A key tool for monitoring breast cancer patients under neoadjuvant treatment is the identification of reliable predictive markers. Ki67 has been identified as a prognostic and predictive marker in ...ER-positive breast cancer. Ninety ER-positive, HER2 negative locally advanced breast cancer patients received letrozole (2.5 mg daily) and cyclophosphamide (50 mg daily) with/without Sorafenib (400 mg/bid daily) for 6 months before undergoing surgery. Ki67 expression and tumor size measured with caliber were determined at baseline, after 30 days of treatment and at the end of treatment. Patients were assigned to a clinical response category according to Response Evaluation Criteria in Solid Tumors, both at 30 days and before surgery and further classified as high-responder and low-responder according to the median variation of Ki67 values between biopsy and 30 days and between biopsy and surgery time. The predictive role of Ki67 and its changes with regard to clinical response and survival was analyzed. No differences in terms of survival outcomes emerged between the arms of treatment, while we observed a higher percentage of women with progression or stable disease in arm with the combination containing Sorafenib (20.5% vs 7.1%, p = 0.06). Clinical complete responders experienced a greater overall variation in Ki67 when compared with partial responders and patients with progressive/stable disease (66.7% vs 30.7%, p = 0.009). High responders showed a better outcome than low responders in terms of both disease-free survival (p = 0.009) and overall survival (p = 0.002). ΔKi67 score evaluated between basal and residual tumor at definitive surgery showed to be highly predictive of clinical complete response, and a potential parameter to be used for predicting disease-free survival and overall survival in luminal breast cancer treated with neoadjuvant endocrine-based therapy.
Mild pulmonary interstitial edema was shown to cause fragmentation of interstitial matrix proteoglycans. We therefore studied compartmental fluid accumulation by light and electron microscopy on ...lungs of anesthetized rabbits fixed in situ by vascular perfusion after 0.5 ml.kg(-1).min(-1) iv saline infusion for 180 min causing approximately 6% increase in lung weight. Morphometry showed that a relevant portion (44%) of extravascular fluid is detected early in the alveolar septa, 85% of this fluid accumulating in the thick portion of the air-blood barrier. The arithmetic mean thickness of the barrier increased in interstitial edema from 1.06 +/- 0.05 (SE) to 1.33 +/- 0.06 microm. The harmonic mean thickness increased from 0.6 +/- 0.03 to 0.86 +/- 0.07 microm, mostly due to thickening of the thin portion causing an increase in gas diffusion resistance. Despite some structural damage, the air-blood barrier displays a relatively high structural resistance providing a safety factor against the development of severe edema. It is suggested that the increase in extra-alveolar perivascular space occurs as a consequence of fluid accumulation in the air-blood barrier.
In the heart mitochondria exert two roles essential for cell survival: ATP synthesis and maintainance of Ca2+ homeostasis. These two processes are driven by the same energy source: the H+ ...electrochemical gradient (delta microH) which is generated by electron transport along the inner mitochondrial membrane. Under aerobic physiological condition mitochondria do not contribute to the beat to beat regulation of cytosolic Ca2+, although Ca2+ transient in mitochondrial matrix has been described. Increases in mitochondrial Ca2+ of mumolars concentration stimulate the Krebs cycle and NADH redox potential and, therefore, ATP synthesis. Under pathological conditions, however, mitochondrial Ca2+ transport and overload might cause a series of vicious cycles leading to irreversible cell damage. Mitochondrial Ca2+ accumulation causes profound alterations in permeability of the inner membrane to solutes, leading to severe mitochondrial swelling. In addition Ca2+ transport takes precedence over ATP synthesis and inhibits utilization of delta microH for energy production. These processes are important to understand the sequence of the molecular events occurring during myocardial reperfusion after prolonged ischaemia which lead to irreversible cell damage. During ischaemia an alteration of intracellular Ca2+ homeostasis occurs and mitochondria are able to buffer cytosolic Ca2+, suggesting that they retain the Ca2+ transporting capacity. Accordingly, once isolated, even after prolonged ischaemia, the majority of the mitochondria is able to use oxygen for ATP phosphorylation. When isolated after reperfusion, mitochondria are structurally altered, contain large quantities of Ca2+, produce excess of oxygen free radicals, their membrane pores are stimulated and the oxidative phosphorylation capacity is irreversibly disrupted. Most likely, reperfusion provides oxygen to reactivate mitochondrial respiration but also causes large influx of Ca2+ in the cytosol as result of sarcolemmal damage. Mitochondrial Ca2+ transport is therefore stimulated at maximal rates and, as consequence, the equilibrium between ATP synthesis and Ca2+ influx is shifted towards Ca2+ influx with loss of the ability of ATP synthesis.
The majority of calcium antagonists used clinically belong to three distinct chemical classes: the phenylalkylamines, the dihydropyridines, and the benzothiazepines. In recent years their mode of ...action has been unravelled, their limitations recognized, and their efficacy and use in the management of patients with a broad spectrum of cardiovascular and other disorders defined. It is clear, however, that these drugs are not all alike, providing an explanation for their differing effects. The final therapeutic effect in humans depends on the mechanisms of action at the molecular level, the tissue selectivity, and the hemodynamic changes of each agent. All these aspects are examined in detail in this article. Concepts that are highlighted are as follows: (a) Molecular biology has allowed recognition of the polypeptide components of the alpha 1 subunit of the L-type Ca2+ channel and the finding of peptide segments covalently labelled by all three classes of drugs. (b) The location of these segments within the peptides is different: Binding sites for dihydropyridines are located externally, whereas those for verapamil and diltiazem are located internally, in the cytosolic part of the membrane. (c) Dihydropyridine binding is voltage dependent. This explains the selectivity of this class of drugs for vascular smooth muscle, which is more depolarized than cardiac muscle. (d) Phenylalkylamines and benzothiazepines reach their receptors at the internal surface of the sarcolemma through the channel lumen. Their binding is facilitated by the repetitive depolarization of atrioventricular and cardiac tissue, a phenomenon described as use dependence. This explains why these drugs are not highly selective, but equipotent for the myocardium, the atrioventricular conducting tissue, and the vasculature. (e) Dihydropyridines act through selective vasodilatation and may increase heart rate and contractility via a reflex mechanism. On the contrary, phenylalkylamines and diltiazem act through a combination of effects, including reduction of afterload, heart rate, and contractility. When taken together, all these differences distinguish the preferential clinical utilization of one of these compounds for a given cardiovascular pathology.
Myelin protein synthesis, as well as ultrastructural and morphometric changes in regenerating peripheral nerve, was studied. Sciatic nerves of rats were crushed unilaterally; sham-operated nerves of ...the contralateral side served as controls. For the in vivo experiments, rats were killed at selected periods after the nerves were crushed (30, 60, 90, and 120 days); seven days prior to killing, the animals were injected intravenously with L-4,5-3Hleucine. For the in vitro experiments, proximal and distal segments of sciatic nerve and equivalent sham-operated nerves were labeled with 3H-amino acid mixture 90 days after axotomy. Purified myelin was isolated from nerve segments; specific radioactivity and gel electrophoretic patterns of proteins were analyzed. Cross-sectional electron microscope (EM) preparations of proximal, distal, and contralateral segments of nerves also were examined. Results showed that the incorporation of labeled amino acids into total myelin proteins was enhanced significantly in the distal segment of sciatic nerves at all of the periods of regeneration studied. The yield of myelin protein per mm distal nerve segment increased as regeneration proceeded. The remyelination of fibers early after nerve crush was weak, whereas it gradually attained the normal range 90-120 days after axotomy. Morphometric analysis of myelin sheath thickness of regenerating axons was consistent with the data obtained for myelin protein synthesis.
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