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Biomedical subjects

F Alba

Publications and source records attributed to F Alba.

At least 37 records · Page 2Linked to original sources
PubMed1998

Influence of dietary supplementation with olive oil on pyroglutamyl-beta-naphthylamide hydrolysing activity in serum and different tissues of mice.

Pyroglutamyl aminopeptidase is an omega peptidase which removes pyroglutamyl N-terminal residues from peptides and arylamide derivatives. To date, three distinct types of this enzyme have been described and called serum thyroliberinase, cytosolic pyroglutamyl aminopeptidase type I and membrane-bound pyroglutamyl aminopeptidase type II. The activity of all of them is thought to be involved in the regulation, more or less restricted in their substrate specificity, of various susceptible endogenous substrates such as TRH, GnRH, neurotensin, bombesin and anorexogenic peptide. It is well known that the type and amount of fat in the diet not only modify blood lipid concentrations, including cholesterol levels, but change the cell membrane lipid composition. Modifications in the composition and physical properties of the membrane lead to alterations in the activities of membrane-bound enzymes and carriers. The aim of this work was to compare the effect of a standard diet and a high fat diet (olive oil, 20% wt/wt) on pyroglutamyl-beta-naphthylamide hydrolysing activity, in serum and in soluble and membrane-bound fractions from different tissues of male mice. After ten weeks of feeding, pyroglutamyl-beta-naphthylamide hydrolysing activity was measured fluorometrically using pyroglutamyl-beta-naphthylamide as substrate. Mice fed the high fat diet had higher rates of body weight than controls starting from the second week of feeding. Serum total cholesterol concentrations were higher after feeding the high fat diet than after feeding the control diet. In serum, no changes were observed in the high fat group. In selected tissues, only pyroglutamyl-beta-naphthylamide hydrolysing activity was modified significantly in the soluble fraction, but not in the membrane-bound one, decreasing in the adrenal gland of high fat fed animals. The results may reflect functional modifications in susceptible endogenous substrates.

Animals↗
PubMed1998

[Polycystic ovary syndrome: relationship of insulin tissular sensitivity, LH secretion and ovarian morphophysiologic changes].

BACKGROUND: Insulin resistance to LH hypersecretion are recognized features of polycystic ovary syndrome. Previous studies have suggested that both defects are independent from each other. AIM: To examine the relationship between insulin sensitivity and LH secretion in women with polycystic ovary syndrome. PATIENTS AND METHODS: Eighteen women with clinical and biochemical evidence of hyperandrogenism, normal oral glucose tolerance test and polycystic ovaries on ultrasonography, were studied. Insulin sensitivity was assessed using the insulin tolerance test. LH secretion was studied integrating LH values of blood samples taken every 10 minutes for 6 h. Testosterone, testosterone index, SHBG and IGFBP-1 were measured in three selected samples and ovarian volume was assessed by ultrasound. RESULTS: Insulin sensitivity ranged from 0.06 to 0.75 and the area under the curve for LH, from 532 to 8.517 IU/L/6 h. No correlation was found between these two parameters and between each parameter and ovarian volume or androgen concentration. Positive correlations were observed between insulin sensitivity and SHBG concentrations (r = 0.612 p < 0.01) and IGFBP-1 concentrations (r = 0.588 p < 0.001). When compared to patients body mass index of less than 30 kg/m2, patients with body mass index over 30 kg/m2 had significantly lower insulin sensitivity and higher LH levels. In the latter a positive correlation between insulin sensitivity and the area under the curve for LH was observed (r = 0.683 p < 0.02). CONCLUSIONS: Obese polycystic ovary syndrome patients exhibited an inverse correlation between insulin resistance and LH hypersecretion, suggesting a relationship between both defects.

Adult↗
PubMed1997

Renal aminopeptidase activities in animal models of hypertension.

Aminopeptidase activity (AP) has been implicated in the metabolism of renal and circulating vasoactive peptides. This activity is involved in the pathogenia of hypertension, essentially in spontaneously hypertensive rats. However, no other animal models, which develop hypertension by other different ways, have been used to study the possible role of aminopeptidase activity. To investigate the role of this activity in the pathogenesis of hypertension, angiotensinase A activity (glutamyl-AP and aspartyl-AP), aminopeptidase M activity (alanyl-AP), aminopeptidase B activity (arginyl-AP), pyroglutamyl-AP, and cystinyl-AP were measured in the serum and kidney of two experimental animal models of renovascular hypertension: Goldblatt two-kidney one clip (G2K-1C) and low renal mass rats (LRM). No differences were found in serum levels of AP in LRM or G2K-1C in comparison with their respective controls. In LRM rats there was a significant decrease in membrane-bound angiotensinase A (glutamyl-AP), arginyl-AP and alanyl-AP activities. In G2K-1C rats there was a significant decrease in soluble and membrane-bound angiotensinase A activity (aspartyl-AP). Our results suggest that AP activities play a role in the regulation of renal vasoactive peptides, and respond differently depending on the cause of hypertension.

Aminopeptidases↗
PubMed1997

Hormonal profile, endometrial histology and ovarian ultrasound assessment during 1 year of nomegestrol acetate implant (Uniplant).

The present study assesses the endocrinological, endometrial histology and vaginal ultrasound profiles of nomegestrol acetate subdermal implant users at varying times after insertion. Follicle stimulatory hormone, luteinizing hormone, oestradiol, progesterone, vaginal ultrasound assessment of the ovaries and the histological dating of the endometrium were serially assessed for a period of 50 days immediately after the insertion, and after at 6 months and 12 months of use. The endocrinological results of this prospective observational clinical trial indicated that 75% of the cycles across the study period in Uniplant users were anovulatory, 63% showing development of a persistent non-luteinized follicle. Anovulatory cycles devoid of follicular development were seen primarily in the first months after Uniplant insertion. Ovulatory cycles represented 25% of the Uniplant cycles. Inadequate luteal phase or disregulation of follicular growth was a common feature of ovulatory cycles. In conclusion, these findings suggest that the contraceptive mechanisms of a single nomegestrol acetate subdermal implant involve prevention of follicular growth, development of a persistent non-luteinized follicle, inadequate luteal phase and disruption of the endometrial architecture.

Adult↗
PubMed1996

Pyroglutamyl peptidase I levels and their left-right distribution in the rat retina and hypothalamus are influenced by light-dark conditions.

To evaluate the effects of light and darkness on pyroglutamyl peptidase I activity (pGluPI) and its left-right distribution, pGluPI was measured bilaterally in the retina and hypothalamus under selected light-dark schedules. Rats under a 12 h light-dark cycle were divided into four experimental groups. After the end of the 12 h dark period, the animals were kept two additional hours in darkness (group 1), or light (group 2). After the end of the 12 h light period, the animals were kept two additional hours in darkness (group 3), or light (group 4). Experiments were done in light or darkness depending on the 2 h period. In the retina, a previous 12 h light period led to higher values of enzyme activity than dark periods. Left-right predominance, however, depended on the previous 2 h period: the light period led to left predominance, whereas right predominance was found after the 2 h dark period. In the hypothalamus, a left predominance was found only in group 3. These results demonstrate that environmental light conditions influence pGluPI activity in the rat retina and hypothalamus.

Adaptation, Ocular↗
PubMed1996

[Characteristics of infantile asthma in patients seen in primary care].

OBJECTIVE: To compare an asthmatic and non-asthmatic group of children by looking at determined characteristics. DESIGN: Study of cases and paired one-to-one controls by age and gender. SETTING: Primary Care. PATIENTS AND OTHER PARTICIPANTS: Children aged 0 to 13 and attended at one particular Paediatrics clinic were studied (1,100 children). All those children diagnosed with asthma in accordance with the standard procedure in the Health District were considered as cases (142). The control group was chosen at random from the age and gender files. MEASUREMENTS AND MAIN RESULTS: A telephone poll with closed questions was carried out by three researchers who were "blind" to whether they were dealing with case or control. Statistically significant differences were found for family background of allergic Rhinitis (cases, 43.2%; controls, 30.4%; p = 0.04), atopic eczema (cases, 36.3%; controls, 14.7%; p < 0.001) and bronchial asthma (cases, 59.8%; controls, 33.3%; p < 0.001). Statistically significant differences were also found for personal case histories of allergic Rhinitis (cases, 36.3%; controls, 2%; p < 0.001) and atopic eczema (cases, 23.5%; controls, 10.7%; p = 0.021); and in the presence of animals (dog and/or cat) in the home (cases, 13.7%; controls, 25.5%; p = 0.04). No statistically significant differences were found for background of breast-feeding, age of starting school, present passive smoking or the existence of older siblings. CONCLUSIONS: The results obtained show that the association of atopic illnesses, such as Rhinitis and Eczema, and the existence of family background of asthma and atopy are more common in the asthmatic patient.

Allergens↗
PubMed1996

Peptidase inhibitors potentiate the effects of neurotensin and neuromedin N on self-stimulation of the medial prefrontal cortex.

The purpose of this study was to examine the possible role of endogenous peptidases in the inhibition of intracranial self-stimulation (ICSS) produced by injections of neurotensin (NT) and neuromedin N (NN) into the medial prefrontal cortex (MPC) of the rat. We studied the effects on ICSS of the MPC of the administration of thiorphan and bestatin, two specific inhibitors of the peptidases that inactivate NT and NN respectively. Microinjections into MPC of thiorphan (10 micrograms) and bestatin (25 micrograms) potentiated in inhibition of ICSS produced by the intracortical administration of NT (10 nmol) and NN (20 nmol) respectively. This potentiation affected both the amplitude and the duration of the inhibition of ICSS produced by the neuropeptides. Our data indicate that endogenous peptidases are involved in the inactivation of NT and NN in the prefrontal cortex.

Animals↗
PubMed1996

Mediation by neurotensin-receptors of effects of neurotensin on self-stimulation of the medial prefrontal cortex.

1 Intracortical microinjections of neurotensin (NT) selectively decreased intracranial self-stimulation (ICSS) of the medial prefrontal cortex in the rat. 2 To elucidate whether this effect is mediated by NT receptors or by the formation of NT-dopamine complexes, we investigated the effects on ICSS of intracortical microinjections of neurotensin (1-11), an NT fragment that forms extracellular complexes with dopamine but does not bind to NT receptors. 3 We also studied the effects of the peripheral administration of SR 48692, a selective antagonist of NT receptors, on the inhibition of ICSS produced by the intracortical administration of NT. 4 Unilateral microinjections of neurotensin (1-11) at doses of 10, 20 and 40 nmol into the medial prefrontal cortex did not change the basal ICSS rate of this area. 5 The intraperitoneal administration of SR 48692 at doses of 0.08 and 0.16 mg kg-1 30 min before microinjection of 10 nmol of NT into the medial prefrontal cortex, antagonized the inhibition of ICSS produced by the neuropeptide. 6 These results demonstrate that the inhibitory effect of NT on ICSS is mediated by NT receptors.

Animals↗
PubMed1996

Developmental changes of soluble and membrane-bound aspartate aminopeptidase activities in rat brain.

Specific soluble and membrane-bound aspartyl-naphthylamide hydrolyzing activities were assayed in brain subcellular fractions from rat fetuses (19-20 days of gestation), and from 1-week-old and 1-, 5- and 24-month-old rats. Both enzymatic activities showed a heterogeneous distribution, with highest concentrations mainly in the microsomal fraction. Membrane-bound activity was in most cases higher than soluble activity. With the exception of soluble activity in the nuclear and microsomal fractions, significant age-related changes were observed in all fractions for both enzymatic activities. Soluble activity showed a homogeneous developmental profile in most of the fractions, with the lowest levels in 1-month-old rats and the highest in 1-week and 5-month-old animals. However, changes in the microsomal fraction did not follow the pattern displayed by the rest of the fractions. No clear developmental profile in specific membrane-bound activity was observed, each fraction exhibiting a different sequence of changes. Whereas in 24-month-old-rats there was a significant increase in activity in homogenate, nuclear and microsomal fractions, a significant decrease was observed in the synaptosomal fraction. These results may reflect the functional status of the endogenous substrates of the enzymes.

Aging↗
PubMed1996

[Subcellular distribution of leucine aminopeptidase during the development and aging of rat brains].

INTRODUCTION: The aminopeptidases are considered to be enzymes which can regulate the activity of various neuropeptides. However, their precise function has not yet been fully determined. OBJECTIVE: With a view to studying the function of these enzymes at the cerebral level, the subcellular distribution of soluble leucine aminopeptidase from left and right cerebral hemisphere, in rats of different pre-natal and post-natal ages was determined as described in this paper. MATERIALS AND METHODS: The activity of soluble leucine aminopeptidase was determined fluorimetrically in the sub-cellular fractions obtained from the left and right cerebral hemispheres of rats of different pre-natal and post-natal ages: fetuses (of 19-21 days gestation), 1 week, 1, 5 and 24 months of age. RESULTS: No differences were observed between the cerebral hemispheres at any of the ages studied. However, significant differences were seen in the evolutionary behaviour of the two hemispheres. At all ages, except 24 months, there were significant differences between the fractions. In the fetuses, most activity was seen at the level of the synaptosomal raw fraction and least in the microsomal. At 1-week-old, the highest levels were seen at a microsomal level. In rats of 1 and 5 months of age, the highest levels were detected at synaptosomal level. With regard to the evolution with age, in the homogenate, nuclear fraction, cytosol and mitochondrial fraction a similar profile was observed, with a decrease after birth and an increase at one month, being stable at the other ages. At a synaptosomal level the profile is similar, although the differences are much more marked, with a drastic decrease in activity at two years of age. By contrast, the microsomal fraction showed a very different evolutionary profile with an increase after birth, becoming stable at later ages. CONCLUSIONS: The activity of soluble leucine aminopeptidase shows a heterogeneous subcellular distribution together with significant differences during cerebral development and ageing. The behaviour of this enzyme may reflect the functional state of its neuropeptide substrates.

Age Factors↗
PubMed1995

[Evaluation of the impact of a care program for asthmatic children on the quality of anti-asthma drug prescriptions].

OBJECTIVE: To determine the influence of a programme of care for asthmatic children (CAC) on the quality of prescription of anti-asthmatic drugs. DESIGN: A controlled non-random intervention study. SETTING: Paediatric clinics operating before 1991 in Health Districts (HD) of Hospitalet. PARTICIPANTS: INTERVENTION GROUP: All the paediatricians ranked in the HD where the programme was set up (n = 3). CONTROL GROUP: All the paediatricians ranked in the rest of the HD (n = 9). INTERVENTION: In april 1992 the CAC programme, which included a pharmaco-therapeutic procedure, was set up in the HD. MEASUREMENTS AND MAIN RESULTS: Prescriptions were evaluated by looking at the billing data of the Catalan Health Service between january and april, 1991, 1992 and 1993. The following Quality Indicators were evaluated: 1. Percentage of dosage of beta 2 adrenergics inhaled as against the total of beta 2 (oral and inhaled). 2. Percentage of DHD of Nedocromil (NC) and Cromoglycate (CG) as against the total of preventive drugs (NC + CG + Ketotifen). 3. Number of packages of oral and/or rectal Theophyllines, counter-indicated combinations and anti-inflammatory drugs (Chromones and inhaled steroids). CONCLUSION: The influence of the programme can be considered very positive, since an increase in all the quality indicators of the prescription of anti-asthmatics was observed, something that did not occur in the Control Group.

Administration, Inhalation↗
PubMed1995

Comparison of soluble and membrane-bound pyroglutamyl peptidase I activities in rat brain tissues in the presence of detergents.

Pyroglutamyl peptidase I activity from soluble and membrane-bound fractions of rat brain homogenates is inhibited by the presence of sodium deoxycholate but not by triton X-100. Biobeads SM2, a polystyrene adsorbent reported to be useful in removing detergents from aqueous solutions, inhibits enzymatic activity in both fractions regardless of the presence of these detergents, probably because of partial adsorption of the enzyme by the polymeric microspheres. These effects seem to be enzyme-specific since other aminopeptidase activities are not affected by detergents or biobeads. The results suggest that soluble and membrane-bound forms of the enzyme represent the same protein in two different cell compartments.

Aminopeptidases↗
PubMed1995

Properties of rat brain dipeptidyl aminopeptidases in the presence of detergents.

Rat brain dipeptidyl aminopeptidases I to IV were assayed in the soluble and membrane-bound fractions of rat brain, and the effects of the detergents Triton X-100 and sodium deoxycholate on their activities were studied. Dipeptidyl aminopeptidases I and II were significantly inhibited in the presence of sodium deoxycholate, but were not affected by the presence of Triton X-100. However, dipeptidyl aminopeptidase III was not influenced by either detergent, whereas the activity of dipeptidyl aminopeptidase IV was stimulated in the presence of Triton X-100, but remained unaffected by deoxycholate. These effects were partially or totally reversed after detergents were removed from the medium with adsorbent polymeric beads. Although detergents may have different effects on each DAP activity, the behavior of each enzyme activity in the presence of these substances was similar regardless of their subcellular location. These findings suggest that, as with other aminopeptidases, each of these proteins corresponds to the same molecular species in two different cell compartments.

Animals↗
PubMed1995

Subcellular distribution of soluble and membrane-bound Arg-beta-naphthylamide hydrolyzing activities in the developing and aged rat brain.

The subcellular distribution of soluble and membrane-bound Arg-beta-naphthylamide-hydrolyzing activities was studied in the left and right rat brain during development and aging. During development, the soluble activity was heterogeneous, whereas adult animals showed the highest activity in the synaptosomal fraction. However, except in fetuses, membrane-bound activity was greatest in the microsomal fraction. Except in microsomal and myelin fractions, soluble and membrane-bound activities showed a decrease in 1-wk-old rats compared with fetuses and a subsequent increase to adult levels in 1-mo-old rats. This profile differed in the microsomal fraction, which increased steadily throughout development. In the synaptosomal fraction, both activities were lower in 24-mo-old rats than in 5-mo-old animals. No differences between the hemispheres were observed in soluble or membrane-bound fractions at any age tested.

Aging↗