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C Rivas

Publications and source records attributed to C Rivas.

At least 91 records · Page 5Linked to original sources
PubMed1994

B-cell follicular lymphomas: clinical and biological characteristics.

Seventy cases of follicular B-cell lymphomas were studied: 37 cases derived from the follicular centre [27 centroblastic-centrocytic (CB-CC) and 10 centroblastic (CB)] and 33 from the mantle zone [mantle-cell lymphoma (ML)]. Presenting features as well as response to therapy, time free of symptoms and survival were reviewed. All the cases were diagnosed and classified with routine and immunohistochemistry methods. In 61 cases tumors were studied with specific markers in a CAS-200 Image Analyser. Flow cytometry (FCM) was also done and correlated with proliferative-values and survival. A minor aggressive course of CB-CC and ML was demonstrated, with ML being the most benign form (lower proliferation rate and longest survival). Ploidy did not correlate with histological subtypes, survival or response to therapy. These results confirm the utility of biodynamic studies in lymphoid neoplasias.

Adult↗
PubMed1994

[Detection of monoclonality in non-Hodgkin's B-cell lymphomas using PCR].

PURPOSE: To evaluate the reliability of a PCR technique for the detection of monoclonal B-cell non-Hodgkin's lymphoma (NHL) in a group of patients previously showing monoclonal gene rearrangement with Southern Blot techniques. PATIENTS AND METHODS: A group of 22 cases of NHL were studied with immunocytochemical techniques by means of a complete monoclonal antibody panel after previous demonstration of monoclonal rearrangement with the JH probe. Specific Fr2 and Fr3 priming of the variable regions of the IgH genes was used. One positive and two negative controls were used on each PCR test. RESULTS: Monoclonal lymphoma was detected in 18 cases (82%), seven of them with Fr2 and Fr3, whereas five cases had Fr2 and the remainders had only Fr3. CONCLUSION: PCR seems a good alternative for detecting monoclonal lymphoproliferative syndromes instead of Southern Blot due to both its specificity and high sensitivity. The hypotheses to explain false negative results are discussed.

Antibodies, Monoclonal↗
PubMed1993

[Follicular mantle lymphoma: clinicopathologic and cell proliferation of 11 cases].

BACKGROUND: The aim of the present was to study the biologic behavior of the lymphomas of the follicular mantle by analysis of different indexes of neoplastic cell proliferation and their relation with the clinical symptoms, prognosis and survival of the patients. METHODS: Light microscope, ultrastructural, and frozen and paraffin immunohistochemical studies were performed including the proliferative markers Ki-67 and PC10, flow cytometry and analysis of cell cycle in biopsy samples. Clinical data of 11 patients were collected in addition to therapeutic response and survival. RESULTS: Lymphoma of the follicular mantle is constituted by small sized cell elements with a variable pattern of tumoral growth in the lymph nodes. In normal lymphocytes of the follicular mantle the immunophenotype shows expression of IgM + IgD and a light chain in the cell surface. From a clinical point of view, massive splenomegaly and disseminated stage are the most outstanding characteristics. One third of the cases analyzed presented an aneuploid neoplastic population. According to the PC10 marker, the proliferative index ranged from 2.9 to 14.7% of neoplastic cellularity (mean 7.0). The percentage of cells in the phases S, G2 and M of the cell cycle by flow cytometry varied from 14 to 35 (mean 23%). Neither the cell ploidy nor the tumoral proliferative index were related with the survival of the patients (53 +/- 51 months). CONCLUSIONS: Lymphoma of the follicular mantle is a clinical pathological entity of low biologic aggressivity. Cell aneuploidy or ploidy and the tumoral proliferative index did not establish differences in prognosis or survival in this series.

Adult↗
PubMed1993

Photodegradation of benzydamine: phototoxicity of an isolated photoproduct on erythrocytes.

Benzydamine hydrochloride (Tantum, 1) is a photoallergic and phototoxic anti-inflammatory and analgesic agent. This drug is photolabile under aerobic and anaerobic conditions. Irradiation of a methanol solution of benzydamine under oxygen or argon at 300 nm affords 5-hydroxybenzydamine (2) and 2-beta-dimethylaminopropyl-1-benzylindalolin-3-one (3) as the main isolated and spectroscopically identified photoproducts. A radical intermediate was evidenced by thiobarbituric acid that was used as a radical sonde, as well as by the dimerization of cysteine. Erythrocyte lysis photosensitized by 1, 2, and 3 was investigated.

Benzydamine↗
PubMed1993

Formation of a perbenzoic acid derivative in the photodegradation of fenofibrate: phototoxicity studies on erythrocytes.

The phototoxic antihyperlipoproteinemic drug fenofibrate (1) is photolabile under aerobic conditions. Irradiation of a methanol solution of 1 produces, under oxygen, photoproducts 2, 3, and 4. A peroxidic photoproduct 2 was isolated and identified. The biologically active antioxidants glutathione and cysteine efficiently reduce 2 to its acid. This photoproduct was also capable of efficiently oxidizing tetramethyl phenylendiamine (TMP) through an electron transfer mechanism, detecting a TMP+ species by UV-visible spectrometry. Fenofibrate was screened in vitro at different concentrations for UV-visible-induced phototoxic effects in a photohemolysis test, under oxygen as well as argon. The photohemolysis rate was low under anaerobic conditions. No hemolysis occurred without irradiation. The isolated photoproduct 2 induced hemolysis without irradiation.

Chlorobenzoates↗
PubMed1993

The detection of B-cell monoclonal populations by polymerase chain reaction: accuracy of approach and application in gastric endoscopic biopsy specimens.

The recently developed strategy for the detection of monoclonal B-cell populations, based on the selective amplification of predominant immunoglobulin heavy chain gene (IgH) rearrangement, is seen to be a suitable alternative to Southern blot analysis. The new technique uses a pair of consensus primers for variable (VH) and joining (JH) regions. We first tested the accuracy of this new approach on a broad series of 67 samples that had been well characterized by both Southern blot and immunohistochemical techniques before being subjected to blind testing. Our results show that this technique gave 100% specificity (absence of false-positive results) and approximately 70% sensitivity (30% false-negative results). The only exception was the presence of an IgH polymerase chain reaction ambiguous result in a case of Sezary's syndrome. The polymerase chain reaction technique was then applied to a panel of 27 frozen gastric endoscopy biopsy specimens following previous clinical suspicion of lymphoma. Monoclonality was detected in nine of 13 samples previously diagnosed as lymphomas and in one of two carcinomas. Further examination of the gastrectomy specimen in the latter case disclosed a B-cell lymphoma associated with the carcinoma. In spite of its limited sensitivity, the high specificity attained by this technique in the detection of monoclonality makes it a useful adjunct to routine morphologic criteria, as it is sometimes capable of detecting true positive cases that conventional morphology studies show to be negative.

Antibodies, Monoclonal↗
PubMed1993

Photoproducts of benzydamine and azapropazone: demonstration of their phototoxicity in vitro.

Red blood cell lysis, photosensitized by the products of the aerobic photolysis of benzydamine (1) and azapropazone (4), was investigated. Irradiation of a methanol solution of 1 and 4 under oxygen produces the photoproducts 3-hydroxy-benzydamine, (2), 2-(3-dimethylaminopropyl)-1-benzylindazolin-3-one (3) and 3-dimethylamino-7-methyl-1,2,4-benzotriazine (5). The mechanism of the photodegradation of 1 was examined. Photoproducts 3 and 5 produce singlet oxygen as demonstrated by trapping with 2,5-dimethylfuran. The photohemolysis rate for the photoproducts 3 and 5 was enhanced by deuterium oxide and oxygen. No change was observed in the presence of reduced glutathione. The photohemolysis rate was low under anaerobic conditions.

Apazone↗
PubMed1993

Peripheral T-cell lymphoma: a clinicopathological study of 41 cases and evaluation of the prognostic significance of the updated Kiel classification.

A total of 41 non-cutaneous peripheral T-cell lymphomas were classified following the updated Kiel classification. Of these, 20 cases belonged to the low-grade group (T-cell chronic lymphocytic leukaemia, 3; lymphoepithelioid, 5; angioimmunoblastic, 4; pleomorphic small cell, 8) and 21 to the high grade group (pleomorphic medium and large cell, 11; immunoblastic, 3; large-cell anaplastic Ki-1 positive, 7). Seventy per cent showed a CD4+/CD8-phenotype, 39% a defective phenotype and 88% an activation phenotype. Eighty per cent had B-symptoms, 63% hepatomegaly, 48% splenomegaly and 26% had involvement of more than three lymphoid areas. Bone marrow was infiltrated in 34%, central nervous system in 4%, lung in 12% and skin in 14.6%. Seventeen per cent presented with extranodal disease and 82.8% had stage III/IV disease. Hypergammaglobulinaemia was found in 29%, hypercalcaemia in 7%, raised LDH serum levels in 58% and HTLV-I antibodies in only one case. Of the 37 treated patients 18 (48%) achieved a complete remission, but 33% relapsed. Mortality was 59% and actuarial overall survival at 38 months was 0.32. In the comparison of the clinical, analytical and immunophenotypic variables and outcome between low and high grade groups, only the average of bone marrow infiltration in the low grade and stage I-II, presence of defective phenotypes and higher Ki-67 positivity in the high grade group were significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1993

Primary pleomorphic T-cell lymphoma of the spleen.

We report a case of primary splenic T-cell lymphoma that posed difficult problems in differential diagnosis with erythrophagocytic T-gamma lymphoma and inflammatory pseudotumor of the spleen. The need for immunophenotypic and molecular studies for establishing the correct diagnosis and the importance of early detection and treatment, is emphasized in the light of the relatively good prognosis of splenic lymphoma, diagnosed in the early stages of disease.

Aged↗
PubMed1993

[Detection of Pneumocystis carinii in clinical samples by the polymerase chain reaction. Comparison with the methenamine silver technique].

BACKGROUND: A comparison of polymerase chain reaction (PCR) with methenamine silver stain was performed on clinical specimens for diagnosis of Pneumocystis carinii pneumonia in immunosuppressed patients. METHODS: 25 clinical samples (10 induced sputa, 12 transthoracic needle aspirations and 2 bronchoalveolar lavages) from 17 patients with AIDS and respiratory symptoms were studied. We performed DNA amplification by using 2 primers that amplify the mitochondrial large rDNA sequence of P. carinii. RESULTS: The sensitivity and specificity of the PCR technique were 92.8% and 100% respectively, with a positive predictive value of 100% and negative predictive value of 92.3%. The sensitivity of the silver stain were 65%, specificity 100%, positive predictive value 100% and negative predictive value 63%. CONCLUSION: The PCR technique is more sensitive than the methenamine silver stain for detecting Pneumocystis carinii in respiratory specimens from patients with pneumonia. Consequently it could be a very good alternative to classical methods in diagnosis of P. carinii infections.

AIDS-Related Opportunistic Infections↗
PubMed1993

[Biology of secondary nodal follicular b-lymphomas. A patho-dynamic study].

PURPOSE: To assess the aggressivity factors and tumour prognosis in a series of non-Hodgkin lymphomas by the use of computer-quantified specific antibodies and flow cytometry. PATIENTS AND METHODS: Sixty-one cases of follicular B-cell lymphoma: 34 of the germinal centre (24 centroblastic-centrocytic, CB-CC, and 10 centroblastic, CC) and 27 of the follicular cortex (FCL), were studied. All the cases had been diagnosed between 1971 and 1992 at the Pathology Department of the Fundación Jiménez Díaz. Morphologic and immunophenotype diagnosis was made on each case. Tumour proliferation studies were performed after labelling nuclei with proliferent nucleic acid-associated protein (PC 10); the positive nuclear areas were later quantified in a CAS-200 image analyser by means of proliferation programmes (PI) and nuclear receptors (ER). A flow cytometry study of ploidy was carried out on each case. The values attained were correlated with survival in months. The Wilcoxon's test for independent variables was used for the statistical study. RESULTS: The PI programme showed lowest proliferation for FCL (7.4%) followed by intermediate proliferation in CB-CC (16.9%) and high proliferation in CB (31.7%). The PC-10 results attained with both PI and ER programmes showed statistically significant correlation (p < 0.01). The correlation between ploidy, as quantified by flow cytometry, and survival showed statistically significant differences between diploid and aneuploid cases (p < 0.01); similar findings apply for diploids and diploids with high synthesis phase (p < 0.01). CONCLUSION: These findings support the usefulness of cell kinetics studies in lymphoma, and contribute to validate different evolutive patterns in accordance with the histologic subtype.

Biomarkers, Tumor↗
PubMed1993

[Acute toxoplasmosis. Laboratory diagnosis].

BACKGROUND: The microbiological diagnosis of acute toxoplasmosis in immunosuppressed patients, cannot, usually, be done through serological techniques. The methods for isolation or direct detection of parasite are the only ones that might be helpful to determine an earlier diagnosis, on these patients. METHODS AND RESULTS: The use of urine in 3 patients with acute toxoplasmosis, allowed us to isolate the parasite after inoculation of the sample in human embryonic fibroblast cell line (MRC-5). CONCLUSION: In our opinion urine could be an adequate sample for isolation or detection of Toxoplasma gondii in immunosuppressed patients, and an alternative to serological methods, as well.

AIDS-Related Opportunistic Infections↗
PubMed1992

Correlation between cytogenetic and molecular analysis of t(14;18) in follicular lymphomas.

A comparison between cytogenetic and molecular results of t(14;18) has been performed in 12 patients with follicular lymphomas: five nodular and seven diffuse. Ten cases showed cytogenetic alterations with different markers, including a 14q+ in eight: in four it was the result of a t(14;18). Molecular analysis by Southern blotting with bcl2 probes from major and minor cluster regions, and PCR with primers from major and minor regions showed differences versus the cytogenetic results. The correlation found between cytogenetic and molecular results suggests other factors, such as geographical differences or different pathogenetic mechanisms, more than methodologic aspects, to explain the different frequencies of this marker among countries.

Adult↗
PubMed1992

Pathogenic activities of live cells and extracellular products of the fish pathogen Pasteurella piscicida.

The pathobiological activities in vivo and in vitro of live cells and extracellular products (ECP) of eleven Pasteurella piscicida strains of different origin were examined. Infectivity trials showed that P. piscicida did not possess strict host specificity since the majority of the isolates were virulent for gilthead seabream, rainbow trout and turbot, with LD50 values ranging between 10(3) and 10(6) live cells. However, none of the strains tested were pathogenic for mice (LD50 > 10(8) cells)). In addition, the ECP were strongly toxic for fish (LD50 ranging from 1.0 to 4.6 micrograms protein per g fish), which clearly demonstrates their important role in the pathogenesis of pasteurellosis. All the ECP samples were cytotoxic for fish and homoiothermic cell lines, possessed notable phospholipase activity and displayed haemolytic activity for sheep, salmon and turbot erythrocytes (but not for trout erythrocytes). However, the production of proteolytic enzymes differed among the P. piscicida strains. Although no strain displayed elastase activity, five isolates (the Japanese and Italian strains) hydrolysed casein and gelatin. All these biological activities in vivo and in vitro were lost after heat treatment (100 degrees C for 10 min). The general enzymic patterns of both live cells and ECP evaluated by the API-ZYM system also revealed some variation among the P. piscicida isolates. Generally, whole cells showed a wider range of enzymic activities than ECP. The results presented here are important for the selection of strains in the development of effective polyvalent pasteurellosis vaccines containing both whole cells and ECP.

Animals↗
PubMed1992

Human tonsil intraepithelial B cells: a marginal zone-related subpopulation.

AIMS: To determine if intraepithelial B cells in reactive human palatine tonsils were similar to the marginal zone cells of the spleen and Peyer's patches. METHODS: Reactive human palatine tonsils were studied using conventional methods of light microscopy, electron microscopy, and a panel of monoclonal antibodies for leucocyte common antigens. RESULTS: Clinically important numbers of marginal zone-related B cells around the mantle zone were absent in lymphoid follicles, but in the cryptal epithelium there were abundant lymphoid cells with centrocyte-like nuclei and clear cytoplasm, intermingled with macrophages and plasma cells. The immunophenotype of these intraepithelial B cells was distinctive and similar to that found in the splenic marginal zone cells (IgM+, IgD-, CD23-, CD10-, CD35+, CD21+, bc12+, KB61+). CONCLUSIONS: Intraepithelial B cells in human tonsil could represent the counterpart of the marginal zone described in Peyer's patches. Their presence within the epithelium could reflect the destination for the malignant B cells in the lymphoepithelial lesion of mucosa associated lymphoid tissue (MALT) lymphomas. Human palatine tonsil lymphoid tissue has morphological, immunophenotypic, and pathological features similar to those of MALT.

B-Lymphocytes↗