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Biomedical subjects

N Alvarez

Publications and source records attributed to N Alvarez.

At least 19 recordsLinked to original sources
PubMed2005

Metabolism and excretion of loratadine in male and female mice, rats and monkeys.

The metabolism and excretion of loratadine (LOR), a long-acting non-sedating antihistamine, have been evaluated in male and female mice, rats and monkeys. Following a single (8 mg kg-1) oral administration of [14C]LOR, radioactivity was predominantly eliminated in the faeces. Profiling and characterization of metabolites in plasma, bile, urine and faeces from male and female mice, rats and monkeys showed LOR to be extensively metabolized with quantitative species and gender differences in the observed metabolites. In all species investigated, the primary biotransformation of LOR involved decarboethoxylation to form desloratadine (DL), subsequent oxidation (hydroxylation and N-oxidation) and glucuronidation. More than 50 metabolites were profiled using liquid chromatography-mass spectrometry (LC-MS) with in-line flow scintillation analysis (FSA) and characterized using LC-MSn techniques. The major circulating metabolite in male rats is a DL derivative in which the piperidine ring was aromatized and oxidized to pyridine-N-oxide. Much lower levels of the pyridine-N-oxide metabolite were observed in female rat plasma. In contrast, the relative amount of DL was notably higher in female than in male rats. The major circulating metabolite in either gender of mouse and male monkey is a glucuronide conjugate of an aliphatic hydroxylated LOR; in the female monkey, the major circulating metabolite is formed through oxidation of the pyridine moiety and subsequent glucuronidation. Qualitatively similar metabolic profiles were observed in the mouse, rat and monkey urine and bile, and the metabolites characterized resulted from biotransformation of LOR to DL, hydroxylation of DL and subsequent glucuronide conjugation. 5-Hydroxy-desloratadine was the major faecal metabolite across all three species irrespective of gender.

Animals↗
PubMed2005

Parallels in the evolution of the two largest New and Old World seed-beetle genera (Coleoptera, Bruchidae).

This study provides the first phylogenetic analysis of a large sample of the two largest genera of seed-beetles, Acanthoscelides Schilsky and Bruchidius Schilsky, which mostly feed on legumes (Fabaceae). The goal of this study was to investigate evolutionary patterns in relation to biogeography and host-plant associations. We used three mitochondrial molecular markers and parsimony and Bayesian inference methods to reconstruct the phylogeny of 76 species. In addition, we critically reviewed host-plant records in the literature for these two bruchid genera. Our results demonstrated the existence of two major clades, one New World and one largely Old World, which generally correspond to the two genera. Yet, current classification of several species is erroneous, so that both genera as currently defined are paraphyletic. We highlighted a strong trend toward specialization (with high taxonomic conservatism in host-plant use) exhibited by the two studied genera. However, we showed the existence of several host shifts during the evolution of this group of bruchids. Our phylogenetic hypotheses and our evaluation of host-plant associations both suggest that the two genera have undergone parallel evolution, as they have independently colonized similar host plants in their respective areas of distribution. Our estimation of divergence times indicated a more ancient origin for bruchids than that suggested by the fossil records. Interestingly, the suggested timing of diversification is consistent with the hypothesis of a radiation that could have occurred contemporaneously with the diversification of their legume hosts.

Animals↗
PubMed2004

Zn adsorption by different fractions of Galician soils.

To evaluate the contribution of organic matter, oxides, and clay fraction to Zn adsorption in six soils from Galicia (Spain), after soil characterization, adsorption isotherms were obtained by adding nine solutions containing between 20 and 500 mg L(-1) concentrations of Zn(NO(3))(2). Distribution coefficients were obtained from the data of adsorption isotherms. Zn adsorption isotherms corresponding to untreated soil and to the organic matter removed samples and organic matter and oxides removed samples were compared with curves pattern and adjusted to Langmuir and Freundlich empirical models. Untreated soils described L-curves whereas when soils were deprived of any component, the curves described were S-type. Distribution coefficients allowed knowing the Zn adsorption capacity of the untreated soil, and of the organic matter, oxides, and clay fraction. Soil organic matter is the main component that affects Zn adsorption as long as soil pH is near neutrality. At acid pH, the oxides are the main component that affects Zn adsorption, although to a much smaller extent than the organic matter near neutral conditions. So soil pH is the main soil factor that determines Zn adsorption, before any other soil property.

Journal Article↗
PubMed2002

In vitro and in vivo antileishmanial activity of 2-amino-4,6-dimethylpyridine derivatives against Leishmania mexicana.

Leishmania mexicana promastigote and intracellular amastigote growths were inhibited by the water-soluble furan-2-carboxamide issued from the pharmacophore 2-amino-4,6-dimethylpyridine with IC50 values of 69 +/- 2 and 89 +/- 9 microM, respectively. This compound was also tested against established L. mexicana infection in susceptible BALB/c mice; an intraperitoneal administration of 10 mg/Kg/day during five consecutive days induced a high reduction in the amastigote burden of the poplitea lymph node (81 +/- 6.4%), the spleen (80 +/- 1.6%) and the liver (73 +/- 9%). Approach of the mechanism of antileishmanial activity of this compound, assessed by the flow cytometry, showed a reduction in the protein and DNA synthesis. Finally, an actual increase of the in vitro antileishmanial activity was obtained by replacement of the amidic function by an imidazolidin-2-one moiety. In this new series, two of the N-substituted derivatives showed IC50 values of 13 +/- 0.5 and 7 +/- 3 microM in intracellular amastigotes constituting new promising compounds for further studies.

Animals↗
PubMed2001

Olanzapine as alternative therapy for patients with haloperidol-induced extrapyramidal symptoms: results of a multicenter, collaborative trial in Latin America.

Conventional antipsychotic agents can induce extrapyramidal symptoms (EPS) that may be alleviated by switching patients to novel agents such as olanzapine. Patients with schizophrenia and related disorders (ICD-10) who were taking haloperidol (N = 94; mean dose = 12.7 mg/day) and had EPS (Simpson-Angus Scale [SAS] > 3) were directly switched to 6 weeks of open-label olanzapine treatment (mean dose = 11.4 mg/day). There were significant mean improvements (p <0.001 for all measurements) from baseline to endpoint on the SAS (-9.69+/-5.33; percentage change, 87.2%), the Barnes Akathisia Scale (-1.00+/-1.19; percentage change, 82.5%), and the Abnormal Involuntary Movement Scale (-1.48+/-2.89; percentage change, 81.1%), and anticholinergic use decreased from 47.9% to 12.8% (mean baseline to endpoint change: -1.52+/-1.91-mg equivalents of benztropine; p < 0.001). Significant mean baseline to endpoint improvements (p < 0.001 for all measurements) were observed on the Positive and Negative Syndrome Scale (PANSS; -25.28+/-18.67; percentage change, 30.3%), the PANSS-extracted Brief Psychiatric Rating Scale (0-6 scale, -13.41+/-10.16; percentage change, 54.4%), and the Clinical Global Impressions Severity scale (-1.16+/-1.19; percentage change, 26.4%). Spontaneously reported treatment- emergent adverse events with a greater than 5% incidence were somnolence (16.0%), increased appetite (14.9%), weight gain (11.7%), headache (8.5%), anxiety (7.4%), dizziness (6.4%), and insomnia (5.3%). Criteria for a successful switch were met by 90.5% of patients. Psychotic symptom exacerbation was experienced by 30.9% of patients at any time during the study and by 11.7% of patients at endpoint. Results suggest that a direct switch to olanzapine is a therapeutic option when patients with haloperidol-induced EPS are unable to tolerate a more gradual switch.

Adolescent↗
PubMed2000

Liquid chromatography/mass spectrometry methods for distinguishing N-oxides from hydroxylated compounds

This study describes the application of liquid chromatography/mass spectrometry (LC/MS) methods for distinguishing between aliphatic and aromatic hydroxylations and between hydroxylations and N-oxidations. Hydroxylations and N-oxidations are common biotransformation reactions of drugs. Electrospray (ESI) and atmospheric pressure chemical ionization (APCI) were used to generate ions from liquid chromatographic effluents. ESI-MS, ESI-MS/MS, APCI-MS, and APCI-MS/MS experiments were performed on several metabolites and derivatives of loratadine (a long-acting and nonsedating tricyclic antihistamine) using an ion trap mass spectrometer (LCQ) and a triple-quadrupole mass spectrometer (TSQ). The observations are as follows: (1) LC/ESI-MS produced predominantly [M + H]+ ions with minor fragmentation. (2) LC/ESI-MS/MS data, however, showed a predominant loss of water from metabolites with aliphatic hydroxylation while the loss of water was not favored when hydroxylation was phenolic. N-Oxides (aromatic and aliphatic) showed only a small amount of water loss in the MS/MS spectra. (3) Under LC/APCI-MS conditions, aliphatic hydroxylation could be readily distinguished from aromatic hydroxylation based on the extent of water loss. In addition, N-oxides produced distinct [M + H - O]+ ions. These [M + H - O]+ ions were not produced in the APCI-MS spectra of hydroxylated metabolites. (4) Similar to the ESI-MS/MS spectra, the APCI-MS/MS spectra from the (M + H)+ ions of N-oxides yielded a small amount of water loss but no [M + H - O]+ ions. These results indicate that LC/APCI-MS can be used to distinguish between hydroxylated metabolites and N-oxides.

Journal Article↗
PubMed2000

Role of 17beta-estradiol and/or progesterone on insulin sensitivity in the rat: implications during pregnancy.

The mechanism for the development of insulin resistance in normal pregnancy is complex and is associated with serum levels of both progesterone and 17beta-estradiol. However, it remains unclear whether estrogens alone or progestins alone can cause insulin resistance, or whether it is a combination of both which produces this effect. We attempted to determine the role played by progesterone and/or 17beta-estradiol on the phenomena of sensitivity to insulin action that take place during pregnancy in the rat. Ovariectomized rats were treated with different doses of progesterone and/or 17beta-estradiol in order to simulate the plasma levels in normal pregnant rats. A euglycemic/hyperinsulinemic clamp was used to measure insulin sensitivity. At days 6 and 11, vehicle (V)- and progesterone (P)-treated groups were more insulin resistant than 17beta-estradiol (E)- and 17beta-estradiol+progesterone (EP)-treated groups. Nevertheless, at day 16, the V, EP and E groups were more resistant to insulin action than the P group. On the other hand, the V, EP and E groups were more insulin resistant at day 16 than at day 6, whereas the P group was more insulin resistant at day 6 than at day 16. Our results seem to suggest that the absence of female steroid hormones gives rise to a decreased insulin sensitivity. The rise in insulin sensitivity during early pregnancy, when the plasma concentrations of 17beta-estradiol and progesterone are low, could be due to 17beta-estradiol. However, during late pregnancy when the plasma concentrations of 17beta-estradiol and progesterone are high, the role of 17beta-estradiol could be to antagonize the effect of progesterone, diminishing insulin sensitivity.

Analysis of Variance↗
PubMed1999

[A strategic family medicine model for controlling borderline and mild arterial hypertension].

OBJECTIVE: To research on the relationship of the patient and his/her family as a non-pharmacological factor for blood hypertension. To determine whether a hyposodic, hypocaloric, hypofat, and hypocholesterolemic diet decreases the blood tension. To determine whether physical exercises in the patient and his/her family help to reduce the hypertension. To observe whether the psychological therapy of muscles relaxation helps to reduce the hypertension. To evaluate in the sample of families, the experience of each member, as well as their suggestions and complaints about the programme. To design the strategic model to control the blood tension by ambulatory means. DESIGN: Controlled intervention study, descriptive, non-randomized, prospective. PLACEMENT: Primary care. PATIENTS AND OTHER PARTICIPANTS: Study group of 10 patients, 10 wives, and 12 children, and control group of 10 patients excluding family members. INTERVENTIONS: With both groups (study and control) there were meetings every 15 days for 6 months according to an established schedule. In the meetings there were given talks, pamphlets, physical exercises, muscles relaxation therapy, all about blood hypertension. There were questionnaires before and after each activity. MEASURING AND MAIN RESULTS: In both groups (study and control) there was a statistically significant (t < 0.01) reduction in the weight. The blood systolic tension decreased in both positions, seated and standing, in the study group (difference statistically significant) but not so in the control group, although there was a non-significant difference (decrease of 1.5 mmHg) in the seated position. The diastolic tension decreased significantly in the study group both in seated and standing positions, not so in the control group. CONCLUSIONS: The study sample showed that systolic tension seated and standing had a statistically significant reduction in the study group but not so in the control group. The weight had statistically significant reduction in both study and control groups. Total cholesterol had statistically significant decrease in the study group but not in the control group. HDL-C had statistically significant reduction in the study group; in the control group there was a decrease but not statistically significant. The triglycerides did not decrease statistically significant in any of the groups (study and control).

Adult↗
PubMed1999

Comparison of treadmill exercise echocardiography before and after exercise in the evaluation of patients with known or suspected coronary artery disease.

OBJECTIVES: We sought to compare the feasibility and accuracy of peak treadmill exercise echocardiography versus postexercise echocardiography imaging. BACKGROUND: Although peak exercise echocardiography has been reported for both supine and orthostatic bicycle exercise and has shown higher sensitivity than postexercise imaging, acquiring images at peak exercise with treadmill has not been explored. METHODS: Peak and post-treadmill exercise echocardiography and coronary angiography were performed on 89 patients with known or suspected coronary artery disease. Positive exercise echocardiography was defined as necrosis or ischemic response. Positive coronary angiography was defined as >/=1 diseased vessels (>/=50% luminal narrowing). Images were analyzed in a blind manner by an expert observer. RESULTS: Postexercise images were acquired within 80 seconds after exercise (40 +/- 14). Mean heart rate (bpm) was 139 +/- 22 at peak versus 118 +/- 25 at postexercise imaging (P <.001). Interpretable peak and postexercise images were obtained for all 89 patients. Of the 72 classified as having positive exercise echocardiography, 23 had new regional wall motion abnormality at peak (21 with positive angiography), which resolved at postexercise imaging. Sensitivity was higher with peak than with postexercise imaging (94% vs 73%, P <.001). Specificity was similar (68% vs 79%), as was predictive positive value (92% vs 93%). Negative predictive value was again higher with peak imaging (76% vs 44%, P <.05). Total accuracy was higher with peak imaging (89% vs 74%, P <.05). CONCLUSIONS: Peak treadmill exercise echocardiography is technically feasible and has higher sensitivity and accuracy than post-treadmill exercise echocardiography. Therefore in the clinical setting peak exercise echocardiography should be performed to diagnose ischemia.

Coronary Angiography↗
PubMed1999

An indigo-reducing moderate thermophile from a woad vat, Clostridium isatidis sp. nov.

A Gram-positive, anaerobic, moderate thermophile, strain Wv6T, capable of reducing indigo dye, was isolated from a fermenting woad vat prepared essentially as in medieval Europe. Strain Wv6T formed rod-shaped cells, which occurred singly, in pairs or in chains and produced terminal oval endospores. Strain Wv6T was saccharolytic. Growth occurred at pH 5.9-9.9 (initial pH) with an optimum at 50 degrees C of pH 7.2 +/- 0.2 (constant pH). At pH 7.8, the temperature range for growth was 30-55 degrees C with the optimum at 49-52 degrees C. Comparative 16S rRNA gene sequence analysis demonstrated that the bacterium represents a hitherto unknown subline within rRNA cluster I Clostridium. Based on the results of the phylogenetic analysis and phenotypic criteria, it is proposed that the unknown moderate thermophile should be classified as Clostridium isatidis sp. nov., a new species of the genus Clostridium. The type strain of Clostridium isatidis is strain Wv6T (= NCFB 3071T).

Bacterial Typing Techniques↗
PubMed1999

Streptococcus pluranimalium sp. nov., from cattle and other animals.

Strains from subclinical mastitis, from the genital tract and tonsils of cattle, from tonsils of a goat and a cat and from the crop and the respiratory tract of canaries were found to constitute a new streptococcal species, for which the name Streptococcus pluranimalium sp. nov. is proposed. Sequencing of 16S rRNA showed that Streptococcus thoraltensis and Streptococcus hyovaginalis were its closest known phylogenetic relatives. The new species showed some phenotypic resemblance to the poorly described species Streptococcus acidominimus, but whole-cell protein analysis and 16S rRNA sequencing revealed that the new species was only distantly related to the type strain of S. acidominimus. Identification of these bacteria, which showed heterogeneous biochemical reaction patterns, was most reliably made by whole-cell protein analysis. Nevertheless, a number of biochemical reactions can be used to differentiate S. pluranimalium from other animal streptococci. Strain LMG 14177T, isolated from mastitic milk of a dairy cow, was designated as the type strain of S. pluranimalium sp. nov.

Animals↗
PubMed1998

Corynebacterium phocae sp. nov., isolated from the common seal (Phoca vitulina).

Phenotypic and phylogenetic studies were performed on four strains of a Gram-positive non-acid-fast coryneform-like organism isolated from the nasal cavities of common seals (Phoca vitulina). Chemotaxonomic investigations revealed the presence of corynomycolic acids in the unidentified isolates, which is consistent with corynebacteria. 16S rRNA gene sequence analysis demonstrated that the strains from seals represent a hitherto unknown subline within the genus Corynebacterium sensu stricto. Based on the results of the phylogenetic analysis and phenotypical criteria, it is proposed that the bacterium should be classified as a new species, Corynebacterium phocae. The type strain of Corynebacterium phocae is CCUG 38205T.

Animals↗
PubMed1998

Use of antiepileptic drugs in the treatment of epilepsy in people with intellectual disability.

The main principles of antiepileptic drug treatment of epilepsy in patients with intellectual disability are basically the same as for other patients with epilepsy. However, some specific issues need to be taken into account These are primarily associated with the diagnostic difficulties of epilepsy in this population. In addition, a number of other relevant issues, including the degree and location of brain lesion, the nature of the underlying disease, the higher frequency of difficult-to-treat epilepsies, the additional intellectual impairment caused by inappropriate antiepileptic medication, or by frequent and prolonged seizures, the appropriate use of monotherapy versus rational polytherapy, and the use of broad-spectrum antiepileptic drugs will be discussed in the present paper. Although the goals of treatment are to keep the patient seizure-free and alert while preventing possible mental deterioration, we have to accept compromises between these primary goals in many cases. Some people with epilepsy and intellectual disability are very vulnerable to insidious neurotoxic effects; for example, sedative effects caused by phenobarbital, or cognitive and/or cerebellar dysfunction caused by long-term phenytoin, especially together with other drugs. Because of the adverse effects of phenobarbital and phenytoin, these drugs are no longer recommended as a first-choice drugs when long-term antiepileptic medication is required. In primary generalized tonic-clonic seizures, valproate, oxcarbazepine/carbamazepine and lamotrigine are recommended in this order of preference. The corresponding recommendations are: in typical absences, valproate, ethosuximide and lamotrigine; in atypical absences, valproate and lamotrigine; in juvenile myoclonic epilepsy, valproate, lamotrigine and clobazam; in infantile spasms vigabatrin, ACTH and valproate; in Lennox-Gastaut syndrome, valproate, lamotrigine and vigabatrin; in atonic seizures, valproate and lamotrigine; in simple and complex partial seizures with or without secondary generalization, oxcarbazepine/carbamazepine, valproate/ vigabatrin and lamotrigine; and in status epilepticus lorazepam, diazepam and clonazepam together with phenytoin or fosphenytoin. In cases of poor response to the monotherapy recommended above, the following combinations may be indicated: in primary generalized tonic-clonic epilepsy, valproate and oxcarbazepine/ carbamazepine, or valproate and lamotrigine; in typical absences, valproate and lamotrigine, or valproate and ethosuximide; in juvenile myolonic epilepsy, valproate and lamotrigine, or valproate and clonazepam; and in partial epilepsies, add to the monotherapy one of the following drugs, vigabatrin, lamotrigine, gabapentin, tiagabine, topiramate, zonisamide or clobazam. So far, the order of preference of these new drugs remains undetermined. More data are needed on the efficacy and adverse effects of the new drugs based on controlled studies on patients with intellectual disability and epilepsy.

Anticonvulsants↗
PubMed1998

Barbiturates in the treatment of epilepsy in people with intellectual disability.

Barbiturates are effective drugs in the treatment of epileptic disorder. The systemic side-effects are minimal. The main limiting factor is the presence of cognitive and behavioural problems. Relevant research is presented in this paper; however, it is somewhat difficult to extrapolate some of these experiences to a population of children and adults with intellectual disability and epilepsy. Recent reviews of this subject have suggested that, although the cognitive deficiencies seem to be a serious problem when phenobarbital is given in high doses, the problem is much less severe when the doses are on the low side. The most consistent findings with regard to behaviour are the exacerbation of behaviour disorders (mostly hyperactivity), as well as sleep disorders and depression in individuals who already have a predisposition to these disorders. However, the clinical experience of many professionals involved with the care of people with intellectual disability strongly suggests that barbiturates, and especially phenobarbital, produces intolerable side-effects at the point that the use of phenobarbital has been reduced to a minimum, and it is no longer considered a drug of choice. It is probably that the simultaneous presence of brain damage, epilepsy, intellectual disability and psychiatric disorders in people with intellectual disability is responsible for the high incidence of behaviour problems observed by clinicians.

Adult↗
PubMed1998

Carbamazepine in the treatment of epilepsy in people with intellectual disability.

Carbamazepine is a major antiepileptic drug which is primarily used to treat epileptic patients suffering from partial seizures with or without secondary generalization, but which also has applications in those suffering from primary generalized tonic-clonic seizures. Besides its antiepileptic effect, carbamazepine is also indicated in the treatment of trigeminal and occipital neuralgia, and in manic depressive disorders. Because of its minimal unwanted effects on cognition and behaviour, carbamazepine is an excellent drug for the treatment of people with intellectual disability and epilepsy. Carbamazepine is still one of the most commonly prescribed medications in the treatment of epileptic disorders.

Anticonvulsants↗
PubMed1997

Actinomyces europaeus sp. nov., isolated from human clinical specimens.

Ten strains of a hitherto undescribed catalase-negative, facultatively anaerobic, coryneform bacterium were isolated or collected by workers at three European clinical bacteriology laboratories or reference centers. These strains were isolated from humans, and most came from abscess material. Biochemical and chemotaxonomic characterization revealed that the strains belonged to the genus Actinomyces. The phenotypic features of the 10 strains were incompatible with the descriptions of the previously established Actinomyces species. A comparative 16S rRNA gene sequence analysis demonstrated that the previously undescribed strains constitute a new line in the genus Actinomyces. The name Actinomyces europaeus sp. nov. is proposed for these clinical isolates. The type strain is CCUG 32789A.

Actinomyces↗