Search PubMed⌕ Search

Biomedical subjects

M Arias

Publications and source records attributed to M Arias.

At least 19 recordsLinked to original sources
PubMed2001

Unusual presentation of a pancreatic insulinoma in helical CT and dynamic contrast-enhanced MR imaging: case report.

Insulinomas are pancreatic neoplasms that can be radiologically characterized typically because of their tendency to present intense and early contrast enhancement with a wash-out phenomenon. In this sense, we report an unusual case of a hypovascular solid pancreatic insulinoma confirmed with surgery and pathologic analysis, in a patient with normal serum insulin levels. In the two-phase helical CT, the mass behaved as a hypodense lesion with respect to the surrounding pancreatic parenchyma during the arterial phase and as a hypointense lesion during the dynamic contrast-enhanced MR imaging. Pathologic examination demonstrated a hypercellular tumor with poor vascularization of intervening stroma which showed prominent amyloid deposits.

Aged↗
PubMed2001

Hypertension and long-term renal allograft survival: effect of early glomerular filtration rate.

BACKGROUND: For many years, hypertension has been related to long-term survival of patients and kidney grafts, although the nature of this relationship has not been completely defined. The aim of this study was to analyse the influence of early glomerular filtration rate on post-transplant hypertension and on graft survival. METHODS: A total of 432 kidney transplanted patients on cyclosporin therapy, with a functioning graft for at least 1 year, were studied. They were divided into two groups depending on their early creatinine clearance: group A [<60 ml/min (n=270)] and group B [>60 ml/min (n=162)]. RESULTS: There were no differences in sex, aetiology of renal failure, number of retransplants, PRA, HLA mismatches and pre-transplant blood pressure. One year after transplantation, blood pressure was higher in group A (systolic BP 148/diastolic BP 86/mean BP 117) than in group B (systolic BP 140/diastolic BP 82/mean BP 111) (P<0.003). We observed a negative correlation between early creatinine clearance and 1-year blood pressure (P<0.01). Five and 10 year graft survival was 60 and 37% in group A and 87 and 69% in group B, respectively (P<0.000). A multivariate Cox analysis showed that 1-year blood pressure (P<0.0029, RR=1.76) and early creatinine clearance (P<0.000, RR=3.27) had a significant influence on graft survival. CONCLUSIONS: The 1-year post-transplant blood pressure is a non-immunological risk factor in long-term graft survival. Patients with a lower initial glomerular filtration rate are more susceptible to the development of secondary hypertension and worse graft survival.

Adult↗
PubMed2001

Fluoxetine in the prevention of depressive recurrences: a double-blind study.

Optimal outcomes from depression treatment are long-term recovery and, in the case of recurrent depression, prevention of new episodes. However, few data are available concerning the long-term efficacy of antidepressants in prophylactic treatment to prevent recurrences of depression. The efficacy and safety of fluoxetine 20 mg/day was evaluated in reducing the number of depressive episodes and in extending the time free of symptoms in patients with recurrent unipolar major depression. Patients with recurrent unipolar major depression according to DSM-III-R criteria and who responded to 32 weeks of open-label fluoxetine were randomly assigned to receive fluoxetine 20 mg/day (N = 70) or placebo (N = 70) for 48 weeks of double-blind maintenance treatment. Outcome measures were the percentage of recurrences and time to recurrence. Safety assessments included treatment-emergent adverse events, reasons for discontinuation, vital signs, and laboratory measures. Fluoxetine was associated with a statistically significantly smaller percentage of patients who had a recurrence compared with placebo (20% vs. 40%; chi2 analysis, p = 0.010). The symptom-free period was significantly longer for patients treated with fluoxetine versus placebo (295 vs. 192 days; Kaplan-Meier estimates, log-rank test, p = 0.002). Treatments were well tolerated during maintenance treatment. The only statistically significant difference in adverse events between treatment groups was anxiety, which was more frequent in the placebo group (fluoxetine, 12.9% vs. placebo, 30%; chi2 analysis, p = 0.013). Two placebo-treated patients and no fluoxetine-treated patients were withdrawn because of adverse events. In conclusion, fluoxetine at 20 mg/day was effective and well tolerated for the prophylactic treatment of recurrent unipolar major depression.

Adolescent↗
PubMed2001

[Inverted metamorphopsia: an alteration in the perception of a special situation of objects].

OBJECTIVES: This study describes the characteristics of six patients who consulted because of episodes of perceptive alteration of extrapersonal space consisting in an inversion of the situation of objects although without changes in shape or size (inverted metamorphopsia). PATIENTS: Six patients (4 males and 2 females) who presented episodes of inverted metamorphopsia were studied: 4 referred right-left inversion (axial plane), 1 upwards-downwards (saggital plane) and 1 inclination of environment (clockwise movement). None had any alteration in the perception of their own bodies during the episodes which lasted from 3 minutes to 1 hour, reporting from 1 to 40 episodes. The most notable antecedents were: traumatism and forced cervical posture (2), arterial hypertension (3), migraine (2), hyperlipemia (2) and protuberantial ischemia (1). RESULTS: Intercritical neurologic exploration was normal. MR study showed leukoaraiosis (4), protuberantial paramedian infarctions (1) and was normal in one case of basilar migraine. Study of vestibular function (performed in 4 cases) did not show alterations. Three patients received antiepileptic drugs (1 carbamazepine and 2 gabapentin) with favorable response. CONCLUSIONS: Inverted metamorphopsia is a paroxistic phenomenon which transduces a dysfunction of the posterior parietal cortex or its afferences (propioceptive, vestibular, retinian). The causes may be multiple (traumatism, migraine, ischemia). Antiepileptic drugs may have a therapeutic role in the cases with multiple episodes.

Adult↗
PubMed2001

Surfactant treatment in premature infants with Respiratory Distress Syndrome in Curaçao.

Surfactant replacement therapy for Respiratory Distress Syndrome (RDS) in premature neonates has been established as an effective treatment, although significant mortality and morbidity remain. In Curaçao, surfactant became available as a therapeutic option in 1994. A retrospective cohort study was performed to describe the results of surfactant treatment in premature newborns with RDS in Curaçao between 1994 and 1998. Of 429 infants admitted to the study hospital in this period, 7.5% (n = 32) developed RDS and were treated with surfactant. Twenty-five per cent (n = 8) of these infants died, most of them in the first year of surfactant treatment. Twenty-eight per cent (n = 9) developed bronchopulmonary dysplasia (BPD), the most frequently observed complication. The highest incidence of BPD (44%) was found in the very low birth weight infants (750-1500 g); all infants with BPD were 27-30 weeks of gestational age. The duration of ventilator dependence was significantly associated with the development of BPD (p < 0.05). No other risk factors for complications during the treatment course could be identified. The mean time between birth and the first surfactant treatment was more than nine hours. In this study, we found low incidence rates of RDS and BPD, and a considerable mortality in surfactant treated newborns. This pilot study shows that surfactant treatment of premature infants is feasible in Curaçao. Earlier administration of surfactant, preferably within 2-3 hours after birth, is expected to lower the risk of death and oxygen dependence.

Bronchopulmonary Dysplasia↗
PubMed2000

Resistance to glucocorticoid-induced apoptosis in PLP peptide-specific T cell clones from patients with progressive MS.

Glucocorticoids (GC) are commonly used to treat inflammatory disorders such as multiple sclerosis (MS) and may exert their immunosuppressive activity by inducing apoptosis in activated lymphocytes. However, unlike relapsing-remitting MS patients, those with progressive disease respond poorly to GC treatment. The data in this communication indicate that PLP peptide-specific T cell clones from progressive, but not relapsing-remitting MS patients are resistant to GC-induced apoptosis in vitro, in a fashion associated with expression of B-7 co-stimulatory molecules. Thus, failure to respond to GC treatment may reflect defect in apoptosis that develop during the progressive stages of chronic inflammatory disease.

Adult↗
PubMed2000

Innate recognition of bacteria in human milk is mediated by a milk-derived highly expressed pattern recognition receptor, soluble CD14.

Little is known about innate immunity to bacteria after birth in the hitherto sterile fetal intestine. Breast-feeding has long been associated with a lower incidence of gastrointestinal infections and inflammatory and allergic diseases. We found in human breast milk a 48-kD polypeptide, which we confirmed by mass spectrometry and sequencing to be a soluble form of the bacterial pattern recognition receptor CD14 (sCD14). Milk sCD14 (m-sCD14) concentrations were up to 20-fold higher than serum sCD14 from nonpregnant, pregnant, or lactating women. In contrast, lipopolysaccharide (LPS)-binding protein was at very low levels. Mammary epithelial cells produced 48-kD sCD14. m-sCD14 mediated activation by LPS and whole bacteria of CD14 negative cells, including intestinal epithelial cells, resulting in release of innate immune response molecules. m-sCD14 was undetectable in the infant formulas and commercial (cows') milk tested, although it was present in bovine colostrum. These findings indicate a sentinel role for sCD14 in human milk during bacterial colonization of the gut, and suggest that m-sCD14 may be involved in modulating local innate and adaptive immune responses, thus controlling homeostasis in the neonatal intestine.

Amino Acid Sequence↗
PubMed2000

Tacrolimus is highly effective in both dual and triple therapy regimens following renal transplantation. Spanish and Italian Tacrolimus Study Group.

This open, multicenter, randomized, parallel-group study evaluated the efficacy and safety of tacrolimus-based dual and triple therapy regimens. For this 3-month study (with 12-month follow up), 491 adult renal transplant patients were randomized and received either dual therapy (tacrolimus/corticosteroids; 246 patients) or triple therapy (tacrolimus/corticosteroids/azathioprine; 245 patients). Patient survival rates at months 3 and 12 were 99.2 (dual) vs 99.6% (triple) and 97.8 vs 98.7%, respectively. Graft survival rates at months 3 and 12 were 94.1 (dual) vs 95.4% (triple) and 92.8 vs 93.3%, respectively. After 3 months, the incidences of treated acute rejection were 28.8 (dual) and 29.7% (triple); and 7.6 (dual) and 5.4% (triple) for corticosteroid-resistant acute rejections. Between months 4 and 12, three new first rejections were reported, (dual: 2, triple: 1). For leukopenia (1.3 vs 11.7%; P < 0.001) and anemia (14.8 vs 23.0%, P = 0.026), significantly higher incidences were reported in the triple therapy group. The incidence of de novo insulin-dependent diabetes was 5.6 (dual) and 4.0% (triple) at month 3. In terms of efficacy, no difference between the treatment groups was observed.

Acute Disease↗
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

Removal of xenoreactive antibodies by protein-A immunoadsorption: experience in 22 patients.

The presence of naturally occurring anti-Galalpha1-3Gal (antialphaGal) Ab in human serum is believed to be a major factor in the pathogenesis of hyperacute rejection of discordant organ xenografts such as the pig-to-human combination. Galalpha1-3Gal epitopes are expressed on pig tissues and the binding of anti-Galalpha1-3Gal leads to endothelial cell activation and complement-mediated hyperacute graft rejection. Several strategies have been suggested in donor animals or in the xenograft recipient to overcome the anti-alphaGal barrier. Protein-A immunoadsorption (PAIA) was developed for the in vivo removal of circulating Ab and it has been shown to be effective in cases where pathogenic auto or alloAb are present. The aim of our study was to analyze the effect of PAIA on total and xenoreactive serum anti-alphaGal immunoglobulin levels in a group of patients treated with this technique for different diseases. After three consecutive sessions of PAIA, total and xenoreactive IgG and IgM immunoglobulin levels were decreased by more than 50% of pre-treatment levels. So we conclude that PAIA is an effective method to significantly reduce circulating Ab, including xenogeneic IgM and IgG Ab. This mode of therapy might be considered as a tool to overcome hyperacute xenograft rejection. PAIA combined with other therapeutic approaches may well protect the xenograft.

Adolescent↗
PubMed2000

Elevated serum concentrations of soluble CD14 in HIV- and HIV+ patients with tuberculosis in Africa: prolonged elevation during anti-tuberculosis treatment.

Data are limited regarding serum concentrations of soluble CD14 (sCD14), a marker of macrophage activation, in patients with active tuberculosis (TB) and during drug treatment. In this study, concentrations of sCD14 were measured in serum samples obtained from 105 African subjects who were categorized into one of four groups: persons with pulmonary TB alone (TB+HIV-, n = 30), pulmonary TB and HIV co-infection (TB+HIV+, n = 20), or HIV infection alone (TB-HIV+, n = 25), and healthy controls (TB-HIV-, n = 30). Mean total sCD14 was significantly increased in serum of patients with newly diagnosed pulmonary TB (mean = 6.6 g/ml, s.d. = 1.6 g/ml) compared with healthy controls (mean = 3.1 g/ml, s.d. = 0.6 g/ml; P < 0.0001), and this elevation comprised proportionate increases in the alpha (2.1-fold greater, P < 0.0001) and beta (2.0-fold greater, P < 0. 0001) forms of sCD14. Total sCD14 was also increased in serum of HIV-infected patients (mean = 4.1 g/ml, s.d. = 1.9 g/ml; P < 0.01), but the highest concentrations were observed in patients with pulmonary TB and HIV co-infection (mean = 8.7 g/ml, s.d. = 3.1 g/ml; P < 0.0001). Analysis of serum samples prospectively collected from TB+HIV-patients during the first 3 months of successful anti-TB treatment demonstrated steep reductions in mean concentrations of the acute-phase protein, C-reactive protein, and the soluble lymphocyte activation marker, sCD25. In contrast, levels of sCD14 increased during the first month of treatment and slowly declined thereafter. These data indicate that the serum concentration of sCD14 is not a sensitive index of response to anti-TB treatment and suggest that cellular activation resolves more slowly in the macrophage pool compared with the lymphocyte pool during anti-TB treatment.

Adult↗
PubMed2000

Hemodiafiltration with online regeneration of the ultrafiltrate.

The concept of regeneration of dialysis fluids and of ultrafiltrate in particular has been recently revisited. Hemodiafiltration with online regeneration of the ultrafiltrate allows the concomitant infusion of sodium, calcium, and bicarbonate. Here, we studied the adsorptive characteristics of an integrated two-step sorbent system relative to different solutes present in the ultrafiltrate: sodium, calcium, phosphate, bicarbonate, uric acid, creatinine, and beta2-microglobulin. In vitro studies were performed in order to differentiate the relative roles for each sorbent (mineral-activated charcoal or hydrophobic resin) in adsorbing a given solute. Ex vivo studies were performed in order to evaluate the presence of cytokines (interleukin-1 beta and tumor necrosis factor-alpha), of cytokine (interleukin-1 beta and tumor necrosis factor-alpha)-inducing activities, and of the cytokine release in response to exogenous bacterial lipopolysaccharide by normal whole blood incubated with ultrafiltrate samples obtained at 15, 120, and 240 minutes after the start of treatment. The results of the present studies show the presence of immunomodulatory substances in the ultrafiltrate and the significant (P < 0.01) increase in the lipopolysaccharide-induced release of both interleukin-1 beta and tumor necrosis factor-alpha. The biological relevance of the ultrafiltrate and the possible relevance of the online, endogenous reinfusion are discussed.

Adsorption↗
PubMed2000

Circulating levels of matrix metalloproteinases MMP-3 and MMP-2 in renal transplant recipients with chronic transplant nephropathy.

BACKGROUND: Chronic transplant nephropathy remains the major cause of graft loss after the first year post transplant, with the exception of death with functioning graft. The histological hallmark of chronic kidney rejection is progressive fibrosis in which extracellular matrix turnover plays an important role. This turnover is regulated by several systems of connective tissue proteases, the matrix metalloproteinases family being one of them. Every metalloproteinase exerts a different function over extracellular matrix proteins and can contribute to the pathogenesis of several diseases, such as rheumatoid arthritis and glomerulonephritis. The role of metalloproteinases in the pathogenesis of chronic transplant nephropathy and in kidney transplantation has not yet been addressed. METHODS: We measured the serum levels of proMMP-1, proMMP-2 and proMMP-3 by ELISA in 40 patients with chronic transplant nephropathy, 30 with acute rejection, 30 with stable graft function for a time equivalent to chronic transplant nephropathy, 30 with stable graft function for a time equivalent to acute rejection, and 30 healthy age-paired blood donors. RESULTS: Serum proMMP-2 and proMMP-3 were significantly higher in patients with chronic transplant nephropathy than in patients with acute rejection, stable graft function and healthy donors. The most striking finding was the significant positive correlation observed between serum levels of proMMP-3 and serum creatinine, and between circulating levels of proMMP-2 and proteinuria. Serum concentration of proMMP-1 was increased in patients with acute rejection compared with those with stable graft function and healthy donors. CONCLUSIONS: Serum proMMP-2 and proMMP-3 reflect the changes of glomerular and interstitial extracellular matrix in chronic transplant nephropathy, suggesting that they could play a role in the pathogenesis of this condition. Acute rejection is associated with increased levels of proMMP-1, which could be a reflection of the stimulation induced by a number of inflammatory cytokines produced in such a process.

Acute Disease↗
PubMed2000

B lymphopenia in uremia is related to an accelerated in vitro apoptosis and dysregulation of Bcl-2.

BACKGROUND: Lymphopenia has been described in patients with chronic renal failure (CRF). It is postulated that the decline in lymphocytes is due to accelerated apoptosis. We investigated whether dysregulation of programmed cell death plays a role in the immunodeficiency described in CRF. METHODS: Peripheral blood lymphocytes (PBL) from pre-dialysis uraemic patients (nHD) and haemodialysed patients (HD) were cultured with no stimulus for 96 h. Apoptosis of lymphocytes was measured by propidium iodide staining and flow cytometry. Expression of Fas and Bcl-2 was also analysed by flow cytometry. RESULTS: Peripheral blood B cells were significantly lower in pre-dialysis and haemodialysis uraemic patients compared to control. Lymphocytes from both groups of patients had a higher rate of apoptosis in vitro than those from healthy controls. This effect was more pronounced in B lymphocytes and a significant correlation between the B lymphopenia and the percentage of apoptotic B cells after 48 h of culture without stimulus was observed. The increased lymphocyte apoptosis in CRF was accompanied by a significantly lower in vitro Bcl-2 expression. However, Fas did not seem to play a role in spontaneous lymphocyte apoptosis in end-stage renal disease. CONCLUSIONS: Our data indicate that B lymphopenia in CRF may be partially attributed to an increased susceptibility to cell death by apoptosis that is associated with a decreased expression of Bcl-2.

Adolescent↗