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Biomedical subjects

G Espinosa

Publications and source records attributed to G Espinosa.

At least 55 records · Page 3Linked to original sources
PubMed2000

Neural network based quantitative structural property relations (QSPRs) for predicting boiling points of aliphatic hydrocarbons

Quantitative structural property relations (QSPRs) for boiling points of aliphatic hydrocarbons were derived using a back-propagation neural network and a modified Fuzzy ARTMAP architecture. With the back-propagation model, the selected molecular descriptors were capable of distinguishing between diastereomers. The QSPRs were obtained from four valance molecular connectivity indices (1chiv,2chiv,3chiv,4chiv), a second-order Kappa shape index (2kappa), dipole moment, and molecular weight. The inclusion of dipole moment proved to be particularly useful for distinguishing between cis and trans isomers. A back-propagation 7-4-1 architecture predicted boiling points for the test, validation, and overall data sets of alkanes with average absolute errors of 0.37% (1.65 K), 0.42% (1.73 K), and 0.37% (1.54 K), respectively. The error for the test and overall data sets decreased to 0.19% (0.81 K) and 0.31% (1.30 K), respectively, using the modified Fuzzy ARTMAP network. A back-propagation alkene model, with a 7-10-1 architecture, yielded predictions with average absolute errors for the test, validation, and overall data sets of 1.96% (6.79 K), 1.83% (6.45 K), and 1.25% (4.42 K), respectively. Fuzzy ARTMAP reduced the errors for the test and overall data sets to 0.19% (0.73 K) and 0.25% (0.95 K), respectively. The back-propagation composite model for aliphatic hydrocarbons, with a 7-9- architecture, yielded boiling points with average absolute errors for the test, validation, and overall set of 1.74% (6.09 K), 1.25% (4.68 K), and 1.37% (4.85 K), respectively. The error for the test and overall data sets using the Fuzzy ARTMAP composite model decreased to 0.84% (1.15 K) and 0.35% (1.35 K), respectively. Performance of the QSPRs, developed from a simple set of molecular descriptors, displayed accuracy well within the range of expected experimental errors and of better accuracy than other regression analysis and neural network-based boiling points QSPRs previously reported in the literature.

Journal Article↗
PubMed2000

Prevalence and clinical significance of antiprothrombin antibodies in patients with systemic lupus erythematosus or with primary antiphospholipid syndrome.

BACKGROUND AND OBJECTIVE: Antibodies to prothrombin (aII) have been identified in patients with antiphospholipid antibodies, but their clinical significance is not well known. The aim of our study was to investigate their prevalence and association with clinical manifestations of the antiphospholipid syndrome (APS) in patients with primary APS or with systemic lupus erythematosus (SLE). DESIGN AND METHODS: A series of 177 patients with autoimmune diseases was studied: 70 with primary APS and 107 with systemic lupus erythematosus. A control group of 87 healthy volunteers were included in the study. aII were investigated in sera by an ELISA, using human prothrombin as antigen fixed in irradiated polystyrene plates. RESULTS: aII prevalence in patients with autoimmune disease was 47% (57% and 40% in patients with primary APS or with SLE, respectively) significantly higher than in controls (5%) (p<0.0001). In the whole series, thrombotic events were more prevalent in patients with aII (45% vs 28%; p=0.02). Moreover, aII was found to be an independent risk factor for arterial thrombosis (OR=2.4; p=0. 04). Similarly, in patients with SLE, aII were associated with both arterial and venous thrombosis (35% vs 14%; p=0.01), although only IgG-aII (OR=3.7; p=0.01) had an independent value as risk factor for thrombosis. However, a relationship between aII and thrombosis was not found in primary APS. aII were associated with thrombocytopenia only in patients with primary APS (OR=6.7; p=0.007). INTERPRETATION AND CONCLUSIONS: aII seem to be a serological marker of thrombosis in autoimmune diseases, mainly in SLE patients and/or in the arterial territory.

Abortion, Spontaneous↗
PubMed1999

Clinical study and follow-up of 100 patients with the antiphospholipid syndrome.

OBJECTIVES: To study the clinical characteristics at diagnosis and during follow-up of patients with the antiphospholipid syndrome (APS) and to analyze the influence of treatment on their outcome. PATIENTS: One hundred patients with APS were included (86% female and 14% male; mean age, 36 years). Sixty-two percent had primary APS and 38% had APS associated with systemic lupus erythematosus (SLE). The median length of follow-up was 49 months. RESULTS: Fifty-three percent of the patients had thromboses, 52% had thrombocytopenia, and 60% of the women had pregnancy losses. Patients with APS associated with SLE had a higher prevalence of hemolytic anemia (P = .02), thrombocytopenia (platelet count lower than 100 x 10(9)/L) (P = .004), antinuclear antibodies (P = .0002), and low complement levels. Fifty-three percent of the patients with thrombosis had recurrent episodes (86% in the same site as the previous thrombotic event). Recurrences were observed in 19% of the episodes treated with long-term oral anticoagulation, in 42% treated prophylactically with aspirin, and in 91% in which anticoagulant/antiaggregant treatment was discontinued (P = .0007). Multivariate analysis showed that prophylactic treatment and older age had an independent predictive value for rethrombosis. Prophylactic treatment during pregnancy (usually with aspirin) increased the live birth rate from 38% to 72% (P = .0002). CONCLUSIONS: Patients with APS have a high risk of recurrent thromboses. Long-term oral anticoagulation seems to be the best prophylactic treatment to prevent recurrences. Prophylactic treatment with aspirin during pregnancy reduced the rate of miscarriages remarkably.

Adolescent↗
PubMed1999

Identification of a natural soluble form of human CD5.

CD5 is a 67 kDa type I glycoprotein which belongs to the Scavenger Receptor Cysteine-Rich (SRCR) family of receptors. This family includes either cell-surface (e.g. CD6) or secreted (e.g. Spalpha) proteins implicated in the development of the immune system and the regulation of immune responses. In this study, we purified and characterised a circulating natural soluble CD5 form (nsCD5) which is indistinguishable (in apparent molecular mass, glycosylation pattern, and antibody reactivity) from a recombinant soluble CD5 form (rsCD5) composed of the three extracellular SCRC domains. The nsCD5 is a N-glycosylated 52 kDa molecule present in normal human serum and in supernatants of in vitro phorbol ester- and CD3-stimulated peripheral blood mononuclear cells. The nsCD5 concentration in sera from healthy donors is relatively low (median 1.75 ng/ml, rn=166) and is similar to that found in sera from patients suffering of various autoimmune (systemic lupus erythematosus, primary Sjogren syndrome, rheumatoid arthritis) and non-autoimmune (chronic renal failure, B-cell chronic lymphocytic leukemia) disorders. In vitro experiments indicate that nsCD5 is released by proteolytic cleavage of the membrane form. These results represent the first evidence of proteolytic release of a transmembrane SRCR family member following cell activation.

Animals↗
PubMed1998

Systemic lupus erythematosus (SLE) in childhood: analysis of clinical and immunological findings in 34 patients and comparison with SLE characteristics in adults.

OBJECTIVE: To define the pattern of disease expression in patients with childhood onset systemic lupus erythematosus (SLE). METHODS: Prospective analysis of clinical manifestations and immunological features of 34 patients in whom the first manifestations appeared in childhood from a series of 430 unselected patients with SLE. RESULTS: Thirty one (91%) patients from the childhood onset group were female and three male (9%) (ratio female/male, 10/1, with no difference compared with the adult onset group). Mean age of this group at disease onset was 11 years (range 5-14) compared with 32 years (15-48) for the remaining patients. The childhood onset patients more often had nephropathy (20% v 9% in adult onset SLE, p = 0.04; OR:2.7; 95% CI:1.1, 7), fever (41% v 21%, p = 0.006; OR:2.6, 95% CI:1.2, 5.7), and lymphadenopathy (6% v 0.5%, p = 0.03, OR: 12.3, 95% CI: 1.2, 127.6), as presenting clinical manifestations. During the evolution of the disease, the childhood onset patients had an increased prevalence of malar rash (79% v 51%, p = 0.002; OR:3.7; 95% CI:1.5, 9.5) and chorea (9% v 0%, p < 0.0001). This group exhibited a higher prevalence of anticardiolipin antibodies (aCL) of the IgG isotype when compared with the remaining patients (29% v 13%, p = 0.017; OR:2.9, 95% CI:1.2, 6.8). No significant differences were found among the other antibodies between the two groups. Childhood onset patients more often received azathioprine (15% v 6%, p = 0.00004; OR:11.2; 95% CI:2.8, 44.9) but no differences were detected between the groups concerning side effects or drug toxicity. CONCLUSIONS: The presentation and the clinical course of SLE varied in this series of 430 patients depending on their age at disease onset. Nephropathy, fever, and lymphadenopathy were more common in childhood onset patients as presenting clinical manifestations, while malar rash, chorea, and detection of IgG aCL were more common during the evolution of the disease.

Adolescent↗
PubMed1998

Young onset of primary Sjögren's syndrome: clinical and immunological characteristics.

The objective of our study was to determine the clinical and immunological characteristics of primary Sjögren's syndrome (SS) in patients with a young onset of the disease. We included 144 consecutive patients (134 female and 10 male; mean age at onset 53 y; range 20-87 y) visited in our Units. All patients were white and fulfilled four or more of the diagnostic criteria for SS, proposed by the European Community Study Group in 1993. Disease onset was determined on the basis of the appearance of symptoms strongly suggestive of SS. In 13 (9%) patients, disease onset occurred before the age of 35. All were female and the disease onset occurred between 20-34 y (mean, 28 y). When compared with patients with older onset, patients with a young onset of the primary SS presented a higher prevalence of lymphadenopathy (54% vs 6%, P < 0.001), rheumatoid factor (70% vs 39%, P=0.034), anti-Ro/SS-A antibodies (70% vs 28%, P=0.004) and monoclonal immunoglobulins (23% vs 4%, P=0.02) in their sera. From the initial diagnosis of SS, three patients with a young-onset of the primary SS have developed lymphoproliferative disease at the time of the study, compared with one patient of the older-onset group (23% vs 1%, P=0.002). Our study shows several differences between younger and older onset patients, including a higher incidence of lymphomas in the younger, thus conferring to the age at onset of the disease a prognostic value.

Adult↗
PubMed1997

[Primary Sjögren's syndrome: clinical and immunologic study of 80 patients].

BACKGROUND: To determine the clinical and immunologic characteristics of a large cohort of patients with primary Sjörgen's syndrome (SS) and to asses if the sex, the age at onset, the time of evolution and the immunologic pattern define different subsets with specific characteristics. PATIENTS AND METHODS: We included 80 patients (76 female and 4 male) that were prospectively studied at our Unit. All patients fulfilled the European Community criteria proposed in 1993 for the diagnosis of SS. RESULTS: Mean age of patients was 62 years with a mean disease duration of 8 years. The most frequently observed clinical manifestations were xerostomia (96%), xerophthalmia (94%) and parotidomegaly (46%). The main extraglandular manifestations were arthritis (45%), Raynaud's phenomenon (20%) and liver involvement (19%). The immunologic study showed antinuclear antibodies in 82% of patients, rheumatoid factor in 45%, anti-Ro/SS-A in 40% and anti-La/SS-B in 20%. In patients with an onset of disease before the age of 40 years, a higher prevalence of parotidomegaly, peripheral neuropathy, cutaneous vasculitis, rheumatoid factor, anti-Ro/SS-A and anti-La/SS-B antibodies was observed. A disease duration longer than 10 years was associated with a higher prevalence of pulmonary involvement and more focus of mononuclear cells in the minor salivary glands. Clinical manifestations associated to any one or more immunologic marker (rheumatoid factor, anti-Ro/SS-A and/or anti-La/SS-B) were Raynaud's phenomenon, arthritis, thyroid disease, cutaneous vasculitis and peripheral neuropathy. CONCLUSIONS: Primary SS is an autoimmune disease characterized by a marked heterogeneity in the clinical presentation and evolution, thus allowing the definition of several subsets of patients with their own clinical and immunological characteristics.

Adult↗
PubMed1997

Optic neuropathy in the "primary" antiphospholipid syndrome: report of a case and review of the literature.

Several visual disturbances have been associated with the presence of antiphospholipid antibodies, including vaso-occlusive retinopathy and ischaemic optic neuropathy. The latter has been rarely described in patients with "primary" antiphospholipid syndrome, and, when present, is generally associated with neurological disorders. We describe the case of a patient presenting with optic neuropathy in whom a "primary" antiphospholipid syndrome was diagnosed, and review all previously reported similar cases. The pathogenesis and treatment are also discussed.

Anticoagulants↗
PubMed1997

Hepatitis C virus infection in 'primary' Sjögren's syndrome: prevalence and clinical significance in a series of 90 patients.

OBJECTIVES: To determine the prevalence and clinical significance of hepatitis C virus (HCV) infection in a large cohort of patients with "primary' Sjögren's syndrome (SS). METHODS: 90 consecutive patients (83 female and seven male) were included, with a mean age of 62 years (range 31-80) who prospectively visited our unit. All patients fulfilled the European Community criteria for SS and underwent a complete history, physical examination, as well as biochemical and immunological evaluation for liver disease. Serum from all patients was tested for antibodies to HCV by third generation enzyme linked immunoassay and positivity was confirmed by polymerase chain reaction. RESULTS: Antibodies to HCV were present in 13 (14%) patients with 'primary' SS. When compared with patients without HCV infection, patients with HCV infection presented a higher prevalence of hepatic involvement, (100% v 8%, p < 0.05). Transcutaneous liver biopsy was performed in five patients with HCV infection, and specimens obtained showed in all cases a chronic active hepatitis with varying degrees of portal inflammation. CONCLUSION: HCV infection is frequent in patients with "primary' SS and liver involvement is presented in all these patients. The possible pathogenic role of HCV infection in these patients is still unclear.

Adult↗
PubMed1997

[Severe Plasmodium falciparum malaria. Description of 5 cases].

In the last few years a considerable number of imported malaria has been reported in Spain, probably due the increased tourism to areas with endemic malaria, particularly with P. falciparum. This is the species more frequently associated with severe complications and the only one capable of causing cerebral malaria. In this report we review five cases of malaria which required intensive care because of their severity. None of the patients had received chemoprophylaxis. In all cases the admission criterion to the intensive care unit was the organic failure of one or more systems (renal failure and disseminated intravascular coagulation [DIC] mainly) or the presence of changes in the central nervous system. Parasitemia at admission was higher than 5% in all patients. One patient died on account of cerebral malaria. Only one patient had severe complications not directly associated with malaria. In patients who already have severity criteria, a negative parasitemia test during the clinical course does not necessarily implies a clinical improvement nor does it exclude the emergence of complications. On the other hand, a low parasitemic degree is never a contraindication for admission to the intensive care unit when severity criteria are present.

Adult↗
PubMed1996

[Obstructive apnea syndrome during sleep secondary to a pharyngeal lymphoma. Improvement with continuous pressure treatment of the upper airway].

Obstructive sleep apnea syndrome (OSAS) is characterized by multiple episodes of upper airway (UA) obstruction during sleep. Patients experience daytime hypersomnia, sluggishness and inability to concentrate; snoring at night is common. We report the case of a man with Hodgkin's lymphoma without full remission and with pharyngeal recidivism leading to OSAS. He experienced marked diurnal hypersomnia accompanied by behavior disorders. Examination revealed flow-volume OSAS, suggesting UA instability. Cervical computed tomography showed a prevertebral lymphomatous mass in the pharynx causing significant UA compression. UA size increased considerably after use of continuous positive airway pressure (CPAP), which normalized sleep and produced significant relief of symptoms. Later, after chemotherapy, OSAS resolved and the patient was able to abandon CPAP treatment.

Hodgkin Disease↗
PubMed1996

Role of endothelin in the pathophysiology of renal ischemia-reperfusion in normal rabbits.

The present study addressed the acute effects of endothelin-1 on renal function and neutrophils accumulation in the setting of in vivo severe (60 min) acute ischemia/reperfusion. Ischemia/reperfusion decreased renal functional parameters and increased renal neutrophil accumulation and medullary congestion. All these parameters markedly improved with the intrarenal administration of anti-endothelin-1 antiserum. Comparatively, the intrarenal infusion of endothelin-1 decreased renal function and increased neutrophil accumulation. Abnormalities in renal histology were, however, less pronounced than with ischemia/ reperfusion. In experiments using rabbit isolated perfused kidneys, endothelin-1 induced the accumulation of labeled neutrophils. This accumulation was similar to that observed in kidneys obtained after 60 minutes of ischemia plus 60 minutes of reperfusion. Both endothelin and ischemia/ reperfusion effects were counteracted by an anti-endothelin antibody. In further in vitro studies, we found that endothelin-1-induced the expression of the CD18 antigens on the neutrophil surface. In subsequent experiments based on this effect of ET-1 on CD18 antigens, a blockade of both ischemia/reperfusion-induced and endothelin-1-induced neutrophil accumulation was obtained by infusion an anti-CD18 antibody. In conclusion, our experiments disclosed the critical role of endothelin-1 as a major promoter of early neutrophil accumulation after ischemia/reperfusion, which occurred through an integrin-mediated mechanism.

Animals↗
PubMed1996

Role of endothelium-related mechanisms in the pathophysiology of renal ischemia/reperfusion in normal rabbits.

The present study addressed the effect of interventions aimed to increase NO in the setting of acute renal ischemia/reperfusion (I/R) in uninephrectomized rabbits. In the 60-minute post-I/R period, L-arginine+superoxide (O2.-) dismutase (SOD) synergistically improved the renal functional (69.4% versus 10.4% of the pre-I/R glomerular filtration rate with or without L-arginine+SOD, respectively; p < .01) and histological parameters (82.9% decrease of medullary congestion in L-arginine+SOD, P < .01 versus vehicle) and blocked the I/R-dependent neutrophil accumulation (89.3% reduction). In spite of these results over the short term, a second set of experiments disclosed that the protection by L-arginine+SOD was no longer present at 24 and 48 hours (plasma creatinine in vehicle-treated versus L-arginine+SOD-treated animals [mg/100 mL]: 24 hours after I/R, 9.4 +/- 1.9 versus 8.07 +/- 0.65; 48 hours after I/R, 11.6 +/- 3.6 versus 9.7 +/- 0.9; P = NS in all the cases). Additional experiments were conducted using a milder 30-minute ischemic model, which showed no significant functional or histological protection by using L-arginine+SOD. In conclusion, our experiments disclosed the following: (1) the critical importance of the interaction between NO and O2.- in the acute protective effect of L-arginine (this effect not only improved renal function and histology but also reduced neutrophil accumulation) and (2) the discordance existing between the immediate protection afforded by L-arginine+SOD and the lack of protection observed at 24 and 48 hours. This finding suggests that a punctual intervention on the NO system at the time of I/R is not sufficient to reduce renal damage over the long term.

Animals↗
PubMed1996

[Aggressive behavior of the male volcano mouse Neotomodon alstoni (Rodentia: Cricetidae)].

A study was carried out on the agonistic behavior of the male volcano mouse, Neotomodon alstoni, with 50 pairs of males which were classified as possible dominants (D) and subordinates (S), utilizing Melzack-Thompson's Method. The aggressiveness levels exhibited by this mouse were recording in the combinations: D vs. D and S vs. S. Two groups were formed: Group I with 12 pairs of D males and 13 of S males, and Group II with 11 pairs of D males and 14 of S males. In Group I the aggressiveness level was quantified after one week of mating and after another week of isolation, and in Group II the sequence of observation was inverted. The aggressiveness level was measured by the number of attacks per hour, an attack being defined as the aggressive physical contac of an animal (aggressor) with another (attacked). The kinds of behavior registered, including offense, defense, and submission patterns, revealed hierarchic relationships. Dominance was correlated significatively (p < 0.05) with a higher level of aggressiveness.

Agonistic Behavior↗
PubMed1995

The effect of systemic lupus erythematosus and long-term steroid therapy on bone mass in pre-menopausal women.

The aim of our study was to assess bone mineral density (BMD) in pre-menopausal women with systemic lupus erythematosus (SLE) and the influence of disease activity and use of corticosteroids. Lumbar and femoral BMD were measured in 43 patients with SLE (28 on regular steroid therapy, 15 with recent onset, non-treated) and compared with 43 healthy women matched for age. In addition, 21 SLE patients treated with corticosteroids were followed-up with a mean of 36.6 +/- 12.7 months. BMD was significantly lower in SLE patients with prednisone doses > or = 7.5 mg/day than those of recent onset (lumbar: 1.07 +/- 0.11 vs 1.15 +/- 0.13, P = 0.039; femur: 0.85 +/- 0.13 vs 0.98 +/- 0.21, P = 0.034) and the control group (lumbar: 1.07 +/- 0.11 vs 1.13 +/- 0.10, P = 0.040; femur: 0.85 +/- 0.13 vs 0.93 +/- 0.10, P = 0.028). In addition, 18% of SLE steroid users had osteoporosis. Lumbar and femoral BMD were inversely correlated with the time of treatment and the cumulative doses of prednisone. There were no significant BMD changes during the 3-yr follow-up period. In conclusion, in SLE pre-menopausal patients lumbar and femoral BMD is decreased and related to long-term corticosteroid therapy.

Adult↗