Concrete enclosure for shielding a neutron source.

In the aim to design a shielding for a 0.185 TBq (239)PuBe isotopic neutron source several Monte Carlo calculations were carried out using MCNP5 code. First, a point-like source was modeled in vacuum and the neutron spectrum and ambient dose equivalent were calculated at several distances ranging from 5 cm up to 150 cm, these calculations were repeated modeling a real source, including air, and a 1×1×1 m(3) enclosure with 5, 15, 20, 25, 30, 50 and 80 cm-thick Portland type concrete walls. At all the points located inside the enclosure neutron spectra from 10(-8) up to 0.5 MeV were the same regardless the distance from the source showing the room-return effect in the enclosure, for energies larger than 0.5 MeV neutron spectra are diminished as the distance increases. Outside the enclosure it was noticed that neutron spectra becomes "softer" as the concrete thickness increases due to reduction of mean neutron energy. With the ambient dose values the attenuation curve in terms of concrete thickness was calculated.

Opsonization by anti-dsDNA antibodies of apoptotic cells in systemic lupus erythematosus.

In order to asses the role of the soluble mediators of serum from patients with SLE in the apoptotic cell clearance, we measured the in vitro phagocytosis of apoptotic Jurkat cells by normal healthy donor macrophages in the presence of SLE patients' sera. A significant increase of the phagocytic index (NHD = 1.0 +/- 0.3; SLE = 1.9 +/- 0.6; p < 0.01) was to be observed in the presence of serum from patients with SLE. The increased phagocytic index correlated to the anti-dsDNA antibodies titers. We conclude that anti-dsDNA antibodies present in sera of patients with SLE favor the apoptotic cell phagocytosis by opsonization of the target cells. This may represent a deviation of the clearance process towards inflammation and a new pathologic feature of these autoantibodies in SLE.

Further description of early clinically silent lupus nephritis.

Thirty silent lupus nephritis (SLN) patients were compared to 16 individuals bearing overt lupus nephritis (OLN). Results included: years of systemic lupus erythematosus (SLE) diagnosis were significantly earlier (4.6 +/- 2.8 years) in SLN than in OLN (7.18 +/- 3.61) (P < 0.05). Neurological compromise, hypertension, normocitic anemia and lymphopenia were significantly prevalent in OLN than in SLN (P < 0.05). Beside normal urinary sediment and renal function tests, the SLN group showed a moderate increase of both activity (AI) and chronicity (CI) renal pathology index when compared to highly increased AI and CI in OLN (P < 0.05). Seventy percent of SLN patients were ISN/RPS Classes I (6.6%) and II (63.3%) while 81% of OLN cases were Classes III, IV (37.5%) and V. IgG, IgA, IgM, lambda chain, C3 and fibrinogen immune deposits were found in 90% or over in both SLN and OLN individuals while in 60% or over, both groups also showed kappa chain, Clq and C4 deposits. While prevalence of ANA, anti-dsDNA and anti-C1q antibodies were similar in both groups, anti-histone, anti-RNP, CIC and CH50 serum levels were significantly different in OLN versus SLN (P < 0.05). We strongly suggest that indeed SLN is the earliest stage in the natural history of lupus nephritis.

[The clinical laboratory in the diagnosis of autoimmune liver diseases]. / El laboratorio clínico en el diagnóstico de las enfermedades hepáticas autoinmunes.

The mechanism of production of autoimmune diseases is a loss of tolerance to autoantigens, which in turn produces a destruction of target organs. We review two autoimmune liver diseases which are non-organ specific: autoimmune chronic active hepatitis and primary biliary cirrhosis. The former is classified in three types according to its' profile of autoantibodies: type 1, in which anti smooth muscle and antinuclear autoantibodies are found in high titers; type 2, is characterized by the presence in serum of anti liver/kidney and anti cytosolic 1 autoantibodies; in type 3 anti soluble liver antigen antibody is present, results in this last type of autoimmune hepatitis await confirmation. In primary biliary cirrhosis the most important advance in the serologic diagnosis has been in the classification of anti mitochondrial antibodies. Up to now 9 different types of these antibodies are known, 4 of which are found in this disease: anti M2, anti M4, anti M8 and anti M9. Anti M2 and/or anti M9 are associated with a benign course of the disease, whereas anti M2, anti M8 and anti M8 are associated with a progressive course.

Early detection of complications in amebic liver abscess.

A retrospective analysis of 140 cases with amebic liver abscess (ALA) seen at the AUNL University Hospital was done to see if patients with complications can be identified earlier in order to decrease morbidity and mortality. Sixteen patients (11.4%) presented complications and six patients died (4.2%). Patients with complications presented jaundice, large or multiple abscesses, acute abdomen, liver failure and sepsis more often than patients without complications. Hemoglobin, hematocrit, prothrombin time, total proteins, albumin, LDH, and BUN were more altered in patients who presented complications. The titer of antibodies against E. histolytica was higher in this group of patients. The six patients who died had been operated on. The causes of death were septic shock in two, sepsis in one, peritonitis in one, liver failure in one and colon perforation in one patient. Pleural effusion, jaundice and acute abdomen were seen in three patients, respectively (50%), two cases had multiple abscesses (33.3%), one patient had a ruptured abscess (16.7%). Patients who died exhibited more alterations in six laboratory examinations at admission: partial prothrombin time, total bilirubin, albumin, BUN, LDH, and leukocytes. Clinical data together with the severe alterations in laboratory examinations at admission for patients with ALA should alert the clinician to suspect complications earlier in order to decrease morbidity and mortality.

Complement activation in patients with amebic liver abscess.

Serum or plasma concentrations of components of the classical (C1q, C4) and alternative (C3, factor B) pathways, regulatory protein factor H, and one of the C3 products of degradation, C3d, were determined in 19 patients with amebic liver abscess (ALA). Patients were divided into two groups. Thirteen patients that recovered under medical treatment who had a significantly shorter clinical course on admission (P less than 0.05) (group 1) exhibited either normal (C1q; C4; factor B; C3d) or increased levels of these components (C3, P less than 0.001; factor B, P less than 0.01). On the other hand, 16 patients that recovered after medical treatment and abscess drainage (group 2) exhibited significantly diminished serum levels of C1q (P less than 0.05), C3 (P less than 0.001), factor B (P less than 0.01) and factor H (P less than 0.05), and normal levels of C4, and C3d as compared to the control group. The relationships among the complement components studied were suggestive of activation of the complement system through the classical pathway in patients within group 1 and through both pathways in group 2. Sera of 3 out of the 5 patients who initially exhibited low plasma levels of C3d showed an increase during convalescence. Plasma levels of C3d were demonstrated to show a direct correlation with serum albumin and SGOT in this group of patients. Possible implications of the complement system in the immunopathogenesis of ALA are discussed.