Biomedical subjects

A Acevedo

Publications and source records attributed to A Acevedo.

At least 19 recordsLinked to original sources

PubMed2006

Gastric MALT lymphoma: clinical characteristics and prevalence of H. pylori infection in a series of 37 cases.

OBJECTIVE: to perform a retrospective review of the clinical characteristics and prevalence of H. pylori infection in patients with gastric MALT lymphoma diagnosed in our hospital during the last 15 years. METHODS: patients with gastric MALT lymphoma diagnosed in our hospital during the last 15 years were retrospectively included. Demographic, clinic, analytic, endoscopic, and histological variables were reviewed. The extension study, the staging classification, and the presence of H. pylori infection were assessed. RESULTS: thirty-seven patients with gastric MALT lymphoma were identified. Mean age was 61 years, with 62% of males. The most common presentation symptom was dyspepsia (76%), followed by digestive bleeding (11%) and constitutional syndrome (8%). At endoscopy, erosive lesions were identified in 41%, and proliferative or exophytic lesions in 43%. Most lymphomas were classified as low-grade (68%). The stage distribution was EI for 56%, EII for 13%, EIII for 3%, and EIV for 28%. The prevalence of H. pylori infection (histology in all cases, rapid urease test in 19%, and 13C-urea breath test in 24%) was 46%. When only low-grade lymphomas in stage EI were considered, H. pylori prevalence increased to 55%. When H. pylori infection was evaluated by 13C-urea breath testing (in addition to histology), the prevalence of H. pylori infection increased to 78%. CONCLUSIONS: it is probable that the reduced H. pylori prevalence found in some studies, as in ours, could be explained by false-negative results obtained when only one diagnostic method was used. Therefore, at least two (invasive) diagnostic methods should be performed. Furthermore, the performance of a non-invasive diagnostic method (such as a 13C-urea breath test) before the exclusion of H. pylori infection should be considered.

Aged↗

PubMed2005

Apoptosis and cell cycle arrest in oral lichen planus Hypothesis on their possible influence on its malignant transformation.

The quantitative importance of cell cycle arrest and apoptosis mechanisms in oral lichen planus (OLP) was analysed in order to assess the cell response to T lymphocyte aggression and establish a hypothesis on the influence of these phenomena in the malignant transformation process. The TUNEL assay and immunohistochemical methods were used to detect caspase-3, bax, and p21 in 32 tissue samples of oral mucosa with OLP and in 20 samples of normal oral mucosa. Positivity for TUNEL, caspase-3 and p21 was significantly more frequent in cases than in controls (p<0.001). Both TUNEL and caspase-3 positivity was significantly greater in the basal versus suprabasal layer (p=0.004 and 0.052, respectively). The basal and suprabasal expression of p21 was significantly higher in cases with a more intense liquefaction degeneration (p<0.01). There was no significant difference in basal expression of bax between cases and controls. The quantitative importance of apoptosis was small in OLP. Epithelial cells attacked in OLP have a very low response to apoptosis and cell cycle arrest mechanisms, which may produce an epithelial substrate that favours malignant transformation.

Adult↗

PubMed2003

Mild cognitive impairment: directions for future research.

Mild cognitive impairment (MCI), an intermediate state between normal aging and dementia, is characterized by acquired cognitive deficits, without significant decline in functional activities of daily living. Studies conducted on MCI have introduced new concepts regarding the possible distinctions between normal and pathologic aging of the brain. Neuroimaging and genetic testing have aided in the identification of individuals at increased risk for dementia. The measurement of change in cognitive and functional status in MCI remains challenging, because it requires instruments that are more sensitive and specific than those considered adequate for research in dementia. The authors provide an overview of the many methods that have been used to study MCI and directions that may help achieve greater uniformity in methodology. Considerable heterogeneity exists in research methodology used to study the epidemiology, thresholds for cognitive and functional impairment, rate of progression, risk factors, and defining subtypes of MCI. This article emphasizes the need for uniformity in the use of 1) appropriate and sensitive neuropsychological and functional measures to diagnose MCI, 2) reliable methods to determine progression or improvement of cognitive impairment, and 3) instruments in epidemiologic studies to establish population estimates for diverse ethnic and cultural groups. Greater consensus is needed to standardize definitions and research methodology for MCI, so as to make future studies more comparable and more useful for designing effective treatment strategies.

Aged↗

PubMed2003

Delayed neutrophil apoptosis in chronic periodontitis patients.

BACKGROUND, AIMS: Neutrophil cells constitute the first defense barrier against the oral bacterial challenge in the periodontium. Reduction of neutrophils could impair this response against periopathogenic bacteria such as Porphyromonas gingivalis. Our previous work implicates the apoptosis of neutrophils in the pathogenesis of periodontitis. We now demonstrate that granulocyte monocyte-colony stimulating factor (GM-CSF) present in the gingival crevicular fluid (GCF) and secreted during the immune response reduces the apoptosis of neutrophils. METHOD: In this study, the presence of GM-CSF and tumor necrosis factor-alpha (TNF-alpha) in GCF was determined in samples obtained from adult patients with periodontitis and from control subjects with clinically healthy gingiva. GCF was collected for 30 s using Periopaper(R) strips, and cytokines were quantified by ELISA. We used ex vivo culture of gingival tissue biopsies for 2 and 4 days in the presence of GM-CSF. Apoptosis was determined using the terminal TdT-mediated dUTP-biotin nick end labeling (TUNEL) technique, and expression of Bax by immunohistochemistry. RESULTS: The presence of GM-CSF and TNF-alpha was detected in the majority of sites from periodontal patients (83.3% and 63.3%, respectively), presenting a total amount of 27.65 and 42.38 pg, respectively. GM-CSF reduces the neutrophil apoptosis determined by double staining with TUNEL and myeloperoxidase and by a reduction of Bax expression. CONCLUSIONS: These findings suggest a novel mechanism by which neutrophils specifically accumulate in adult patients with periodontitis.

Adult↗

PubMed2002

Isolation and molecular characterization of atrazine tolerant barley mutants.

Two atrazine-tolerant barley mutants were isolated from atrazine-selection experiments performed on barley chloroplast-mutator plants. Genetic analysis demonstrated that atrazine tolerance was maternally inherited. Molecular characterization of the mutants was performed by PCR amplification of an internal fragment of the chloroplast gene psbA. The BstXI restriction patterns of the amplified fragments showed two bands in both tolerant barley mutants and only one in the atrazine-sensitive control. The 277-bp amplified fragments from the parental line and both atrazine-tolerant mutants were cloned and sequenced. Sequence analysis showed a single nucleotide substitution in both barley atrazine-tolerant mutants, i.e. A to G at the +790 position of the psbA gene-coding sequence. This point mutation corresponds to an amino-acid change of serine- to -glycine and creates a BstXI restriction site. Our results confirmed the conservative variability involved in atrazine tolerance which was previously reported for several other species. To our knowledge this is the first report on the obtention of atrazine-tolerant barley. This finding provides support to the hypothesis that, in addition to a wide variety of chlorophyll deficiencies, the barley chloroplast mutator genotype induces variability in other traits, which could include agronomically valuable mutants.

Atrazine↗

PubMed2002

Photodynamic therapy with 5-aminolevulinic acid for recalcitrant familial benign pemphigus (Hailey-Hailey disease).

Familial benign pemphigus is a chronic, recurrent, autosomal dominant blistering disease that may significantly affect quality of life. Surgical methods are often needed to control flares in difficult cases. We describe the use of photodynamic therapy (PDT) with topical 5-aminolevulinic acid (ALA) followed by irradiation with incoherent light (ALA-PDT) in 2 patients with chronic, recalcitrant familial benign pemphigus.

Aminolevulinic Acid↗

PubMed2001

Estrogen modulates norepinephrine-induced accumulation of adenosine cyclic monophosphate in a subpopulation of immortalized luteinizing hormone-releasing hormone secreting neurons from the mouse hypothalamus.

A subpopulation of luteinizing hormone-releasing hormone (LHRH)-producing cells that express the intermediate filament protein vimentin and the neuronal marker neurofilament 145, but not neurofilament 200 nor glial fibrillary acidic protein, has been isolated from GT1-7 cultures. These cells express the mRNA encoding estrogen receptor alpha (ERalpha) and respond to physiological concentrations of 17beta-estradiol (E2) by reducing the accumulation of cyclic adenosine monophosphate induced by norepinephrine, but not that induced by direct activation of adenylate cyclase. These results indicate that the activity of LHRH-producing neurons may be directly modulated by estrogen. In addition, they are suggestive of an estrogen-dependent desensitization of the beta-adrenoceptor in these cells.

Animals↗

PubMed2001

Catalase deficiency reduces survival and pleiotropically affects agronomic performance in field-grown barley progeny.

Field-grown plants of the catalase-deficient mutant RPr79/4 show necrotic lesions in leaves and preferentially die. Initially, necrotic lesions exhibited by RPr79/4 were used to indirectly assess the role of distinct levels of catalase on the survival and agronomic performance of field-grown barley progeny. The segregation of three control traits was also analyzed to eliminate the influence of any obvious meiotic disturbance in case a reduction of plant survival was observed. The RPr79/4 necrotic phenotype had recessive expression in field-grown F1 plants. F2 progeny studies performed in the greenhouse revealed that the inheritance of necrotic lesions was monofactorial, and that the control traits segregated as expected. Progeny test analyses of field-grown F2 plants demonstrated that necrotic homozygous plants died preferentially. While the few surviving necrotic homozygous families were catalase-deficient, healthy homozygous families had normal levels of catalase. Progeny test analyses of the control traits confirmed the inheritance calculated in F2. Taken together, these findings indicate that abnormal segregation of necrotic lesions cannot be attributed to any obvious abnormal meiotic behavior but to the incapacity of catalase-deficient plants to overcome field stress conditions. Thus, catalase deficiency in barley reduced survival and pleiotropically affected the agronomic performance by diminishing seed weight and yield.

Journal Article↗

PubMed2001

Characterization of cellular infiltrate, detection of chemokine receptor CCR5 and interleukin-8 and RANTES chemokines in adult periodontitis.

Leukocyte migration is essential for immune surveillance of tissues by focusing immune cells to sites of antigenic challenge. The control of leukocyte migration depends on the combined actions of adhesion molecules and a vast array of chemokines and their receptors. The purpose of the present study was to investigate the involvement of Interleukin-8 (IL-8), RANTES, the associated infiltrating cells and expression of CCR5 chemokine receptors in periodontitis; furthermore, the effect of periodontal therapy on these parameters was evaluated. Patients included in the study had moderate to advanced periodontal disease with at least 5-6 teeth with probing depth > 6 mm, attachment loss > or =3 mm and extensive radiographic bone loss. The inflammatory infiltrate was analyzed by immunohistochemistry in gingival biopsies obtained from subjects at the beginning of the study and 2 months after periodontal treatment. Gingival crevicular fluid (GCF) was collected for 30 seconds using periopaper strips, and chemokines were quantified by ELISA. The cellular components of the inflammatory infiltrate included B (CD19) and T (CD3, CD4+ and CD8+) lymphocytes and monocytes/macrophages (CD11c). CCR5 chemokine receptor expressing cells were exclusively found in periodontitis gingiva. IL-8 and RANTES were detected in the periodontitis group, obtaining a total amount of 212.5 pg and 42.0 pg, respectively. However, IL-8 was also detectable in the GCF of the healthy group (total amount of 44.8 pg). Periodontal therapy reduced the cell number in the infiltrate and the levels of IL-8 and RANTES, suggesting a relationship between these chemokines and periodontal status. We propose that the presence of these chemokines and the expression of chemokine receptors may represent a marker of lymphocyte subsets with the ability to migrate to inflammatory sites.

Adult↗

PubMed2001

CXCR3 chemokine receptor distribution in normal and inflamed tissues: expression on activated lymphocytes, endothelial cells, and dendritic cells.

Using new human CXCR3 chemokine receptor-specific monoclonal antibodies, we studied human CXCR3 tissue distribution in lymphoid and nonlymphoid organs, as well as in inflammatory conditions, including rheumatoid arthritis, Hashimoto's thyroiditis, and dermal vasculitis. CXCR3 was expressed by certain dendritic cell subsets, specifically myeloid-derived CD11c positive cells, not only in those present in normal lymphoid organs, but also in germinal centers generated in inflammatory conditions. CXCR3 expression was also detected in some lymphocyte subsets such as intraepithelial lymphocytes of secondary lymphoid organs and infiltrating lymphocytes in inflammatory conditions. In addition, CXCR3 was constitutively expressed by endothelial cells (EC) of vessels of medium and large caliber but not in small vessels from different organs. Finally, enhanced CXCR3 expression was found in EC and in infiltrating lymphocytes with an activated phenotype in inflammatory diseases. The CXCR3 chemokine receptor may play a role in the regulation of leukocyte migration to inflammatory sites.

Animals↗

PubMed2001

An evaluation of the NINCDS-ADRDA neuropsychological criteria for the assessment of Alzheimer's disease: a confirmatory factor analysis of single versus multi-factor models.

Neuropsychological test batteries are frequently used to assess the nature and severity of cognitive deficits among patients with early Alzheimer's Disease (AD) and related disorders. The NINCDS-ADRDA criteria are among the most widely used guidelines to diagnose dementia (McKhann et al.,1984). These criteria specify eight distinct areas of neuropsychological function that should be evaluated in patients with suspected cognitive impairment. Recent studies have suggested that neuropsychological deficits observed in AD may be explained by a single general factor related to memory deficits or to executive dysfunction. In contrast, the results of other investigations have indicated that multiple qualitatively different factors underlie cognitive abilities in AD. In the present study, we used confirmatory factor analysis to examine the structure of cognitive abilities in AD and to assess the extent to which single and multiple ability factors accurately represent neuropsychological test data obtained from patients with AD. Results indicated that the NINCDS-ADRDA model fit the data better than a single factor model. However, a more parsimonious model specifying memory, verbal abilities, visuospatial skills, executive function, and higher as well as lower functional activities of daily living fit the data better than the NINCDS-ADRDA model. These results have important theoretical and practical implications for diagnostic evaluation.

Activities of Daily Living↗

PubMed2001

Caregivers' judgments of the functional abilities of the Alzheimer's disease patient: a comparison of proxy reports and objective measures.

The assessment of functional capacity is essential for the diagnosis of dementia by DSM-IV criteria and has important implications for patient intervention and management. Although ratings of functional disability by family or other proxy informants are widely used by clinicians, there have been concerns and empirical evidence that potential reporter biases may result in either overestimation or underestimation of specific functional deficits. In this study, we compared family members' judgments of the functional abilities of seventy-two patients diagnosed with Alzheimer's disease (AD). These judgments were compared to actual objective functional performance on an array of real-world tasks using the Direct Assessment of Functional Status (DAFS) scale. The results indicate that caregivers were extremely accurate in predicting the functional performance of AD patients who were not impaired during objective evaluation. In contrast, caregivers significantly overestimated the ability of impaired AD patients to tell time, to identify currency, to make change for a purchase, and to utilize eating utensils. Higher patient MMSE scores were associated with caregivers' overestimation of functional capacity, while the degree of caregivers' depressive symptoms, as measured by the CES-D depression scale, was not related to either overestimation or underestimation of patients' functional performance.

Activities of Daily Living↗

PubMed2001

Apoptosis in chronic adult periodontitis analyzed by in situ DNA breaks, electron microscopy, and immunohistochemistry.

BACKGROUND: Apoptosis is an evolutionary form of physiological cell death. Previous studies suggest that apoptosis is involved in the pathogenesis of periodontal diseases. Therefore, we studied the apoptotic events in the gingival tissue of chronic adult periodontitis patients. METHODS: Gingival tissue biopsies from 22 patients with chronic adult periodontitis and from 11 healthy controls were obtained. Criteria for patient inclusion in the periodontitis group were a minimum of 14 natural teeth, excluding third molars, with at least 10 posterior teeth; 5 to 6 sites with probing depth > or = 5 mm; attachment loss > or = 3 mm; and extensive radiographic bone loss. The control group included healthy subjects with no prior history of periodontal disease. Apoptosis was determined using the terminal TdT-mediated dUTP-biotin nick end labeling (TUNEL) technique; electron microscopic analysis; and expression of Caspase-3, Fas, FasL, Bcl-2, and p53 by immunohistochemistry. RESULTS: TUNEL-positive cells and cells exhibiting chromatin condensation by electron microscopy were observed in the inflammatory infiltrate of biopsies obtained from periodontitis patients. Most of the TUNEL-positive cells belonged to neutrophil cell populations as they were stained with anti-myeloperoxidase. Positive staining for active-caspase 3, Fas, FasL, and p53 was only observed in the inflammatory infiltrate from periodontitis biopsies, whereas Bcl-2 cells were present in both periodontitis patients and healthy controls. CONCLUSIONS: Our findings establish that apoptosis is induced in the periodontal tissue by host and microbial factors and support the hypothesis that apoptotic mechanisms could be implicated in the inflammatory process associated with gingival tissue destruction observed in adult periodontitis patients.

Adult↗

PubMed2001

Colocalization of tyrosine hydroxylase and GAD65 mRNA in mesostriatal neurons.

Although dopamine has been considered as the only neurotransmitter in the nigrostriatal pathway, studies carried out in the last two decades have suggested the existence of a nondopaminergic nigrostriatal projection, and more recently, gamma-aminobutyric acid (GABA) has been identified as its neurotransmitter. In this study, we used the combination of immunocytochemistry for tyrosine hydroxylase (TH; a marker of dopaminergic neurons), in situ hybridization (ISH) for two different isoforms of glutamic acid decarboxylase (GAD65 and GAD67, the rate-limiting enzyme in GABA synthesis) and retrograde tracing techniques to investigate the possible existence of nigrostriatal neurons containing both neurotransmitters (dopamine and GABA) in the rat. Our results revealed that approximately 10% of mesostriatal dopaminergic neurons, most of them lying in the medial region of the substantia nigra pars compacta (SNC) and neighbouring A10 region, contain GAD65 mRNA. These findings reveal a third nigrostriatal pathway formed by dopaminergic/GABAergic neurons. Contrasting with the idea that in the basal ganglia, dopamine and GABA are released from different cell populations, the results suggest a more complex dopamine/GABA interaction than previously assumed, probably including cotransmission.

Animals↗

PubMed2001

Factor structure of the Cornell Scale for Depression in Dementia for Anglo and Hispanic patients with dementia.

The authors assessed the equivalence of the factor structure of the Cornell Scale for Depression in Dementia (CSDD) in samples of Anglo and Hispanic patients with Alzheimer's disease (AD). Comparing the factor structure of the CSDD in these groups helps establish its validity and aids in its clinical interpretation with Hispanic patients. CSDD ratings were first subjected to preliminary exploratory factor analyses; then the factor structure of the CSDD across groups of English- and Spanish-speaking patients was tested using structural equation modeling. Analyses showed overall similarity in the CSDD factor structure for the two groups but also revealed differences in factor content for several items. The authors discuss the relevance of these differences for those using the CSDD with Hispanic AD patients.

Aged↗

PubMed2000

[Hematopoietic stem cell transplantation as salvage treatment in patients with aggressive non-Hodgkin's lymphoma].

BACKGROUND: The indication of early hematopoietic stem cell transplantation (HSCT) in patients with aggressive non-Hodgkin's lymphoma (LNH) is controversial. PATIENTS AND METHODS: Retrospective analysis of 86 patients with aggressive NHL treated with MACOP/VACOP-B chemotherapy. HSCT was performed as salvage treatment to patients under 65 years of age with progressive disease or chemosensitive relapse. Progression free survival (PFS) and overall survival (OS) were determined by the Kaplan-Meier method. Rates of response and survival functions were compared between the International Prognostic Index (IPI) groups using the Chi-square and log-rank tests, respectively. RESULTS: Patients median age was 48 years; 22% had T cell NHL and 57% had intermediate-high and high risk (high risk) IPI. There were 6 toxic deaths (7%), and treatment failure was observed in 42 patients (48.8%). Thirty one of them were candidates for TPH due to age under 65 years, although 21 were finally transplanted (including 13 with high risk IPI). A significant association between PFS and IPI was observed, 61.9% for low risk (low and low-intermediate) versus 28.2% for high risk groups (p = 0.0007). With a median follow up of 4.8 years, OS was 64%; 80.5% for low risk versus 52.6% for high risk IPI groups (p = 0.01), and 83.7% versus 62% for the same groups in patients under 65 years of age (p = 0.02). The median follow up after failure to chemotherapy was 42.7 months. CONCLUSIONS: In this retrospective study, OS rate in high risk IPI patients with NHL using HSCT as salvage treatment is similar to that reported using HSCT during earlier phases of treatment.

Adolescent↗

PubMed2000

Utility of a modified Mini-Mental State Examination with extended delayed recall in screening for mild cognitive impairment and dementia among community dwelling elders.

The objective of this study was to test the utility of additional delayed recall of the three recall items of the Folstein Mini Mental State Evaluation (MMSE) as a screening measure for mild cognitive impairment and dementia in the elderly. It used a cross-sectional study of subjects, who were administered a brief memory screening battery which included the MMSE and extended delayed recall of the three MMSE recall items at 5 minute intervals. The criteria for cognitive status was determined on the basis of the neurological and neuropsychological evaluation. One hundred and two elderly persons who were recruited through a memory screening program were diagnosed as cognitively normal (N=52), mild cognitively impaired (N=24), or demented (N=26). The observed sensitivity of 83.3% and specificity of 90.4% was achieved across three delayed recall trials in differentiating cases with mild cognitive impairment (without dementia) from individuals with normal cognition and was superior to the total MMSE score alone (sensitivity/specificity: 70.8%/84.6%). Cumulative recall for the three MMSE items across only two delayed recall trials demonstrated a sensitivity of 96.2% and specificity of 90.4% in differentiating between cases of dementia versus cases diagnosed with no cognitive impairment. The three trial delayed recall score enhanced prediction of mild cognitive impairment in at-risk elderly living with the community and may have promise in the development of future screening batteries.

Aged↗

PubMed2000

Category fluency test: normative data for English- and Spanish-speaking elderly.

Category fluency tasks are an important component of neuropsychological assessment, especially when evaluating for dementia syndromes. The growth in the number of Spanish-speaking elderly in the United States has increased the need for appropriate neuropsychological measures and normative data for this population. This study provides norms for English and Spanish speakers, over the age of 50, on 3 frequently used measures of category fluency: animals, vegetables, and fruits. In addition, it examines the impact of age, education, gender, language, and depressed mood on total fluency scores and on scores on each of these fluency measures. A sample of 702 cognitively intact elderly, 424 English speakers, and 278 Spanish speakers, participated in the study. Normative data are provided stratified by language, age, education, and gender. Results evidence that regardless of the primary language of the examinee, age, education, and gender are the strongest predictors of total category fluency scores, with gender being the best predictor of performance after adjusting for age and education. English and Spanish speakers obtained similar scores on animal and fruit fluency, but English speakers generated more vegetable exemplars than Spanish speakers. Results also indicate that different fluency measures are affected by various factors to different degrees.

Aged↗