Catabolism of the human erythrocyte C3b/C4b receptor (CR1, CD35): vesiculation and/or proteolysis?

Human erythrocytes (E) react by exocytosis of membrane vesicles to various stresses including the fixation of the membrane attack complex of Complement. E from normal individuals loose a notable proportion of their initial number of surface CR1 molecules during the ageing process. An acquired decrease of CR1 on E also occurs in pathological conditions such as Systemic Lupus Erythematosus or AIDS. The present study investigated whether calcium ionophore A23187 (Ca-ion) induced vesicle formation of human E in vitro is responsible for a preferential loss of CR1 as well as whether CR1 molecules at the surface of Ca-ion treated E or vesicles are: (i) functional, (ii) native or protease degraded, or (iii) more clustered than CR1 on native E. A study of E from 137 normal individuals showed that a one-hour Ca-ion induced vesicle formation preferentially removed one third of E surface CR1. Kinetic experiments suggested that all surface CR1 could be removed from E upon longer incubation times. CR1 molecules on vesicles were still able to inhibit Complement activation, and were found in larger clusters than on native E. These data suggest that a significant part of surface CR1 molecules may be removed from E by vesicle formation during the life of E in normal individuals. This phenomenon could be exacerbated in pathological conditions.

Lhermitte-Duclos disease associated with syringomyelia

A 23-year-old man presented with a 2-week history of intracranial hypertension. CT showed a large, nonenhancing cerebellar mass with surrounding calcification and displacement of the fourth ventricle. MRI revealed a septate lesion, with low signal on T1-weighted and high signal on T2-weighted images. The cerebellar tonsils were displaced below the foramen magnum and there was associated syringomyelia. The MRI features were characteristic of Lhermitte-Duclos (LD) disease (dysplastic gangliocytoma) and the diagnosis was confirmed following surgery. In this case, we emphasise the usefulness of MRI in the diagnosis of LD disease and consider the possible pathogenesis of the associated syringomyelia.

[Granular-cell tumor: review of the literature apropos of a case of bronchial site]

Abrikossoff's tumor, also called granular cell tumor, is an uncommon condition, generally benign, which can affect every organ and specially skin and tongue. The authors report an observation of a bronchial tumor and review the literature. Possible relapse after treatment, locally or everywhere in the body, may occur as local or regional complication that may necessit heavy surgery. It appears that a benign tumor can have macroscopic and even microscopic aspect of malignancy, when real malignant tumors are extremely rare. Wide excision still remain current treatment of Abrikossoff's tumor. Endoscopic methods are an interessant and less invasive alternative to treat some deep tumors.

Kinetics study of the localization and quantitation of target antigens of immunoglobulin a antibodies in acquired and congenital toxoplasmosis

The cellular distribution (localization and quantitation) of the target parasite's antigens in the tachyzoite along the IgA kinetics was determined in the course of acquired toxoplasmosis and congenital toxoplasmosis. In the case of acquired toxoplasmosis, throughout the IgA kinetics a correlation was noted between the membrane and submembrane immunolabeling and the results of the immunocapture and enzyme-linked immunosorbent assay IgA (ELISA-A) tests. The rhoptries' immunolabeling remained higher. The immunolabeling evolution and the results of the immunology tests were not closely related to the treatment (Rovamycin). From the congenital toxoplasmosis cases it was observed that membrane immunolabeling correlated with the results of the serology tests and with the treatment (Fansidar). The rhoptry antigens were recognized throughout the IgA kinetics; even when the serology tests became negative, immunolabeling persisted. Rhoptries appeared as secretory organelles of antigens recognized during acute, chronic, and congenital stages of Toxoplasma infection.

Early neonatal diagnosis of congenital toxoplasmosis: value of comparative enzyme-linked immunofiltration assay immunological profiles and anti-Toxoplasma gondii immunoglobulin M (IgM) or IgA immunocapture and implications for postnatal therapeutic strategies

Diagnostic strategies for congenital toxoplasmosis have changed profoundly in recent years. Immunological diagnostic methods, long considered disappointing, can now be used at a very early stage. Over a 3-year period, 1,050 infants at risk of congenital toxoplasmosis (born to 1,048 mothers infected during pregnancy) were monitored for a minimum of 12 months and a maximum of 7 years. More than 6,000 serum specimens were analyzed by comparative mother-infant immunological profiles (CIPs) based on an enzyme-linked immunofiltration assay (ELIFA) and an immunocapture method for the detection of specific immunoglobulin M (IgM) and IgA. IgG antibodies were also titrated. One hundred three cases of congenital toxoplasmosis were demonstrated. The CIP-ELIFA method had a better diagnostic yield (sensitivity, 90%) than specific IgM and/or IgA detection by immunocapture assay (sensitivity, 77%). By using a combination of these tests, congenital infection was diagnosed in the first month and the first 3 months of life in 90 and 94% of infants with toxoplasmosis, respectively, with a specificity of 99.8% and a positive predictive value of 99% at 8 months of age. This dual diagnostic approach (ELIFA and IgM-IgA immunocapture) is highly efficient and has important implications for therapy. Indeed, early postnatal diagnosis based on objective evidence enables therapy with pyrimethamine-sulfadoxine to be started immediately for 24 months, while spiramycin (which used to be given preventively for 9 to 12 months to all infants at risk) can be stopped after the first 3 months of life.

[Leiomyosarcoma of the inferior vena cava. Apropos of a new case]

A leiomyosarcoma was diagnosed in the mid portion of the inter-renal inferior vena cava. Survival was long (6 years) but required 14 reoperations to remove metastases. During the first operation, vascular integrity was reestablished with a cava-cava prosthesis after exeresis of the upstream cava without removal of the left renal vein ostium. The right renal vein was sectioned and directly implanted onto the prosthesis. The pathology report confirmed the diagnosis of leiomyosarcoma with multiple metastases presenting cytonuclear anomalies which worsened with time.

Molecular characterization of Charcot-Marie-Tooth patients in 15 pedigrees from France

Molecular characterization of Charcot-Marie-Tooth patients in 15 pedigree from France: We collected 15 Charcot-Marie-Tooth (CMT) pedigrees from France. DNA polymorphisms analysis by Southern blotting with probes at the D17S122 locus demonstrated 17p duplication in three CMT1a families and in one sporadic case. Two families affected by CMT2 showed no evidence of the duplication.

Epstein-Barr virus-associated primary malignant lymphomas of the pleural cavity occurring in longstanding pleural chronic inflammation

Primary pleural non-Hodgkin's lymphomas (NHLs) have been described mostly in Japan and occasionally in western countries. We report three cases occurring in nonimmunocompromised patients demonstrating close similarities to the Japanese cases. These lymphomas occurred more than 20 years after thoracoplasty for the treatment of pleural or pulmonary tuberculosis. They were all high grade lymphomas of B phenotype (two immunoblastic with plasmocytoid differentiation and one immunoblastic with anaplastic large cells). In situ hybridization (ISH) detected small nuclear RNAs encoded by Epstein-Barr virus (EBERs) in most lymphomatous cells in all cases. This suggests a link between primary pleural lymphoma and the longstanding chronic inflammation, which could favor a clonal evolution of Epstein-Barr virus (EBV)-infected B cells through the production of growth factors or immunosuppressive cytokines produced by inflammatory cells.

Subcellular localization and quantitative analysis of Toxoplasma gondii target antigens of specific immunoglobulins G, M, A, and E

The target antigens of specific immunoglobulins G, M, A, and E from patients with acquired acute toxoplasmosis were determined using immunocytochemistry. The relative repartition of these antigens in four cellular compartments of Toxoplasma (membrane complex, apical area, rhoptries, and dense granules) was quantitatively evaluated. Rhoptry antigens mainly react positively with IgA. Membrane, submembrane area (membrane complex), and rhoptry antigens are immunodominant for IgA and IgM. Apical area antigens are recognized by IgM two times more than IgG and IgA. IgE recognized only rhoptry antigens. The localization of pathogenetically antigenic components and their identification by the immune system appeared to be of importance for selection of immunodominant or recombinant antigens. Such localization would improve laboratory diagnosis of serious congenital toxoplasmosis or in immunocompromised patients with toxoplasmic complications after cyst reactivation.

Epidermal growth factor receptors in breast cancer: comparison of radioligand and immunocytochemical assays

Epidermal growth factor receptors (EGFR) are part of second generation biological factors that clinicians caring for breast cancer patients wish to evaluate for their prognostic value. This aim requires the standardization of methods: the radioligand assay (RLA) for the quantification of EGF binding sites was performed on membrane pellets from 261 breast cancer samples (ligand binding and hydroxylapatite separation as recommended by the EORTC Receptor Study Group); the immunocytochemical assay (ICA) for the staining of EGFR antigenic sites was performed on fine needle aspiration (FNA) cytology or touch imprints from 97 surgical specimens. The percentage of EGFR positivity by RLA (specific binding higher than 1% of total radioactivity) and the EGFR positive rate by ICA (more than 5% of stained cells) were respectively 43% and 38%. For 61 cases assayed on the same patient both methods revealed a concordance of 85%. Our results show that both methods are complementary and give quantitative data and information on tumor heterogeneity when they are performed in parallel. The next step of this study will be to determine the prognostic value of EGFR in these subpopulations of tumors for the adjustment of adjuvant treatment.

Cytogenetic changes in 67 cranial and spinal meningiomas: relation to histopathological and clinical pattern

The cytogenetic analysis of 67 meningiomas (58 intracranial and 9 spinal tumors) identified chromosomal abnormalities in 63% of cases. When chromosomes involved in numerical and structural changes with a frequency of more than one standard deviation above the mean were considered, distinct cytogenetic patterns could be identified according to sex, anatomical location and histology. The chromosomes more frequently affected were 1, 2, 3, 4, 8, 14, 15, 19, 22, Y. No conclusion could be drawn regarding the prognostic significance of these karyotypic alterations.

Subcellular calcium localization in Toxoplasma gondii by electron microscopy and by X-ray and electron energy loss spectroscopies

The localization of calcium in Toxoplasma gondii tachyzoites was studied at the ultrastructural level, with a cytochemical pyroantimonate precipitation method (PA) and controlled by EGTA chelating and EDX and EELS microanalyses. Appropriate conditions for material preparation, fixation and embedding, were defined. The proportion of precipitates that were either free or inside vacuoles and their distribution inside Toxoplasma appeared to be PA dose-dependent. Precipitation mainly occurred in the anterior pole of the Epon-embedded tachyzoites. EDX and EELS analyses showed that out of 30 PA precipitates inside tachyzoites, 78% contained Ca. In Melamine sections, 96% of the tachyzoites had intracellular precipitates and the membrane complex was stained; 25% of the tachyzoites inside host cells contained PA-Ca precipitates, but most of them were retained in the reticular network of the parasitophorous vacuole. Melamine embedding appeared to improve the preservation of calcium pyroantimonate precipitates.

[Myocardial metastasis of bronchial carcinoma. Disclosed by x-ray computed tomography]

One case of cardiac metastasis of epidermoid carcinoma discovered with CT during the preoperative assessment is reported. The authors stress that the discovery of cardiac metastases in vivo is relatively infrequent. They emphasize the role of imaging, which allows ruling out the operation in these cases.

Quantitative immunolocalization of four immunodominant antigens of Toxoplasma gondii

Ultrastructural localization of four immunodominant antigens of Toxoplasma gondii was investigated quantitatively on thin sections and replicas by an immunogold technique using four monoclonal antibodies (Mab). On immunoblot Mab IV47, GII9, II38 and IE10 identified proteins of 28, 30, 45 and 66-70 kDa, respectively. Use of digital image analyzer and a semi-automatic procedure developed by us, the patterns of label distribution were compared in three cell structures: cell surface, submembrane area and rhoptries. On the whole cell surface, protein P28 and P30 were 2.5 and 4 times more abundant than P66-70 respectively. The protein P28 was essentially concentrated in the submembrane area with a labeling of 195.4 +/- 46.7 gold particles/microns 2 that follows a decreasing gradient from this area to the cell centre. In the rhoptries, all four antigens were detected, P45 and P66-70 being major with a labeling of 97.1 +/- 31.1 gold particles/microns 2 and 155.1 +/- 39.3 gold particles/microns 2 respectively. The results support the hypothesis that rhoptries are the essential site for antigen storage.

Toxoplasma gondii: immunocytochemistry of four immunodominant antigens with monoclonal antibodies

Four monoclonal antibodies in which diagnostic usefulness has been observed, concerning congenital, acquired, and reactivated toxoplasmosis, were raised against Toxoplasma gondii tachyzoïtes in order to localize immunodominant antigens. On immunoblots, it appears that McAb IV47, McAB GII9, McAb II38, and McAb IE10 identify families of proteins with estimated molecular weights of 28-30 kDa, 30 kDa, 45-50 kDa, and 66-70 kDa, respectively. By immunogold preembedding techniques one can observe an homogeneous labeling of the outer pellicle of the tachyzoïtes with the McAb GII9 and IV47 and a light labeling with the McAb II38 and IE10. The three-dimensional observation of cell surface antigens is performed by applying a modified metal extraction replica method, i.e., A plasma polymerization method of glow discharge by Tanaka (1979). By immunogold preembedding techniques [with saponin permeabilization (0.1%)], and by immunogold postembedding techniques, a labeling of the rhoptries is observed with McAb GII9 and McAb IV47 but essentially all label is found with McAb II38 and IE10. With McAb GII9 a uniform labeling is observed on the cell surface. By immunoenzymatic techniques (peroxidase) a cell surface labeling is observed with the four McAb. Intracellular Toxoplasma, the outer pellicle, and the vesicles of the network (elaborated by Toxoplasma in parasitophorous vacuole) are also labeled with McAb IE10. These results indicate that McAb GII9 recognizes antigens of the antigen family (P 30) located on the cell surface and in the rhoptries. The antigen recognized by McAb IV47 is essentially located on and beneath the Toxoplasma cell surface membrane, and McAb II38 and IE10 identify preferentially rhoptry proteins.

[Malignant histiocytofibroma of the heart simulating myxoma of the left atrium]

The authors report a case of malignant fibrous histiocytoma of the left atrium which was excised but rapidly recurred in a 47-year-old woman. Clinical examination, echocardiography and the absence of biochemical abnormalities were in favour of the diagnosis of left atrial myxoma. This report illustrates the clinical similarity between myxoma and sarcoma of the left atrium. Very careful anatomopathological examination of multiple sections of the tumour are necessary to distinguish it from benign tumours, especially myxomas.

Evaluation of morphological criteria in the cytological diagnosis of thyroid cold nodules. A preliminary study

Although cytological diagnosis plays a significant role in the management of thyroid cold nodules, the rather high rates of false negative cases diminishes its usefulness. The purpose of this preliminary study is to evaluate the utility of numerous morphological criteria used by the cytologist to exclude benign tumours. Thirty-one cytological criteria were routinely scored as binary (yes/no) or as categories: 6 referred to the general arrangement and frequency of thyroid cells, 9 to the associated cellular and cell product elements, and 16 to the morphological features of the cells. We examined the manner in which these criteria, alone or combined, contributed to the diagnosis. The data base consisted of 171 intraoperative imprint cytological samples (143 histologically benign, 1 atypical adenoma and 27 cancers), as well as 257 thyroid cold nodule aspirates from another set of patients (198 histologically benign, 7 atypical adenomas and 52 cancers). For the imprint cytology, the diagnostic power of each criterion was individually assessed by the likelihood ratio (LR) which eliminated 11 as being undiscriminatory. The remaining independent criteria were subjected to logistic regression analysis to determine the most discriminant. Three were selected: Cellular clustering organisation, nuclear hypertrophy and colloid quantity with the latter being somewhat less powerful. Furthermore, it appears that the diagnostic power of the criteria was significantly lower when there was at least one nucleolus (number of nucleoli greater than 0). The smears gave essentially the same results as the imprints.(ABSTRACT TRUNCATED AT 250 WORDS)

[Melanoma of the uvea in young patients. Apropos of 3 cases]

The authors report 3 cases of uveal melanoma, appeared on young women: 20, 23 and 28 years old. The melanomas were localized on the iris, the ciliary body and on the choroid. The authors studied the different notions of the literature about happened age of these lesions.

[Benign tumor of pilar origin of the upper eyelid. Apropos of a case]

The authors report a case of superior eyelid tumour, pilary originated, trichofolliculoma type. They considered the diagnostic and therapeutic problems about this type of tumour.

Contribution of quantitative cytology to the cytological diagnosis of thyroid neoplasms

In a previous study we determined that the fine needle aspiration (FNA) biopsy of thyroid produces 16% of false-negative cases (FNC). In order to determine the value of quantitative cytology (QC) as a tool for predicting the FNC result, thirty-seven cases, 18 of which were operated (histologically benign: 13; malignant: 3; atypical adenoma; 2) were examined for quantitative morphologic characteristics. The smears were stained by the Feulgen method and nuclear parameters of morphometry, densitometry and texture were computed by a cell image processor. The system was first taught to recognize the benign and malignant cells from 3 histologically benign and malignant lesions. Thereafter, prospective cases were submitted to decisional analysis. For 10 histologically benign cases, the benign cell rate (bcr) ranged from 65% to 99.4 (95% confidence interval). Among the patients with a cytologically benign lesion (and an unknown histological diagnosis), 2 had a bcr less than 65% and so were not to be regarded as benign. The follow-up of these patients will show whether they represent FNC and whether QC can be of predictive value in assessing the FNC.

[Stereomorphological relationship between colonic adenomas and peri-adenomatous mucosa in scanning electron microscopy. Histogenetic correlations]

Using scanning electron microscopy (SEM), then light microscopy, the authors have studied 25 colonic adenomas, 5 specimens of peri-adenomatous mucosa and 9 specimens of normal colonic mucosa. Comparison between SEM features and histological characteristics has shown that each of the three histological entities had an specific surface architecture. Comparative analysis of the different aspects observed at SEM has shown a close architectural relationship between the adenomas and the adjacent mucosa, and suggests the hypothesis that adenomatous polyps are formed by invagination of the surface epithelium which has a well-known capacity of proliferation.