Search PubMed⌕ Search

Biomedical subjects

O Jiménez

Publications and source records attributed to O Jiménez.

At least 19 recordsLinked to original sources
PubMed2005

A new, mild, and efficient synthesis of 2,2-difluoro-3-hydroxyacids through a selective haloform reaction.

[reaction: see text] Long-chain 2,2-difluoro-3-hydroxyacids have been synthesized in a new, straightforward manner by treatment of 4-hydroxy-1,1,1,3,3-pentafluoroalkyl ketones, easily obtained by reaction of pentafluoroenolate 2 with aldehydes and ketones, with base under mild conditions. The reaction sequence is marked by the selective cleavage of the CO-CF3 bond, as well as the absence of products arising from the alternative CO-CF2R bond cleavage. The process represents a convenient approach for the synthesis of 2,2-difluoro-3-hydroxyacids, as it is short, provides good to excellent yields under mild conditions, and uses hexafluoro-2-propanol, a very cheap reagent, as the fluorine source.

Journal Article↗
PubMed2004

New concepts in cyclosporine pharmacokinetic and dynamic monitoring: the impact of concomitant immunosuppression on target C2 concentrations.

BACKGROUND: There is a correlation between cyclosporine (CsA) pharmacokinetics (PK) and pharmacodynamics (PD), especially 2 hours after drug administration. AIM: To evaluate the relationship between CsA PK and PD profiles in two groups of stable renal transplant patients treated with CsA alone or CsA plus mycophenolate mofetil (CsA+MMF), so as to define the best target for C2 and clarify the impact of concomitant immunosuppression. METHODS: Thirty-eight stable renal transplant recipients were treated with CsA (n=20) or CsA+MMF (n=18). Twelve nontreated normal healthy controls (NHC) were also included. Calcineurin activity (CNa), IL-2 production, and CsA levels were measured at 0 and 2 hours postdose. RESULTS: There were no significant differences in median CsA C2 values and CNa between the CsA alone and the CsA+MMF groups (388 microg/L and 497.5 microg/L and CNa 2h; 3.92% alkaline phosphatase [AP]; 3.94% AP, respectively). In vitro production of IL-2 was significantly lower in the CsA+MMF group than in the CsA group (median IL-2 2h: 280.52 ng/L, 169.48 ng/L, P<.001). The correlations (r) between C2 and CNa 2h were: CsA r=0.74; CsA+MMF r=0.84 (P<.001 in both cases). CONCLUSIONS: In stable renal transplant patients, median CsA C2 values below 500 microg/L were associated with inhibition of CNa and IL-2 synthesis. CNa and IL-2 production may be good biological markers of CsA immunosuppression. The measurement of CNa depends mainly on CsA concentration, whereas in vitro IL-2 production reflects the effect of both CsA and MMF. Further studies are necessary to define the optimal C2 target concentration and the possible impact of concomitant immunosuppression.

Calcineurin Inhibitors↗
PubMed2003

Pharmacokinetic and pharmacodynamic correlations of cyclosporine therapy in stable renal transplant patients: evaluation of long-term target C(2).

We investigated the relationship between the pharmacokinetics and pharmacodynamics of cyclosporine in 15 stable renal transplant patients in order to define an effective and safe therapeutic range. The area under the curve of the first 4 h (AUC(0-4)), trough (C(0)) and 2 h (C(2)) levels showed median values of 1655 ng x h/ml, 114 ng/ml and 384 ng/ml, respectively. C(2) showed a strong correlation with AUC(0-4) (r=0.942, p=0.0005). C(0) correlated poorly with C(2) and AUC(0-4) (r=0.596, p=0.019 and r=0.538, p=0.031, respectively). Calcineurine activity (CNa) was 6.74% at 0 h and 3.90% at 2 h, representing significant reductions (82% and 89.6%, respectively; p<0.0005) compared with normal healthy controls (median basal value 37.4%). IL-2 production was 349 pg/ml at 0 h and 276.35 pg/ml at 2 h; both results were significantly lower (reductions of 44.5% and 56.1%, respectively; p=0.04 and 0.005) than the controls of 629.1 pg/ml. IFN-gamma at 2 h post-dose (8.16 UI/ml) was significantly lower (72.1% reduction, p=0.005) than in controls (29.2 UI/ml). There was a good correlation between CNa and IFN-gamma production, particularly at 2 h post-dose (r=0.537, p=0.007), and a fair correlation between CNa and IL-2 concentration (p=0.030, r=0.426). C(2) showed an inverse significant correlation with CNa (Spearman's p=0.000, r=-0.753), IL-2 (p=0.000, r=-0.725) and IFN-gamma (p=0.000, r=-0.701) production. In treated patients, the Emax inhibitory sigmoidal model showed that a C(2) of 279 ng/ml was needed to achieve a 50% inhibition (EC50) of IL-2 and INF-gamma production. The results demonstrated a significant inhibition of calcineurin activity and IL-2 and IFN-gamma production in patients receiving cyclosporine monotherapy compared to healthy controls. A median C(2) value of 384 ng/ml was associated with a good degree of inhibition of CNa and IL-2 and IFN-gamma synthesis, and the lack of rejection episodes and relevant toxicity.

Area Under Curve↗
PubMed2000

Organochlorine and heavy metal residues in the water/sediment system of the Southeast Regional Park in Madrid, Spain.

A study into levels of contamination by organochlorine compounds (insecticides and PCBs) and heavy metals (Cd and Pb) in the water/sediment system of the Southeast Regional Park (SERP) in Madrid, Spain, has been carried out. Residue levels of xenobiotics were determined in surface and underground waters and sediments from selected sites throughout the protected area. The results showed these contaminants to be widespread throughout the studied area. p,p'-DDT concentration levels were consistently higher than its metabolite p,p'-DDE, indicating a recent use of this organochlorine insecticide in the area. PCB levels exceeded, in the majority of the cases, the levels taken as the maximum (100 ng/microl) for highly polluted waters. Cd and Pb levels found in water samples were under the detection limits of the methodology used. Pb levels found in sediment samples were higher than Cd.

Benzophenones↗
PubMed2000

The relationship between idiopathic thrombocytopenic purpura and pernicious anaemia.

Some reports on the simultaneous presence of chronic idiopathic thrombocytopenic purpura (ITP) and pernicious anaemia (PA) may be found in the literature. However, little is known about the coexistence of these autoimmune disorders. For this reason, we studied the prevalence of PA in a series of patients with a diagnosis of chronic ITP by means of the analysis of the concentration of the most sensitive marker of type A atrophic (autoimmune) gastritis, serum pepsinogen I. Serum pepsinogen I was low in 20.3% of the 133 patients studied. Gastrin was elevated in 15. 2% of patients, but the coexistence of both abnormalities was rather low (7.6% of patients). However, the progressive decrease in serum cobalamin as biochemical abnormalities related with atrophic gastritis appeared was noticeable. The time to progression to frank PA from type A atrophic gastritis may span some years.

Adult↗
PubMed1998

Anterior pituitary development and Pit-1/GHF-1 transcription factor.

Anterior pituitary differentiation is a well-established paradigm in mammalian organogenesis. PIT1/GHF1, a homoeotic gene, plays a key role in terminal pituitary differentiation. Recently, a new set of transcription factors involved in early pituitary differentiation have been identified: Lhx-3, Lhx-4, P-OTX and Prop1. A pituitary-specific transcriptional cascade regulating a developmental programme leads to the determination of the mature cell types.

Animals↗
PubMed1992

[Polyps of the colon and the rectum].

This is a retrospective study en 189 cases of colorectal polyps, from 1985-1989 including medical record review, pathologic diagnosis and surgical management. The main symptom was rectal bleeding. The follow up period and it's relation to colorectal cancer was evaluated, considering this entity as a premalignant lesion. 189 histopathology slides were reclassified according to the actual classification. Males were predominant (69%), with increasing incidence from the fifth decade (62% of the total); a 2% malignization rate was found.

Adolescent↗
PubMed1989

[Mirizzi syndrome: experience of 77 cases].

Mirizzi syndrome is estimated to occur in about 1% of cases requiring urgent or elective biliary tract surgery. The key anatomic finding is extrinsic compression of the common duct by a stone located in the gallbladder or cystic duct. Among patients operated on in the last 12 years we have found 77 patients meeting criteria to diagnose Mirizzi syndrome. 76% were females, usually over 40 years of age; jaundice was present in 98% and elevated alkaline phosphatase in 97% of cases. Percutaneous transhepatic cholangiography allowed the diagnosis in 32 of 41 patients. The most common surgical technique involved a patch repair of the gallbladder over the Kehr tube in 45 patients. Eight patients required biliary-jejunal bypass. Eleven patients were reoperated on for benign stenosis of the biliary tract over a 1 month to 10 year period of follow up.

Adolescent↗