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Biomedical subjects

A R Torres

Publications and source records attributed to A R Torres.

At least 37 records · Page 2Linked to original sources
PubMed1993

Enhanced proliferation of peripheral blood mononuclear cells and tumor-infiltrating lymphocytes in a plasma-derived cell culture fluid.

The proliferation and activation of murine and human T-lymphocytes in a high-protein lymphocyte culture fluid (LCF) is compared to that of cells cultured in 10% fetal bovine serum (FBS). Tumor-infiltrating lymphocytes (TIL) proliferate exponentially in the LCF for up to 46 days and generate cell numbers that are nearly 100,000-fold greater than cells cultured in FBS. This rapid growth of T cells in LCF could have an important impact in adoptive immunotherapy and gene therapy since cell growth is a limiting factor in these technologies.

Animals↗
PubMed1992

Purification of complex protein mixtures by ion-exchange displacement chromatography using spacer displacers.

The anion-exchange separation of complex protein mixtures by displacement chromatography using spacer displacers driven by high-affinity final displacers is demonstrated. Guinea pig serum was separated on a medium-resolution adsorbent using a single heterogeneous mixture of carboxymethyldextran displacers to space the protein components. Mouse liver cytosol was separated on a low-resolution adsorbent using six carboxymethyldextran spacer displacers of increasing column affinity. The demonstration of the purification of alkaline phosphatase from E. coli periplasm by displacement chromatography on a high-performance liquid chromatography column is reviewed. The benefits of spacer displacers for separating minor components from complex biological protein mixtures is discussed. A simplified method for preparing carboxymethyldextran displacers is presented.

Adsorption↗
PubMed1992

Growth of hybridoma cells and antibody production in agamma calf serum.

An agamma calf serum (ACS) was compared to fetal bovine serum (FBS) and calf serum supplemented growth media for both murine and human fusion partners and derived hybridoma cells. The variables analyzed were cloning efficiencies, growth characteristics, and MAb production levels. Cultures were established in each serum source, and supernatants were kept for analysis. For cloning efficiencies, the results indicate that although there is no clear advantage in the performance of FBS-supplemented medium, ACS-supplemented RPMI 1640 medium can be used to clone hybridomas and the fusion partners. When analyzed for MAb production in the various sera, the hybridoma cell lines used in this study appeared to produce up to twice as much immunoglobulin when grown in ACS as when grown in supplemented medium. IgG- and IgM-secreting hybridoma cultures should be checked independently for antibody production. Six out of eight murine and human hybridoma cell lines produced higher levels of MAbs when grown in ACS.

Animals↗
PubMed1992

Right submammarian thoracotomy in female patients with atrial septal defects and anomalous pulmonary venous connections. Comparison between the transpectoral and subpectoral approaches.

A right submammarian incision with anterior thoracotomy was performed in 89 female patients to repair simple and complex forms of atrial septal defects. Patients' ages ranged from 8 to 38 years (mean 21.5 years). Seventy-seven had secundum-type atrial septal defects, one had the primum type, and 11 had an associated partial anomalous pulmonary venous connection. The patients were divided into two groups: 57 patients in group A, in whom, after a breast flap was elevated, a transpectoral approach was used to enter the chest; 32 patients in group B, in whom the pectoral muscle was not divided and a subpectoral approach was used. Aortic cannulation was accomplished without difficulty in all 89 patients. There were no early or late deaths in either group. Follow-up ranged from 24 to 108 months (mean 63.7 months) and included 86 patients, who were free of symptoms. In group A, however, among 54 patients examined, the volume of the right breast and pectoral muscle was smaller than the left in four patients (7.4%), and 21 (38.8%) had persistent right periareolar numbness. In 32 patients evaluated in group B, no difference was noted in the size of the breasts, and persistent numbness was present in four patients (12.5%). In summary, atrial septal defects or anomalous pulmonary venous connections can be safely repaired through a right submammarian thoracotomy in female patients. The subpectoral approach offers better results because breast asymmetry and paresthesias are significantly less prevalent (p less than 0.01).

Adolescent↗
PubMed1992

Risk of recoarctation in neonates and infants after repair with patch aortoplasty, subclavian flap, and the combined resection-flap procedure.

Between September 1980 and August 1988, 47 patients younger than 12 months (27 neonates and 20 infants) underwent repair of aortic coarctation. Three surgical techniques were used: patch aortoplasty (group A: 5 neonates and 3 infants, mean age 4.5 months), subclavian flap (group B: 11 neonates and 8 infants, mean age 3.1 months), and the combined resection-flap procedure (group C: 11 neonates and 9 infants, mean age 2.7 months). There were 8 early deaths (3 in group A, 3 in group B, and 2 in group C) and 2 late deaths (both in group B), all of which occurred in patients with complex coexisting anomalies. Follow-up included 37 patients (5 in group A, 14 in group B, and 18 in group C) and ranged from 28 to 108 months (mean 68.0, 60.8, and 51.7 months, respectively). Residual arm-leg pressure gradients greater than 10 mm Hg were detected in 4 of 5 patients in group A, 11 of 14 patients in group B, and 1 of 18 patients in group C (p less than 0.005). There were no reoperations in any infant operated on after 1 month of age in any group (0% risk). However, 4 patients who underwent repair during their neonatal period, with recurrent gradients greater than 20 mm Hg, have required reoperation: in group A, 1 of 5 patients (20% risk) (1 of 2 neonates or 50% risk); in group B, 3 of 14 patients (21% risk) (3 of 9 neonates or 33% risk); and none in group C (0% risk in infants and neonates) (p less than 0.001). In summary, residual gradients and risk of recoarctation are significantly higher when a patch or a subclavian flap had been used for repair. The combined resection-flap procedure (an end-to-end anastomosis enlarged with a subclavian flap) is more effective in avoiding gradients and preventing recoarctation, especially in neonates.

Anastomosis, Surgical↗
PubMed1990

Purification of monoclonal antibodies by complex-displacement chromatography on CM-cellulose.

A single high-capacity chromatographic procedure was used to purify a monoclonal antibody from ascites fluid. A new displacement procedure involving a displacer protein complex is described. The scale-up from 1 ml to 450 ml of ascites sample was easily accomplished with this complex-displacement system. A monoclonal antibody recovery of 79% was measured for the largest-scale purification.

Animals↗
PubMed1989

Right atrial approach for surgical correction of tetralogy of Fallot.

Total correction of tetralogy of Fallot was performed without a ventriculotomy in 39 patients aged 8 months to 39 years (mean age, 9.1 years) between May 1984 and July 1988. A transatrial approach was used to resect the obstructed infundibulum and to close the ventricular septal defect. In 14 patients, the pulmonary annulus was not enlarged (group 1). Twenty-five patients required a transannular patch (group 2), placed by extending the pulmonary artery incision 1 cm into the right ventricular infundibulum. Eleven patients had repair of pulmonary artery branch stenosis, and associated intracardiac anomalies were simultaneously corrected in 10 patients. After repair, the right ventricular to left ventricular systolic pressure ratios ranged from 0.36 to 0.59 (mean ratio, 0.45) in group 1 and 0.33 to 0.70 (mean ratio, 0.51) in group 2. There were no hospital or late deaths in group 1. Two patients in group 2 with a small left ventricle died shortly after operation. The 37 survivors were followed for 2 to 51 months. Postoperative catheterization in 7 patients detected no residual ventricular septal defects, mild pulmonary regurgitation in 2 patients (group 2), and right ventricular to left ventricular pressure ratios ranging from 0.25 to 0.42 (mean ratio, 0.34). Only 1 patient with a previous total repair by ventriculotomy is symptomatic and requires antiarrhythmic agents and diuretics. The other 36 patients are asymptomatic. In conclusion, tetralogy of Fallot can be safely repaired at any age without a ventriculotomy. The results indicate a minimal incidence of postoperative arrhythmias and pulmonary regurgitation, as well as improved right ventricular function.

Adolescent↗
PubMed1989

Cultural and biochemical characterization of Actinobacillus and Actinobacillus-like species from ram lambs with epididymitis.

Cellular, colonial, cultural, and biochemical characteristics of 25 field strains of gram-negative pleomorphic bacilli from rams with epididymitis were compared with Actinobacillus actinomycetemcomitans American Type Culture Collection (ATCC) strain 29522 and Actinobacillus seminis ATCC strain 15768. Three field strains were identified as A. actinomycetemcomitans, 15 as A. seminis, and 2 as Haemophilus agni; however, 5 strains (3 in group A and 2 in group B) were not identified as species in the genera Actinobacillus, Haemophilus, or Pasteurella based on the taxonomic criteria in Bergey's manual of systematic bacteriology. The 5 Actinobacillus-like organisms in groups A and B were predominantly gram-negative coccobacilli and exhibited less pleomorphism than the 2 Actinobacillus species. The colonial morphologies of groups A and B were similar to the 2 Actinobacillus species but were smaller in diameter and had a pale yellow color. Groups A and B, like the actinobacilli, were facultative anaerobic and capnophilic, did not grow on MacConkey agar, and were catalase-positive and oxidase-positive. Group A reduced nitrate but group B did not. The A. seminis strains utilized ornithine, and group A utilized arginine; but group B did not utilize either ornithine or arginine. All strains failed to utilize lysine or tryptophane. All strains produced acid but no gas from glucose, and the utilization of other carbohydrates varied markedly both between and within the 5 groups of bacteria.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinobacillus↗
PubMed1988

Purification of Escherichia coli alkaline phosphatase on an ion-exchange high-performance liquid chromatographic column using carboxymethyl dextrans.

Carboxymethyl dextrans (CM-Ds) were used on an HPLC ion-exchange column to obtain significantly enriched alkaline phosphatase (EC 3.1.3.1) from a sample of Escherichia coli periplasmic space proteins without significant loss of enzymatic activity. The ability of CM-Ds to separate alkaline phosphatase even when the column was 80-85% saturated with protein demonstrates the potential for high column capacity using CM-Ds. In addition, the fractions containing alkaline phosphatase and CM-Ds were reapplied to the same ion-exchange column under different buffer conditions and purified to homogeneity by salt gradient elution chromatography, thus demonstrating the compatibility of CM-Ds with the latter chromatographic method. The two-step chromatographic procedure yielded enzyme of purity comparable to that of electrophoretically purified E. coli alkaline phosphatase obtained commercially. These studies demonstrate that HPLC displacement chromatography is a mild procedure which allows rapid, quantitative purification of an enzyme. Scaling up with larger columns should allow purification of enzymes of a commercial basis.

Alkaline Phosphatase↗
PubMed1987

Preparative high-performance liquid chromatography of proteins on an anion exchanger using unfractionated carboxymethyldextran displacers.

It has been previously demonstrated that carboxymethyldextran (CMD) displacers fractionated on an ion-exchange column can be used for the resolution and high capacity displacement chromatography of proteins on high-performance ion-exchange columns. It is shown, in this manuscript, that high resolution and high capacity are obtainable using unfractionated CMD displacers. Up to 25 mg of a mixture of ovalbumin, alpha-lactalbumin, and soy-bean trypsin inhibitor along with many impurities were separated on a 3.3-ml Altex DEAE-5PW column using three unfractionated CMD displacers and a final CMD displacer. A method for removing the displacers from proteins, on a hydrophobic interaction column, is also described.

Anion Exchange Resins↗
PubMed1987

Coarctation of the aorta: anastomotic enlargement with subclavian artery: two new surgical options.

Recoarctation is still observed following surgical treatment of coarctation in small infants. Modifications to conventional surgical techniques are suggested to avoid this serious complication. Coarctectomy is performed. To obtain a much wider noncircumferential anastomosis, the subclavian artery is used to enlarge it either as a flap or by reimplantation. No residual pathological tissue is left behind, and this should help prevent recurrence.

Aorta↗
PubMed1986

Selective enrichment of specific DNA, cDNA and RNA sequences using biotinylated probes, avidin and copper-chelate agarose.

We have developed a general procedure for the rapid and efficient enrichment of specific DNA, RNA or cDNA sequences. Biotinylated DNA or RNA is used as a hybridization probe in solution, avidin is then added to label both the probe and hybrid molecules, and the hybridization mixture chromatographed over cupric-iminodiacetic acid agarose beads. Avidin-probe and avidin-hybrid molecules are selectively retained on the column; non-hybridized sequences are contained in the flow-through fraction. Sequences retained on the column are recovered in high yield by the addition of ethylenediamine tetracetic acid in the buffer. The method can be used in both subtractive enrichment and positive selection protocols. Here we report its application to the isolation of Neisseria gonorrhoeae specific genomic DNA clones and the purification of a cDNA subpopulation representing mRNA sequences that are over-expressed in murine Friend cells after dimethylsulfoxide induction.

Avidin↗
PubMed1985

Purification of Gc-2 globulin from human serum by displacement chromatography: a model for the isolation of marker proteins identified by two-dimensional electrophoresis.

A protein that was initially known only as a minor spot in two-dimensional electrophoresis patterns of serum obtained from certain psoriasis patients, particularly those with a pustular component to their disease, has been purified by two stages of ion-exchange displacement chromatography on DEAE-Sephacel at different pH levels, followed by elution chromatography on hydroxylapatite. The purification was followed by examining the column fractions directly by two-dimensional gel electrophoresis. The capacity of the displacement system, which utilized carboxymethyldextrans as displacers, was very high; 6 ml of dialyzed serum applied to a 7-ml column in the initial stage resulted in a very substantial enrichment of the target protein. The second displacement stage yielded a highly purified product, contaminated only by A-1 lipoprotein. The latter was removed by hydroxylapatite chromatography. The purified protein was subsequently identified as Gc-2 globulin, a vitamin D-binding protein, by immunological procedures. The results demonstrate the effectiveness of ion-exchange displacement chromatography in focusing resolving power on the relatively narrow range of affinities represented by the target protein and its immediate neighbors in a chromatogram, as well as the applicability of the system to the isolation of a protein known only by its position in a two-dimensional electrophoretic pattern.

Animals↗
PubMed1985

Measurement of active constitutive beta-D-glucosidase (esculinase) in the presence of sodium desoxycholate.

The hydrolysis of esculin in the presence of bile has been utilized for many years for the identification of bacteria. It is especially useful in differentiating species of the genus Streptococcus. The procedure is a two-step one. First, the bacterium must grow in a particular concentration of bile, and second, it must hydrolyze esculin. The hydrolysis of esculin has traditionally been determined by the brown-black color that results when one of the hydrolysate products, esculetin, reacts with iron in the medium. The procedure requires incubation for 24 h or more. A method was developed based on the measurement of constitutive beta-glucosidase (esculinase) with the repression of this enzyme by bile equivalent (sodium desoxycholate) that required only 30 min. p-Nitrophenyl-beta-D-glucopyranoside was the esculinase substrate, and sodium desoxycholate was substituted for bile salts. After inoculation, a yellow color was equivalent to the brown-black seen in the 40% bile-esculin reaction. The reagent was dispensed in test tubes and was stable for 6 months. The 30-min procedure correlated well with the conventional 24-h bile-esculin agar tube. Streptococcus pneumoniae could also be identified because of the rapid lysis it exhibited in the substrate solution.

Bacteria↗
PubMed1985

Elastin covalent structure as determined by solid phase amino acid sequencing.

The amino acid sequences of 16 large tryptic fragments of aortic tropoelastin have been determined establishing the presence of several repeating structures: GVP, GGVP, PGVGV, PGVGVA, and AGVPGFGVG. The methodologies for achieving these results by solid phase sequencing are reviewed and also the possible biologic significance of the unusual primary structures of elastin are discussed.

Amino Acid Sequence↗
PubMed1984

Differentiation of Neisseria gonorrhoeae from other Neisseria species by use of the restriction endonuclease HaeIII.

We used the restriction endonuclease HaeIII to differentiate Neisseria gonorrhoeae from other Neisseria species and Branhamella catarrhalis. A total of 16 clinical isolates and four American Type Culture Collection strains of N. gonorrhoeae were resistant to HaeIII digestion, whereas 17 isolates and four American Type Culture Collection strains from eight different bacterial species were susceptible. This resistance was not caused by an enzyme inhibitor. We propose that protection of the HaeIII recognition sequence by methylation is the mechanism of resistance since N. gonorrhoeae DNA became susceptible to digestion when passed in Escherichia coli as part of a plasmid clone.

Base Sequence↗