.01-10 ng/ml) production of metalloproteinases (collagenase, gelatinase, stromelysin) and prostaglandin E2 (PGE2) in rabbit articular chondrocytes (RAC). Exposure of RAC to recombinant human platelet-derived growth factor homodimer BB (PDGF-BB; 2-200 ng/ml) in the presence of stimulatory and substimulatory concentrations of IL-1 alpha resulted in a marked augmentation of metalloproteinase and PGE2 production. PDGF-BB exerted no agonist effects on RAC responsiveness. PDGF-BB up-regulated the number of IL-1 receptors per chondrocyte but had no effect on receptor affinity. Cycloheximide and actinomycin D caused a concentration-dependent suppression of the PDGF-BB-mediated potentiation of radiolabeled IL-1 alpha binding to RAC and cell responsiveness to IL-1 alpha. Similarly, IL-1 increased the number of PDGF receptors on RAC without changing receptor affinity. These data are discussed within the context of cytokine-growth factor interactions as components of the pathogenesis of arthritic diseases.

The effect of endocervical PGE2-gel (Prepidil) gel on plasma levels of 13,14-dihydro-15-keto-PGE2 (PGEM) in women at term.

Term pregnant patients undergoing preinduction cervical softening were randomized to receive no treatment (controls) or 0.5 mg PGE2-triacetin gel (Prepidil gel) endocervically. Plasma samples containing PGEM collected 4 hrs post-treatment and converted to the stable bicyclo degradation product (bicyclo-PGEM) were assayed by RIA. Positive clinical effect (responders) during 12 hrs after treatment (Bishop score increase greater than or equal to 3, in labor or delivered) were assessed. All evaluations were blind. In nonresponders (n = 35), the means of the bicyclo-PGEM variables (mean, maximum, area under the curve) were all about 18% higher in gel-treated patients (n = 6) than controls (n.s.). In responders (n = 38), the variables were all about 80% higher in gel-treated women (n = 32) than controls (p less than .01). In controls (n = 35), the responders (n = 6) had 50% higher levels than nonresponders (n.s.). In the gel-treated women (n V 38), responders (n = 32) had about 140% higher levels than nonresponders (less than .01). The results suggest that both exogenous and endogenous bicyclo-PGEM were measured. Differences in pairwise comparisons suggest that there may be substantially less exogenous bicyclo-PGEM in the gel nonresponders than in gel responders or substantially more endogenous bicyclo-PGEM in gel responders than in control-responders.

Steroid-induced urogenital tract changes and urine retention in laboratory rodents.

Since previous literature suggested that estrogen-treated male mice are models for human benign prostatic hypertrophy, a series of studies was designed to examine urine retention and urogenital tract changes in rodents given chronic estradiol-17 beta (E) and dihydrotestosterone (DHT) treatments. In Study 1, intact and castrate male mice received E, DHT or E plus DHT for four weeks via subcutaneous Silastic capsules. Bladder urine volume increased in the groups given E and this effect was not altered by castration, DHT or removal of E capsules two weeks before necropsy. Estrogen treatment also increased mortality. In Study 2, intact male, intact female, adrenalectomized (Adx) male and sham Adx male mice received 16 weeks of steroid treatments. Bladder urine volume increased in all E treated groups regardless of sex or Adx. Hydronephrosis, hydroureter and increased mortality were found in the E treated mice of both sexes. Estrogen induced epithelial changes and edema of the prostate, vas deferens and the utriculus prostaticus. In further studies male rats, hamsters and guinea pigs were given several different dosages of E but no evidence of urine retention or increased mortality was found. Taken together these studies suggest that E-induced urine retention is unique to mice. Although urine retention and hydronephrosis found in the mice were similar to those in humans with BPH, the lesion that results in the urine obstruction is not similar.