Search PubMed⌕ Search

Biomedical subjects

J Gutierrez

Publications and source records attributed to J Gutierrez.

At least 19 recordsLinked to original sources
PubMed1992

Identity of 4a-carbinolamine dehydratase, a component of the phenylalanine hydroxylation system, and DCoH, a transregulator of homeodomain proteins.

The principal pathway for the metabolism of phenylalanine in mammals is via conversion to tyrosine in a tetrahydrobiopterin-dependent hydroxylation reaction occurring predominantly in the liver. Recently, the proposal that certain hyperphenylalaninemic children may have a deficiency of carbinolamine dehydratase, a component of the phenylalanine hydroxylation system, has widened the interest in this area of metabolism. Upon cloning and sequencing the dehydratase, we discovered that this protein is identical to DCoH, the cofactor which regulates the dimerization of hepatic nuclear factor 1 alpha, a homeodomain transcription factor. The identity of the nuclear and cytoplasmic proteins is demonstrated by size, immunoblotting, stimulation of phenylalanine hydroxylase, and dehydratase activity. The evolution of the dual functions of regulation of phenylalanine hydroxylation activity and transcription activation in a single polypeptide is unprecedented.

Amino Acid Sequence↗
PubMed1992

Molecular approach in spider mites (Acari: Tetranychidae): preliminary data on ribosomal DNA sequences.

DNA sequence data were used to examine phylogenetic relationships between six species of economically important Tetranychidae mites: Eotetranychus carpini (Oudemans), E. pruni (Reck), Tetranychus pacificus McGregor, T. mcdanieli McGregor, T. turkestani Ugarov & Nikolski and T. urticae Koch. With primers directed toward conserved elements flanking the target region, the Polymerase Chain Reaction was used to amplify the ITS2 spacer of the ribosomal DNA molecule. The nucleotide sequence of a 300-bp fragment of the ITS2 was determined by direct sequencing and nucleotide divergence used for intra-generic comparison in mites. The resulting phylogenetic tree expressing interspecific relationships in genus Tetranychus agrees with morphological data. The study demonstrates the usefulness of the approach in the assessment of the systematics and evolution of the group.

Acari↗
PubMed1991

Effect of intrathoracic pressure on plasma arginine vasopressin levels.

Abdominal distention during pneumoperitoneum results in a marked increase in plasma arginine vasopressin levels, which has been ascribed to an increase in intrathoracic pressure. Because of this relationship, tense ascites could contribute to nonosmotic release of antidiuretic hormone, to the development of hyponatremia, and eventually to further ascites formation. The effect of pneumoperitoneum, thoracocentesis, and paracentesis on plasma arginine vasopressin levels was studied in three groups of patients, and the mechanism by which these maneuvers may induce these changes was investigated. Patients with pleural effusion, pneumothorax, or ascites showed a significant increase in plasma arginine vasopressin levels, and thoracocentesis or paracentesis resulted in a decrease in these levels. Plasma vasopressin levels increased significantly during pneumoperitoneum, as did intrathoracic and atrial pressures; the atrial transmural pressure gradient declined. However, no changes in plasma levels of norepinephrine, aldosterone, and renin activity were observed during pneumoperitoneum. Changes in plasma arginine vasopressin levels correlated with the changes in intrathoracic and atrial pressures and transmural pressure gradient. The authors conclude that increased intrathoracic pressure is associated with an increase in plasma arginine vasopressin levels and propose that ascites could be a factor promoting vasopressin release by acting on intrathoracic volume receptors in decompensated cirrhotics.

Adult↗
PubMed1991

Some plasma hormones and metabolites in the Pyrenean brown trout (Salmo trutta fario).

1. Pyrenean brown trout (Salmo trutta fario) from 200 to 1700 g were analysed in lots of 12 specimens in March, April, July and October 1988, and in January 1989. 2. Hormones (insulin, glucagon, cortisol) and metabolites (glucose, lactate, proteins, triglycerides) were determined in plasma. 3. Body parameters (length and weight) increased progressively, while plasma metabolites and hormones were more dependent on seasonal and sexual conditions. 4. Plasma insulin presented a maximum in spring (11 ng/ml) and a minimum in January (5 ng/ml). A clear relationship between insulin and annual growth rates was established. Plasma glucagon showed annual values between 700 and 1500 pg/ml, with significant seasonal variations. The molar ratio glucagon/insulin oscillated from 0.21 in January to 0.38 in July. 5. Plasma glucose variations agreed with those of pancreatic hormones, especially evident with glucagon levels. Proteins were more uniform throughout year, and plasma lipids were especially associated to the reproductive state in females.

Animals↗
PubMed1991

A comparative study of the activity of first and second generation cephalosporins and their combinations with beta-lactamase inhibitors against Bacteroides fragilis.

The sensitivity of 160 strains of Bacteroides fragilis, 74 beta-lactamase-positive and 86 negative, to two first generation and four second generation cephalosporins, alone and in combination with clavulanic acid and sulbactam, was investigated. For the susceptibility test the dilution method in agar was used. The detection of beta-lactamase production by this micro-organism was performed by means of the method using chromogenic cephalosporin of Nitrocefin. In both strains an important improvement in the activity of cephalothin, cephazolin, cefonicid and cefamandole was noted when they were combined with the two inhibitors. In combinations of cefoxitin and cefmetazole, no significant improvement was evident in the values of the parameters studied in the beta-lactamase-producing strains; and even in beta-lactamase-negative strains these values showed only a slight increase.

Bacteroides fragilis↗
PubMed1990

Sequence analysis, tissue distribution and regulation by cell depolarization, and second messengers of bovine secretogranin II (chromogranin C) mRNA.

Secretogranin II is a very acidic, tyrosine-sulfated protein found in secretory granules of cells belonging to the diffuse neuroendocrine system. It gained more general importance recently as a universal immunohistochemical marker for endocrine neoplasms. Sequence information was obtained from secretogranin II isolated from bovine anterior pituitaries, allowing the isolation of cDNA clones and deduction of its primary structure. Bovine secretogranin II is a 586-amino acid protein of 67,455 Da which is preceded by a signal peptide of 27 residues and contains 9 pairs of basic amino acids in its sequence which are used as potential cleavage sites for generation of physiologically active peptides. Moderately abundant mRNA levels were found in adrenal medulla, pituitary, hippocampus, and caudate. Secretogranin II message was absent from parathyroid gland, adrenal cortex, kidney, liver, and spleen. Depolarization of isolated chromaffin cells by various secretagogues significantly up-regulated secretogranin II mRNA levels by mechanisms distinct from those established for chromogranins and neuropeptides, components maintained along with secretogranin II in neuroendocrine storage vesicles.

Adrenal Medulla↗
PubMed1990

Class II HLA antigen expression in familial polyposis coli is related to the degree of dysplasia.

Class II HLA antigen expression was studied in 30 polyps from 3 patients who were diagnosed with familial polyposis coli. The highest levels of this expression were associated with the most severe grades of dysplasia (p less than 0.00001), the sequence of positivity being HLA-DR greater than DQ greater than DP. No association was observed between the expression of these antigens and the presence of a specific inflammatory leukocytic infiltrate. Our results imply that HLA class II molecule expression is somehow related to malignant transformation in familial polyposis coli in accordance with the adenoma-dysplastic adenoma-adenocarcinoma sequence. Thus these antigens may be useful markers to tumoral progression.

Adenocarcinoma↗
PubMed1990

The influence of clinical and pharmacological factors on enuresis treatment with imipramine.

1. The aim of this study has been to evaluate the response to imipramine treatment in enuretic children through the use of a series of clinical and pharmacological variables and by applying a multivariate (principal components) analysis technique. 2. The study was carried out on 146 children whose ages ranged from 5 to 14 years, and who received variable doses of imipramine (12.5 to 100 mg day-1). 3. The quantitative variables analyzed were: drug dosage, serum levels of imipramine and its metabolite desipramine, the relationship between them both, the duration of treatment, age and weight. 4. The qualitative variables were: compliance, presence of side-effects, enuretic and/or psychiatric antecedents, intelligence quotient (I.Q.), the existence (or absence) of related pathologies, sex, and the type of enuresis. 5. The response to treatment was quantified by means of the percentage of decrease in frequency of enuresis as compared with the initial frequency. 6. The results obtained show that the variables which are most associated with the reduction of enuresis are, in decreasing order: the dosage of imipramine administered, the duration of treatment, compliance and the level/dose ratio for the sum of the drug and metabolite levels.

Adolescent↗
PubMed1990

Post-antibiotic effect of three quinolones against gram negative isolates from urine.

The post-antibiotic effect (PAE) is defined as the bacterial growth suppression which persists after a limited exposure to an antimicrobial agent. The PAE and the bactericidal effect of the quinolones ciprofloxacin, norfloxacin and nalidixic acid have been studied against several urinary isolates of Gram-negative bacteria. The PAE was determined after one hour's exposure to the antimicrobial agent using an initial inoculum of 10(5) to 10(6) cfu/ml; the drug was rapidly removed by a 10(-2) dilution technique in antibiotic-free medium. When ciprofloxacin was used at four times its MIC the PAEs were 1.37 +/- 0.09; 2.45 +/- 0.63 and 2.86 +/- 0.15 h against Esch. coli, Klebs. pneumoniae and Pseudomonas aeruginosa, respectively. We found lower values for norfloxacin under the same conditions, and nalidixic acid did not induce a significative PAE. These results could support changes in dosing intervals of norfloxacin and ciprofloxacin, with possibly greater intervals between doses.

4-Quinolones↗
PubMed1990

Increase in the activity of third-generation cephalosporins in combination with clavulanic acid and Sulbactam against Bacteroides fragilis.

We studied the sensitivity of 160 strains of Bacteroides fragilis (74 beta-lactamase-positive and 86 beta-lactamase-negative) to four third-generation cephalosporins, alone as well as in combination with clavulanic acid and Sulbactam. For susceptibility testing we used a dilution method in agar. Detection of beta-lactamase production by this micro-organism was performed using chromogenic cephalosporin (Nitrocefin). There was a substantial improvement in cephalosporin activity with both positive and negative strains when they were combined with the inhibitors, although this was more significant in beta-lactamase-producing organisms. Generally, the results achieved in combination with clavulanic acid were better than those with Sulbactam, the highest increase in activity being obtained with Ceftizoxime in combination with any one of the inhibitors.

Bacteroides fragilis↗
PubMed1989

Promising new drugs in the treatment of tuberculosis and mycobacteriosis.

The aims of this work were to investigate the possible effect of several antimicrobial agents alone and in combinations against 190 clinical isolates of Mycobacterium tuberculosis and 30 isolates of Mycobacterium avium, 30 Mycobacterium fortuitum and 30 Mycobacterium chelonei. The susceptibility was determined in Müller-Hinton agar and Middlebrook 7H 10 agar. For interpretation of the results the minimum inhibitory concentration (MIC) was determined and for the combinations of antimicrobials we used the Fractional Inhibitory Concentration Index (FIC). The possible clinical efficacy was determined by the Inhibitory Quotient. The synergistic effect of several combinations of these compounds was demonstrated.

Anti-Bacterial Agents↗
PubMed1989

Reproductive function and sexual behaviour in female rats exposed to immobilization stress or ACTH injections during gestation.

Pregnant primiparous rats were exposed to low immobilization stress or ACTH injections (one unit) throughout pregnancy. We measured the following parameters in the female offsprings: puberty (vaginal opening and first oestrous), oestrous cycle and sexual behaviour. Compared to the controls, female sexual receptivity measured by means of lordosis and the lordosis quotient (LQ) increased in both the experimental groups, but the puberty parameters of the offspring did not alter.

Adrenocorticotropic Hormone↗
PubMed1988

Pseudomelanosis of the duodenum. Endoscopic, histologic, and ultrastructural study of a case.

We present the endoscopic, microscopic, and histochemical studies of a patient with pseudomelanosis of the duodenum. The pigment was located mainly in the lysosomes of macrophages in the lamina propria and was heterogeneous, showing features of melanin, pseudomelanin, and hemosiderin. The origin of this pigment remains unknown, but antihypertensive medication may have played a role.

Aged↗
PubMed1988

In vitro activity of antimicrobial agents against mycobacteria.

The aims of this study were to investigate the possible effects of new antimicrobial agents, the conventional antituberculosis drugs and several combinations of these agents against 190 clinical isolates of Mycobacterium tuberculosis and 30 of M. avium.

Anti-Bacterial Agents↗