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Biomedical subjects

G Bernal

Publications and source records attributed to G Bernal.

At least 19 recordsLinked to original sources
PubMed2006

Recruiting of somatotroph cells after combined somatostatin, GHRH and growth hormone (GH) secretagogue stimulation in a study of pituitary GH reserve in prepuberal female rats.

Diagnostic confirmation of growth hormone (GH) deficiency in children and adults is based on stimulation tests designed to assess the pituitary reserve by measuring the amount of GH released into the bloodstream; however, the results obtained by this means cannot provide any direct indication of the amount of GH actually produced by pituitary somatotroph cells. The present paper sought to test the hypothesis that release of GH following administration of specific stimuli does not accurately reflect the somatotroph cell response, and that the amount of GH released into the bloodstream may often be greater or smaller than the amount synthesized. GH release and changes in the proportion of somatotroph cells were charted in prepuberal female Wistar rats, following administration of several different GH stimuli: GHRH (1 microg/kg), GHRP-6 (1 microg/kg), GHRELIN (1 microg/kg) and combined GHRH-based treatments, with or without SRIH pretreatment (1 microg/kg) 90 minutes earlier. Peak serum GH values were recorded 15 minutes after administration of GHRH+GHRELIN and GHRH+GHRP-6; maximum stimulation in terms of an increased proportion of somatotroph cells occurred 15 minutes after combined adminstration of GHRH + GHRELIN. SRIH pretreatment (- 90 min) inhibited GH release, with a subsequent "escape" and lack of response to stimulation which lasted at least 30 minutes except following administration of GHRH. However, combined administration of GHRH+GHRELIN maintained stimulation of the somatotroph cell population. In conclusion, the results suggest that the enhanced GH release prompted by stimulation tests used to diagnose GH deficiency in prepuberal female rats does not fully reflect somatroph cell dynamics, and that not all the GH produced and stored by somatotroph cells is released into the bloodstream.

Animals↗
PubMed2005

Influence of the current management of renal transplant recipients on the prevalence of anemia and related costs.

The use of mycophenolate mofetil (MMF) and renin-angiotensin system blockers (RAB) to prevent and treat chronic graft nephropathy may affect the incidence of anemia in renal transplant recipients. We compared 2 sets of cadaver-donor recipients, namely those followed at the end of 1995 (group 1; n = 252) versus 2003 (group 2; n = 530) in terms of general characteristics, incidence of anemia (hemoglobin [Hb] < or =13 g/L males, 12 g/L females) or severe anemia (Hb < or =11 g/L males, 10 g/L females) and use cost of treatment with erythropoietin (EPO). Group 2 was significantly older, heavier and longer since grafting. Fifty-seven percent received MMF, 21% received azathioprine, and 5% received rapamycin. In group 1, 83% were given azathioprine. RAB were administered to 35.1% in group 2 versus 14.7% in group 1 (P < .001). Mean blood pressure was identical in the 2 groups, but graft function was worse in group 2 (Cockroft, 62 vs 74 mL/min; P < .001). Mean Hb levels (13.66 + - 3.1 vs 13.82 + - 1.7 g/L) and prevalence of anemia (36.9% vs 34.5%) for groups 1 and 2, respectively, were similar. The rate of severe anemia, however, was lower in group 2 (2.3% vs 8.7%; P < .001). The use of EPO increased from 2.8% (group 1) to 8.7% (group 2; P < .01). In 2003, the cost of EPO was calculated at 1982 Euros/patient-year and 91,150 Euros per year for the whole patient group. Despite accumulation of predisposing factors, the control of anemia in our patients has improved due to the expanded use of EPO. Along with its high cost, EPO therapy has potential positive repercussions on the quality of life and patient prognosis. Therefore, we need to precisely define the optimal use of EPO in renal transplant recipients.

Adult↗
PubMed2002

Influence of chronic treatment with the growth hormone secretagogue Ipamorelin, in young female rats: somatotroph response in vitro.

Growth hormone (GH) is secreted in the anterior pituitary gland by the somatotroph cells. Secretion is regulated by growth hormone releasing hormone (GHRH) and somatostatin. Morever, GH secretagogues (GHS) can exert a considerable effect on GH secretion. In order to determine the effects of chronic treatment with the GHS Ipamorelin on the composition of the somatotroph cell population and on somatotroph GH content, an in vitro analysis was performed of the percentage of somatotroph cells (% of total), the ratio of different GH cell types (strongly/weakly-staining) and individual GH content, in pituitary cell cultures obtained from young female rats receiving Ipamorelin over 21 days (Ipamorelin group) and the effects were compared with those of GHRH (GHRH group) or saline (saline group). The ultrastructure of somatotroph cells did not change, but the volume density of secretion granules was increased (P<0.05) by previous in vivo Ipamorelin or GHRH treatment. In 3-day basal pituitary cell monolayer cultures, the percentage of somatotroph cells showed no modifications between groups, nor was there any change in the ratio of strongly/weakly immunostaining GH cells. In the Ipamorelin group alone, in vitro treatment with Ipamorelin (10(-8) M), or GHRP 6 (10(-8) M), or GHRH (10(-8) M) for 4 hours, increased the percentage of somatotroph cells, without modifying the ratio of strongly/weakly immunostained GH cells. Basal intracellular GH content in somatotroph cells over 4 hours was lower in the Ipamorelin group and the GHRH group than in the saline group. Only in the Ipamorelin group did Ipamorelin (10(-8) M), GHRP 6 (10(-8) M) and GHRH (10(-8) M) prompt increased intracellular GH content. These data suggest that, at least in the young female rat, the GHS Ipamorelin is able to exert a dynamic control effect on the somatotroph population and on GH hormone content.

Animals↗
PubMed2001

Are empirically supported treatments valid for ethnic minorities? Toward an alternative approach for treatment research.

The psychological community has given considerable attention to the problem of establishing empirically supported treatments (ESTs). The authors argue that a scientific practice that discriminates against some approaches to knowledge undermines the EST's relevance for communities of color. They examine the EST project's contribution to knowledge of effective treatments for ethnic minorities by considering both how knowledge is constructed and the limits of research (e.g., external validity). Alternatives on how to best contribute to treatment research of clinical utility with diverse populations are articulated. An approach for treatment research, derived from an integration of the hypothesis-testing and discovery-oriented research approaches, is presented, and recommendations to advance treatment research with ethnic minority communities are offered.

Cultural Characteristics↗
PubMed2001

Diversity in the rhizobia associated with Phaseolus vulgaris L. in Ecuador, and comparisons with Mexican bean rhizobia.

Common beans (Phaseolus vulgaris L.) have centers of origin in both Mesoamerica and Andean South America, and have been domesticated in each region for perhaps 5000 years. A third major gene pool may exist in Ecuador and Northern Peru. The diversity of the rhizobia associated with beans has also been studied, but to date with an emphasis on the Mesoamerican center of origin. In this study we compared bean rhizobia from Mexico and Andean South America using both phenotypic and phylogenetic approaches. When differences between the rhizobia of these two regions were shown, we then examined the influence of bean cultivar on the most probable number (MPN) count and biodiversity of rhizobia recovered from different soils. Three clusters of bean rhizobia were distinguished using phenotypic analysis and principal-component analysis of Box AIR-PCR banding patterns. They corresponded principally to isolates from Mexico, and the northern and southern Andean regions, with isolates from southern Ecuador exhibiting significant genetic diversity. Rhizobia from Dalea spp., which are infective and effective on beans, may have contributed to the apparent diversity of rhizobia recovered from the Mesoamerican region, while the rhizobia of wild Phaseolus aborigineus from Argentina showed only limited similarity to the other bean rhizobia tested. Use of P. vulgaris cultivars from the Mesoamerican and Andean Phaseolus gene pools as trap hosts did not significantly affect MPN counts of bean rhizobia from the soils of each region, but did influence the diversity of the rhizobia recovered. Such differences in compatibility of host and Rhizobium could be a factor in the poor reputation for nodulation and N2 fixation in this crop.

Colony Count, Microbial↗
PubMed2000

Dissociation, psychopathology, and abusive experiences in a nonclinical Latino university student group.

A variety of clinical and experimental data suggest that many individuals who report abusive and traumatic experiences also report a wide array of dissociative and other psychopathological symptoms. In this study, 198 Puerto Rican undergraduate students participated in a study to examine the possible relationship between different types of traumatic experiences and the self-report of dissociative experiences, depressive symptoms, and general psychopathology. Another aspect of this study was the examination of the psychometric properties of the Dissociative Experiences Scale (DES) in a Latino sample. Results supported the hypothesis that those individuals who reported frequent and severe traumatic experiences were also the most likely to experience psychological malaise and scored higher on the DES. Of interest was the finding that the psychometric characteristics of the DES are consistent with those reported in the United States and other countries. The authors conclude that individuals with a marked history of trauma and abuse are more likely to use dissociative defenses as a coping response.

Adolescent↗
PubMed2000

Morphological changes to somatotroph cells and in vitro individual GH release, in male rats treated with recombinant human GH.

The effect of in vivo chronic administration of recombinant human growth hormone (rhGH) on morphology and individual GH release in somatotroph cells was evaluated in young male Wistar rats. Over an 18-day period, 30-day-old male rats were injected daily with 1.5 1U rhGH/kg (GPG group) or saline (VPG group) by subcutaneous injection. Electron-immunocytochemical, ultrastructural and morphometric studies of somatotroph cells were carried out. Additionally, rat pituitary cells were dispersed and overall and individual GH release was studied by radioimmunoassay and cell immunoblot assay (quantified by image analysis), respectively. The ultrastructure and size of somatotroph cells did not change, but volume density of secretion granules was reduced (p<0.01) by previous in vivo GH treatment. At four days, basal GH release of rat pituitary cell monolayer cultures was lower in the GPG group than in the VPG group (p<0.05); after 12 hours of culture, GHRH stimulation of GH release was lower in the GPG group than in the VPG group (p<0.05), and GHRH+SRIH inhibited GH release in the GPG group (p<0.05), but not in the VPG group. The percentage of somatotroph cells was not modified, but the ratio of strongly/weakly GH-immunostained cells had changed; weakly GH-immunostained cells increased from 34% to 55%. Moreover, in vitro treatment with GHRH, SRIH, and both, easily changed the strongly/weakly GH-immunostained cell ratio. Individual GH release, however, was not changed by previous in vivo GH treatment, although GHRH preferably stimulated a subpopulation of GH cells and SRIH did not inhibit individual GH release. These data suggest that exogenous chronic rhGH treatment down-regulates somatotroph function by modifying the proportion of GH cell subpopulation.

Animals↗
PubMed1999

The efficacy of cognitive-behavioral and interpersonal treatments for depression in Puerto Rican adolescents.

This study evaluated the efficacy of cognitive-behavioral therapy (CBT) and interpersonal psychotherapy (IPT) with depressed adolescents in Puerto Rico. Seventy-one adolescents meeting Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.; American Psychiatric Association, 1987) criteria for a diagnosis of depression were randomly assigned to 1 of 3 conditions: CBT, IPT, or wait list (WL). Pretreatment, posttreatment, and 3-month follow-up measures of depression symptoms, self-esteem, social adjustment, family emotional involvement and criticism, and behavioral problems were completed. Results suggest that IPT and CBT significantly reduced depressive symptoms when compared with the WL condition. IPT was superior to the WL condition in increasing self-esteem and social adaptation. Clinical significance tests suggested that 82% of adolescents in IPT and 59% of those in CBT were functional after treatment. The results suggest that both IPT and CBT are efficacious treatments for depressed Puerto Rican adolescents. IPT's impact in other levels of outcome is discussed in terms of its consonance with Puerto Rican cultural values.

Adolescent↗
PubMed1999

Impaired kidney transplant survival in patients with antibodies to hepatitis C virus.

BACKGROUND: With a few exceptions, most published studies do not show an influence of antibodies to the hepatitis C virus (HCV) on the success of a kidney transplant. METHODS: We studied all our renal transplant recipients who had received kidneys from cadaver donors (n = 335) and had been treated with quadruple immunosuppression (steroids, azathioprine, and antilymphocyte antibodies, followed by cyclosporin). We had information on the status of the hepatitis C antibodies before and/or after the transplant in 320 cases (95.5%; in 300, pre-transplant). Patients with HCV antibodies before and/or after the transplant were considered to be HCV positive (HCV+). RESULTS: The HCV+ patients had more time in dialysis and a greater number of transfusions, hyperimmunized cases, and re-transplants. The evolution in the first post-transplant year was similar in both groups, but afterwards, the HCV+ patients had proteinuria more often as well as worse kidney function. The survival rate of the graft was significantly less in the HCV+ cases: 90.6, 68.3 and 51.0% at respectively 1, 5 and 10 years, compared with 91.5, 84.7 and 66.5% in HCV-patients (P<0.01). The patient survival rate was: 96.4, 87.0, and 71.9% in the HCV+ patients at 1, 5, and 10 years, compared with 98.2, 96.0 and 90.0% in the HCV- cases respectively (P<0.01). The differences remained the same in stratified studies according to time spent in dialysis or pre/post-transplant evolution of HCV antibodies, even when immunologically high-risk patients were excluded. In multivariant analysis, the presence of HCV antibodies acted as a independent prognostic factor for the survival of the kidney and the patient: 3.0 (1.8-5.0) and 3.1 (1.2-7.8) odds-ratio (95% of the confidence interval), respectively. The main cause of death among HCV+ patients was cardiovascular; there was no apparent increase in mortality rate due to infections or chronic liver disease. The loss of organs was mainly due to chronic nephropathy or death with a functioning kidney. CONCLUSION: The presence of hepatitis C antibodies, before or after transplantation, is associated with a worse long-term survival rate for both the patient and the transplanted kidney in our patients treated with quadruple therapy.

Adult↗
PubMed1998

Factors associated to outcome in psychotherapy: an effectiveness study in Puerto Rico.

Psychotherapy research has not received much attention among Latinos in the U.S. or in Latin America including Puerto Rico. The present study explores factors associated with the effectiveness of psychotherapy with a sample of Puerto Ricans. Seventy-nine persons who received psychotherapy participated in a study aimed at evaluating the process and outcome of psychotherapy. Participants completed a questionnaire on the effects of treatment on the presenting problem. Information from the questionnaire and other information from the clinical records included the BDI and the Symptom Check List-36 scores, the number of sessions received, etc. constituted the data set. The results show that symptomatic severity, age. the number of sessions, and the therapeutic alliance were associated with effectiveness. Also, the alliance explained 45% of the variance in effectiveness. The results suggest that the therapeutic alliance merits further study in psychotherapy research and in clinical training.

Adolescent↗
PubMed1998

Continuous intravenous intradialysis versus intravenous postdialysis erythropoietin therapy in chronic haemodialysis patients: a randomized, controlled, crossover study.

BACKGROUND: Subcutaneous recombinant human erythropoietin seems to be more effective than intravenous administration. Local pain, however, may diminish patient compliance with the subcutaneous route. Recently continuous intravenous intradialysis administration of rHuEpo has been reported to be more efficacious in stimulating erythropoiesis than the usual postdialysis intravenous bolus. METHODS: We conducted a randomized, controlled, crossover study on stable chronic haemodialysis patients to compare the efficacy of continuous intradialysis rHuEpo therapy with intravenous postdialysis administration. Twenty patients were selected and randomly assigned to receive rHuEpo either postdialysis (control phase) or by continuous intradialysis perfusion (slow Epo phase) for 12 weeks. After this period, patients were switched to the alternative method for 12 additional weeks. The erythropoietin dose remained unchanged during the study. Haematocrit was monitored weekly and iron metabolism, serum Epo, and vitamins were measured monthly. Urea kinetics and iPTH measurements were performed every 3 months. RESULTS: Three patients were excluded because of unrelated problems. The final mean haematocrit was unchanged from previous basal values in both phases and no statistical differences were found for any parameter between the groups. No differences were found in iron metabolism nor in urea kinetic parameters. CONCLUSIONS: Continuous intravenous intradialysis administration of rHuEpo is not more effective than an intravenous postdialysis bolus as rHuEpo maintenance therapy in stable chronic haemodialysis patients.

Adolescent↗
PubMed1998

Diet energy requirements of growing Holsteins.

The conceptual bases of recent NRC publications of nutrient requirements to meet dietary energy needs of growing Holsteins, emphasizing heifers gaining 0.75 kg/d, are described and compared with several world systems and with body composition data. Requirements of Holsteins for net energy for maintenance are generally thought to be higher (from 7 to 20%) than those of British beef breeds. Total estimates of metabolizable energy requirements are quite similar for most energy systems for cattle at 200 to 400 kg of body weight. For heavier cattle, the energy density estimates based on beef breed equations project higher metabolizable energy for gain and total metabolizable energy requirements. Extrapolations from the chemical composition of growing Holstein heifers indicate that, at the slower growth that is typical of replacements, energy densities are lower than for more rapidly growing heifers and that net energy requirements are consistent with current US standards.

Animals↗
PubMed1995

Ecological validity and cultural sensitivity for outcome research: issues for the cultural adaptation and development of psychosocial treatments with Hispanics.

This article has two objectives. The first is to provide a culturally sensitive perspective to treatment outcome research as a resource to augment the ecological validity of treatment research. The relationships between external validity, ecological validity, and culturally sensitive research are reviewed. The second objective is to present a preliminary framework for culturally sensitive interventions that strengthen ecological validity for treatment outcome research. The framework, consisting of eight dimensions of treatment interventions (language, persons, metaphors, content, concepts, goals, methods, and context) can serve as a guide for developing culturally sensitive treatments and adapting existing psychosocial treatments to specific ethnic minority groups. Examples of culturally sensitive elements for each dimension of the intervention are offered. Although the focus of the article is on Hispanic populations, the framework may be valuable to other ethnic and minority groups.

Cross-Cultural Comparison↗
PubMed1995

Prevention of depression with primary care patients: a randomized controlled trial.

The prevention of major depression is an important research goal which deserves increased attention. Depressive symptoms and disorders are particularly common in primary care patients and have a negative impact on functioning and well-being comparable with other major chronic medical conditions. The San Francisco Depression Prevention Research project conducted a randomized, controlled, prevention trial to demonstrate the feasibility of implementing such research in a public sector setting serving low-income, predominantly minority individuals: 150 primary care patients free from depression or other major mental disorders were randomized to an experimental cognitive-behavioral intervention or to a control condition. The experimental intervention group reported a significantly greater reduction in depressive levels. Decline in depressive levels was significantly mediated by decline in the frequency of negative conditions. Group differences in the number of new episodes (incidence) of major depression did not reach significance during the 1-year trial. We conclude that depression prevention trials in public sector primary care settings are feasible, and that depressive symptoms can be reduced even in low-income, minority populations. To conduct randomized prevention trials that can test effects on incidence with sufficient statistical power, subgroups at greater imminent risk have to be identified.

Adolescent↗
PubMed1994

Latinos and Latinas in community psychology: a review of the literature.

Latinos and Latinas are one of the largest minority groups in the United States yet they remain a silent group. The article begins by considering the social, historical, and economic backgrounds of Latino and Latina groups in the U.S. as a context for understanding diversity and as a resource for explaining the participation of this minority group in community psychology. This article then examines the extent to which Latinos and Latinas are present and participate in community psychology throughout its publications and explores the nature of their participation through a thematic analysis of the published literature. A content analysis was conducted on 1,851 articles published from 1973 through 1992 in the American Journal of Community Psychology and the Journal of Community Psychology to evaluate the presence of Latinos and Latinas in the community psychology literature. The quantitative analysis revealed that 3.7% (n = 69) of all the articles reviewed focused on Latinos and Latinas or had samples with at least 15% of the participants coming from this ethnic group. Mexican Americans/Chicanos were the focus of the largest number of articles about specific Latino and Latina subgroups, followed by Cubans and Puerto Ricans. The results indicated less attention to Latino and Latina populations in the community psychology literature than would be expected from the field's goals. However, a qualitative review of the articles was more encouraging since many articles by and about Latinos and Latinas reflected values consonant with the field such as cultural pluralism or employed conceptual tools of the discipline such as empowerment or ecological approaches. Nevertheless, some of the articles reviewed also lacked a concern for the field's values in relation to Latinos and Latinas as a group. Finally, suggestions and strategies to empower this group are offered.

Acculturation↗
PubMed1992

Effects of environmental factors on maxillofacial elastomers: Part IV--Optical properties.

The optical properties of four currently used and two recently introduced maxillofacial prosthetic materials were evaluated after the materials were subjected to the following seven environmental variables: natural weathering; normal aging; two types of adhesives; two types of cleaning agents; and cosmetics. Optical density and color changes were evaluated. The currently used silicones Silastic 4-4210 and Silastic 4-4515, Medical Adhesive type A material, and polyurethane all showed more changes in color and optical density than the newly introduced silicone A-102 material.

Analysis of Variance↗
PubMed1992

Effects of environmental factors on maxillofacial elastomers: Part I--Literature review.

Part I of a four-part report presents a comprehensive review of the literature pertaining to physical property testing of materials for facial and somatoprostheses. The report was conducted in preparation for testing four current maxillofacial elastomers: MDX 4-4210, Silastic 4-4515, Medical Adhesive type A, and Epithane-3, and two recently introduced materials: Silicone A-2186 and Silicone A-102.

Biocompatible Materials↗