Biomedical subjects
M García-Granero
Publications and source records attributed to M García-Granero.
[Submucosal lipoma of the colon].
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Factor analysis and correlation between Dizziness Handicap Inventory and Dizziness Characteristics and Impact on Quality of Life scales.
In order to assess the different dimensions of disability and handicap analyzed in the Dizziness Handicap Inventory (DHI) and Dizziness Characteristics and Impact on Quality of Life (UCLA-DQ) questionnaires a factor analysis study was done. The instruments used were the corresponding transculturally adapted versions of the originals into Spanish. The study included 337 patients with dizziness, independent of location and etiology, who were able to respond to all the items in the questionnaires given before vestibular testing. Factor analysis was used to determine the structure of both scales; a principal components analysis with orthogonal rotation (Varimax) was conducted on data collected from the patients. A three-factor solution was obtained in the DHI and a two-factor solution for the UCLA-DQ. The factors obtained from the DHI were related to vestibular handicap, vestibular disability and visuo-vestibular disability; the factors from the UCLA-DQ were related to frequency and severity of dizziness. There was no coincidence between the items in each of the factor obtained in the DHI questionnaire and the items in the subscales provided in the original version. The main relation between factors was found between vestibular handicap and frequency. The DHI and UCLA-DQ questionnaires are multidimensional questionnaires for the assessment of the impact of dizziness and provide a model for vestibular disability and handicap.
Specific and general HLA-DR binding motifs: comparison of algorithms.
Using panels of peptides well characterized for their ability to bind to HLA DR1, DRB1*1101, or DRB1*0401 molecules, algorithms were deduced to predict binding to these molecules. These algorithms consist of blocks of 8 amino acids containing an amino acid anchor (Tyr, Phe, Trp, Leu, Ile, or Val) at position i and different amino acid combinations at positions i+2 to i+7 depending on the class II molecule. The sensitivity (% of correctly predicted binder peptides) and specificity (% of correctly predicted non-binder peptides) of these algorithms, were tested against different independent panels of peptides and compared to other algorithms reported in the literature. Similarly, using a panel of 232 peptides able to bind to one or more HLA molecules as well as 43 non-binder peptides, we deduced a general motif for the prediction of binding to HLA-DR molecules. The sensitivity and specificity of this general motif was dependent on the threshold score used for the predictions. For a score of 0.1, the sensitivity and specificity were 84.7% and 69.8%, respectively. This motif was validated against several panels of binder and non-binder peptides reported in the literature, as well as against 35, 15-mer peptides from hepatitis C virus core protein, that were synthesized and tested in a binding assay against a panel of 19 HLA-DR molecules. The sensitivities and specificities against these panels of peptides were similar to those attained against the panels used to deduce the algorithm. These results show that comparison of binder and non-binder peptides, as well as correcting for the relative abundance of amino acids in proteins, is a useful approach to deduce performing algorithms to predict binding to HLA molecules.
A prospective study of incident nonmelanoma skin cancer in heart transplant recipients.
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Age-related differences in the thermogenic and ponderal effects following the administration of fragment peptides from the rat ob protein.
The ob gene encodes a protein, which regulates satiety, metabolic rate and fat storage. The administration of a pool of five 20-amino-acid fragment peptides derived from the carboxy-terminal region of the ob protein produced a statistically significant reduction in body weight gain in adult rats, while rectal temperature showed a statistically significant increase. Administration of the same pool of peptides to young rats did not produce changes in body weight gain, although a statistically significant transient increase in rectal temperature was observed. These results envisage the possibility that small sequences of amino acids derived from the ob protein may mimic the effects of the whole protein on temperature and ponderal regulation. Furthermore, data suggest possible age-related differences in the response to leptin administration.
Cellular immunity to hepatitis C virus core protein and the response to interferon in patients with chronic hepatitis C.
To investigate the involvement of T-cell response against hepatitis C virus (HCV) antigens in viral clearance after interferon therapy, we measured interleukin-2 (IL-2) production by peripheral mononuclear cells in response to HCV core in patients with chronic hepatitis C. In a cohort of 43 patients, we investigated the frequency of circulating core-specific T-helper (Th) cell precursors by the limiting-dilution assay, and in a second cohort of 60 patients, we analyzed the response to specific core epitopes using 52 synthetic 15-mer overlapping peptides. We observed that the frequency of core-specific Th cell precursors was significantly higher in patients with sustained biochemical and virological response (SR) after interferon (IFN) therapy (median, 1/55,736) than in untreated patients (1/274,023) or that in patients who remained viremic after completion of the treatment-nonresponders (NR) plus transient responders (TR) (1/1,909,972). Patients who failed to respond to IFN (NR) and those who relapsed after IFN discontinuation (TR) had a similarly low number of precursors. The number of core peptides recognized by SR, TR, NR, UT, and healthy controls was 8.2 +/- 1.5, 6.5 +/- 1.2, 2.0 +/- 0.5, 2.7 +/- 0.9, and 0.3 +/- 0.2, respectively. In SR, the intensity of the proliferative response to core peptides as estimated by the summation of stimulation indexes (sigmaSI) was significantly higher than in NR and than in UT, but not different from that of TR. Our results indicate that both expansion of HCV-specific Th cell precursors and Th cell recognition of multiple core epitopes seem to be important in the elimination of HCV after IFN therapy.
Role of fragment peptides from ob protein on body weight and thermogenesis control: a screening.
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Simple strategy to induce antibodies of distinct specificity: application to the mapping of gp120 and inhibition of HIV-1 infectivity.
In this study 96 15-mer peptides encompassing the entire sequence of HIV-1 gp120 were synthesized and used to immunize BALB/c mice (i) alone or (ii) in conjunction with the T helper cell determinant FISEAIIHVLHSR (FIS) from sperm whale myoglobin, which is well recognized by major histocompatibility complex (MHC) class II molecules of BALB/c. Of these peptides 39 were immunogenic per se and 57 were not. Out of the 57 non-immunogenic peptides 53 could be rendered immunogenic with the second immunization protocol. With the exception of 4 cases, the anti-peptide antibody titers induced in (ii) were equal (14 cases) or higher (78 cases) than those induced in (i). From the 96 anti-peptide antibodies tested, 12 were able to recognize recombinant gp120 with good antibody titers, a result in agreement with previously identified B cell epitopes from gp120 by anti-peptide antibodies induced with longer peptides conjugated to a carrier protein. Moreover, 4 of the 12 anti-peptide antisera that recognized gp120 were able to neutralize HIV-1 infectivity in vitro, showing that the strategy of co-immunization with FIS may afford functional antibodies.
Prediction of sustained remission of chronic hepatitis C after a 12-month course of alfa interferon.
alpha-Interferon therapy normalizes aminotransferase levels in approximately 50% of the patients with chronic hepatitis C, but post-therapy relapses are common and predictive factors of sustained response remain largely unknown. We retrospectively assessed several parameters as predictors of sustained remission after a 12-month course of lymphoblastoid alpha-interferon: the Knodell histological activity index, serum levels of procollagen type III peptide, serum HCV-RNA, anti-alpha-interferon antibodies, and anti-HCV antibodies (C-100-3), all at month 12. Thirty-seven patients were studied. Fourteen patients were non-responders (38%), 15 patients experienced a sustained response (40.5%) and eight patients responded similarly but relapsed after alpha-interferon withdrawal (21.5%). A decrease in the histological activity index above 5, normalization of procollagen type III peptide levels (< 12 ng/ml) and the absence of viremia after treatment were all significantly associated with a sustained response (p = 0.008, p = 0.007 and p = 0.037, respectively). Anti-interferon antibodies were detected in only one non-responder patient. Anti-C-100-3 antibodies became undetectable at month 12 in 5 of the 15 sustained responders. The best prediction of sustained response was obtained from the three variables independent of multivariate analysis according to the following equation: F = 0.872 + 0.067 x K (decrease of histological index) -0.052 x P (procollagen type III peptide levels at month 12) -0.28 x R (HCV-RNA at month 12; R = 2 when present and R = 1 when absent). A score higher than 0 predicted sustained remission with a 100% sensitivity and specificity in this series of patients.(ABSTRACT TRUNCATED AT 250 WORDS)
Detection of anti-hepatitis C virus antibodies by ELISA using synthetic peptides.
A novel ELISA assay for the detection of anti-hepatitis C virus antibodies in the sera of infected individuals is described. This assay is based on a mixture of three 15-amino acid synthetic peptides encompassing regions of core and NS4 proteins of hepatitis C virus. Comparison with other available ELISA assays based on recombinant polypeptides shows that, short synthetic peptides have the advantage over some larger recombinant peptides by giving higher specificity without loss of sensitivity.
Histological outcome of chronic hepatitis C treated with a 12-month course of lymphoblastoid alfa interferon.
To assess the effect of long-term alfa interferon therapy (12 months) on liver histology of chronic hepatitis C, we studied 61 treated patients, and compared their outcome with 28 untreated cases followed as controls. A liver biopsy was taken from all patients, before (month 0) and after the completion of the treatment or the control period (month 12). A third liver specimen taken at month 24 was available in 29 treated cases. Liver biopsies were blindly graded following Knodell's method. In 33 out of the 61 treated patients (54.1%), aminotransferase levels became normal shortly after starting therapy and remained within normal values until the end of treatment (sustained response). Nine (27%) sustained responders relapsed after interferon discontinuation, while the remaining 24 (73%) continued with normal aminotransferase values during follow-up (16.8 +/- 9.9 months). All histological parameters, except fibrosis, improved significantly after 12 months of therapy (periportal necrosis, month 0: 2.7 +/- 1.0, month 12: 1.6 +/- 1.1, p < 0.0001; lobular damage, month 0: 2.5 +/- 1.1, month 12: 1.4 +/- 0.9, p < 0.0001; portal inflammation, month 0: 3.6 +/- 0.5, month 12: 3.0 +/- 0.9, p < 0.0001). Histological improvement was especially marked in patients who did not relapse, although those who relapsed and partial responders also improved. Overall histological diagnoses improved in most patients. A sustained response to interferon was predicted by high periportal and lobular scores, and by a low fibrosis score on the pretreatment liver biopsy. At 24 months, histological improvement persisted in patients without posttreatment relapse, while liver inflammation had returned to pretreatment levels in the remaining cases.
Prediction of the response of chronic hepatitis C to interferon alfa: a statistical analysis of pretreatment variables.
Pretreatment variables that could predict the response of chronic hepatitis C to interferon alfa treatment have not been fully assessed. Eighteen baseline variables were evaluated in a series of 100 consecutive patients treated with a 12 month course of interferon alfa. For the purposes of this study, response was defined as the return to normal of aminotransferase activities before the third month of treatment. Seventy per cent of the patients responded to treatment. Six variables were associated with an increased likelihood of response assessed by univariate analysis. With stepwise multiple regression analysis assessment, however, only three variables remained independently predictive of response: low gamma glutamyltransferase (gamma GT) activities (p < 0.001), absence of obesity (p = 0.005), and absence of cirrhosis (p = 0.01). The response rate in patients with gamma GT activities < 0.66 mu kat/l (n = 55) was 78% and 60% in patients with values > 0.66 mu kat/l (n = 45) (p = 0.048). Response was attained in 75% of non-obese patients (n = 80), compared with only 50% of obese patients (n = 20) (p = 0.03). Finally, 80% of patients without cirrhosis (n = 76) responded, while among those with cirrhosis (n = 24) the response rate was only 37% (p < 0.001). All 23 patients without cirrhosis, <40 years old, and with gamma GT activities <0.66 mu kat/l responded to treatment, while only 28.5% of 14 patients with cirrhosis, >40 years old, and with gamma GT activities >0.66 mu kat/l responded to interferon alfa (p<0.001). Those findings may be useful when evaluating interferon alfa trials and it is suggested that this treatment should be applied early in the course of chronic hepatitis C.
Systemic onset juvenile chronic arthritis, polyarticular pattern and hip involvement as markers for a bad prognosis.
OBJECTIVE: To explore all the common clinical and biological variables that are characteristic of Systemic onset Juvenile Chronic Arthritis (SoJCA) in order to determine which of them are suitable as predictors of a bad articular outcome (persistence of inflammatory symptoms and/or established limitation of the range of motion (ROM). MATERIAL AND METHODS: Clinical charts for 124 SoJCA patients were retrospectively reviewed. From them, 91 were finally included in the study because they had all of the clinical and biological data at disease onset properly recorded. All have been followed for at least 3 years since the beginning of the disease. Data collected at onset, and after 3 and 6 months of the disease included: 1) systemic symptoms; 2) joint involvement, using both the usual articular count and the value of an articular index (Helsinki Index = HI) which intentionally excludes those joints that are not uniformly recorded in clinical charts; and 3) biological data. HI was used to separate the patients into two groups. When applied 3 years after the disease onset, HI > or = 10 represented a bad articular outcome while HI < 10 meant a good prognosis. SPSS for Windows 6.1 was used for both the univariate and multivariate analyses. RESULTS: From the multivariate logistic regression analysis, two different "clusters" of clinical data were found to be the best predictors of a bad articular outcome. A bad prognosis was linked at onset with the presence of generalized lymphadenopathies, age < 8 years and an HI > 6; at six months a bad outcome was linked with the presence of a polyarticular pattern plus hip involvement. CONCLUSION: Clinical parameters at the beginning of the disease were shown to be extremely useful in predicting the articular outcome of SoJCA. Therefore, they could constitute a good instrument to help clinicians tailor the best therapy for their patients.