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Biomedical subjects

R Laguna

Publications and source records attributed to R Laguna.

At least 19 recordsLinked to original sources
PubMed2004

Evaluation by the skin prick test of Anisakis simplex antigen purified by affinity chromatography in patients clinically diagnosed with Anisakis sensitization.

Anisakis simplex crude extracts (CE) (IPI, ASAC and ALK-ABELLO), A. simplex larval antigens purified using a column of IgG anti-A. simplex (PAK) or a column of IgG anti-Ascaris suum (PAS), antigen eluted from columns of IgG anti-A. suum (EAS) and an A. suum adult CE were assayed by the skin prick test. Thirty percent of assayed patients showed a negative reaction in the Anisakis skin prick test. Of 70% positives, two patients had a weal greater than that produced by histamine with the A. simplex extract from ABELLO and IPI. The A. suum skin prick test was positive in 35% of patients, with a lower reaction than that observed with the A. simplex extract from IPI in 57% of the sera and a higher reaction in 28% of the sera. All patients with positive reactions with the crude extract also showed positive weals with the two purified antigens, PAK and PAS. All patients, except three, with a reaction to A. suum antigen, were positive to the EAS antigen. In five patients the weal size produced by PAS was greater than that observed with PAK, whereas in another six patients the contrary was observed. Only one of these six patients did not react to EAS antigen, coincident with the patient showing only a slight increase (7%) in the weal size induced by PAK vs. PAS. When the EAS antigen was tested on patients positive to both PAK and PAS, six patients presented a weal size of >30% and only three patients who were positive to PAS did not react to the EAS antigen. These three patients were also negative against the A. suum CE. Purification by affinity chromatography eliminates from the PAS antigen the proteins responsible for producing cross-reactions with Ascaris (present in the EAS antigen).

Adolescent↗
PubMed2003

Cross-reactivity between Anisakis simplex sensitization and visceral larva migrans by Toxocara canis.

The aim of this work was to study cross-reactivity in the diagnosis of two related ascaridosis. Nineteen patients diagnosed with recidivous acute urticaria (RAU) caused by Anisakis simplex and 26 patients diagnosed with visceral larva migrans (VLM) caused by Toxocara canis were studied employing commercial diagnostic kits and "in house" assay kits. Cross-reactivity observed was greater when using "in house" assay kits, suggesting that T. canis excretory-secretory antigens were not only recognized by antibodies from patients with RAU but with greater intensity compared to the A. simplex excretory-secretory antigens.

Animals↗
PubMed2001

Polymer characterization by size-exclusion chromatography with multiple detection.

Size-exclusion chromatography with coupled multiangle light scattering and differential refractometry detectors has been used to obtain molecular mass and radius of gyration distributions of polydisperse polymer samples. From these data the scaling law between dimensions and the absolute molecular mass is obtained with just one sample of each polymer. Three different kinds of polymers are presented: polystyrene which serves as reference polymer, polyphosphazenes which behave abnormally in solution and poly(ethylene oxide) which is soluble in water. Since the relationship between dimensions and molecular mass depends on the extent of interactions between chain segments and solvent molecules, the scaling law provides information about the solution properties of the polymer.

Chromatography, Gel↗
PubMed2001

Purification of Anisakis simplex antigen by affinity chromatography.

In order to improve the specificity and sensitivity of the techniques for the diagnosis of human anisakidosis, a method of affinity chromatography for the purification of species-specific antigens from Anisakis simplex third-stage larvae (L3) has been developed. New Zealand rabbits were immunized with A. simplex or Ascaris suum antigens or inoculated with Toxocara canis embryonated eggs. The IgG-specific antibodies were isolated by means of protein A-Sepharose CL-4B bead columns. IgG anti-Anisakis simplex, anti-Ascaris suum and anti-T. canis were coupled to CNBr-activated Sepharose 4B. For the purification of the larval Anisakis simplex antigens, it was loaded into the anti-A. simplex column and bound antigens were eluted. For the elimination of the epitopes responsible for the cross-reactions, the A. simplex-specific proteins were loaded into the anti-Ascaris suum and anti- T. canis columns. To prove the specificity of the isolated proteins, immunochemical analyses by polyacrylamide gel electrophoresis and immunoblotting were carried out. Likewise, immunoaffinity columns were prepared using specific IgG from patients with Anisakis simplex sensitization, previously diagnosed by fluoro-enzymo-immunoassay. The protein patterns of antigen after purification by the human columns were similar to those obtained using the rabbit columns.

Animals↗
PubMed2001

Induction of phase variation events in the life cycle of the marine coccolithophorid Emiliania huxleyi.

Emiliania huxleyi is a unicellular marine alga that is considered to be the world's major producer of calcite. The life cycle of this alga is complex and is distinguished by its ability to synthesize exquisitely sculptured calcium carbonate cell coverings known as coccoliths. These structures have been targeted by materials scientists for applications relating to the chemistry of biomedical materials, robust membranes for high-temperature separation technology, lightweight ceramics, and semiconductor design. To date, however, the molecular and biochemical events controlling coccolith production have not been determined. In addition, little is known about the life cycle of E. huxleyi and the environmental and physiological signals triggering phase switching between the diploid and haploid life cycle stages. We have developed laboratory methods for inducing phase variation between the haploid (S-cell) and diploid (C-cell) life cycle stages of E. huxleyi. Plating E. huxleyi C cells on solid media was shown to induce phase switching from the C-cell to the S-cell life cycle stage, the latter of which has been maintained for over 2 years under these conditions. Pure cultures of S cells were obtained for the first time. Laboratory conditions for inducing phase switching from the haploid stage to the diploid stage were also established. Regeneration of the C-cell stage from pure cultures of S cells followed a predictable pattern involving formation of large aggregations of S cells and the subsequent production of cultures consisting predominantly of diploid C cells. These results demonstrate the ability to manipulate the life cycle of E. huxleyi under controlled laboratory conditions, providing us with powerful tools for the development of genetic techniques for analysis of coccolithogenesis and for investigating the complex life cycle of this important marine alga.

Culture Media↗
PubMed2000

Specific and total IgE in patients with recurrent, acute urticaria caused by Anisakis simplex.

Titres of parasite-specific IgE were investigated in 19 patients thought to have recurrent, acute urticaria caused by sensitization to Anisakis simplex (Dujardin, 1845), before and after they were placed on a fish-free diet. Patients with other allergic disease and those being treated with corticosteroids or antihistaminics were excluded. Skin-prick tests were carried out with A. simplex extract, and blue- and white-fish extracts. The CAP system (Pharmacia), a commercial test kit developed for the assay of food-specific IgE, was used to monitor serum concentrations of total IgE and antigen-specific IgE against Anisakis, Ascaris, Echinococcus, Toxocara, tuna, salmon, shrimp, mussel and cod. Before going on a fish-free diet, the 19 patients had CAP scores against A. simplex of 5 (three cases), 3 (seven) or 2 (nine). After a mean of 120 days on the diet, the scores against A. simplex were unchanged in 15 of the cases, reduced in three [from 5 to 4 (one case) or from 2 to 0 (two cases)] and increased in one (from 2 to 3). Most (16) of the patients no longer had any urticaria and the others reported significant reductions in the intensity and frequency of their symptoms.

Acute Disease↗
PubMed2000

Vertebral hemangioma mimicking a metastatic bone lesion in well-differentiated thyroid carcinoma.

The authors report a case of abnormal accumulation of I-131 in a thoracic vertebra in a patient with a well-differentiated thyroid carcinoma. The presumptive diagnosis was metastatic bone disease. Further diagnostic work-up confirmed a benign bone lesion. Bone metastasis, when shown on I-131 whole-body scintigraphy, usually supports a change in the staging and therapeutic approach to a patient with thyroid carcinoma. The authors believe that, although an infrequent lesion, the differential diagnosis of abnormal accumulation of I-131 in the body of a vertebra in patients with well-differentiated thyroid carcinoma should raise the possibility of a benign hemangioma. Complete work-up of the suggested bone metastatic lesion should be performed before tumor restaging and I-131 therapy is recommended.

Carcinoma, Papillary↗
PubMed1999

AM1 theoretical study, synthesis and biological evaluation of some benzofuran analogues of anti-inflammatory arylalkanoic acids.

Using the semi-empirical quantum-mechanical method AM1, the molecular geometries of the arylalkanoic acids, indomethacin, naproxen and ibuprofen, were optimized and their frontier orbital charge distributions evaluated. Then, these molecular parameters were compared in order to identify structure-activity relationships and, on the basis of these, four benzofuran-3-acetic acids were designed as potential non-steroidal anti-inflammatory agents, and rapidly synthesized by a novel and easily generalized route. Notwithstanding the structural similarities between the synthesized compounds and the anti-inflammatory arylalkanoic acids, these compounds did not appreciably inhibit human platelet cyclooxygenase in vitro.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1999

Pyridazines. XVIII. 6-Aryl-3(2H)-pyridazinones inhibit calcium influx in stimulated platelets.

6-Phenyl-5-hydroxymethyl-4,5-dihydro-3(2H)-pyridazinone (1) and 6-thienyl-5-hydroxymethyl-4,5-dihydro-3(2H)-pyridazinone (2) inhibit platelet aggregation induced by thrombin (IC50 = 0.25 and 0.26 mM, respectively) or by the calcium ionophore ionomycin (IC50 = 0.42 and 0.43 mM, respectively). Pyridazinones 1 and 2 also show concentration-dependent attenuation of the increases in platelet cytosolic free calcium concentration induced by thrombin and ionomycin, suggesting that their antiaggregatory activity may be due to their capacity to inhibit the passage of calcium through the cytoplasmic membrane. This effect may be implicated in other pharmacological activities of 6-aryl-5-substituted-pyridazinones.

Blood Platelets↗
PubMed1998

Thrombomodulin modulates the mitogenic response to thrombin of human umbilical vein endothelial cells.

Thrombin interacts with its receptor and thrombomodulin on endothelial cells. We evaluated the respective roles of these two proteins on human umbilical vein endothelial cell (HUVEC) growth by comparing thrombin, S195A (a mutant thrombin in which the serine of the charge stabilizing system had been replaced by alanine), and the receptor activating peptide (TRAP). Thrombin and TRAP induced DNA synthesis (half maximal cell proliferation with 5 nM and 25 microM, respectively), whereas S195A thrombin was inactive, inferring that growth is mediated through the thrombin receptor. Surprisingly, cells stimulated by TRAP exhibited a maximal proliferation twice greater than that obtained with thrombin. Combination of thrombin and TRAP resulted in a mitogenic response higher than by thrombin alone, but lower than by TRAP alone. The role of thrombomodulin was evaluated by adding an anti-thrombomodulin antibody, which prevents formation of the thrombin-thrombomodulin complex. Antibody did not interfere with cell proliferation induced by TRAP, but enhanced that induced by thrombin. We conclude that formation of the thrombin-thrombomodulin complex restrains HUVEC proliferation mediated through the thrombin receptor.

Antibodies, Monoclonal↗
PubMed1998

Technetium-99m-MAG3 in early identification of pyelonephritis in children.

UNLABELLED: The purpose of this study was to determine whether 99mTc-mercaptotriacetylglycine (MAG3) can substitute for 99mTc-glucoheptonate (GH) in the detection of pyelonephritis. METHODS: One hundred thirty renal scintigraphies were evaluated retrospectively in 38 children (21% boys, 79% girls; age range 1 mo-21 yr; mean age 7.2 yr) referred for evaluation during an acute clinical urinary tract infection and for follow-up studies. Twelve topographical regions were designated on each kidney. Each area was graded for severity of decreased radionuclide localization: mild (Grade 1), moderate (Grade 2) or marked (Grade 3). Early posterior views of MAG3 studies were compared to delayed posterior GH images. In all patients, both studies were performed on the same day. RESULTS: Eighty-two studies were performed during an acute clinical infection and 48 were performed as follow-up. Seventy-seven percent of the studies had focal cortical lesions. Of all the cortical lesions identified by GH, MAG3 detected 74% (match lesions). A comparable percentage of lesions was identified in each region by both studies. GH scintigraphy detected 261 lesions (63 Grade 1, 149 Grade 2 and 49 Grade 3), and MAG3 detected 201 lesions (37 Grade 1, 117 Grade 2 and 47 Grade 3). MAG3 was unable to recognize 60 lesions identified by GH studies in 11 patients (mismatch lesions). Of these, 41% (26 of 63) were Grade 1, 21% (32 of 149) were Grade 2 and 4% (2 of 49) were Grade 3. In three cases, MAG3 identified lesions not seen by GH (reverse mismatch); all had acute symptomatic infection. CONCLUSION: These data document that MAG3 in the early phase of the study (1-2 min) can detect Grade 2 to Grade 3 cortical lesions in patients with pyelonephritis, but it is less effective in detecting Grade 1 lesions.

Child↗
PubMed1997

Recidivous acute urticaria caused by Anisakis simplex.

This study aimed to determine the cause of acute recidivous urticaria in patients who usually eat fish or other seafood. Twenty-five patients were studied. The skin prick test with larval Anisakis simplex extract was performed; total and specific IgE against A. simplex was measured with the CAP System; specific antibodies to A. simplex were determined by ELISA; and immunorecognition patterns of the sera were studied by Western blot. Nineteen patients showed specific IgE to A. simplex, but specific IgE to Ascaris was demonstrated in only two patients. No patients reacted to Toxocara canis or Echinoccocus granulosus antigens with the same test. The skin prick test was positive in 16 patients, in two of them persisting for 48 h. Five patients showed neither skin reaction nor specific IgE to A. simplex. Sera showed specific immunoglobulin levels against A. simplex larval crude extract, by both ELISA and Western blot. Likewise, specific immunoglobulin levels against excretory-secretory antigen were also measured by ELISA. Only one patient showed sensitization to fish. A. simplex was found to be the main cause of acute recidivous urticaria in patients who usually eat fish and are not sensitized to it.

Adolescent↗
PubMed1997

Pyridazines. XIII. Synthesis of 6-aryl-5-oxygenated substituted-3(2H)-pyridazinones and evaluation as platelet aggregation inhibitors.

Several 6-aryl-5-oxygenated substituted pyridazinones have been synthesized and evaluated in vitro for inhibition of platelet aggregation induced by adenosine 5'-diphosphate (ADP), thrombin and collagen. All the tested compounds (except 8 and 9) inhibited platelet aggregation in a dose-dependent manner. The IC50 of the most active substance, compound 2b, was around 60 microM against ADP and collagen as inducers. The inhibition of platelet aggregation caused by test compounds was dependent on the level of oxidation of the function at the 5-position, with the order of IC50 values being R-OH (2a, b, 5) < R-CHO (6, 7) < < R-COOH (8, 9). None of the tested compounds increased the intracellular levels of cAMP, indicating a lack of inhibitory activity on cAMP phosphodiesterase (PDE III) in intact cells. These results suggest that the group present at the 5 position of 6-aryl-5-substituted pyridazinones determines the platelet aggregation-inhibitory activity, and that a mechanism other than PDE inhibition is responsible for this effect.

Adenosine Diphosphate↗
PubMed1995

Scintigraphic findings in a Brodie's abscess.

A 9-year-old girl had a 6-month history of left hip pain. Radiographs of the left hip showed a metaphyseal osteolytic lesion with sclerotic borders in the femoral neck. Tc-99m MDP bone imaging and a Ga-67 scan showed focal areas of increased activity in the left femoral neck. These areas of increased uptake corresponded to a lytic area on x-rays, which was due to a Brodie's abscess. The combination of Tc-99m MDP bone and Ga-67 imaging has been widely used in the confirmation of bone infection, increasing the accuracy in the diagnosis of osteomyelitis. However, nuclear scintigraphy has not been previously reported in the confirmation of a Brodie's abscess.

Abscess↗
PubMed1995

[Cytologic and biochemical component in 203 bronchoalveolar lavages. Reference values].

The bronchoalveolar lavage (BAL) is considered a basic technique as a diagnostic aid in Pneumology. However, one of the main problems faced by the clinician is the lack of standardization of the technique. This has been resolved through the drafting of international standards. The other problem is the lack of what might be called a "reference" BAL. In order to establish a reference BAL, we analyzed 203 BAL divided in two groups: a control group and a pathologic group, make up by extrinsic asthma, intrinsic asthma, pulmonary infections, diffuse interstitial pneumopathies, bronchopulmonary tumors and chronic bronchitis. We have studied both the cytologic and the biochemical component of the BAL. Among the biochemical markers, we have considered; carcinoembrionary antigen (CEA), tissular polypeptidic antigen (TPA), neuronal specific enolase (NSE), ferritin (FER), calcitonin (CT), ACTH, histamin (HIS) and prostaglandin (PGE2). In order to establish the reference values, we have used the modified Baye's theorema. The BAL that we obtained was the following: volume 20 ml, cells 35 x 10(5) cells/ml, macrophages 77%, lymphocytes 22%, neutrophils 4%, eosinophils 2%, CEA 14 ng/mg, TPA 84 U/g PT, NSE 5 ng/mg PT, FER 42 ng/mg PT, CT 15 pg/mg PT, ACTH 51 pg/mg PT, HIS 1.22 ng/mg PT, PGE2 35 pg/mg PT.

Adolescent↗
PubMed1987

Clinical signification of natural killer activity in B-cell chronic lymphocytic leukemia.

The natural killer (NK) activity of peripheral blood mononuclear cells (PBMC) and lymphocytes with the capacity to form stable rosettes with neuraminidase-treated sheep red blood cells (E+) was studied in 28 previously untreated patients (11 at stage 0, 10 at stage I and 7 at stages II and III, according to Rai's classification) and 7 treated patients with B-cell chronic lymphocytic leukemia (B-CLL), all of them at stage 0 according to Rai's classification after treatment, and in 15 healthy controls. The mean NK activities of PBMC and E+ lymphocytes from untreated patients were significantly decreased (p less than 0.001) when compared with those of PBMC and E+ lymphocytes, respectively, from healthy controls. However, PBMC and E+ cells from treated patients demonstrated NK activity similar to that of the corresponding cellular populations of controls (p greater than 0.05). Furthermore, there were no significant differences among the NK activities of E+ lymphocytes from untreated B-CLL patients in the different clinical stages 0, I, II and III, according to Rai's classification (p less than 0.05). These results demonstrate that the very low or undetectable levels of NK activity present in PBMC and E+ cell populations from previously untreated patients with B-CLL, regardless of the clinical stage of the disease, can be modified by systemic therapy with alkylating agents. Moreover, the NK activity of PBMC and E+ lymphocytes from some treated patients that have achieved the stage 0 according to Rai's classification after chemotherapy can be found within the range of the lytic activity shown by PBMC and E+ cells from normal donors.

Animals↗