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Biomedical subjects

J Garcia

Publications and source records attributed to J Garcia.

At least 325 records · Page 18Linked to original sources
PubMed1988

Anaphylaxis to amoxycillin but good tolerance for benzyl penicillin. In vivo and in vitro studies of specific IgE antibodies.

Three patients are reported on who suffered anaphylactic reactions after amoxycillin (AX) treatment and challenge but tolerated benzylpenicillin (BP) parenterally and orally. Two of the three patients had positive skin tests and RAST to AX reagents but negative responses to benzyl penicilloyl (BPO) specific skin tests and RAST and the minor determinant mixture (MDM) skin test reagent. The third case was negative to all skin tests and RAST. RAST and RAST inhibition on the two positive sera suggest that the response is related to the acyl side chain of AX.

Adult↗
PubMed1988

Alterations in binding characteristics of the human immunodeficiency virus enhancer factor.

Five regions of the human immunodeficiency virus (HIV) long terminal repeat (LTR) serve as binding sites for cellular proteins as demonstrated by DNase I footprinting. These include the negative regulatory, enhancer, SP1, TATA, and untranslated regions. The HIV enhancer region contains two direct repeats of a sequence, GGGACTTTCC, which is also found in the enhancer sequences of simian virus 40, cytomegalovirus, and the immunoglobulin kappa gene. To further characterize binding to the enhancer sequences in the HIV LTR, DNase I footprinting was performed using extracts prepared from several different cell lines. Extracts prepared from lymphoid cells gave altered binding over the enhancer region as compared with extracts prepared from either monocytes or HeLa cells. This altered binding in extracts prepared from lymphoid cells resulted in protection of both direct repeats in the HIV LTR in contrast to complete protection of only one direct repeat with HeLa cell extracts. When HeLa cells were treated with phorbol esters in either the presence or absence of the protein synthesis inhibitor cycloheximide, the binding characteristics over the enhancer element became similar to those seen in extracts prepared from lymphoid cells. These results suggest that phorbol esters may induce posttranslational modifications of cellular transcription factors that alter their DNA-binding characteristics.

Cells, Cultured↗
PubMed1988

Adenovirus transcriptional regulatory regions are conserved in mammalian cells and Saccharomyces cerevisiae.

The adenovirus early region 3 (E3) promoter is an early viral promoter which is strongly induced by the adenovirus transactivator protein E1A. DNase I footprinting with HeLa cell extracts has identified four factor-binding domains which appear to be involved in basal and E1A-induced transcriptional regulation. These binding domains may bind TATA region-binding factors (site I), the CREB/ATF protein (site II), the AP-1 protein (site III), and nuclear factor I/CTF (site IV). Recently, it has been shown that the DNA-binding domain of transcription factor AP-1 has homology with the yeast transcription factor GCN4 and that the yeast transactivator protein GAL4 is able to stimulate transcription in HeLa cells from promoters containing GAL4-binding sites. These results suggest an evolutionary conservation of both transcription factors and the mechanisms responsible for transcriptional activation in Saccharomyces cerevisiae and higher eucaryotic organisms. To determine whether similar patterns of transcriptional regulation were seen with the E3 promoter in HeLa and yeast cells, the E3 promoter fused to the chloramphenicol acetyltransferase (cat) gene was cloned into a high-copy-number plasmid and stably introduced into yeast cells. S1 analysis revealed that similar E3 promoter mRNA start sites were found in yeast and HeLa cells. DNase I footprinting with partially purified yeast extracts revealed that four regions of the E3 promoter were protected. Several of these regions were similar to binding sites determined by using HeLa cell extracts. Oligonucleotide mutagenesis of these binding domains indicated their importance in the transcriptional regulation of the E3 promoter in yeast cells. These results suggest that similar cellular transcription factor-binding sites may be involved in the regulation of promoters in both yeast and mammalian cells.

Adenoviridae↗
PubMed1988

Esophageal strictures: balloon dilation.

One hundred seventy transnasal balloon catheter dilation procedures were performed in 35 patients with esophageal strictures to assess the efficacy and safety of the procedure. On the average, five dilations were required per patient. Depending on the cause of the esophageal stricture, success rates for the technique ranged from 67% to 87%, with success defined as the resolution of dysphagia to both fluids and solids. Three complications, all perforations, were seen; one perforation required surgical repair. No procedure-related deaths were identified in this series. Balloon catheter dilation can be safely applied to esophageal strictures from a variety of causes, with a high degree of clinical success.

Catheterization↗
PubMed1988

The subtalar sprain. A roentgenographic study.

Subtalar and ankle sprains are more frequently associated than previously suspected. In this study, 40 patients were analyzed, using subtalar arthrograms and ankle stress films. Thirty-two of the 40 patients had a rupture involving components of both subtalar and ankle capsuloligamentous structures. If ignored or improperly treated, these lesions may develop into a sinus tarsi syndrome or a chronically painful and unstable ankle. Negative stress films in the presence of a clinically serious ankle injury should arouse suspicion of an underlying subtalar sprain, as demonstrated in six patients with positive arthrograms.

Adult↗
PubMed1987

Upstream regulatory regions required to stabilize binding to the TATA sequence in an adenovirus early promoter.

Of the five early adenovirus promoters, the early region 3 (E3) promoter is one of the most strongly induced by the E1A protein. To identify cellular proteins involved in both the basal and E1A-induced transcriptional regulation of the E3 promoter, DNase I footprinting using partially purified Hela cell extracts was performed. Four regions of the E3 promoter serve as binding domains for cellular proteins. These regions are found between -156 to -179 (site IV), -83 to -103 (site III), -47 to -67 (site II), and -16 to -37 (site I), relative to the start of transcription. Examination of the DNA sequences in each binding domain suggests that site III likely serves as a binding site for activator protein 1 (AP-1), site II for the cyclic AMP regulatory element binding protein (CREB), and site I for a TATA binding factor. The factors binding to either site II or III were sufficient to stabilize binding to the TATA sequence (site I). Mutagenesis studies indicated that both sites II and III, in addition to site I, are needed for complete basal and E1A-induced transcription. These results suggest that multiple cellular factors are involved in both the basal and E1A-induced transcriptional regulation of the E3 promoter, and that either of two upstream regions are capable of stabilizing factor binding to the TATA sequence.

Adenovirus Early Proteins↗
PubMed1987

Significance of the changes in plasma amino-acid levels in meningococcal infection.

A series of patients with meningococcal infections have been studied and divided in two groups: Group I patients with meningococcal sepsis and group II, those with meningococcal meningitis. Patients in group I presented with more severe encephalopathy, shock, DIC and acute systemic complications. Both groups showed a marked hypoaminoacidemia compared with normal controls (other than for the sulfur containing amino acids and phenylalanine). The concentration of aromatic and basic amino acids, the phenylalanine/tyrosine ratio, the transaminase levels and the negative nitrogen balance were higher in group I patients. The ratio of branched chain to aromatic amino acids was lower in group I. All these differences were statistically significant. The close association between the metabolic derangements and clinical manifestations may help in the understanding of several physiopathological aspects of meningococcal infections.

Adolescent↗
PubMed1987

Conditioned taste aversion in vasopressin-deficient rats (Brattleboro strain).

Brattleboro rats are homozygous for diabetes insipidus (DI), lacking the ability to synthesize vasopressin. Previous studies reported learning deficits in DI rats on passive avoidance tasks using footshock. Other studies, however, could not replicate these results. In two experiments, we studied the learning of DI and control Long Evans (LE) rats in a different avoidance paradigm: conditioned taste aversion (CTA). In the first experiment a mild CTA to saccharin was established gradually using low levels of an illness-inducing agent (lithium chloride). In the second experiment a strong CTA was established in one acquisition trial and the extinction of the conditioned aversion was followed for 12 trials. The two experiments found no differences between the DI and LE rats in either the magnitude or the rate of acquisition and extinction of the CTA. These results suggest that vasopressin is not involved in the acquisition and retention of CTA, and support previous studies indicating that vasopressin may not be involved in avoidance learning.

Animals↗
PubMed1987

Potentiation of odor by taste and odor aversions in rats are regulated by cholinergic activity of dorsal hippocampus.

Limbic cholinergic activity is critically involved in the retention of learned aversions tasks. The purpose of these experiments was to assess the role of cholinergic mechanisms of the dorsal hippocampus in the acquisition of both odor and potentiated odor aversions through taste aversion. Cholinergic activity was increased by physostigmine (Phys). When Phys was applied before the presentation of an odor-taste compound during acquisition, the potentiation of odor-aversion was disrupted, while taste aversion was left intact. When hippocampal cholinergic activity was reduced with the muscarinic antagonist scopolamine (Scop), enhancement of potentiated odor aversion was observed, again with no effect on taste aversion. Moreover, when Phys was applied before an odor alone it also disrupted odor avoidance in two different odor tests conditioning situations, i.e., odor was followed immediately by lithium chloride or foot shock. Neither Scop nor Phys had any effect on taste or potential odor aversions when applied to fronto-parietal cortex. These results suggest that cholinergic activity of the hippocampus is involved in the acquisition of odor aversion conditioning.

Animals↗