Effects of pioglitazone and rosiglitazone on vascular function of mesenteric resistance arteries in rat genetic hypertension

Glitazones exhibit beneficial effects in the vascular system, both on large vessels and at a microcirculatory level. We previously reported the effects of glitazones in the aorta of spontaneously hypertensive rats (SHR). We focus now on the acute and long-term actions of these drugs on mesenteric resistance arteries of the SHR. Incubation with pioglitazone or rosiglitazone (10?? mol/l) improved endothelium-dependent relaxations to acetylcholine and the endothelial modulation of phenylephrine contractions. Acetylcholine relaxations that were abolished by N(G)-nitro-L-arginine methylester were partly recovered by the glitazones, but no effects of these drugs were observed in the presence of indomethacin or indomethacin + L-NAME. Glitazones did not change the contractions to U46619 or the endothelium-independent relaxation to sodium nitroprusside. Three-week oral pioglitazone or rosiglitazone treatment (3 and 10 mg/kg/day, respectively) confirmed the acute experiments. Thus, in microvessels, glitazones improve endothelial function in such a way that they do not alter endothelial nitric oxide release but reduce the production of vasoconstrictor prostanoids from endothelial cells.     

Potent CYP2D6 Inhibiting drugs do not increase relapse rate in early breast cancer patients treated with adjuvant tamoxifen

Endoxifen, the most active metabolite of the prodrug tamoxifen, is produced by cytochrome P450 CYP2D6. Breast cancer patients treated with tamoxifen who have reduced CYP2D6 activity, related to either genetic variation or drug inhibition, may have inferior outcomes. To assess the effect of concomitant CYP2D6 inhibiting drug use on clinical outcomes of breast cancer patients treated with adjuvant tamoxifen. We conducted a retrospective database analysis. Women with non-metastatic estrogen receptor positive tumors who had completed adjuvant tamoxifen therapy for 2 years, without treatment with adjuvant aromatase inhibitors or early relapse, were included. Patients were classified as users of CYP2D6 inhibitors if they purchased strong CYP2D6 inhibiting drugs for ≥4 consecutive months during tamoxifen treatment. Tumors were classified as “high risk” if adjuvant chemotherapy was prescribed. Primary endpoint was disease free (DFS) and secondary endpoint was overall survival (OS). 902 patients treated with tamoxifen (median duration, 4.9 years) were followed for a median period of 5.9 years. Fifty-nine (6.5%) patients were users of CYP2D6 inhibitors (median duration, 23 months). DFS at 3 years (corresponding to 5 years after tamoxifen initiation) did not differ between users and non-users of CYP2D6 inhibiting drugs (92.7 vs. 93.0%, respectively; adjusted P = 0.44). OS at 3 years was lower in the patients using CYP2D6 inhibiting drugs: 89.4 vs. 93.8%, but after adjustment for age and comorbidities this difference was not significant (P = 0.20). Overall recurrence rates did not differ between users and non-users of CYP2D6 inhibiting drugs (11.8 vs. 19.0% respectively, P = 0.23). Concomitant prolonged therapy with strong CYP2D6 inhibiting drugs does not affect adversely DFS and recurrence rates in tamoxifen-treated early breast cancer patients.     

Toward a theory of holistic needs and the brain

This article reviews Maslow's theory of motivation wherein he proposes a hierarchy of human needs. First, it describes the principal elements of Maslow's theory and discusses considerations relating to the flexibility of the hierarchy. Second, it explains the relationship among Maslow's theory of human needs, attachment theory, and evolutionary threat assessment system theory. Third, it provides an overview of the brain structures posited to be involved in attachment and evolutionary threat assessment system theory and their relation to Maslow's hierarchy. Finally, it explains how the 3 theories converge to form a theory of holistic needs.     

Reactive oxygen species are indispensable in ovulation

Ovulation is stimulated by the preovulatory surge of the pituitary luteinizing hormone (LH). Because the ovulatory response is commonly identified with inflammation, we explored the involvement of reactive oxygen species (ROS) in this process. Our experiments show that administration of broad-range scavengers of oxidative species into the ovarian bursa of mice, hormonally induced to ovulate, significantly reduced the rate of ovulation. LH-induced cumulus mucification/expansion, a necessary requirement for ovulation, was prevented by antioxidants both in vivo and in an ex vivo system of isolated intact ovarian follicles. Along this line, H(2)O(2) fully mimicked the effect of LH, bringing about an extensive mucification/expansion of the follicle-enclosed cumulus-oocyte complexes. Impaired progesterone production was observed in isolated follicles incubated with LH in the presence of the antioxidant agents. Furthermore, LH-stimulated up-regulation of genes, the expression of which is crucial for ovulation, was substantially attenuated upon ROS ablation. This system was also used for demonstrating the role of ROS in phosphorylation and activation of the EGF receptor as well as its downstream effector, p42/44 MAPK. Together, our results provide evidence that ovarian production of ROS is an essential preovulatory signaling event, most probably transiently triggered by LH.     

Idiopathic pulmonary fibrosis and polymorphisms of the folate pathway genes

ObjectivesThis study aims to determine the possible association between folate pathway gene polymorphisms and idiopathic pulmonary fibrosis. This represents the first study carried out on folate pathway gene polymorphisms as possible risk factors in this kind of pathology. The premise is that several polymorphisms mapping on genes responsible for folate uptake are associated with the risk of numerous diseases occurring between pregnancy and old age, and that too little is currently known about idiopathic pulmonary fibrosis.Design and methodsWe genotyped 9 single nucleotide polymorphisms and 1 polymorphic insertion in 7 essential genes belonging to the folate pathway in 32 Italian idiopathic pulmonary fibrosis patients and 81 control subjects. This was done by PCR and restriction analysis.ResultsAllelic and genotypic association tests indicated that for all the analysed polymorphisms there were no significant differences between patients and controls. Nevertheless, the haplotype association analysis revealed a significant association between idiopathic pulmonary fibrosis and transcobalamin II gene polymorphisms: specifically the haplotype 776G (rs1801198)–c.1026-394G (rs7286680)–444C (rs10418) (OR = 2.84; 95% C.I. 1.36–5.93, P value = 0.004).ConclusionsThis small-scale preliminary study would suggest the importance of further research focusing on the role of folate in the onset of idiopathic pulmonary fibrosis.     

Protoribosome by quantum kernel energy method

Experimental evidence suggests the existence of an RNA molecular prebiotic entity, called by us the “protoribosome,” which may have evolved in the RNA world before evolution of the genetic code and proteins. This vestige of the RNA world, which possesses all of the capabilities required for peptide bond formation, seems to be still functioning in the heart of all of the contemporary ribosome. Within the modern ribosome this remnant includes the peptidyl transferase center. Its highly conserved nucleotide sequence is suggestive of its robustness under diverse environmental conditions, and hence on its prebiotic origin. Its twofold pseudosymmetry suggests that this entity could have been a dimer of self-folding RNA units that formed a pocket within which two activated amino acids might be accommodated, similar to the binding mode of modern tRNA molecules that carry amino acids or peptidyl moieties. Using quantum mechanics and crystal coordinates, this work studies the question of whether the putative protoribosome has properties necessary to function as an evolutionary precursor to the modern ribosome. The quantum model used in the calculations is density functional theory–B3LYP/3–21G*, implemented using the kernel energy method to make the computations practical and efficient. It occurs that the necessary conditions that would characterize a practicable protoribosome—namely (i) energetic structural stability and (ii) energetically stable attachment to substrates—are both well satisfied.A suggestion of a molecular entity, called “protoribosome,” which may have evolved and emerged from an RNA world before a subsequent evolution into the modern protein/nucleic acid world, has been reported (1–3). In contemporary cells the ribosomes translate the genetic information (stored in the DNA) into proteins. Ribosomes are gigantic complexes, which in prokaryotes are built of some 50 proteins and three RNA chains with a total of 4,500 nucleotides. Aptly referred to as the protein factory of all living cells, the ribosome is essential to the contemporary life, and its activity may have been crucial to the formation of life itself. Structural analysis identified an internal RNA region that exists in all known structures (1–5) and has universally conserved sequence (1), which contains the site of peptide bond formation, and thus may well be that of a remaining RNA world entity. Consistent with the findings that the main ribosomal functions—namely, the decoding of the genetic code, the formation of peptide bonds, and the creation of elongating proteins—are performed by ribosomal RNA and with the universality of this region among all kingdoms of life, we proposed that this region is a remnant of a prebiotic chemical entity with catalytic capabilities, and called it the “protoribosome.” Within the otherwise asymmetric ribosome, this region has a unique fold (6) and could have been the link to the modern world (7). It is characterized by a pseudotwofold symmetry with a highly conserved nucleotide sequence and seems to possess all of the assumed prerequisites for the formation of chemical bonds. This semisymmetric object could be a dimer of self-folding RNA units that formed a pocket within which two activated amino acids, as substrates, might be accommodated.A representation of a plausible sequence for spontaneous self-assembly of a protoribosome is shown in Fig. 1 (2). Here, we put forth the use of quantum mechanics to answer the following question: Is the suggested protoribosome structure a plausible reality? One may systematically remove—that is, mathematically—all surrounding parts of the modern ribosome and use the coordinates of a central symmetric pocket for constructing a putative protoribosome. Here we apply quantum mechanics to the structure of that protoribosome. The most fundamental inquiry followed in this article is that of the energetic stability of the proposed protoribosome. This is not presently known. And obviously if the structure is not energetically stable, it is not likely to be able to act as a biological catalyst, as would be required of a protoribosome. The protoribosome contains almost 200 nucleotides, namely thousands of atoms. Ab initio quantum calculations rise in difficulty as a high power of the number of atoms in the system. Therefore, quantum calculation of the protoribosome energy is a complex computational problem. Fortunately we are in possession of a recently discovered kernel energy method (KEM) (8–24), described below, which alleviates dramatically the computational difficulty of ab initio calculations. Importantly the KEM is highly accurate, as well as computationally efficient.Open in a separate windowFig. 1.The scheme by which small, self-folded RNA molecules dimerize to form a symmetrical pocket allowing accommodation of a pair of substrates. The A-site region (Areg) and the P-site region (Preg), respectively, (Upper Left) dimerize (Upper Right) to allow substrate accommodation. Reproduced by permission from ref. 2 [Davidovich et al. (2009) Research in Microbiology 160(7):487–492]. Copyright Elsevier Masson SAS.As an example of the large size of systems that can be studied with ab initio KEM, we have applied the method to a Hartree–Fock (HF) calculation of a 33,000-atom protein (16). It is entirely feasible to treat even larger molecules within the context of KEM capabilities. Therefore, we performed an ab initio KEM study of the protoribosome and showed that its existence is quite feasible. Using KEM we address the question of whether the basic symmetric structure of the folded dimer pocket that constitutes the protoribosome suggested previously (4) proves to be quantum mechanically stable. If so, the next question to address is: Can it accommodate a pair of amino acids bound to a chain of a few (1–3) nucleotides, representing the tRNA 3′−end, spatially and energetically? Furthermore, such calculations should indicate the energetic preferences for the length of the nucleotide chain and its correlation to the protoribome size, ranging between 120 and 180. If both questions would be validated quantum mechanically, that would be highly suggestive of the protoribosome as an actual remnant from the RNA world still functioning in the chemistry of life, in the modern DNA/RNA/protein world.     

Preoperative and intraoperative brain mapping for the resection of eloquent-area tumors. A prospective analysis of methodology, correlation, and usefulness based on clinical outcomes

Background

Localization of brain function is a fundamental requisite for the resection of eloquent-area brain tumors. Preoperative functional neuroimaging and diffusion tensor imaging can display cortical functional organization and subcortical anatomy of major white matter bundles. Direct cortical and subcortical stimulation is widely used in routine practice, however, because of its ability to reveal tissue function in eloquent regions. The role and integration of these techniques is still a matter of debate. The objective of this study was to assess surgical and functional neurological outputs of awake surgery and intraoperative cortical and subcortical electrical stimulation (CSES) and to use CSES to examine the reliability of preoperative functional magnetic resonance (fMRI) and diffusion tensor imaging fiber tracking (DTI-FT) for surgical planning.

Patients and methods

We prospectively studied 27 patients with eloquent-area tumors who were selected to undergo awake surgery and direct brain mapping. All subjects underwent preoperative sensorimotor and language fMRI and DTI tractography of major white matter bundles. Intra- and postoperative complications, stimulation effects, extent of resection, and neurological outcome were determined. We topographically correlated intraoperatively identified sites (cortical and subcortical) with areas of fMRI activation and DTI tractography.

Results

Total plus subtotal resection reached 88.8%. Twenty-one patients (77.7%) suffered transient postoperative worsening, but at 6 months follow-up only three (11.1%) patients had persistent neurological impairment. Sensorimotor cortex direct mapping correlated 92.3% with fMRI activation, while direct mapping of language cortex correlated 42.8%. DTI fiber tracking underestimated the presence of functional fibers surrounding or inside the tumor.

Conclusion

Preoperative brain mapping is useful when planning awake surgery to estimate the relationship between the tumor and functional brain regions. However, these techniques cannot directly lead the surgeon during resection. Intraoperative brain mapping is necessary for safe and maximal resection and to guarantee a satisfying neurological outcome. This multimodal approach is more aggressive, leads to better outcomes, and should be used routinely for resection of lesions in eloquent brain regions.     

The role of hepatic artery ligation and dearterialization with infusion chemotherapy in advanced malignancies in the liver

Because of limited benefits derived with the use of systemic chemotherapy, 15 patients with metastatic malignancy of the liver or hepatoma were treated by hepatic artery ligation (6) or dearterialization (9) and regional infusion chemotherapy. There were two postoperative deaths and three patients required surgical drainage of hepatic tumor liquefaction necrosis. The median survival was 14 months with two patients still living. The longest survivors were those patients with visceral leiomyosarcoma or carcinoid tumor. Five of the patients had failed to respond to previous chemotherapy, all showed a favorable response to this therapy. Rigid criteria for proper case selection have been developed which should reduce the operative mortality. Hepatic artery ligation is a therapeutic modality that can be of benefit to patients for whom no other satisfactory treatment is available.