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Biomedical subjects

C Nieto

Publications and source records attributed to C Nieto.

At least 19 recordsLinked to original sources
PubMed2005

[Pulsed radiofrequency treatment in idiopathic and secondary glossopharyngeal neuralgia: preliminary results in 2 cases].

OBJECTIVES: To describe the use of pulsed radiofrequency (PRF) to treat 2 cases of glossopharyngeal neuralgia, 1 idiopathic and 1 secondary. PATIENTS: The first case involved a man diagnosed with Hodgkin's lymphoma involving the tonsils and manifesting as glossopharyngeal neuralgia that was refractory to all treatment approaches tried, including opioids and neuromodulation. The second case involved a patient diagnosed with essential glossopharyngeal neuralgia that was also resistant to drug treatment. The PRF procedure was performed in the operating room on an outpatient basis, under fluoroscopic guidance and with conventional monitoring. No perioperative events were reported. RESULTS: The treatment was effective for both patients, leading to decreases in visual analog scale pain reports between 5 and 7 points that were maintained over 6 months, although improvement for the patient with essential neuralgia was less intense and of shorter duration. Overall self-reported improvement assessed subjectively 6 months after PRF was 75% for the patient with Hodgkin's lymphoma and 50% for the patient with essential neuralgia, for whom a second PRF procedure was scheduled. Neither patient suffered complications or side effects that were potentially attributable to the procedure. CONCLUSIONS: PRF seems to be a safe, effective approach to treating neuralgia of the glossopharyngeal nerve, whether the condition is essential or secondary to another process. It is possible that if the condition is secondary, the clinical response may be greater in intensity and last longer.

Electric Stimulation Therapy↗
PubMed2003

Theoretic rates of potential tissue donation in a university hospital.

BACKGROUND: Catalonia and Spain have the highest rates of organ donation in the world. The National Transplant Organization studied the rates of potential and actual donors through the Quality Guarantee Program, but this research did not estimate potential tissue donation (PTD). The aim of this study was to define the theoretical rates of PTD at our university hospital in order to assess the main factors that exerted the greatest influence on tissue donation (TD). METHODS: We prospectively studied all deaths from May 1, of 2001 to May 31, of 2002 using a specific protocol. The selection of cornea, vessels, skin, and bone had been established by the recommendations of the Spanish Association of Tissue Banks (AEBT). We considered each deceased person as a PTD when there was no medical contraindication (MC), and obtained blood samples for serologic determinations. RESULTS: Among the 1960 deaths, 1444 (73.6%) displayed MC for TD. Only 516 (26.3%) patients were evaluated as PTD cases. Two hundred twenty-two cases (65%) were rejected due to lack of blood samples for serologic determination. The remaining 294 PTD cases were considered: family refusal of TD in 120 (40%) and consent in 174 (60%). All were corneal donors; 46 (26%) had been multitissue donors (20 vessels, 35 skin, and 30 bones) including 26 (56.5%) who were also organ donors. CONCLUSIONS: PTD cases at a university hospital represented about 25% of deaths but only 30% of PTDs actually became donors.

Cause of Death↗
PubMed2001

MalR-mediated regulation of the Streptococcus pneumoniae malMP operon at promoter PM. Influence of a proximal divergent promoter region and competition between MalR and RNA polymerase proteins.

The Streptococcus pneumoniae mal regulon contains two operons, malXCD and malMP involved in the uptake and utilization of maltosaccharides. Both operons are transcribed from two divergent promoters, P(X) and P(M), and are negatively regulated by the MalR transcriptional repressor. Purified MalR protein binds to two DNA regions that encompasses both promoters, thus occupying its two operators, O(M) and O(X). However, the levels of occupation and repression were different, being higher when MalR was bound to O(M) than when it was anchored to O(X). Competition experiments between MalR and the Escherichia coli RNA polymerase on promoters P(M) and P(X) showed that the affinity of either protein for the promoter/operator DNA sequences was important to determine the frequency of transcription initiation. In addition to the control exerted by MalR, expression from promoter P(M) was affected by upstream sequences located within or close to P(X) promoter.

Bacterial Proteins↗
PubMed2001

[Inverted duplication of the short arm of chromosome 8].

We report two cases of agenesis of corpus callosum in which high resolution G-band cytogenetic study revealed inverted duplication of the short arm of chromosome 8. The application of hybridization techniques with fluorescence in situ hybridization (FISH) confirmed chromosomal alteration in both cases. The definitive karyotype was 46, XY or XX inv dup del (8) (qter-p23.1::p23.1-p11.2).ish (WCP 8 ) (tel 8p-).

Abnormalities, Multiple↗
PubMed2000

Expression of green fluorescent protein in Lactococcus lactis.

The gfp gene from Aequorea victoria, encoding the green fluorescent protein (GFP) has been expressed in Lactococcus lactis subsp. lactis biovar cremoris MG1363, upon construction and introduction of plasmid pLS1GFP into this host. GFP was monitored in living cells during growth to evaluate its use in molecular and physiological studies. Quantification of the levels of GFP expressed by cultures was feasible by fluorescence spectroscopy. Phase-contrast and fluorescence microscopy allowed us to distinguish, in mixed cultures, lactococcal cells expressing GFP. Our results indicate that GFP can be used as a reporter in L. lactis.

Genes, Reporter↗
PubMed2000

Construction of a tightly regulated plasmid vector for Streptococcus pneumoniae: controlled expression of the green fluorescent protein.

We have constructed a regulated plasmid vector for Streptococcus pneumoniae, based on the streptococcal broad-host-range replicon pLS1. As a reporter gene, we subcloned the gfp gene from Aequorea victoria, encoding the green fluorescent protein. This gene was placed under the control of the inducible P(M) promoter of the S. pneumoniae malMP operon which, in turn, is regulated by the product of the pneumococcal malR gene. Binding of MalR protein to the P(M) promoter is inactivated by growing the cells in maltose-containing media. Highly regulated gene expression was achieved by cloning in the same plasmid the P(M)-gfp cassette and the malR gene, thus providing the MalR regulator in cis. Pneumococcal cells harboring this vector gave a linear response of GFP synthesis in a maltose-dependent mode without detectable background levels in the absence of the inducer.

Bacterial Proteins↗
PubMed1998

[Brachmann-de-Lange syndrome in our population: clinical and epidemiological characteristics].

INTRODUCTION: We present the study of the clinical and epidemiological characteristics of Brachmann-de Lange syndrome in our population. PATIENTS AND METHODS: In this study we present the analysis of 13 cases of Brachmann-de Lange syndrome identified among 24,696 infants with congenital defects registered by the Spanish Collaborative Study of Congenital Malformations (ECEMC) between April 1976 and June 1996. RESULTS: The minimum estimation of the prevalence in our population is 0.97 per 100,000 live births. We have epidemiologically confirmed the presence of intrauterine growth retardation and have observed that parental ages tend to be relatively young. We have observed a wide range of clinical expression of this syndrome. One hundred percent of our cases have limb reduction defects, followed in frequency by craniofacial alterations (84.62%), abnormal hair distribution (76.92%) and genital defects (69.23%). Upper limbs are predominantly affected and one case of diaphragmatic hernia is worth mentioning. We underline the importance of the differential diagnosis with Fryns'syndrome. CONCLUSIONS: The cases studied correspond to the most severe form of the syndrome, reason for which the prevalence is a minimal estimate. However, the mild forms of the syndrome are more frequent and it is important to consider that the face, especially the form of the eyebrow, could be a good guide for the diagnosis of mild forms of the syndrome.

De Lange Syndrome↗
PubMed1997

The maltose/maltodextrin regulon of Streptococcus pneumoniae. Differential promoter regulation by the transcriptional repressor MalR.

The Streptococcus pneumoniae MalR protein regulates the transcription of two divergent operons, malXCD and malMP, involved in maltosaccharide uptake and utilization, respectively. MalR belongs to the LacI-GalR family of transcription repressors. The protein binds specifically to two operator sequences in the intergenic region between these operons. The affinity of MalR for the malMP binding sequence is higher than for the malXCD site. Results obtained in vivo using transcriptional fusions with reporter genes indicate low repression level of malXCD by MalR when compared with malMP. This behavior may be correlated with the existence of separate induction pathways for maltose, maltotriose, and maltotetraose. The similarities found at the operator sequences and binding domains for MalR and enterococcal repressor proteins suggest that the pneumococcal maltosaccharide regulation system is closely related to several Gram-negative metabolic pathways, but not to the structurally similar Escherichia coli maltose regulon.

Amino Acid Sequence↗
PubMed1995

Dual DNA binding specificity of a petal epidermis-specific MYB transcription factor (MYB.Ph3) from Petunia hybrida.

The MYB.Ph3 protein recognized two DNA sequences that resemble the two known types of MYB DNA binding site: consensus I (MBSI), aaaAaaC(G/C)-GTTA, and consensus II (MBSII), aaaAGTTAGTTA. Optimal MBSI was recognized by animal c-MYB and not by Am305 from Antirrhinum, whereas MBSII showed the reverse behaviour. Different constraints on MYB.Ph3 binding to the two classes of sequences were demonstrated. DNA binding studies with mutated MBSI and MBSII and hydroxyl radical footprinting analysis, pointed to the N-terminal MYB repeat (R2) as the most involved in determining the dual DNA binding specificity of MYB.Ph3 and supported the idea that binding to MBSI and MBSII does not involve alternative orientations of the two repeats of MYB.Ph3. Minimal promoters containing either MBSI and MBSII were activated to the same extent by MYB.Ph3 in yeast, indicating that both types of binding site can be functionally equivalent. MYB.Ph3 binding sites are present in the promoter of flavonoid biosynthetic genes, such as the Petunia chsJ gene, which was transcriptionally activated by MYB.Ph3 in tobacco protoplasts. MYB.Ph3 was immunolocalized in the epidermal cell layer of petals, where flavonoid biosynthetic genes are actively expressed. This strongly suggests a role for MYB.Ph3 in the regulation of flavonoid biosynthesis.

Acyltransferases↗
PubMed1995

MYB.Ph3 transcription factor from Petunia hybrida induces similar DNA-bending/distortions on its two types of binding site.

MYB.Ph3 from Petunia is a member of the MYB transcription factor family that recognizes two types of binding site, resembling direct and inverted repeats of the motif GTTA, respectively, and flanked on their 5' side by an A-rich sequence. In this study, it is shown that MYB.Ph3 induces similar conformational changes in both of its DNA-binding sites. Circular permutation assays indicate that the center of the distortions induced by MYB.Ph3 maps near the center of either MYB.Ph3-binding site. The degree of the distortion induced by MYB.Ph3 appears to be greatly affected by regions of the protein other than the DNA-binding domain, and differs from the distortion caused by animal c-MYB. Phasing analysis reveals that part of the distortion induced by MYB.Ph3 is DNA bending, oriented towards the minor groove, as is the case of its animal counterpart, c-MYB. DNA-binding by both MYB.Ph3 and animal c-MYB is more efficient in the presence of Ba2+, a divalent cation known to promote/stabilize DNA bending, than in the presence of other cations which do not favor this distortion, such as Na+ and Mg2+. In addition, both MYB proteins show higher affinity to selectively nicked DNA, which has increased DNA flexibility, strongly suggesting that DNA binding by these MYB proteins and DNA structural properties are mutually influenced.

Barium↗
PubMed1995

[A controlled study of the effect of oral contraceptives on blood pressure].

The possible hypertensive effect of oral contraceptives is a controversial issue. We studied 371 women, admitted to the family planning program of a state funded outpatient clinic, that were followed during 12 months. These women were divided in four groups: Group 1 was constituted by 98 women that used intrauterine devices. Group 2 by 98 women taking 30 micrograms of estrogen and 300 micrograms of progestogen. Group 3 by 83 women taking 35 micrograms of estrogen and 500 micrograms of progestogen and Group 4 by 92 puerperal women taking 30 micrograms of levonorgestrel, that after six months started to use an intrauterine device (n = 35) or the contraceptives of group 2 (n = 38) or group 3 (n = 19). Age, initial blood pressure and weight were similar in the four groups. There was no significant change in blood pressure after 6 or 12 months of follow up in any group. It is concluded that contraceptives containing estrogen concentrations up to 35 micrograms and progestogen concentrations between 300 and 500 micrograms do not induced changes in blood pressure.

Adult↗
PubMed1994

On-line fully automated solid-phase extraction-liquid chromatography analysis of 1,2-dihydro-4-(1,2-dihydro-2-oxo-1-pyridyl)-2,2-dimethyl-1-oxonaphthale ne-6- carbonitrile (UR-8225), a new potassium channel opener, in plasma samples.

A fully automated reversed-phase HPLC method for pharmacokinetic studies was developed for the determination in plasma samples of 1,2-dihydro-4-(1,2-dihydro-2-oxo-1-pyridyl)-2,2-dimethyl-1-oxonaphtha lene-6- carbonitrile (compound I), a new potassium channel opener. On-line solid-phase extraction was performed with disposable C18 cartridges. After clean up, the samples were eluted and transferred onto an RP-18 analytical column, where separation was performed with a mobile phase of acetonitrile-10 mM di-n-butylamine phosphate (28:72, v/v). Ultraviolet absorbance detection was used at 236 nm. The detector response was linear in the range 25-2500 ng/ml, and the lowest limit of quantitation was determined at 2.5 ng/ml. The inter-day variability was < 4% for samples at 1000 ng/ml and < 15% for samples at 10 ng/ml. This method was used for the pharmacokinetic study of compound I in rats at three different dosage levels.

Animals↗
PubMed1994

Short rib-polydactyly syndrome and pericentric inversion of chromosome 4.

We report on a newborn infant with clinical and radiological manifestations of some type of short rib-polydactyly syndrome who died soon after birth. Chromosomal studies on peripheral blood lymphocytes and chondrocytes demonstrated an apparently balanced pericentric inversion of chromosome 4 (present in the mother also). This association may have occurred by chance but, if not, the chromosomal breakpoints could interrupt the gene responsible for short rib-polydactyly syndromes, or else be related to the mechanism of short rib-polydactyly syndromes.

Abortion, Habitual↗
PubMed1993

Petunia hybrida genes related to the maize regulatory C1 gene and to animal myb proto-oncogenes.

The maize C1 gene is a regulatory gene of the anthocyanin pathway. It is a part of a multigene family whose predicted protein products contain a region with homology to the DNA-binding domain of myb proto-oncogene products. Using as a probe an oligonucleotide mixture encoding a highly conserved region in plant MYB proteins, cDNAs encoding three related polypeptides expressed in the flower of Petunia hybrida have been isolated. Predicted proteins are 280-517 amino acids long and show sequence similarities among themselves as well as with other MYB proteins (45-80% amino acid identity) in the MYB DNA-binding domain. Outside this domain no significant sequence similarity was found. However, in all cases regions with structural characteristics of activator domains were found. Analysis with Southern blots allowed an estimation of at least 20-30 myb genes in P. hybrida. Expression patterns were specific for each gene as shown by Northern blotting analysis. Subcellular location studies of the largest MYB product, by both immunoblotting of the protein in subcellular fractions and by 'in situ' immunolocation experiments, showed that it is a nuclear protein. The role of MYB proteins as transcriptional activators regulating the synthesis of different anthocyanin(flavonoid)-related compounds is discussed.

Amino Acid Sequence↗
PubMed1993

[Hypertension in rural communities. Study in the VIII Region, Chile].

The aim of this work was to study the prevalence of hypertension in rural populations of the VIII region of Chile. Six thousand twenty four non institutionalized subjects. 14 years old or older, coming from eight randomly chosen rural communities were studied. Blood pressure was measured by trained personnel in two occasions within 30 minutes; in those classified as hypertensive, a third measurement was performed within 24 hours, eliminating alcohol intake and medications. Results show prevalence rates in the first, second and third measurement of 38.5, 30.8 and 22.8% respectively. The elimination of alcohol intake and medications decreased the prevalence in 3.9%. All the chosen communities has similar rates (19.8 to 21.2%) except Arauco, that had a significantly higher frequency of 31.9%. Zones of extreme ruralness had higher rates than small towns (23.8 vs 21.7%). There was a secular increase in the prevalence of hypertension from 4.9 in the 15 to 24 years old group to 57.8% among people 75 years old or older. Forty three percent of hypertensives were aware of such condition, 26.1% were receiving treatment and in 8.2% it was successful; all these figures were slightly better among women.

Adolescent↗