Biomedical subjects
Publications and source records attributed to R Quintero.
A case of fetus in fetu was diagnosed prenatally using ultrasound. The differential diagnosis between a fetus in fetu and a highly differentiated teratoma is discussed. The importance of prenatal diagnosis of fetus in fetu and the effect on subsequent management are described.
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Based on traditional medicinal knowledge, it was possible to identify the plant species Solanum chrysotrichum as the source of a new antimycotic agent designated SC-1. Cell suspension batch cultures from this plant were established in shake flasks, in which the production of SC-1 was optimized, reaching values fifty times higher than those registered in field grown plants. Large-scale cultivation of the active biomass from S. chrysotrichum was established in 10 l airlift bioreactors, and productivity levels of SC-1 were increased by 60% when using a draw-fill mode in the bioreactors.
PURPOSE: The aim of this study was to analyze the indications and results of fundoplication in 110 infants under 3 months of age. METHODS: A retrospective review was conducted on the charts of all infants operated on for gastroesophageal reflux disease (GERD) at the UCLA Medical Center from January 1980 to December 1997. There were 59 boys and 51 girls. Recurrent emesis was the indication for operation in 62 of 110 infants, and respiratory symptoms in 85 of 110, with 54 of 110 having both. Neurological impairment was present in 32%. Prematurity was present in 21%; 35% had associated anomalies. Overall, 81 of 110 infants (73.6%) had one or more associated major malformations or disorders. Reflux was confirmed by upper gastrointestinal series findings in 63 of 78, esophageal pH monitoring in 60 of 62, and endoscopy in five of seven. RESULTS: Mean age at operation was 1.8+/-0.1 months and mean weight was 3,686+/-90.2 g. A Nissen fundoplication was performed on 104 children, and six underwent a Thal procedure. Thirty-one had a gastric emptying procedure for delayed gastric emptying. Complications occurred in 7 infants. Emesis was controlled in 57 of 62 patients, aspiration in 38 of 48, and apneic spells in 54 of 57. Follow-up greater than 6 months was available for 73 patients. There were nine late deaths, all related to severe associated malformations. Seven patients required a redo fundoplication for recurrent reflux. CONCLUSIONS: Nissen fundoplication can be performed safely in symptomatic infants under 3 months of age with low mortality and morbidity rates and with resolution of the presenting symptoms in 79% of infants.
PURPOSE: Although several centers often perform gastric emptying procedures (GEP) together with fundoplication for gastroesophageal reflux (GER) and delayed gastric emptying (DGE), the benefit of GEP is controversial. The present study addresses the question of whether adding a GEP in children with preoperatively diagnosed GER and DGE affects the recurrence rate of GER after Nissen fundoplication (NF). METHODS: A retrospective chart review was performed on all children under the age of 16 years, operated on for GER from 1980 to 1997, who had a preoperative diagnosis of DGE, and at least 6 months of follow-up. Gastric retention of more than 50% of a radiolabeled meal at 90 minutes was considered DGE. Recurrent reflux was defined as reappearance of GER symptoms, confirmed by postoperative esophagram or 24 hours of pH monitoring. RESULTS: Of the 183 patients with DGE, 92 were available for long-term follow-up. Of these, 20 had no gastric emptying procedure performed (no-GEP group) and 72 had a GEP performed together with an NF (GEP group). Groups were comparable as to age at operation, mean follow-up time, male to female ratio and prevalence of associated anomalies. A higher prevalence of neurological impairment (NI) was present in the GEP group (48.6% v20.0%). Mean preoperative gastric retention was significantly higher in the GEP group (69.9 +/- 1.3%) than in the no-GEP group (61.4 +/- 2.2%). No complications resulted from the GEP. Recurrent reflux rate was 18.1% in the GEP group (13 of 72) versus 35.0% (7 of 20) in the no-GEP group. Actuarial analysis disclosed a marginally significant difference in the rate of recurrent reflux between the groups (P = .057) and estimation of the relative risk showed a 1.94 increase of recurrent reflux risk in the no-GEP (0.89<RR<4.20). CONCLUSIONS: Children with DGE, who did not have GEP, had twice the frequency of recurrent reflux as those who had a GER Preoperative screening for DGE, as well as operative correction of DGE at the time of fundoplication, is therefore recommended.
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Mexico is located in a transition zone between the Nearctic and Neotropical biogeographical regions and contains a rich and unique biodiversity. A total of 496 Bacillus thuringiensis strains were isolated from 503 soil samples collected from the five macroregions of the country. The characterization of the strain collection provided useful information on the ecological patterns of distribution of B. thuringiensis and opportunities for the selection of strains to develop novel bioinsecticidal products. The analysis of the strains was based on multiplex PCR with novel general and specific primers that could detect the cry1, cry3, cry5, cry7, cry8, cry9, cry11, cry12, cry13, cry14, cry21, and cyt genes. The proteins belonging to the Cry1 and Cry9 groups are toxic for lepidopteran insects. The Cry3, Cry7, and Cry8 proteins are active against coleopteran insects. The Cry5, Cry12, Cry13, and Cry14 proteins are nematocidal. The Cry11, Cry21, and Cyt proteins are toxic for dipteran insects. Six pairs of general primers are used in this method. Strains for which unique PCR product profiles were obtained with the general primers were further characterized by additional PCRs with specific primers. Strains containing cry1 genes were the most abundant in our collection (49.5%). Thirty-three different cry1-type profiles were identified. B. thuringiensis strains harboring cry3 genes represented 21.5% of the strains, and 7.9% of the strains contained cry11 and cyt genes. cry7, cry8, and cry9 genes were found in 0.6, 2.4, and 2.6% of the strains, respectively. No strains carrying cry5, cry12, cry13, cry14, or cry21 genes were found. Finally, 14% of the strains did not give any PCR product and did not react with any polyclonal antisera. Our results indicate the presence of strains that may harbor potentially novel Cry proteins as well as strains with combinations of less frequently observed cry genes.
This article describes a computer system to support decisions in Intensive Medicine developed for a multipurpose Intensive Care Unit (13 beds and about 700 yearly patients). The system is used in a microcomputer (486DX4). Works done in this area are mentioned; and the different programs which integrate the system, the advantages of its use and the results accomplished are described. Some of the most important results are the quality increment of the medical care given, physicians' possibilities of dedicating more time to their patients, cost reductions, and improvements in the development of teaching and in the conditions to carry out research work in the Intensive Care Unit (ICU). An analysis is made of the system requirements that guarantee its integration to the Unit work, and the easy and safe use of it by the physicians and nurses.
OBJECTIVE: To incorporate conservative management of a heterotopic pregnancy using injection of KCl into the ectopic pregnancy (EP). DESIGN: A retrospective case report. SETTING: A patient referred to an academic institution in the division of Reproductive Endocrinology, Department of Obstetrics and Gynecology, incorporating the ultrasound (US) and operating room facilities. INTERVENTION(S): Using US as a guide, KCl was injected into the chorionic cavity of an EP. MAIN OUTCOME MEASURE(S): Resolution of ectopic gestational tissue with resultant hematosalpinx requiring exploratory laparotomy. Uncomplicated prenatal course of intrauterine pregnancy. RESULT(S): Injection of KCl into the chorionic cavity of EP resulting in resolution of gestational tissue but complicated by hematosalpinx in the fallopian tube. CONCLUSION(S): Selective embryo reduction of a tubal heterotopic pregnancy remains a viable therapeutic option.
Membrane potential measurements using a fluorescent dye indicated that two specific toxins active against Spodoptera frugiperda larvae (CryIC and CryID) cause immediate permeability changes in midgut epithelial brush border membrane vesicles (BBMV). The initial response and the sustained permeability change are cationic, not very K+ selective, and occur at in vivo lethal doses (nM). The toxin response has a different ion selectivity and is more sensitive to Ba2+ than the intrinsic cation permeability of BBMV. Experiments incorporating BBMV into planar lipid bilayers (PLB) demonstrated that these vesicles contain cation channels (31, 47 and 76 pS). A 2-40 fold conductance increase was induced by nM concentrations of toxin in PLB containing BBMV. Cationic single channel transitions of 50, 106, 360 and 752 pS were resolved. Thus, Bacillus thuringiensis delta-endotoxins induce an increase in cation membrane permeability involving ion channels in BBMV-containing functional receptors.
In this paper we describe a PCR strategy that can be used to rapidly identify Bacillus thuringiensis strains that harbor any of the known cryI or cryIII genes. Four general PCR primers which amplify DNA fragments from the known cryI or cryIII genes were selected from conserved regions. Once a strain was identified as an organism that contains a particular type of cry gene, it could be easily characterized by performing additional PCR with specific cryI and cryIII primers selected from variable regions. The method described in this paper can be used to identify the 10 different cryI genes and the five different cryIII genes. One feature of this screening method is that each cry gene is expected to produce a PCR product having a precise molecular weight. The genes which produce PCR products having different sizes probably represent strains that harbor a potentially novel cry gene. Finally, we present evidence that novel crystal genes can be identified by the method described in this paper.
We present the first report in our country of endoscopic fetal surgery in a patient with a twin pregnancy and twin reversal arteral perfusion (TRAP sequence). We performed fetoscopic ligation of the umbilical cord of an acardiac twin at 26 week's gestation.
Although it was described many years ago, laryngeal electromyography is of limited use. It can easily be performed in the doctor's surgery by the intercrico-thyroid approach. The author reports on 70 examinations, 64 for mobility disorders, 6 for abnormal spasmodic movements. 15 normal plots made it possible to correct a faulty diagnosis of palsy. The prognostic contribution is not so clear-cut and must take account of the clinical circumstances and the time elapsed before examination. EMG must be performed systematically before any irreversible therapeutic decision.
Exponentially fed-batch cultures (EFBCs), fed with medium containing a highly concentrated carbon source, are commonly employed for attainment of high cell densities. However, large variations in environmental conditions occur, and quasi-steady-state is usually achieved only for the limiting substrate concentration, restricting the use of such cultures in kinetic characterization studies. In this work we report the production of recombinant penicillin acylase (PA) in EFBC of an E. coli JM101 transformed with the pPA102 plasmid, which includes the PA gene under regulation of the lacZ gene promoter and using isopropyl-beta-thio-galactopyranoside (IPTG) as inducer. The culture was fed with nonconcentrated complete medium, resulting in the attainment of quasi-steady-state conditions not only in substrate concentration, but also in cell concentration, and in the specific rates of growth, product production, and substrate consumption. Similar transient behavior was observed between EFBC and chemostat results. At quasi-steady-state, the dilution rate in the EFBC equaled the growth rate. Specific PA production rate during the fed-batch phase remained relatively constant at each dilution rate and followed typical Luedeking-Piret kinetics, with growth-associated and non-growth-associated constants of 142 U gDCW-1 and 7.2 U gDCW-1 h-1, respectively. Specific glucose consumption rate linearly increased from 0.025 to 0.6 g gDCW-1 h-1 as the dilution rate increased from 0.01 to 0.35 h-1. The maximum specific PA activity increased with decreasing dilution rate, reaching its highest value of 2.0 U mg-1 at a dilution rate of 0.01 h-1, the lowest dilution tested.(ABSTRACT TRUNCATED AT 250 WORDS)
A method allowing rapid and accurate identification of different subgroups within the insecticidal crystal CryI protein-producing family of Bacillus thuringiensis strains was established by using PCR technology. Thirteen highly homologous primers specific to regions within genes encoding seven different subgroups of B. thuringiensis CryI proteins were described. Differentiation among these strains was determined on the basis of the electrophoretic patterns of PCR products. B. thuringiensis strains, isolated from soil samples, were analyzed by PCR technology. Small amounts of bacterial lysates were assayed in two reaction mixtures containing six to eight primers. This method can be applied to rapidly detect the subgroups of CryI proteins that correspond with toxicity to various lepidopteran insects.
Treatment of fetal anomalies has allowed the intact survival of increasing numbers of fetuses with previously fatal or very likely fatal disorders. Percutaneous in-utero surgery for obstructed bladders and thoracic effusions, and open surgery for diaphragmatic hernias and lung malformations has become increasingly successful. Medical and gene therapy approaches are likewise expanding and will continue to become more available.
Fermentation conditions were developed in order to achieve simultaneously a high biomass concentration and high-level expression of a hybrid cI-human insulin B peptide gene. In our system, this hybrid gene is under control of the Escherichia coli trp promoter, in a trp- derivative strain of E. coli W3110. The dual role of tryptophan concentration on cellular growth and hybrid gene regulation was studied in 10-1 batch fermentations. In the best batch conditions, a biomass concentration of 12 g dry weight/l can be obtained, and 0.53 g/l of cI-insulin B hybrid protein is produced. Tryptophan in the culture medium is consumed by the growing culture, until a level is reached that causes induction of the hybrid gene. Plasmid loss was detected, as only 62% of the cells retained the recombinant plasmid. In order to increase the hybrid protein production level, a fed-batch culture strategy was developed whereby the specific growth rate of the cells was restrained. Using the same amount of nutrients as in the batch fermentations, it was possible to increase the final biomass concentration to 20 g/l, plasmid-bearing cells in the population to 90% and recombinant hybrid protein to 1.21 g/l.
A complete characterization of a penicillin acylase biocatalyst is presented, including the determination of physicochemical and kinetic parameters. Stability studies are detailed in terms of both storage temperature and pH as well as operational stability after 150 batch reactions of two hours duration each. An Arrhenius-type model was used to simulate the effect of pH on biocatalyst stability. A kinetic model is proposed to describe batch and continuous stirred tank reactors and to predict the long-term behavior of the process.