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Biomedical subjects

C Conde

Publications and source records attributed to C Conde.

At least 19 recordsLinked to original sources
PubMed2006

Association of a non-synonymous single-nucleotide polymorphism of DNASEI with SLE susceptibility.

OBJECTIVES: To investigate the association of a non-synonymous single-nucleotide polymorphism (SNP) in DNASEI with susceptibility to systemic lupus erythematosus (SLE) and the production of autoantibodies to nuclear antigens. METHODS: The Gln244Arg (rs1053874) SNP was studied in 276 SLE patients and in 368 healthy controls of Spanish ancestry. Its relationship with SLE susceptibility, serum DNase I activity, anti-ribonucleoprotein (RNP), anti-double-stranded DNA (dsDNA), anti-nucleosome and anti-single-stranded DNA (ssDNA) antibodies was determined. RESULTS: An association of the Gln244Arg SNP with SLE susceptibility that followed a recessive genetic model (P=0.002) was found. The GG genotype was more common in SLE patients (59.8%) than in controls (47.3%). However, the Gln244Arg genotype did not correlate with DNase I activity in sera from SLE patients or from controls. In addition, the Gln244Arg SNP did not influence autoantibody titres significantly. CONCLUSION: The association of the Gln244Arg SNP with SLE susceptibility indicates that common polymorphisms in DNASEI play a role in the genetics of SLE. However, the lack of effect of the Gln244Arg SNP on serum DNase I activity calls into question the direct involvement of this specific SNP.

Antibodies, Antinuclear↗
PubMed2005

[Functional impairment in elderly patients hospitalised in an Internal Medicine unit].

To determine the functional status in elderly patients after a hospitalisation in an Internal Medicine unit. We prospectively studied patients aged 80 or above hospitalised in the Hospital Provincial de Ciudad Real in an Internal Medicine unit, between February and July, 2003. The functional status was determined by Barthel Index. We examined 206 patients (77.4%). They showed a previous Barthel Index of 70.9; one of 48.9 in the hospitalisation stage and one of 58.6 when discharged (p<0.001). We noticed a Barthel Index when discharged which was lower than the previous Barthel one in 73.8% patients. Hospitalisation implies a great functional impairment in the functional status elderly patients. It would be convenient, therefore, to identify the risk factors to be able to set some guidelines for a preventive model.

Activities of Daily Living↗
PubMed2004

Finite-difference and finite-volume methods for nonlinear standing ultrasonic waves in fluid media.

In the framework of the application of high-power ultrasonics in industrial processing in fluid media, the mathematical prediction of the acoustical parameters inside resonators should improve the development of practical systems. This can be achieved by the use of numerical tools able to treat the nonlinear acoustics involved in these phenomena. In particular, effects like nonlinear distortion and nonlinear attenuation are fundamental in applications. In this paper, three one-dimensional numerical models in the time domain for calculating the nonlinear acoustic field inside a one-dimensional resonant cavity are presented and compared. They are based on the finite-difference and the finite-volume methods. These different algorithms solve the differential equations, from the linear up to the strongly nonlinear case (including weak shock). Some physical results obtained from the modelling of ultrasonic waves and a comparison of the efficiency of the different algorithms are presented.

Journal Article↗
PubMed2004

A novel missense mutation, c.584A > C (Y195S), in two unrelated Argentine patients with hypoxanthine-guanine phosphoribosyl-transferase deficiency, neurological variant.

The hypoxanthine-guanine phosphoribosyl-transferase (HPRT) deficiency is an inborn error of purine metabolism, responsible for classic Lesch-Nyhan disease and its neurological and hyperuricemic variants. We report a novel mutation in the HPRT gene, c.584A > C (Y195S), in two unrelated Argentine patients affected with the neurological variant with no HPRT activity in lysed erythrocytes. Using PCR plus DNA sequencing and/or restriction enzyme digestion we were able to confirm the diagnosis and identify new cases and potential carriers.

Adolescent↗
PubMed2004

[Treatment of central neurocytoma. Experience at a single institution].

Central neurocytomas are classically considered as a rare, intraventricular benign tumours with neuronal differentiation derived from precursor cells of subventricular matrix. However some patients with neoplasms with histologic atypia and elevated proliferation potential may have a poor outcome. Treatment of choice is complete surgical excision. Adjuvant therapy is reserved for patients with residual or recurrent lesions including reoperation, radiotherapy or chemotherapy. We review our experience with the treatment of this neoplasm. Five patients with an intraventricular mass studied with magnetic resonance imaging underwent craniotomy for tumour resection. All cases were reviewed retrospectively. Histopathological analysis confirmed central neurocytoma in all cases. Proliferation index was assessed by Ki-67 immunohistochemistry. Complete radiological tumor resection through transcortical approach was achieved in all except one patient. In this case adjuvant therapy with radiosurgery was given with important reduction in tumor size. All the tumours had a proliferation index below 2% except one with 5%. Follow-up in four patients ranged from 12 to 36 months. There were no tumour recurrences in this period. Complete surgical excision of central neurocytoma provides better local control and survival compared with other treatments. Radiosurgery as adjuvant therapy in incomplete resections may eliminate the need of reoperation and avoid long-term side effects from conventional radiotherapy.

Adolescent↗
PubMed2001

Tumoral calcinosis presenting as an extradural mass: MR findings and pathological correlation.

Two cases of idiopathic tumoral calcinosis presenting as an extradural mass are reported. There are few reports in the literature of this pathological process presenting as extradural masses, so both cases represent very unusual locations for tumoral calcinosis. Magnetic resonance imaging features and pathological correlation of these two cases are presented. Tumoral calcinosis might be considered as a rare but possible cause of extradural mass.

Calcinosis↗
PubMed2001

Loss of poly(ADP-ribose) polymerase-1 causes increased tumour latency in p53-deficient mice.

PARP-1-deficient mice display a severe defect in the base excision repair pathway leading to radiosensitivity and genomic instability. They are protected against necrosis induced by massive oxidative stress in various inflammatory processes. Mice lacking p53 are highly predisposed to malignancy resulting from defective cell cycle checkpoints, resistance to DNA damage-induced apoptosis as well as from upregulation of the iNOS gene resulting in chronic oxidative stress. Here, we report the generation of doubly null mutant mice. We found that tumour-free survival of parp-1(-/-)p53(-/-) mice increased by 50% compared with that of parp- 1(+/+)p53(-/-) mice. Tumour formation in nude mice injected with oncogenic parp-1(-/-)p53(-/-) fibroblasts was significantly delayed compared with parp-1(+/+)p53(-/-) cells. Upon gamma-irradiation, a partial restoration of S-phase radiosensitivity was found in parp-1(-/-)p53(-/-) primary fibroblasts compared with parp-1(+/+)p53(-/-) cells. In addition, iNOS expression and nitrite release were dramatically reduced in the parp-1(-/-)p53(-/-) mice compared with parp-1(+/+)p53(-/-) mice. The abrogation of the oxydated status of p53(-/-) cells, due to the absence of parp-1, may be the cause of the delay in the onset of tumorigenesis in parp-1(-/-)p53(-/-) mice.

Animals↗
PubMed2000

MR imaging findings in granular cell tumor of the neurohypophysis: a difficult preoperative diagnosis.

Granular cell tumor is a rare neoplasm arising within the neurohypophysis. We describe the MR imaging findings in two symptomatic patients. In one patient with history of panhypopituitarism, MR images showed a large sellar and suprasellar mass. The other patient presented with acute loss of vision in her left eye, and MR images showed a suprasellar mass with compression of the optic chiasm.

Female↗
PubMed2000

Granulomatous amebic encephalitis in a patient with AIDS: isolation of acanthamoeba sp. Group II from brain tissue and successful treatment with sulfadiazine and fluconazole.

A patient with AIDS, treated with highly active antiretroviral therapy and trimethoprim-sulfamethoxazole, presented with confusion, a hemifield defect, and a mass lesion in the right occipital lobe. A brain biopsy confirmed granulomatous amebic encephalitis (GAE) due to Acanthamoeba castellanii. The patient was treated with fluconazole and sulfadiazine, and the lesion was surgically excised. This is the first case of AIDS-associated GAE responding favorably to therapy. The existence of a solitary brain lesion, absence of other sites of infection, and intense cellular response in spite of a very low CD4 count conditioned the favorable outcome. We review and discuss the diagnostic microbiologic options for the laboratory diagnosis of infections due to free-living amebae.

Acanthamoeba↗
PubMed2000

Effects of emotional reactivity on inhibitory avoidance in the elevated T-maze.

The possibility of the presence of inter-individual emotional differences and the memory performance of rats was examined in the elevated T-maze. Two kinds of aversively motivated behaviors, inhibitory avoidance and escape learning, were measured. Based on the number of trials to achieve a learning criterion, rats were divided into two subgroups with either low or high avoidance reactivity (LAR or HAR, respectively). Retention test avoidance latencies showed that HAR animals had better avoidance memory (Mann-Whitney rank sum test, P = 0.0035). No such differences were found for the escape component of this test. These data suggest that individual emotional differences affect inhibitory avoidance performance, which may help to explain the dispersion of the data observed in other studies using this paradigm.

Animals↗
PubMed2000

[Symptomatic cluster headache: presentation of 2 cases].

Cluster headache is a primary headache with well-defined diagnostic criteria. Nevertheless, in 3-5% of patients this syndrome is secondary to diverse cranial structural abnormalities. Atypical features which suggest a secondary or symptomatic origin include absence of periodicity and regular hourly recurrence, persistence of background pain among attacks, unsatisfactory response to treatment, and presence of neurological signs other than ptosis or miosis. We present two patients with symptomatic cluster-like headache. In one, the syndrome was associated with a fistula of the right superficial temporal artery. After embolization the pain attacks ceased. The second patient presented a ventricular xanthoma, located in the occipital horn; after surgical excision, the pain attacks did not recur. The progressive increase in frequency and absence of regularly hourly recurrence of pain episodes was a common feature in both cases. We comment and revise the pathophysiology of this syndrome, with emphasis on the case of the xanthoma, since we did not find a similar case described. If a secondary cluster-like headache is suspected, neuroimaging studies should be done.

Adolescent↗
PubMed1999

Different roles for LFA-1 and VLA-4 integrins in T-B-cell interactions in vivo.

Adhesion molecules are critical in the cellular interactions involved in specific immune responses. They are used for homing, cell migration, cell-cell contact and, in some cases, for the delivery of costimulatory signals. Since the host-versus-graft (HVG) reaction represents a particular form of T-B-cell interaction, we have explored whether the inhibition of lymphocyte function-associated antigen-1/intracellular adhesion molecule-1 (LFA-1/ICAM-1) interactions and the signalling through very late activation antigen-4 (VLA-4) have any effect on the development of a lupus-like disease in BALB/c mice injected at birth with (BALB/cxC57BL/6)F1 spleen cells. In close association with the development of tolerance to donor allografts, these mice show a polyclonal activation of F1 donor B cells by alloreactive host CD4+ T cells, manifested by the production of autoantibodies (autoAbs) and the development of a mild glomerulonephritis. The dose of the monoclonal antibody (mAb) employed has been adjusted to block completely the molecule on the surface of peripheral lymphocytes without interfering with the induction of neonatal tolerance. Injection of saturating doses (100 microg/2 days) of either anti-LFA-1alpha or anti-ICAM-1 mAbs, but not anti-VLA-4alpha or anti-LFA-1beta mAbs, blocks the production of anti-ssDNA autoAbs and the thrombocytopenia characteristic of this HVG disease (HVGD). However, anti-VLA-4alpha treatment is only able to delay the production of autoAbs and the anti-LFA-1beta treatment, not to modify the evolution of the HVGD. These results point to the relevance of LFA-1/ICAM-1 interactions, but not of the VLA-4-mediated signal, in the polyclonal B-cell activation occurring during the allogeneic interactions between host T helper type 2 cells and donor B cells in HVGD.

Animals↗
PubMed1998

Terminal deoxynucleotidyl transferase deficiency reduces the incidence of autoimmune nephritis in (New Zealand Black x New Zealand White)F1 mice.

Terminal deoxynucleotidyl transferase (TdT) enzyme activity in lymphocytes generates diversity in the Ag receptor repertoires by adding template-independent N nucleotides and disrupting homology-directed rearrangements. The importance of this diversity in vivo and the significance of the suppression of TdT during fetal life remain uncertain. Previous studies have shown that in TdT knockout mice (TdT(0)) 1) the T cell repertoire is less peptide oriented; and 2) natural autoantibody, particularly anti-DNA autoantibodies, are less polyreactive, and their mean affinities are reduced. Consequently, the suppression of TdT during early T/B cell ontogeny may participate in controlling autoimmunity. To study the impact of TdT suppression in autoimmune-prone mice, we introduced the TdT null mutation into the (NZB x NZW)F1 (B/W) mouse strain. We show that TdT deficiency significantly reduces the incidence of autoimmune nephritis and prolongs survival compared with those in control mice. Surprisingly, the long-term survivor TdT(0) mice produced amounts of anti-ADN and anti-histone autoantibodies similar to those of their TdT+ littermates. However, these TdT(0) mice showed no evidence of renal inflammation, and the immune deposits were restricted to the mesangium, whereas basal membrane deposits were clearly correlated with overt renal disease. The present study supports the idea that the absence of TdT enzyme activity in lymphocytes protects mice against autoimmunity and could offer a therapeutic approach to autoimmune diseases. Moreover, our results may help to unravel the mechanisms of lupus nephritis.

Animals↗
PubMed1997

Autoantibodies in mice lacking terminal deoxynucleotidyl transferase: evidence for a role of N region addition in the polyreactivity and in the affinities of anti-DNA antibodies.

The generation of terminal deoxynucleotidyl transferase knockout mice (TdT0) has demonstrated that TdT is the only major activity involved in N region addition. This enzyme generates diversity by adding random nucleotides at the V-D-J junctions and by disrupting the formation of repetitive "homology-directed" junctions. Several studies have demonstrated that the Ig heavy chain third complementarity-determining region (H-CDR3) and the N region play a critical role: 1) in distinguishing between polyreactive and monospecific combining sites in natural and Ag-induced Abs; and 2) in the specificity and polyreactivity of natural autoantibodies (autoAbs) and in particular of anti-DNA Abs. To examine the impact of the lack of TdT on the natural autoAb repertoire in adult mice, we have stimulated TdT0 and TdT+ littermates with LPS. Serum studies demonstrate that TdT is not critical for the generation of B cells expressing autoAbs including anti-DNA Abs and rheumatoid factors. However, the generation of a large collection of hybridomas indicates that the frequencies of these cells are reduced in TdT0 mice mainly due to a lower incidence of polyreactivity; also, the lack of N region diversity seems to negatively affect the affinity of anti-DNA Abs. The physiologic relevance of these data is discussed.

Amino Acid Sequence↗
PubMed1997

Inhalatory pentamidine therapy and the duration of the QT interval in HIV-infected patients.

We evaluated the effect of chronic Pneumocystis carinii pneumonia (PCP) prophylaxis, with a once a month dose of 300 mg of inhalatory pentamidine isethionate, on QT interval duration. We included 22 human immunodeficiency virus (HIV)-infected patients: 11 were on this medication and 11 were not. The two groups were matched for age, sex and HIV infection stage. No patient had any clinical condition or was under any medication known to affect the duration of the QT interval. The heart rate-corrected QT (QTc) was obtained by averaging the observations of three independent observers. QTc duration was similar in both groups. The time separating pentamidine administration and the performance of the ECG did not influence the results, neither did the duration of inhalatory pentamidine therapy. Our results suggest that inhalatory pentamidine does not prolong the QT interval duration and so, as opposed to what has been reported concerning intravenous pentamidine therapy, does not seem to induce an increased risk of torsades de pointes.

Administration, Inhalation↗