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M Quiroga

Publications and source records attributed to M Quiroga.

At least 37 records · Page 2Linked to original sources
PubMed1983

Structure of a mouse submaxillary messenger RNA encoding epidermal growth factor and seven related proteins.

The structure of the messenger RNA (mRNA) encoding the precursor to mouse submaxillary epidermal growth factor (EGF) was determined from the sequence of a set of overlapping complementary DNA's (cDNA). The mRNA is unexpectedly large, about 4750 nucleotide bases, and predicts the sequence of preproEGF, a protein of 1217 amino acids (133,000 molecular weight). The EGF moiety (53 amino acids) is flanked by polypeptide segments of 976 and 188 amino acids at its amino and carboyxl termini, respectively. The amino terminal segment of the precursor contains seven peptides with sequences that are similar but not identical to EGF.

Amino Acid Sequence↗
PubMed1983

Isolation and nucleotide sequence of a cDNA encoding the precursor of mouse nerve growth factor.

Nerve growth factor (NGF) is a polypeptide that enhances survival, nerve fibre outgrowth and neurotransmitter biosynthesis in sympathetic and sensory neurones. Administration of antibodies against NGF to developing animals leads to atrophy of the sympathetic system. NGF is not normally detectable in innervated tissues but ablation of the innervating neurones leads to the production of measurable NGF in the target tissue. After transplantation of the denervated tissue, reinnervation occurs, then NGF decreases to undetectable levels. Thus NGF seems to act as a neurotrophic messenger and its level is regulated by innervating neurones. Because of the minute levels present it is very difficult to study NGF biosynthesis in innervated tissue. However, NGF can be isolated from male mouse submaxillary glands, where it exists in inexplicably high levels. Its amino acid sequence has been determined, and the synthesis of NGF and its larger precursors has been demonstrated in cultured submaxillary glands. We report here the nucleotide sequence of a submaxillary cDNA encoding the mouse NGF precursor (preproNGF). In contrast to previous suppositions the NGF moiety is situated near the carboxyterminus of the polyprotein precursor. It is flanked at the amino-terminus by 187 amino acids which may be cleaved at dibasic residues to generate three peptides; there are only two additional amino acids at the carboxy-terminus.

Amino Acid Sequence↗
PubMed1982

Rat preprocarboxypeptidase A: cDNA sequence and preliminary characterization of the gene.

Rat carboxypeptidase A cDNA clones have been isolated from a cDNA library prepared from pancreatic mRNA. An almost complete mRNA sequence has been deduced that predicts a polypeptide having 78% amino acid sequence homology with bovine carboxypeptidase A. The amino acid sequence of the activation and signal peptides of the carboxypeptidase A precursor were inferred from the nucleotide sequence. The cDNA was used as a probe to identify DNA fragments containing carboxypeptidase A sequences in a bacteriophage lambda library of rat genomic DNA. Heteroduplexes revealed that the DNA coding sequence occupies 5.5 kilobases and is interrupted by nine intervening sequences. The nucleotide sequence of the 5' end of the gene and the adjacent flanking region provides information on the site of initiation of transcription and the putative control regions. There is no evident relationship between the localization of intervening sequences in the gene and functional/structural domains of the protein.

Animals↗
PubMed1981

Nucleotide and corresponding amino acid sequences encoded by alpha and beta tubulin mRNAs.

Most of the mRNA sequences coding for alpha and beta tubulin in embryonic chick brain have been determined by sequencing of cloned cDNA copies of these mRNA copies of these mRNAs. From a 1,682-base pair cDNA sequence we have deduced the entire protein sequence for beta tubulin. For alpha tubulin, all but about 38 N-terminal amino acids have been deduced from the cDNA sequence. Although tyrosine has previously been shown to be post-translationally added to the C-terminus of alpha tubulin by a specific ligase, we conclude that the primary post-translational even must be the removal, not the addition of tyrosine because a terminal tyrosine is encoded by the mRNA.

Amino Acid Sequence↗
PubMed1981

Effect of polyestradiol on lecithin: cholesterol acyltransferase in male and female rats.

The effects of two doses of polyestradiol phosphate of lecithin: cholesterol acyltransferase activity and on liver and plasma cholesterol levels have been studied on female and male rats. Both treatments increased the hepatic content of esterified cholesterol, but the LCAT activity expressed as a percentage of cholesterol esterification was unaltered. The progress of esterification was not affected by the administration of the hormone. The LCAT activity in terms of the initial rate of esterification was decreased by the high dose of estradiol. This decrease was associated with a reduction of free plasma cholesterol level, as there is a significant positive correlation between these two parameters. The findings suggest that the increased esterified cholesterol in liver of estradiol-treated rats ins not mediated by an alteration in the LCAT activity.

Animals↗
PubMed1981

Preoperative estimation of risk in cardiac surgery.

In order to determine the usefulness of the preoperative subjective estimation of risk and compare it with preoperative estimation of risk based upon objective data, two groups of patients subjected to open heart surgery at the Catholic University of Chile Hospital were studied prospectively. Group I comprised 227 consecutive patients operated on in 1975 and group II comprised 181 consecutive patients operated on in 1979. There were several important differences in management and techniques between the two groups, which resulted in different factors perioperative mortality. Mortality in group I was related to extreme age subsets (p less than 0.01) and to duration an anoxic arrest (p less than 0.001); mortality in group II correlated only to preoperative functional class (NYHA) (p less than 0.02). Despite these differences, subjective risk estimation as preoperatively recorded by the anesthesiologist was accurate in both groups (r = 0.969, p less than 0.05 in group I and r = 0.998, p less than 0.01 in group II). It was concluded that in the absence of a universally valid objective risk index, subjective risk estimation provides a clinical index as useful as reliance upon presently available objective data.

Adolescent↗
PubMed1979

Isolation of yeast tRNALeu genes. DNA sequence of a cloned tRNALeu3 gene.

A library of cloned yeast DNA fragments generated by digestion of yeast DNA with the restriction endonuclease Bam HI has been screened by colony hybridization to total yeast [32P]tRNA. Four hundred colonies carrying yeast tRNA genes were isolated. By hybridization to 125I-tRNALeu3, we have isolated from this collection 14 colonies carrying fragments containing yeast tRNALeu genes. The size of the yeast Bam HI inserts ranged from 2.45 x 10(6) to 14 x 10(6) daltons. One of these fragments was mapped in detail by restriction endonuclease digestion and hybridization to 125I-tRNALeu3. The presence of a tRNALeu3 gene was confirmed by DNA sequence. The results indicate that the tRNALeu3 coding region is not co-linear with the tRNALeu3. An intervening tract of 33 base pairs interrupts the coding sequences 1 base pair past the anticodon coding region. The putative structure of a tRNALeu3 precursor is deduced in which the anticodon base pairs with residues from the intervening sequence.

Base Sequence↗
PubMed1979

Nucleotide sequence of the gene coding for the major protein of hepatitis B virus surface antigen.

DNA extracted from hepatitis B virus Dane particles has been cloned in bacteria using a plasmid vector. A full-length clone has been examined by restriction endonuclease analysis, and the nucleotide sequence of an 892-base pair fragment from cloned hepatitis B viral DNA encoding the surface antigen gene is reported. The amino acid sequence deduced from the DNA indicates that the surface antigens is a protein consisting of 226 amino acids and with a molecular weight of 25,398. The portion of the gene coding for this protein apparently contains no intervening sequences.

Antigens, Surface↗
PubMed1979

Bloodless cardiac surgery utilizing a new low-prime oxygenator.

One hundred consecutive patients undergoing open-heart surgery were subjected to a prospective protocol designed for reduction of homologous blood utilization. The main points of this protocol were careful surgical hemostasis, normovolemic hemodilution, and retransfusion of blood lost to the operating field. It included use of the new Bentley BOS-10 Spiraflo oxygenator (Bentley Laboratories, Inc., Irvine, California, U.S.A.). The patients' ages ranged from 6 to 68 years and their weights from 18 to 84 kg. Fifty-four patients were subjected to valvular surgery, 30 to coronary revascularization, 13 to congenital defects repair, and 3 to resection of atrial myxomas. All patients could be weaned from bypass without receiving any blood. Eighty patients completed their surgery, and 60 were discharged from the intensive care unit without receiving any homologous blood or its derivatives. Total blood usage for the series throughout the entire stay in hospital was 1.32 units/patient, which included six reoperations for excessive bleeding. This reduction in blood utilization was achieved without excessive hemodilution and did not produce significant complications.

Adolescent↗
PubMedDate not supplied

A decade of adult liver transplantation in a single center in Chile.

INTRODUCTION: Since the early days, liver transplantation (OLT) has conquered several barriers worldwide to become a proven therapy. We assessed the evolution of our adult liver transplant program. METHODS: We studied all adult patients who underwent OLT since the inception from November 1993 through May 2003. Donor data, recipient pretransplantation evaluation, surgical technique, results, and costs were examined over our evolution, stratifying 3 groups over time, based on the number of adult OLT per year. RESULTS: Between November 1993 and May 2003, 70 OLT were performed in 64 patients older than 15 years of age. Preoperative Child score, preoperative creatinine level, donor and recipient age, and proportion of emergencies were similar in the 3 groups. Over time, the predominant surgical technique was the piggyback technique (97% of OLT) with a decrease in the use of bypass from 63% to 5% during the last time period. Over the 10 years of our program's existence, warm ischemia time has been reduced to less than 1 hour, whereas cold ischemia time has remained constant at around 5 hours. Biliary and vascular complications decreased over time to around 10%. The mean length of hospital stay (LOS) decreased to 12 days (excluding emergencies). Since inception, our 1-year patient survival rate average is 91%; however, in just the last 3 years of our program (2000 through 2003), the 1-year patient survival rate is 97%. CONCLUSIONS: In summary, our surgical technique has evolved toward piggyback use without veno-venous bypass with a significant decrease in warm ischemia times. As expected, our results have improved over time and our LOS and costs have decreased. Finally, our current results are similar to the best ones reported in the medical literature today.

Adult↗
PubMedDate not supplied

Trends in mechanical ventilation and immediate extubation after liver transplantation in a single center in Chile.

INTRODUCTION: Some groups have reported early extubation post-liver transplantation in patients with previously defined criteria, in an attempt to shorten the ICU stay and decrease costs. We review our experience with trends in mechanical ventilation and resource utilization. METHODS: We retrospectively reviewed the length of mechanical ventilation, ICU stay, hospital stay, transfusions, and costs of liver transplants performed since the program's inception in 1993 and 2002 including 82 OLT in 71 patients. We also report our experience with immediate postoperative extubation, which we have done from October to December of 2002. We compare different periods: the early days (1993 to 1997), namely, fewer than 10 OLT per year, with the subsequent years assessed individually. RESULTS: There has been a progressive decrease over time in the length of mechanical ventilation, ICU stay, hospital stay, and costs. Since the program's inception actuarial adult patient 1- and 5-year survival rates were 88.7% and 78%, respectively. The 1-year survival rate increased to 97% during the period of 2000 to 2002 (n = 30). From October to the present, we extubated four of seven adult patients who met criteria with none of them requiring reintubation. CONCLUSIONS: We demonstrate improved results, decreased length of mechanical ventilation, ICU, and hospital stay, and costs. The immediate postoperative extubation may be feasible for patients who meet previously defined criteria.

Blood Transfusion↗
PubMedDate not supplied

Scorpion sting epidemiology in Montes Municipality of the State of Sucre, Venezuela: geographic distribution.

Scorpion stings were surveyed in the Montes Municipality of the State of Sucre, Venezuela, aiming to extend the information on these poisonous accidents by characterizing their geographic distribution. From 1980 to 1990, 184 cases of scorpion stings were recorded with an incidence rate of 38.6 cases per 10,000 inhabitants. The locality of San Fernando presented the highest incidence (68.3/1000) of poisonous accidents. The highest percentages of severe cases were recorded in the towns of Arenas (27%), San Lorenzo (21%), and Cocollar (19%), which are located at the foot of the Turimiquire Mountains. This region is a dispersion area of scorpions of the Tityus genus. Our results show that this region of the State of Sucre is endemic for scorpion stings which are an important public health problem.

Animals↗
PubMedDate not supplied

Prospective study of enteropathogens in two communities of Misiones, Argentina.

Children under five years of age, from two communities of different socio-economic strata (97 from Zaiman and 55 from Las Dolores) were examined epidemiologically during 2 years, by means of quarterly visits of the working team, who carried out the collection of faecal samples. During the study, one or more enteropathogens were identified in 73.9% of samples in children from Zaiman and in 58.3% of the samples from Las Dolores, being associated to diarrhoea in 70.5% and to asymptomatic infections in 65.7%. The number of diarrheic episodes was higher in Zaiman (15.45%) than in Las Dolores (12.35%), being more frequent in the spring-summer seasons. In Zaiman, the bacterial enteropathogen proportion was relevantly higher (p < 0.005) in children with diarrhoea, whereas the presence of parasites was more frequent in asymptomatic children (p < 0.01). Rotavirus had an even distribution within diarrheic and asymptomatic children. In Las Dolores, no relevant differences were found in the detection of enteroparasites between diarrheic and asymptomatic children. Mixed infections were detected; enterotoxigenic Escherichia coli (ETEC)-rotavirus and ETEC-parasites being the most frequent ones. ETEC was involved in 85% of these infections. These data, together with the high enteropathogen carriage, suggest an elevated level of environmental contamination. The latter plays an important role in diarrheic diseases, and added to the most extreme poverty, it affects children's lives.

Argentina↗
PubMedDate not supplied

Asymptomatic infections by diarrheagenic Escherichia coli in children from Misiones, Argentina, during the first twenty months of their lives.

Diarrheagenics Escherichia coli are the major agents involved in diarrheal disease in developing countries. The aim of this study was to evaluate the time of appearance of the first asymptomatic infection by the different categories of diarrheagenic E. coli in 44 children since their birth and during the first 20 months of their lives. In all of the children studied, we detected at least one category of diarrheagenic E. coli through the 20 months of the study. 510 diarrheagenic E. coli (33.5%) were obtained from the 1,524 samples collected from the 44 children during the time of the study (31.4% EAggEC, 28.8% EPEC, 27.1% DAEC, and 12.7% ETEC). Neither EHEC nor EIEC were identified. The median age for diarrheagenic E. coli colonization was 7.5 months. The mean weaning period was 12.8 months and the mean age for introduction of mixed feeding (breast fed supplemented) was 3.8 months. A significantly lower incidence of diarrheal disease and asymptomatic infections was recorded among the exclusively breast-fed rather than in the supplemented and non breast-fed infants. For ETEC, EPEC and EAggEC the introduction of weaning foods and complete termination of breast-feeding were associated with an increase of asymptomatic infections.

Argentina↗
PubMedDate not supplied

Identification of enteropathogens in infantile diarrhea in a study performed in the city of Posadas, Misiones, República Argentina.

The following work informs of the results of isolation, frequency and distribution of enteropathogens in children under five years old, without previous antibiotic treatment, less than seven days with diarrhoea, ambulatory or in Hospital "Dr. Ramón Madariaga" de Posadas, Misiones, República Argentina, from June 1986 to May 1989. From a total of 972 children with diarrhoea, 78% required to be hospitalized. The greatest number of cases were found during spring and summer in children from 1 to 11 months of age. Distribution of the main enteropathogens was: enteropathogenic Escherichia coli (EPEC) (29.4%), parasites (22%), Shigella (16.3%), enterotoxigenic Escherichia coli (ETEC) (14%) and rotavirus (12.9%). Highest incidence of rotavirus was registered in the coldest months and Shigella, ETEC, Salmonella and parasites in the warm months. The group of most affected children were from 1 to 11 months of age, with higher incidence of EPEC, Salmonella and rotavirus, and parasites were found in older children. ETEC and Shigella had no relationship with the age of children. The most frequent association was EPEC with rotavirus. This is the first finding of Salmonella zaiman in humans and of Salmonella hadar in Argentina. Cryptosporidium, etiological agent of serious diarrhoea in the immunocompetent, was isolated in 3.9% of our cases.

Child, Preschool↗