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M J Jiménez

Publications and source records attributed to M J Jiménez.

At least 19 recordsLinked to original sources
PubMed2001

A regulatory cascade involving retinoic acid, Cbfa1, and matrix metalloproteinases is coupled to the development of a process of perichondrial invasion and osteogenic differentiation during bone formation.

Tissue-remodeling processes are largely mediated by members of the matrix metalloproteinase (MMP) family of endopeptidases whose expression is strictly controlled both spatially and temporally. In this article, we have examined the molecular mechanisms that could contribute to modulate the expression of MMPs like collagenase-3 and MT1-MMP during bone formation. We have found that all-trans retinoic acid (RA), which usually downregulates MMPs, strongly induces collagenase-3 expression in cultures of embryonic metatarsal cartilage rudiments and in chondrocytic cells. This effect is dose and time dependent, requires the de novo synthesis of proteins, and is mediated by RAR-RXR heterodimers. Analysis of the signal transduction mechanisms underlying the upregulating effect of RA on collagenase-3 expression demonstrated that this factor acts through a signaling pathway involving p38 mitogen-activated protein kinase. RA treatment of chondrocytic cells also induces the production of MT1-MMP, a membrane-bound metalloproteinase essential for skeletal formation, which participates in a proteolytic cascade with collagenase-3. The production of these MMPs is concomitant with the development of an RA-induced differentiation program characterized by formation of a mineralized bone matrix, downregulation of chondrocyte markers like type II collagen, and upregulation of osteoblastic markers such as osteocalcin. These effects are attenuated in metatarsal rudiments in which RA induces the invasion of perichondrial osteogenic cells from the perichondrium into the cartilage rudiment. RA treatment also resulted in the upregulation of Cbfa1, a transcription factor responsible for collagenase-3 and osteocalcin induction in osteoblastic cells. The dynamics of Cbfa1, MMPs, and osteocalcin expression is consistent with the fact that these genes could be part of a regulatory cascade initiated by RA and leading to the induction of Cbfa1, which in turn would upregulate the expression of some of their target genes like collagenase-3 and osteocalcin.

Animals↗
PubMed2001

A Medicago truncatula homoglutathione synthetase is derived from glutathione synthetase by gene duplication.

Glutathione (GSH) and homo-GSH (hGSH) are the major low-molecular weight thiols synthesized in Medicago truncatula. Two M. truncatula cDNAs (gshs1 and gshs2) corresponding to a putative GSH synthetase (GSHS) and a putative hGSH synthetase (hGSHS) were characterized. Heterologous expression of gshs1 and gshs2 cDNAs in an Escherichia coli strain deficient in GSHS activity showed that GSHS1 and GSHS2 are a GSHS and an hGSHS, respectively. Leucine-534 and proline-535 present in hGSHS were substituted by alanines that are conserved in plant GSHS. These substitutions resulted in a strongly stimulated GSH accumulation in the transformed E. coli strain showing that these residues play a crucial role in the differential recognition of beta-alanine and glycine by hGSHS. Phylogenetic analysis of GSHS2 and GSHS1 with other eukaryotic GSHS sequences indicated that gshs2 and gshs1 are the result of a gene duplication that occurred after the divergence between Fabales, Solanales, and Brassicales. Analysis of the structure of gshs1 and gshs2 genes shows they are both present in a cluster and in the same orientation in the M. truncatula genome, suggesting that the duplication of gshs1 and gshs2 occurred via a tandem duplication.

Amino Acid Sequence↗
PubMed2001

Gas exchange and pulmonary hemodynamics during lung resection in patients at increased risk: relationship with preoperative exercise testing.

STUDY OBJECTIVES: To evaluate the intraoperative evolution of patients with COPD during lung resection and to test whether exercise testing could be helpful in the prediction of the intraoperative course. DESIGN: Prospective study. SETTING: University teaching hospital. PATIENTS: Forty patients (mean [+/- SD] age, 65 +/- 9 years) with COPD (ie, FEV(1), 55 +/- 11% of predicted) and resectable lung neoplasms. INTERVENTIONS: Preoperatively, pulmonary function testing, quantitative lung perfusion scanning, and exercise performance testing were administered. Intraoperatively, pulmonary, hemodynamic, and blood gas measurements were performed at five stages, including periods of two-lung ventilation (TLV) and periods of one-lung ventilation (OLV). RESULTS: During OLV, compared with TLV, the PaO(2)/fraction of inspired oxygen (FIO(2)) ratio decreased from 458 +/- 120 to 248 +/- 131 mm Hg (p < 0.05), whereas pulmonary artery pressure (PAP) increased from 18 +/- 5 to 23 +/- 5 mm Hg (p < 0.05). Cardiac output (t) also increased from 4.0 +/- 1.2 to 5.1 +/- 1.9 L/min (p < 0.05), yielding to a higher mixed venous PO(2). Both PaO(2) and t during OLV were significantly lower in patients who had undergone right thoracotomies compared with those who had undergone left thoracotomies. The PaO(2)/FIO(2) ratio during OLV correlated with the PaO(2) during exercise (r = 0.39; p = 0.01) and with the perfusion of the non-neoplastic lung (r = 0.44; p = 0.005). CONCLUSIONS: In COPD patients, OLV leads to a significant derangement of gas exchange, which is more pronounced in right thoracotomies. Preoperative measurement of PaO(2) during exercise and the distribution of perfusion by lung scan might be useful to identify those patients who are at the greatest risk of abnormal gas exchange during lung resections.

Aged↗
PubMed1999

Collagenase 3 is a target of Cbfa1, a transcription factor of the runt gene family involved in bone formation.

Collagenase 3 (MMP-13) is a recently identified member of the matrix metalloproteinase (MMP) gene family that is expressed at high levels in diverse human carcinomas and in articular cartilage from arthritic patients. In addition to its expression in pathological conditions, collagenase 3 has been detected in osteoblasts and hypertrophic chondrocytes during fetal ossification. In this work, we have evaluated the possibility that Cbfa1 (core binding factor 1), a transcription factor playing a major role in the expression of osteoblastic specific genes, is involved in the expression of collagenase 3 during bone formation. We have functionally characterized a Cbfa motif present in the promoter region of collagenase 3 gene and demonstrated, by cotransfection experiments and gel mobility shift assays, that this element is involved in the inducibility of the collagenase 3 promoter by Cbfa1 in osteoblastic and chondrocytic cells. Furthermore, overexpression of Cbfa1 in osteoblastic cells unable to produce collagenase 3 leads to the expression of this gene after stimulation with transforming growth factor beta. Finally, we show that mutant mice deficient in Cbfa1, lacking mature osteoblasts but containing hypertrophic chondrocytes which are also a major source of collagenase 3, do not express this protease during fetal development. These results provide in vivo evidence that collagenase 3 is a target of the transcriptional activator Cbfa1 in these cells. On the basis of these transcriptional regulation studies, together with the potent proteolytic activity of collagenase 3 on diverse collagenous and noncollagenous bone and cartilage components, we proposed that this enzyme may play a key role in the process of bone formation and remodeling.

3T3 Cells↗
PubMed1998

[Our experience in treating obstructive lesions of the main airway by Nd-Yag laser resection].

We performed 164 laser resections with a neodymiumyttrium-aluminum-garnet (Nd-Yag) laser in 116 patients between January 1992 and December 1997. Seventy-eight patients had malignant neoplasms, 5 had neoplasms of intermediate malignancy and 33 had inflammatory tracheal lesions. Eighteen resections were emergency procedures. All resections were performed with the patient under general anesthesia and preferably breathing spontaneously. Immediate results varied according to the nature and location of the lesion. Treatment was palliative for tumors showing intraluminal proliferation, providing successful reopening of the airway as shown endoscopically in 70% of patients. Mean survival of the 44 patients with malignant lesions who could be followed was 29 weeks, with a median of 15.19 (range, 1-120). The tracheas of patients with inflammatory stenosis were reopened rapidly and emergency tracheostomy was avoided in all cases. One patient with malignant tracheal tumors died during the procedure due to asphyxia related to tracheal hemorrhage.

Adult↗
PubMed1993

[Influence of iron status on attention and intellectual performance of a population of Spanish adolescents].

Dietetic, hematologic and biochemical data were used to asses the iron status of a group of 64 adolescents (37 males and 27 females), aged 15 to 18 (mean age 15.94 +/- 0.76 years), who study in a High School in the comunidad Autónoma de Madrid. All were asked to keep a dietary record during 5 days, one of which had to be a sunday. Iron intake was estimated using the Food Composition Tables of the Instituto de Nutrición (1990). The hematologic survey determined hemoglobin hematocrit mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), serum iron and serum ferritin. These data were correlated with the scores obtained in the attention and school capability test (AT), that gave information about the verbal (V), reasoning (R) and calculus (C) capabilities. There is a positive correlation between MCV (r = 0.2705), MCH (r = 0.3370) ferritin (r = 0.3383) and attention. MCV (r = 0.2995), MCH (r = 0.3998), MCHC (r = 0.3134) and ferritin (r = 0.3970) were also correlated with the speed capability shown on the attention test and the hemoglobin level was correlated with the calculus capability (r = 0.2905). The students who obtained higher scores in the school capability test had also better blood parameter values. This was statistically significant for serum ferritin in males students and for hemoglobin and MCHC in female students. 19.6% of the adolescents had ferritin levels lower than 12 ng/ml. Their intelligence test scores were lower to those who had serum ferritin > or = 12 ng/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

[Biochemical and nutritional studies of germinated soybean seeds].

The purpose of this work was to determine the biochemical and nutritional changes of soybean seeds during germination. Soybean seeds were soaked for a period of eight hours and then germinated for 0, 1, 3 and 5 days. Part of them was subjected to an autoclave process. Then, both the raw and cooked seeds were dried, ground and analyzed. During the germination process an increase in the percentage content of protein and fiber in the seeds occurred; cooked seeds, in contrast, showed a slight decrease with respect to the former. Ether extract increased in percentage until the third day, and then decreased on the fifth. In the cooked seeds, higher values than in the raw seeds were obtained, due to the fact that when seeds were autoclaved, protein and carbohydrate losses occur. In regard to ash content, this diminished in percentage as germination advanced; the same happened to the free-protein extract. The raffinose and stachyose sugars, factors which cause flatulence, disappeared on the third germination day. As to nitrogen extraction, a greater percentage was obtained using distilled water as solvent, both for the raw and cooked seeds, than when using NaOH and NaCl. The trypsin inhibitors content increased on the first day of germination and then decreased. Ungerminated, autoclaved seeds, showed no trypsin inhibitors activity, whereas in the germinated cooked seeds, it increased slightly as germination days went by. Regarding protein efficiency ratio (PER), seeds with 0, 1 and 3 germination days presented no significant differences among them, the cooked seeds exhibiting higher values than the raw seeds. Apparent digestibility increased as the germination period advanced, having obtained better values when they were autoclaved. In the soybean milk acceptability test, no significant differences were observed between milk from ungerminated soybean seeds, and milk from the 3-day germinated seeds.

Animals↗
PubMedDate not supplied

The study cellular subpopulations in peripheral blood from a normal reference group population (blood donors).

The spectacular development of monoclonal antibodies against cellular antigens an technology such as flow cytometry allow the investigation of cellular subpopulations that until now have been unknown. At the same time, the functional study of these subpopulations becomes of maximal interest, as this information could have future applications for pathological processes. Due ti this basic need for information, we have studied diverse lymphocytic subpopulations in a normal population that serves as a reference group, using the following antigens: CD3, CD4, CD8, CD20, CD45RA, CD25, LAM1, CD29, CD11b and CD23. Some of these subpopulations had not been previously studied in a normal reference group.

Antibodies, Monoclonal↗
PubMedDate not supplied

[Tremor and epidural anesthesia].

To evaluate the influence of temperature of the injected anesthetic solution on the development of tremor during epidural anesthesia, 66 patients divided in three homogeneous groups were evaluated: group I (n = 22; bupivacaine 4 degrees C), group II (n = 24; bupivacaine 20 degrees C), and group III (n = 24; bupivacaine 37 degrees C). The incidence of tremor was 20% (4 patients) in group I, 9% (2 patients) in group II and 12.5% (3 patients) in group III. No significant differences were found between the groups. The overall incidence was 13.6%. The epidural injection of 5 ml of saline at 37 degrees C achieved the attenuation and/or disappearance of tremor in three (3/4) group I patients (4 degrees C) and in one (1/3) group III patient (37 degrees C), whereas it was ineffective in one patient from group I and one from group III. In the two patients from group II (20 degrees C) and in one from group III (37 degrees C), tremor was self-limited. We conclude that the incidence of tremor during epidural anesthesia is not correlated with the temperature of anesthetic solutions, and that the epidural injection of saline at 37 degrees C may give some therapeutic benefit.

Adolescent↗