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Biomedical subjects

D Torres

Publications and source records attributed to D Torres.

51 records · Page 3Linked to original sources
PubMed1986

Imipramine in adolescent major depression: plasma level and clinical response.

Thirty-four adolescents with mean age 14.25 years who met RDC criteria for major depressive disorder as assessed with the K-SADS, were treated for 6 weeks on a fixed schedule of imipramine hydrochloride titrated to a dosage of 5.0 mg/kg/day except as limited by side effects. Mean dose was 246 mg/day (4.5 mg/kg/day). In spite of good indications of compliance with treatment only 44% of the adolescents improved to the level of no or only slight depressed mood or anhedonia, though most had less depressive symptomatology at the end of treatment. There was neither a linear nor curvilinear relationship between total plasma level of IMI plus DMI and clinical response, despite a wide range of both plasma level (77 ng/ml to 986 ng/ml) and outcome. Adolescents with associated separation anxiety had significantly poorer response to treatment of their depressive disorder than those with major depression alone. Poor response was also weakly associated with being female, having endogenous subtype of depression, and having higher plasma IMI (but not DMI) level. In the context of similar studies of IMI on depression in other age groups, it is hypothesized that high levels of sex hormones during adolescence and young adulthood may interfere with IMI's antidepressant effects. It is concluded that other types of antidepressants should be tested in adolescents with major depression.

Adolescent↗
PubMed1984

Clonal heterogeneity in the fibroblast response to mononuclear cell derived mediators.

Human dermal fibroblasts were examined for heterogeneity in proliferation and prostaglandin E2 (PGE2) synthetic response to supernates of mitogen activated mononuclear cell cultures. Eleven substrains from a single neonatal foreskin culture displayed marked clonal heterogeneity in the fibroblast response to mononuclear cell derived mediators. Supernates of mononuclear cell cultures stimulated fibroblast PGE2 synthesis and suppressed proliferation. Substrains displayed tenfold differences in PGE synthesis and the extent of growth suppression. Release of immunologic mediators at sites of inflammatory lesions could lead to alterations in the clonal composition and phenotypic expression of connective tissue cells.

Autoradiography↗
PubMed1976

The helminth fauna of CHIle: IV. Nematodes of the genera Anisakis Dujardin, 1845 AND Phocanema Myers, 1954 in relation with gastric ulcers in a South American Sea Lion, Otaria byronia.

A gastric ulcer was diagnosed in a South American Sea Lion, Otario byronia, captured along the northern coast of Chile. Species of Anisakis and Phocanema were found to be associated with the lesions. A discussion of the histopathologic damage observed is presented, along with probable etiology of the ulcer.

Animals↗
PubMedDate not supplied

Chitosan nanocapsules as carriers for oral peptide delivery: effect of chitosan molecular weight and type of salt on the in vitro behaviour and in vivo effectiveness.

We have recently reported preliminary data showing the efficacy of chitosan nanocapsules as carriers for oral peptide delivery. In the present work, our aim was to investigate the influence of some chitosan properties, such as the molecular weight and type of salt, on the interaction of these nanocapsules with the Caco-2 cells and also on their in vivo effectiveness. Chitosan nanocapsules were prepared by the solvent displacement technique using high (450 kDa) and medium (160 kDa) molecular weight chitosan glutamate as well as high molecular weight chitosan hydrochloride (270 kDa). The results indicated that the size of the nanocapsules was dependent on the chitosan molecular weight, whereas the zeta potential and the association efficiency of salmon calcitonin were not affected by the chitosan properties. Upon incubation with the Caco-2 cells, chitosan nanocapsules exhibited a dose-dependent cellular viability, which was hardly affected by, either the chitosan molecular weight or, the type of salt. In addition, it was observed that the transepithelial electrical resistance of the Caco-2 monolayer was not significantly modified upon their exposure to chitosan nanocapsules. The results of the in vivo studies, following oral administration to rats, indicated that chitosan nanocapsules were able to reduce significantly the serum calcium levels, and to prolong this reduction for at least 24 hours, irrespective of the type of chitosan salt and molecular weight of chitosan. Consequently, the performance of chitosan nanocapsules as oral carriers for salmon calcitonin was not affected by the characteristics of chitosan.

Administration, Oral↗
PubMedDate not supplied

Joint effects of monomer and stabilizer concentrations on physico-chemical characteristics of poly(butyl 2-cyanoacrylate) nanoparticles.

A rotatable central composite design was applied to the formulation of poly(butyl 2-cyanoacrylate) nanoparticles with the aim of modifying some physico-chemical properties of these carriers in a controlled way. The joint effect of stabilizer concentration and monomer concentration on the mean particle size, on the electrophoretic mobility and on the polymer molecular weight has been investigated. The results demonstrate that the particle size is only dependent on the stabilizer concentration, nevertheless the electrophoretic mobility and the molecular weight distribution were affected simultaneously by the monomer and the stabilizer concentrations. Moreover, using the response surface diagrams it is possible to deduce the experimental conditions to design particles with the desired properties. Finally, the degradation rates for two different molecular weight formulations were compared, showing the relevance of this property.

Capsules↗
PubMedDate not supplied

Development of a microencapsulated form of cefuroxime axetil using pH-sensitive acrylic polymers.

Cefuroxime axetil (CA) was encapsulated in pH-sensitive acrylic microspheres in order to formulate a suspension dosage form. Using this microencapsulated form it was expected to prevent leaching of the drug from the microspheres into the suspension medium and to assure the release of the drug in the first part of the intestine, thus avoiding changes to its bioavailability. For this purpose, CA was microencapsulated within several types of acrylic polymers by the solvent evaporation and the solvent extraction techniques. The acrylic polymers selected were: Eudragit E (positively charged and soluble at pH 5), Eudragit L-55 (negatively charged and soluble at pH > 5.5) and Eudragit RL (neutral, insoluble, but readily permeable). The influence of the polymer electrical charge on the stability and in vitro release of CA was investigated. Though Eudragit E microspheres presented good morphological characteristics and dissolution behaviour, the analysis of the stability of CA in the presence of Eudragit E by HPLC, indicated a negative interaction between both compounds. However, formulations made of Eudragit L-55 and RL in the ratios 100:0 and 90:10 were adequate in terms of the stability of the encapsulated CA. The dissolution studies showed a critical pH between 5.2 and 6.0, which allowed the complete release of CA in a short period. Furthermore, these polymer microspheres were shown to be efficient in masking the taste of CA.

Acrylic Resins↗
PubMedDate not supplied

[The prevalence of asthma and the utilization of medical services among those insured by a health-services company in Puerto Rico, 1996-1997].

OBJECTIVE: To describe the prevalence and pattern of utilization of medical services in insured of SSS with a diagnosis of asthma during 1996 and 1997. METHODS: The medical claims of SSS insured whose main diagnosis was asthma (ICD-9 9 493-493.9) were selected for analysis. The prevalence and medical service utilization (medical visits, emergency and hospital admissions) were estimated. Differences in health service utilization by age group were analyzed by the Poisson model. RESULTS: The asthma prevalence was 14.5%, being larger in patients younger than 18 years of age and in females. 54.3% of the asthmatic patients visited medical offices and the larger proportion of users was observed in the younger group (< 18 years). However, the larger proportion of users of the emergency room was observed in the 18-44 age group, while the hospital admissions was larger in the 45-64 age group. More than half (56%) of the cost per service was attributed to hospital admissions while 31% was for pharmacy services. 65.9% of the insurers with asthma had prescriptions for short relief beta-antagonist. CONCLUSIONS: The prevalence of asthma in this study was high and similar to rates of the disease reported in Puerto Ricans residing in the U. S. and in other areas of the island. Similarly, the prevalence differed by age in the utilization of medical services as well as the high cost of hospital admissions. Prevalence studies using other sources as well as a standard definition of the condition may be helpful to confirm these results.

Adolescent↗
PubMedDate not supplied

[Intestinal parasitic infections in 4 child day-care centers located in San Miguel del Padrón municipality, Havana City, 1998].

A coproparasitologic study was performed on 456 children aged 1-5 years from 4 day-care centers located in San Miguel del Padrón municipality during November 1998, with the aim of finding out the behaviour of the main intestinal parasites and particularly how Giardia lamblia was affecting this child population. Three fecal specimens were collected from each child in every other day, which were processed by coproparasitologic methods such as direct testing and Ritchie's concentration technique. The most frequently identified parasite was G. lamblia with 249 positive cases for a prevalence rate of 54.6%. The second one was Blastocystis hominis (29.6%) followed by Endolimax nana(23.9%). Coccidia like Crystosporidium parvum and Cyclospora cayetanensis exhibited low frequencies, 0.6 and 1.5% respectively, being the majority of the cases located in only one day care center. These results confirmed that G. lamblia is the most prevailing parasite in day care centers, with peak frequency values in 2-4y age group and no differences between sexes.

Child Day Care Centers↗