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I Noguera

Publications and source records attributed to I Noguera.

15 recordsLinked to original sources
PubMed2006

Pig liver gene therapy by noninvasive interventionist catheterism.

The efficacy of noninvasive interventionist catheterism in large animals as an alternative to the hydrodynamic procedure, described for small animals, is evaluated. Basically, gene transfer is performed by implantation and fixation of a balloon catheter within the suprahepatic vein of anesthetized pigs, through the femoral vein. The catheter tip is identified by fluoroscopy, injecting a contrast solution that marks large or small hepatic territories. Animals were injected with a 100 ml pTG7101 plasmid solution (40 microg/ml), which contains the human alpha-1 antitrypsin gene, perfused at a rate of 7.5 ml/s and efficacy and toxicity of the procedure were evaluated. The results show: (i) the highest efficacy in protein production is reached when perfusion is limited to small areas of the liver; (ii) no relevant hepatic toxicity was observed; (iii) gene transfer is mainly located in the areas around the central vein, as seen in the immunohistochemical studies; (iv) the electron microscopy studies indicate that the areas with good transfection efficacy show the presence of abundant endocytic vesicles that may even fuse among themselves. These data suggest that retrovenous injection by noninvasive interventionist catheterism could become an efficient procedure for hepatic gene transfer with potential clinical applications.

Animals↗
PubMed2006

Alterations in the phenotype and function of immune cells in ovariectomy-induced osteopenic mice.

BACKGROUND: Within the last few years, much evidence has been presented on the involvement of the immune system in certain types of bone loss, such as activated T cells in rheumatoid arthritis and in periodontitis. Estrogen deficiency induces bone loss; however, how this deficiency affects the immune system has not been sufficiently studied. METHODS: To evaluate the effects of estrogen withdrawal on the status and functionality of the immune system, mice were ovariectomized or sham-operated, and 5 weeks after surgery, when osteopenia had developed, several parameters were analysed in spleen and in bone marrow. We analysed bone turnover, cell phenotype by flow cytometry, cell function by cell proliferation assays, and the expression of several genes related to the process. RESULTS: Five weeks after ovariectomy, augmented osteoclastogenesis persisted in the bone marrow. In addition, the ovariectomized mice had more B-cells and CD3+ T-cells expressing the receptor activator of NF-kappaB ligand (CD3+/RANKL+). The ovariectomized mice had lower serum alkaline phosphatase activity, a normal amount of T cells, lower percentages of CD11b+ and CD51+ cells in the bone marrow, and a lower serum interferon-gamma level compared with sham-operated controls. CONCLUSIONS: The data suggest that, 5 weeks after ovariectomy, bone turnover remains imbalanced, with increased osteoclastogenesis and a decreased rate of bone formation. Moreover, there is an increase in B-cell formation, with normal and decreased percentages of T cells and myelomonocytic cells (CD11b+), respectively, in the bone marrow. Decreased serum interferon-gamma levels could be involved in the increased osteoclastogenesis found in the present work.

Alkaline Phosphatase↗
PubMed2001

Endothelin-1-induced potentiation of adrenergic responses in the rabbit pulmonary artery: role of thromboxane A(2).

To examine whether low concentrations of endothelin-1 potentiate the vasoconstrictor response to adrenergic stimulation, we recorded the isometric response of rings of rabbit pulmonary artery to electrical stimulation and noradrenaline. Endothelin-1 (10(-10) M) potentiated the contractions induced by electrical stimulation and noradrenaline. The endothelin ET(B) receptor antagonist (2,6-dimethylpiperidinecarbonyl-gamma-methyl-Leu-N(in)-[Methoxycarbonyl]-D-Trp-D-Nle) (BQ-788, 10(-6) M), but not the endothelin ET(A) receptor antagonist cyclo(D-Asp-Pro-D-Val-Leu-D-TRP) (BQ-123, 10(-6) M), inhibited the potentiating effects of endothelin-1. Pretreatment with the cyclooxygenase inhibitor indomethacin, the thromboxane synthase inhibitor furegrelate and the thromboxane receptor antagonist [1S-[1alpha,2alpha(Z),3alpha,4alpha]]-7-[3-[[[[(1-oxoheptyl)amino]acetyl]amino] methyl]-7-oxabicyclo-[2.2.1]hept-2-yl]-5-heptenoic acid (SQ-30741) (all at 10(-5) M) prevented the potentiation induced by endothelin-1 on adrenergic stimulation. The Ca(2+) channel antagonist nifedipine (10(-6) M) did not affect the potentiation induced by endothelin-1. The results indicate that endothelin-1 potentiates the responses to electrical stimulation and noradrenaline by activating endothelin ET(B) receptors. This potentiation depends on the production of cyclooxygenase-generated factors, probably thromboxane A(2).

Animals↗
PubMed2000

The latent transforming growth factor-beta-binding protein-1 promotes in vitro differentiation of embryonic stem cells into endothelium.

The latent transforming growth factor-beta-binding protein-1 (LTBP-1) belongs to a family of extracellular glycoproteins that includes three additional isoforms (LTBP-2, -3, and -4) and the matrix proteins fibrillin-1 and -2. Originally described as a TGF-beta-masking protein, LTBP-1 is involved both in the sequestration of latent TGF-beta in the extracellular matrix and the regulation of its activation in the extracellular environment. Whereas the expression of LTBP-1 has been analyzed in normal and malignant cells and rodent and human tissues, little is known about LTBP-1 in embryonic development. To address this question, we used murine embryonic stem (ES) cells to analyze the appearance and role of LTBP-1 during ES cell differentiation. In vitro, ES cells aggregate to form embryoid bodies (EBs), which differentiate into multiple cell lineages. We analyzed LTBP-1 gene expression and LTBP-1 fiber appearance with respect to the emergence and distribution of cell types in differentiating EBs. LTBP-1 expression increased during the first 12 d in culture, appeared to remain constant between d 12 and 24, and declined thereafter. By immunostaining, fibrillar LTBP-1 was observed in those regions of the culture containing endothelial, smooth muscle, and epithelial cells. We found that inclusion of a polyclonal antibody to LTBP-1 during EB differentiation suppressed the expression of the endothelial specific genes ICAM-2 and von Willebrand factor and delayed the organization of differentiated endothelial cells into cord-like structures within the growing EBs. The same effect was observed when cultures were treated with either antibodies to TGF-beta or the latency associated peptide, which neutralize TGF-beta. Conversely, the organization of endothelial cells was enhanced by incubation with TGF-beta 1. These results suggest that during differentiation of ES cells LTBP-1 facilitates endothelial cell organization via a TGF-beta-dependent mechanism.

Animals↗
PubMed1999

Proteolytic control of growth factor availability.

Most growth factors are released from cells in a form that does not permit immediate interaction with their high affinity receptors. An important mechanism for presentation of these released latent growth factors is activation by the plasminogen activator-plasmin system. The involvement of this system in the biology of Transforming Growth Factor-beta (TGF-beta) is reviewed.

Animals↗
PubMed1997

TGF-beta latency: biological significance and mechanisms of activation.

Transforming growth factor (TGF-) beta is secreted as a latent complex in which the mature growth factor remains associated with its propeptide. In order to elicit a biological response, the cytokine must be released from the latent complex, a process termed latent TGF-beta activation or TGF-beta formation. Although latent TGF-beta activation is a critical step in the regulation of its activity, little is known about the molecular mechanisms that lead to the production of active TGF-beta. In this article, we present an overview of the data available on this topic, and we propose a tentative model for the mechanism of TGF-beta formation based upon the observations with different cell systems and on recent findings on the structure of the latent TGF-beta complex.

Animals↗
PubMed1997

Phosphorylation of HSP25 during lens cell differentiation.

Small heat shock proteins and alpha-crystallins are related proteins with several common structural and functional properties including homologous amino acid sequences and similar chaperone-like activity. Furthermore, small heat shock proteins and alpha-crystallins are phosphorylated in vivo at serine residues within homologous amino acid sequences. During the differentiation of lens epithelial cells to fiber cells, significant changes in the patterns of expression and phosphorylation of alpha-crystallins take place, leading to the accumulation of phosphorylated forms of these proteins in lens fiber cells. To determine whether the small heat shock protein HSP25 undergoes phosphorylation in lens cells and to ascertain whether its phosphorylation state changes during lens cell differentiation, a comparative analysis of the HSP25 phosphorylation pattern in epithelial and fiber cells was undertaken. Analysis of phosphorylated and non-phosphorylated forms of HSP25 was carried out in cell extracts from rat lens epithelium and cortex by isoelectric focusing and Western blot using an antibody specific for the recombinant murine protein. The phosphorylated forms were identified by their isoelectric points and the characteristic shift upon in vitro dephosphorylation with phosphoprotein phosphatase 2B. HSP25 accounted for up to 2.4% of the protein content of rat lens extracts where it was present predominantly in mono- and bi-phosphorylated forms. Compared to epithelial cells extracts, the fiber cells extracts contained 67% more total HSP25 and a significantly higher proportion of bi-phosphorylated form. Phosphorylated HSP25 was sensitive to dephosphorylation by phosphoprotein phosphatase 2B in both cell extracts but the apparent dephosphorylation rate was significantly slower in the fiber cell extracts. The results demonstrate that HSP25 is phosphorylated in the lens in vivo. Furthermore, synthesis and phosphorylation of HSP25 change with lens cell differentiation resulting in a significant accumulation of bi-phosphorylated form in the fiber cells. These findings indicate that HSP25 and its phosphorylation may have important roles in lens cell differentiation.

Animals↗
PubMed1997

Potentiation by vasopressin of adrenergic vasoconstriction in the rat isolated mesenteric artery.

1. The aim of the present study was to investigate in rat mesenteric artery rings whether low concentrations of vasopressin could modify the contractile responses to noradrenaline and electrical stimulation of perivascular nerves. 2. Vasopressin (10[10]-10[-7] M) caused concentration-dependent contractions (pD2 = 8.36+/-0.09). The V1-receptor antagonist d(CH2)5Tyr(Me)AVP (10[-9]-10[-8] M) produced parallel rightward shifts of the control curve for vasopressin. Schild analysis yielded a pA2 value of 9.83 with a slope of 1.10+/-0.14. 3. Vasopressin (3 x 10[-10] and 10[-9] M) caused concentration-dependent potentiation of the contractions elicited by electrical stimulation (2-8 Hz; 0.2 ms duration for 30 s) and produced leftward shifts of the concentration-response curve for noradrenaline. The V1-receptor antagonist induced concentration-dependent inhibitions of potentiation induced by vasopressin. The selective V1-receptor agonist [Phe2, Orn8]-vasotocin (3 x 10[10] and 10[-9] M) induced potentiation of electrical stimulation-evoked responses which was also inhibited in the presence of the V1 antagonist (10[-8] M). In contrast, the V2-receptor agonist deamino-8-D-arginine vasopressin (desmopressin 10[-8]-10[-7] M) did not modify the electrical stimulation-induced responses and the V2-receptor antagonist [d(CH2)5, D-Ile2, Ile4, Arg8]-vasopressin (10[-8]-10[-7] M) did not affect the potentiation evoked by vasopressin. 4. In artery rings contracted by 10(-6) M noradrenaline in the presence of 10(-6) M guanethidine and 10(-6) M atropine, electrical stimulation (2, 4 and 8 Hz) produced frequency-dependent relaxations which were unaffected by 10(-9) M vasopressin but abolished by 10(-6) M tetrodotoxin. 5. Vasopressin also potentiated contractions elicited by KCl and contractions induced by addition of CaCl2 to KCl depolarized vessels. The augmenting effects were inhibited by the V1 antagonist. 6. In the presence of the calcium antagonist nifedipine (10[-6] M), vasopressin failed to enhance the contractile responses to electrical stimulation, noradrenaline and KCl. 7. The results demonstrate that low concentrations of vasopressin strongly potentiate the contractions to adrenergic stimulation and KCl depolarization. This effect appears to be mediated by V1 receptor stimulation which brings about an increase in calcium entry through dihydropyridine-sensitive calcium channels.

Animals↗
PubMed1997

Enhancement by vasopressin of adrenergic responses in human mesenteric arteries.

Vasopressin not only acts directly on blood vessels through V1-receptor stimulation but also may modulate adrenergic-mediated responses in animal experiments in vitro and in vivo. The aim of the present study was to investigate whether subpressor concentrations of vasopressin could modify the constrictor responses to norepinephrine and electrical stimulation of the perivascular nerves in human mesenteric arteries. Human mesenteric artery rings (3-3.5 mm long, 0.8-1.2 mm OD) were obtained from 38 patients undergoing abdominal operations. The arterial rings were suspended in organ bath chambers for isometric recording of tension. Vasopressin (3 x 10(-11) M) enhanced the contractions elicited by electrical stimulation at 2, 4, and 8 Hz (by 100, 100, and 72%, respectively) and produced a leftward shift of the concentration-response curves to norepinephrine (half-maximal effective concentration decreased from 2.2 x 10(-6) to 5.0 x 10(-7) M; P < 0.05) without any alteration in maximal contractions. Vasopressin also potentiated KCl- and calcium-induced contractions. The V1-receptor antagonist 1-[beta-mercapto-beta,beta-cyclopentamethylenepropionic acid-2-O-methyl-tyrosine, 8-arginine]vasopressin (10(-6) M) prevented the potentiation evoked by vasopressin in all cases. The calcium antagonist nifedipine (10(-6) M) did not affect the potentiation of electrical stimulation and norepinephrine induced by vasopressin but abolished KCl-induced contractions. The results suggest that vasopressin, in addition to its direct vasoconstrictor effect, strongly potentiates the responses to adrenergic stimulation and KCl depolarization. Both the direct and indirect effects of vasopressin appear to be mediated by V1-receptor stimulation. The amplifying effect of vasopressin on constrictor responses may be relevant in those clinical situations characterized by increased plasma vasopressin levels.

Adult↗
PubMed1992

Blood biochemical characteristics of cattle at sea level and at moderately high altitude (3,000 m).

We investigated the biochemical composition of blood from Holstein cows, native breed (criollas), and cows descended from fighting bulls (Vacas de lidia) raised at an altitude of 3,000 m (moderately high altitude, MHA), and compared the results with those from Holsteins and cows of similar genetic ancestry as the criollas (scrub cows), both raised at sea level (SL), to determine blood biochemical values characteristic of adaptation to high altitude. Only potassium and calcium concentrations were similar among groups. Glucose concentration was lower in MHA cows, with the exception of Vacas de lidia. Serum bicarbonate concentration was lower in MHA cows; this finding can be explained by hyperventilation in the hypoxic environment. Serum magnesium concentration was lower in SL and MHA Holsteins than in other groups. Serum phosphate concentration was lower in scrub cows, MHA Holsteins, and criollas than in other groups. Cholesterol concentrations were lower in SL Holsteins, whereas triglycerides were higher in scrub cows and MHA Vacas de lidia. Concentration of high-density lipoprotein was significantly greater in Vacas de lidia and less in MHA criollas than in the other groups. Uric acid and total protein were higher in MHA groups. Using radioimmunoassay for human proteins, thyroxine-binding globulin was undetectable. Total and free thyroxine and free triiodothyronine were higher in scrub cows, followed by Vacas de lidia; lower values were detected in SL and MHA Holsteins and MHA criollas.

Altitude↗
PubMed1977

New practical treadmill protocol for clinical use.

A new continuous treadmill protocol (USAFSAM) has been designed using a constant treadmill speed (3.3 miles/hour) and regular equal increments in treadmill grade (5%/3min). The constant treadmill speed requires only initial adaptation in patient stride, reduces technician adjustments and produces less electrocardiographic motion artifact than do protocols using multiple or higher treadmill speeds, or both. The regular equal increments in treadmill grade are easy to implement and provide a larger number of work loads than do protocols that are discontinuous or require larger changes in work load. The USAFSAM protocol was compared with the older Balke-Ware protocol in 26 healthy men (aged 30 to 59 years). Each fasting subject completed two maximal treadmill tests from each protocol. Measurements included minute heart rate from the electrocardiogram, auscultatory blood pressures and oxygen consumption obtained with standard techniques. Similarities in between-protocol measurements for submaximal and maximal treadmill efforts were impressive; differences were small and unimportant. Further, both protocols showed equal reproducibility for the measurements noted. Importantly, time to maximal effort was reduced by 24% with the USAFSAM protocol. The USAFSAM treadmill protocol has since been used in more than 500 clinical and screening examinations, thus confirming its advantages and practicality for routine clinical stress testing. Normal reference values previously established for the Balke-Ware protocol are shown to apply to the new USAFSAM protocol as well.

Adult↗
PubMedDate not supplied

Estrogen receptor agonists and immune system in ovariectomized mice.

Several data implicate the immune system in bone lost after estrogen deficiency, however, some of the effects on the immune system of estrogen deficiency or of estrogen receptor (ER) modulation are not well established. In this study, the effect of ER agonists on the immune system in ovariectomized mice is analyzed. Mice were ovariectomized and were administered 17beta-estradiol (E2), raloxifene (RAL) or genistein (GEN). The effect of a 4-week treatment on bone turnover and on several parameters that reflect the status of the immune system was studied. Results show that ovariectomy provoked both uterine atrophy and thymic hypertrophy. Although RAL corrected thymic hypertrophy, only E2 corrected both. Ovariectomized mice showed increased levels of serum calcium and cathepsin K gene expression and decreased levels of serum alkaline phosphatase (ALP) activity, which suggests that there is a persistent alteration in bone metabolism. Moreover, ovariectomy increased B-cells and CD25+ cells, and decreased the percentages of T-cells and Cbfa1 gene expression in bone marrow (BM). All ER agonists corrected, although to different degrees, changes induced by the ovariectomy. Furthermore, results showed that it is essential to adjust ER agonist doses to avoid immunosuppression, since all ER agonists decreased BM T-cell levels.

Animals↗