Search PubMed⌕ Search

Biomedical subjects

A Peña

Publications and source records attributed to A Peña.

At least 19 recordsLinked to original sources
PubMed1997

Local and remote sustained trigger point therapy for exacerbations of chronic low back pain. A randomized, double-blind, controlled, multicenter trial.

STUDY DESIGN: A randomized, double-blind, controlled, multicenter trial was conducted. OBJECTIVES: To assess the efficacy of neuroreflexotherapy in the management of low back pain. SUMMARY AND BACKGROUND DATA: Neuroreflexotherapy consists of temporary implantation of epidermal devices in trigger points in the back and referred tender points in the ear. METHODS: The rheumatology and rehabilitation departments of three teaching hospitals in Madrid recruited 78 patients with chronic low back pain. These patients were randomly assigned to the control group (37 patients) or to the treatment group (41 patients). Patients in the treatment group underwent one neuroreflexotherapeutic intervention. The control group received sham treatment consisting of placement of the same number of epidermal devices within a 5-cm radius of the target zones. Patients from both groups were allowed to continue drug treatment as previously prescribed. The use of medications during the trial was recorded. RESULTS: Patients underwent clinical evaluations on three occasions: within 5 minutes before intervention, within 5 minutes after intervention, and 45 days later. The preintervention assessment was carried out by the physician from each hospital department who included the patient in the study. Each of the two follow-up assessments were carried out independently by two of three physicians who had no connection with the research team. Patients in the treatment group showed immediate lessening of pain compared with the results in patients in the control group. The pain relief was clinically relevant and statistically significant, and it persisted up to the end of the trial. CONCLUSIONS: Neuroreflexotherapy intervention seems to be a simple and effective treatment for rapid amelioration of pain episodes in patients with chronic low back pain. At this time, the duration of pain relief beyond 45 days has not been evaluated.

Adult↗
PubMed1997

Total urogenital mobilization--an easier way to repair cloacas.

The surgical treatment of persistent cloaca is a serious challenge. The operation is technically difficult and the final results for urinary and fecal function are far from excellent. The repair of a cloaca includes, among other maneuvers, the separation of the vagina from the urinary tract. This step is a serious technical challenge and is very time consuming. Devascularization of these structures is the main source of complications such as urethro-vaginal fistula, vaginal stricture, and acquired vaginal atresia. To avoid these complications and to facilitate the cloacal repair, a new technical variation using total urogenital mobilization was performed in 11 patients. In this procedure, after the rectum is separated from the vagina, both the urethra and the vagina are mobilized together as a single unit. The surgical time spent during the reconstruction was reduced by approximately 70%. All patients recovered well from the operations and have been followed up for 1 to 14 months. The blood supply of the vagina and urethra in all cases remained excellent. No patient developed urethrovaginal fistula, vaginal stricture, or acquired vaginal atresia. The cosmetic appearance in these patients is superior to the one achieved with previous techniques. Although this maneuver may not render better urinary or fecal control, the urethra is more accessible for catheterization. These preliminary results suggest that the total urogenital mobilization maneuver provides a definite technical advance in the repair of cloaca malformations.

Child, Preschool↗
PubMed1997

Molecular epidemiology of human rotaviruses in Santiago, Chile.

BACKGROUND: Protective immunity against rotavirus infection is directed against antigenic epitopes on the outer capsid proteins VP7 and VP4. Our aim was to characterize the epidemiology of rotavirus antigenic types over time in Santiago, Chile. METHODS: We prospectively obtained 2097 stool samples for rotavirus testing, VP7 (G1 to G4) and VP4 (P4, P6, P8, P9) typing from children with diarrhea evaluated in emergency rooms of 5 base hospitals of Santiago. In addition 256 rotavirus-positive samples collected between 1985 and 1987 in the north health care area of Santiago were studied. RESULTS: Of 995 rotavirus-positive samples obtained 825 (82%) were typable for 1 or more VP7 types. G1 represented 81% of the G-typed samples during 1993 through 1995 and 77% during 1985 through 1987, predominating in all health care areas. G2 was next most common in all 5 areas, representing 6 to 23% of typed samples, with 1 area, the Southeast concentrating a significantly higher number of G2 infections. G2 declined from 35% of rotavirus-positive samples in 1993 to 0% in 1995 (P < 0.001), and from 25% to 2% in the north health care area from 1985 to 1987 (P < 0.001). G4 was uncommon and significantly more prevalent in 1985 through 1987 than in 1993 through 1995 (7% vs. 3%, P = 0.015). G3 was not detected. G1P8 (53%) and G2P4 (16%) combinations were by far the most commonly detected G-P associations. CONCLUSIONS: In Santiago, Chile, rotavirus antigenic type G1P8 has been highly prevalent and G2P4 has circulated in cycles. Differences in epidemiology of rotavirus antigenic types worldwide may prove to be relevant in efficacy of rotavirus vaccines.

Child↗
PubMed1996

H+/K+ exchange in reconstituted yeast plasma membrane vesicles.

The activity of a putative H+/K+ exchange system in the plasma membrane of yeast was studied following the alkalinization of the interior of vesicles prepared with lecithin and yeast plasma membrane containing pyranine entrapped inside. The fluorescence of pyranine was used as an indicator of the internal pH of the vesicles. The addition of monovalent cations produced an increase of the internal pH, probably due to the activity of an exchange system, allowing H+ to leave the vesicle in an exchange for the cation added. The system showed partial selectivity towards K+ against other monovalent cations, and it was inhibited by amiloride. The activity of this system required the presence of the yeast plasma membrane in the vesicles, and it did not produce important changes of the membrane potential of the vesicles. The exchange depended partially on the relative values of the internal and the external pH of the vesicles. The system shows low affinity for the cations, and appears to be different from the mitochondrial H+/K+ exchange system, which is non-selective toward the different monovalent cations. This system could be involved in the regulation of the internal pH of the cells when they accumulate high concentrations of K+.

Amiloride↗
PubMed1996

Overexpression of Mxi1 inhibits the induction of the human ornithine decarboxylase gene by the Myc/Max protein complex.

We have previously shown that the Myc/Max protein complex plays a role in the growth-associated expression of the human ornithine decarboxylase gene. Mxi1 and Mad, novel Max-associated proteins have been identified and shown to form heterodimers with Max which bind efficiently to the Myc/Max consensus recognition sequence, CACGTG, in vitro. However, formation of Max/Mxi1 or Max/Mad heterodimers results in a reduction in Myc/Max dependent transcriptional activation of reporter plasmid constructs containing the consensus element. In light of the evidence that ODC is transcriptionally regulated in vitro and in vivo by the Myc/Max protein complex and the potential role of Mxi1 and Mad as antagonists of Myc transactivation activity, we set out to determine if one of these Max associated proteins, Mxi1, could affect the regulation of ODC expression by Myc/Max and if this regulation was correlated to growth status. Our results show that overexpression of Mxi1 does in fact inhibit ODC gene expression in a dose-dependent manner both in vivo and in vitro. In addition, evidence is presented which shows that levels of Mxi1 are up-regulated during long term quiescence and down-regulated following growth stimulation by serum. These results suggest that alterations in the levels of Max-associated proteins such as Mxi1 can modulate critical levels of functional Myc/Max protein complexes. This can alter transcriptional transactivation of Myc-regulated targets and as a consequence affect levels of genes essential for initiation and/or maintenance of growth.

Base Sequence↗
PubMed1996

Cocaine does not compromise cerebral or myocardial oxygen delivery in fetal sheep.

Eight time-dated pregnant ewes at 125 days' gestation (145 days = term) underwent surgery for placement of fetal vascular catheters, electrodes for recording fetal behavioural state, and maternal venous catheters. Three days later, fetal cerebral and myocardial blood flow were determined by the coloured microsphere technique under four conditions: (1) during rapid-eye movement (REM) sleep, before fetal cocaine infusion, (2) 30 min after initiation of a cocaine infusion to the fetus at 0.2 mg/kg per min, (3) during REM sleep, before maternal cocaine infusion, and (4) 30 min after initiation of a cocaine infusion to the ewe at 0.3 mg/kg per min. Cocaine infusion directly to the fetal lamb did not cause hypoxaemia or significantly change cerebral or myocardial blood flow or oxygen delivery. Cocaine administered to the ewe led to a drop in fetal oxygen tension from 3.0 +/- 0.5 to 2.5 +/- 0.3 kPa (P < 0.0001) and in fetal oxygen content from 3.8 +/- 0.7 to 2.8 +/- 0.4 mmol O2/L (P < 0.0001). Prior to maternal cocaine administration, fetal cerebral blood flow was 146 +/- 103 mL/100 g per min and during maternal cocaine infusion it went to 184 +/- 147 mL/100 g per min (P = NS) while myocardial blood flow increased from 156 +/- 92 to 333 +/- 178 mL/100 g per min (P < 0.002). This increase in blood flow negated the effects of hypoxaemia so that cerebral oxygen delivery was unaffected while myocardial oxygen delivery increased an average of 67%. It is concluded that cocaine administration to pregnant sheep does not impede fetal cerebral or myocardial oxygen delivery.

Analysis of Variance↗
PubMed1995

Nucleotide sequence and chromosomal localization of the gene encoding the Old Yellow Enzyme from Kluyveromyces lactis.

A 6.6 kb genomic DNA fragment from the yeast Kluyveromyces lactis was isolated. Sequence analysis of this fragment revealed the presence of two incomplete open reading frames (ORFs) in one strand, one coding for the carboxyl terminus of the plasma membrane H(+)-ATPase and the other for the amino terminus of an unidentified product. In the complementary strand, a full-length ORF which encodes for a protein homologous to the yeast NADPH-dependent Old Yellow Enzyme was found. The deduced amino acid sequence of this ORF predicts a protein of 398 residues with 84% similarity in its full length to OYE1 from Saccharomyces carlsbergensis and OYE2 from Saccharomyces cerevisiae. In addition, an internal region showed considerable similarity to the bile acid-inducible polypeptide from Eubacterium sp., to the NADH oxidase from Thermoanaerobium brockii, to the trimethylamino dehydrogenase from bacterium W3A1 and to the estrogen-binding protein from Candida albicans, suggesting a functional or structural relationship between them. Inactivation of the KYE1 (Kluyveromyces Yellow Enzyme) gene by deletion of 0.6 kb fragment between positions +358 and +936 produced viable cells with a slight increase in their generation time. Haploid cells carrying the disrupted allele showed one-third of the NADPH oxidase activity, compared to wild-type cells. Southern blotting analysis of digested DNA and chromosomes separated by contour-clamped homogeneous electric field electrophoresis from K. lactis indicated that this is a single-copy gene and it is localized on chromosome II, whose molecular size has been estimated to be approximately 1.3 Mb.

Amino Acid Sequence↗
PubMed1995

Regulation of human ornithine decarboxylase expression following prolonged quiescence: role for the c-Myc/Max protein complex.

WI-38 cells can remain quiescent for long periods of time and still be induced to reenter the cell cycle by the addition of fresh serum. However, the longer these cells remain growth arrested, the more time they require to enter S phase. This prolongation of the prereplicative phase has been localized to a point early in G1, after the induction of "immediate early" G1 genes such as c-fos and c-jun but before maximal expression of "early" G1 genes such as ornithine decarboxylase (ODC). Understanding the molecular basis for ODC mRNA induction can therefore provide information about the molecular events which regulate the progression of cells out of long-term quiescence into G1 and subsequently into DNA synthesis. Studies utilizing electrophoretic mobility shift assays (EMSA) of nuclear extracts from short- and long-term quiescent WI-38 cells identified a region of the human ODC promoter at -491 bp to -474 bp which exhibited a protein binding pattern that correlated with the temporal pattern of ODC mRNA expression. The presence of a CACGTG element within this fragment, studies with antibodies against c-Myc and Max, the use of purified recombinant c-Myc protein in the mobility shift assay, and antisense studies suggest that these proteins can specifically bind this portion of the human ODC promoter in a manner consistent with growth-associated modulation of the expression of ODC and other early G1 genes following prolonged quiescence. These studies suggest a role for the c-Myc/Max protein complex in regulating events involved in the progression of cells out of long-term quiescence into G1 and subsequently into S.

Base Sequence↗
PubMed1995

Chemotaxonomic characterization of yeast cells.

Yeast species are analyzed on the basis of their lipid composition to evaluate if chemotaxonomic classification of different species is feasible. The cell walls of samples of Baker's and Brewer's yeast are disrupted by smashing the cells with glass beads at low temperatures. The liberated lipids are extracted with chloroform-methanol. Fractionation of the extract into simple lipids and complex lipids (phospholipids) is performed by column chromatography on silica gel. Elution with methanol produces the simple lipids fraction, whereas elution with methanol-chloroform-ammonium hydroxide produces the phospholipid fraction. The latter fraction is analyzed by high-performance liquid chromatography with light-scattering detection. High-temperature capillary gas chromatography of the simple lipids fraction permits the separation of waxes, sterols, squalene, sterol esters, free fatty acids, monoglycerides, diglycerides, and triglycerides.

Cell Wall↗
PubMed1995

Helicobacter pylori-associated gastroduodenal disease in symptomatic Chilean children: diagnostic value of serological assay.

A newly developed enzyme-linked immunosorbent assay (ELISA) IgG serological assay for the diagnosis of Helicobacter pylori infection was used recently in two epidemiological surveys in Chile. To evaluate the diagnostic efficacy of this assay in a local symptomatic pediatric population, we studied 70 school-age patients referred for upper gastrointestinal endoscopy because of complaints suggestive of gastroduodenal disease. Evidence for antral H. pylori infection was sought by three biopsy-related methods: culture, histology, and urease activity. IgG anti-H. pylori serum antibodies were determined by ELISA. Altogether, chronic antral gastritis was found in 55 patients and duodenal ulcers in nine; 11 subjects had normal histology. Sixty (86%) patients had H. pylori in the antrum. This group had significantly higher mean IgG optical density values when compared with the H. pylori-negative group (1.860 versus 0.669; p < 0.001). The sensitivity and specificity of the assay in detecting antral H. pylori were both 90%; the positive predictive value was 98% and the negative, 60%. Accuracy of the assay was superior in predicting the presence or absence of gastroduodenal lesions with a sensitivity of 96%, a specificity of 92%, a positive predictive value of 98%, and a negative predictive value of 86%. We conclude that the diagnostic efficiency of this assay renders it appropriate both to screen for H. pylori-associated gastroduodenal disease in individual patients and to be used in seroepidemiological surveys.

Adolescent↗
PubMed1995

Proton pumping and the internal pH of yeast cells, measured with pyranine introduced by electroporation.

The internal pH of yeast cells was determined by measuring the fluorescence changes of pyranine (8-hydroxy-1,3,6-pyrene-trisulfonic acid), which was introduced into the cells by electroporation. This may be a suitable procedure for the following reasons. (i) Only minor changes in the physiological status of the cells seemed to be produced. (ii) The dye did not seem to leak at a significant rate from the cells. (iii) Different incubation conditions produced large fluorescence changes in the dye, which in general agree with present knowledge of the proton movements of the yeast cell under different conditions. (iv) Pyranine introduced by electroporation seemed to be located in the cytoplasm and to avoid the vacuole, and therefore it probably measured actual cytoplasmic pH. (v) Correction factors to obtain a more precise estimation of the internal pH are not difficult to apply, and the procedure may be useful for other yeasts and microorganisms, as well as for the introduction of other substances into cells. Values for the cytoplasmic pHs of yeast cells that were higher than those reported previously were obtained, probably because this fluorescent indicator did not seem to penetrate into the cell vacuole.

Arylsulfonates↗
PubMed1995

Molecular cloning of the plasma membrane H(+)-ATPase from Kluyveromyces lactis: a single nucleotide substitution in the gene confers ethidium bromide resistance and deficiency in K+ uptake.

A Kluyveromyces lactis strain resistant to ethidium bromide and deficient in potassium uptake was isolated. Studies on the proton-pumping activity of the mutant strain showed that a decreased H(+)-ATPase specific activity was responsible for the observed phenotypes. The putative K. lactis PMA1 gene encoding the plasma membrane H(+)-ATPase was cloned by its ability to relieve the potassium transport defect of this mutant and by reversing its resistance to ethidium bromide. Its deduced amino acid sequence predicts a protein 899 residues long that is structurally colinear in its full length to H(+)-ATPases cloned from different yeasts, except for the presence of a variable N-terminal domain. By PCR-mediated amplification, we identified a transition from G to A that rendered the substitution of the fully conserved methionine at position 699 by isoleucine. We attribute to this amino acid change the low capacity of the mutant H(+)-ATPase to pump out protons.

Amino Acid Sequence↗
PubMed1995

Anorectal malformations.

The posterior sagittal approach was used to treat 792 patients with anorectal malformations. From these, 387 cases were evaluated 6 months to 13 years later. Voluntary bowel movements were present in 74.3% of the entire series. When distributed by diagnosis, the percentages varied: 100% in patients with rectal atresia and perineal fistula; 93.2% in those with vestibular fistula; 80.9% in those with bulbar fistula; 71.1% in those with cloacas; 66.7% in those with prostatic fistula, and 15.8% in those with bladder-neck fistula. Soiling was present in 57% of all cases. Patients with voluntary bowel movements and no soiling were classified as totally continent; 40.8% of the series belong to this group. Distributed by diagnosis, it varied from 100% in cases with rectal atresia or perineal fistula, 65.9% in those with vestibular fistula, 34% in those with bulbar fistula, 31.6% in those with cloacas, 26.3% in those with prostatic fistula; none of the patients with vaginal fistula or bladder-neck fistula was totally continent. Constipation was detected in 43.1% of all patients, and was more frequent in those with simple defects. Urinary incontinence was found in 19% of patients with cloacas who had a common channel shorter than 3 cm, and in 68.8% of the patients who had longer common channels. Other patients suffered from urinary incontinence only when they had an absent sacrum or other severe bladder or urethral congenital defects. An accurate diagnosis and evaluation of the sacrum allows us to establish, with reasonable accuracy, functional prognosis in most children. Those with functional disorders must be treated properly medically, to improve their quality of life.

Anus, Imperforate↗
PubMed1995

[Antigenic types of circulating rotavirus in children with acute diarrhea in Santiago de Chile].

Protective immunity against rotavirus infection is directed against antigenic epitopes on the outer capsid proteins VP7 and VP4. The aim of this study was to characterize the VP7 and VP4 antigenic types circulating in different hospital areas of Santiago, Chile, over different time periods. Between April 1993 and April 1994 a total of 1206 stool samples were obtained from children consulting for acute no bloody diarrhea in 5 hospitals representative of the 5 major health areas of Santiago. In addition, 256 rotavirus positive samples, obtained from children with acute diarrhea consulting in the north health area of Santiago between 1985-1987 were studied. All samples were processed for rotavirus by an ELISA and all rotavirus positive samples were VP7 typed (types G1-G4) by a monoclonal antibody based ELISA. 50 rotavirus positive samples were selected for VP4 typing by PCR (types P1-P4). A total of 782 rotavirus positive samples were obtained of which 618 (79%) were typable for one specific VP7 type. VP7 type G1 represented 63% of the rotavirus positive samples and predominated in all areas evaluated throughout the entire period of observation. VP7 type G2 represented 13% of rotavirus samples, following G1 in predominance. G2 types decreased progressively in all areas in both study periods. G4 types were detected mainly during 1985-1987, and G3 types have so far not been detected. Preliminary analysis of VP4 types suggests that P1 types are predominant and closely associated with VP7 G1 type. These results are relevant for the adoption of appropriate preventive strategies for rotavirus infection, specifically aimed to the development of effective vaccines.

Acute Disease↗
PubMed1995

[Clinical and psychological characterization of children and adolescents with recurrent abdominal pain].

There is ample empirical evidence supporting the view of emotional disturbances in children with recurrent abdominal pain (RAP) as well as in their parents. However, controlled studies have reported that such manifestations can also be found in patients with other chronic ailments. In order to characterize further the nature of emotional factors in RAP patients, we conducted a controlled psychological evaluation of 46 consecutive new patients with RAP, aged 7-17 years, (group A) by means of structured interviews and questionnaires. Two control groups of pediatric patients with chronic illnesses were also assessed using the same methodology. Group B consisted of 22 individuals with chronic abdominal pain and endoscopy-proven peptic ulcer or duodenitis, and group C consisted of 24 individuals with chronic, stable, non-gastroenterological diseases (e.g., diabetes mellitus or physical handicaps). Parents were evaluated for depressive symptoms. One-way analysis of variance and contingency tables were used for statistical comparisons. There was a higher proportion of female patients in group A than in group B (70 vs 41%; p < 0.05). There were significantly more patients in group A than in group B that reported that their abdominal pain: a) never appeared during sleep, b) began soon after the patient's arousal in the morning, c) remitted completely or was alleviated during school holidays, d) its remission was usually spontaneous during the day and e) did never interfere with recreational activities. Emotional problems were significantly more prevalent in patients in group B than in those in group A (p = 0.016). Past diagnosis of depression was more frequent in group A mothers (40%) than in those in group B (27%), or group C (17%), but these differences did not attain statistical significance. These results suggest that psychological profiles of children suffering from certain chronic conditions (and those of their parents) may be more complex and particular than hitherto recognized. The role of type II error and of some potential socioeconomic and demographic confounding factors must be considered when analyzing the validity of these data.

Abdominal Pain↗