[Breast cancer invasion: the key role of normal cells of host tissues]

Tumor progression is influenced by extracellular matrices and by soluble factors or cytokines locally produced by host tissue cells (fibroblasts, immune cells ...). Such factors may also accumulate in close association with some extracellular matrix molecules in the tumor. They may also be unmasked during breaking down of extracellular matrices. The most insidious aspect of tumors is their propensity to locally invade normal tissues of the host and to form secondary foci in organs at distant sites from the primary tumor called metastases. During this process, invasive cells come into contact with host tissue cells such as fibroblasts, endothelial cells, macrophages, lymphocytes. These cells are not the passive witnesses of the metastatic cascade but actively participate to the malignant invasion. Through soluble messages (cytokines) and through insoluble molecules of the extracellular matrix, neoplastic and normal cells mutually modulate their activities. Cancer cells regulate the biosynthetic activities of fibroblasts and alter in this way the scaffold of the tumor. Reciprocally, host cells secrete extracellular matrix proteins and cytokines which influence the growth and activities of tumor cells. They also produce at the periphery of tumor cells proteolytic enzymes which promote host tissue destruction and cancerous cells migration. Among these enzymes, matrix metalloproteinases appear to play a key role during invasion and metastasis. Tumors represent thus a complex ecosystem. Tumor cells interact with several components of the extracellular matrix and with host cells (immune cells, fibroblasts, endothelial cells). Such multiple cell-cell and cell-matrix interactions condition angiogenesis, tumor growth, destruction of host tissues, local migration of cancer cells and their metastatic dissemination. It is probable that a precise knowledge of the genes which are selectively activated in tumors under the influence of the host cells or of the tumor cells will allow to define new therapeutic strategies. These treatments will aim not at destroying the metastatic neoplastic cells but at preventing their growth by interfering with their microenvironment.

Fibronectin promotes lung colony formation in the mouse by B16 melanoma cells spheroids

By microscopical observation and using an original method of automatic image analysis, we studied on histological sections the rate of lung colony formation after intravenous injection into the mouse of B16 melanoma cells previously cultivated in vitro as pure or mixed spheroids (B16 + 3T3 fibroblasts). The preincubation in vitro of pure spheroids with fibronectin significantly increased the percentages of lung section area occupied by tumors and the relative number of internal lung colonies. This effect of fibronectin was even more obvious when mixed spheroids were injected.

The stimulation of fibroblasts' collagen synthesis by neoplastic cells is modulated by the extracellular matrix

Human fibroblasts cocultured with neoplastic MCF7 cells produce increased amounts of collagen. A maximal stimulation requires direct cell-cell contacts between tumor cells and fibroblasts. However, this effect could be reproduced, although to a lesser extent, by medium conditioned by MCF7 cells, suggesting that it is mediated by a factor produced by MCF7 cells and secreted, at least partly, under a soluble form (Noël et al., 1992). This Collagen Stimulating Factor ("COSF") present in the culture medium displayed a molecular mass between 3,500 to 10,000 daltons, bound to heparin and appeared to be different from the growth factors described until now. The "COSF" can be released from the surface of MCF7 cells by treatment with heparin. The aim of the present work was to investigate the influence of various extracellular matrix components on the production and the release of "COSF". A 3- to 4-fold enhancement of collagen synthesis was observed in coculture on plastic and collagen type I substrates without significant modification of the non-collagen proteins. The increased collagen synthesis was paralleled by an elevation of specific collagen mRNAs level suggesting a regulation at a pretranslational level. On the opposite, in the presence of soluble or insoluble laminin, this stimulation was abolished. Similarly, coculture on "reconstituted basement membrane matrix", matrigel, did not increase collagen production. The "COSF" was found to bind to matrigel and could be released from the basement membrane matrix by treatment with heparin.

Basement membrane components (matrigel) promote the tumorigenicity of human breast adenocarcinoma MCF7 cells and provide an in vivo model to assess the responsiveness of cells to estrogen

The ability to transplant human tumors into athymic nude mice allows studies of tumor cells in vivo. However, after s.c. injection the incidence of tumor and metastases in nude mice is frequently low. We have studied the tumorigenicity in nude mice of estradiol (E2)-sensitive breast adenocarcinoma MCF7 cells. Matrigel, an extract of basement membrane proteins, induces rapid tumor development after s.c. injection of MCF7 cells. In the absence of this matrice, MCF7 cells failed to induce tumor growth. In this in vivo model, MCF7 cells were analysed for their E2 sensitivity. Two weeks after inoculation in the presence of matrigel, cells formed growing tumors in intact mice supplemented with E2. In ovariectomized or untreated mice, tumor appearance was delayed and the growth level was very low. Thus, MCF7 cells formed tumors in the absence of E2 but retained in vivo their responsiveness to estrogen. Growing human tumors in nude mice provides a rapid and useful model for testing the sensitivity of cells to hormone.

Influence of laminin or fibroblasts upon colony formation in the mouse by B16 melanoma cell spheroids: a morphometric analysis

By microscopical observation and using an original morphometric method, we analyzed on histological sections the rate of lung colony formation after the intravenous injection into the mouse of B16 melanoma cells previously cultivated in vitro as aggregates. After the injection of B16 pure spheroids, superficial lung colonies were more numerous than internal lung colonies. After the injection of mixed spheroids (B16 + 3T3 fibroblasts), the size of colony sections was increased. Addition of laminin to pure or mixed spheroids decreased the size of colony sections but increased the number of internal lung colonies.

Modulation of collagen and fibronectin synthesis in fibroblasts by normal and malignant cells

The influence of various normal and malignant human cells on the level of collagen synthesis by human fibroblasts was tested in coculture. As revealed by immunoperoxidase staining, in cocultures with breast adenocarcinoma cells (MCF7, SA52, T47D) fibroblasts synthesized collagen while tumor cells did not. Fibroblasts displayed increased collagen production without change in the overall protein synthesis. Several other types of cells derived from normal human tissues (keratinocytes, normal mammary cells) or from fibrosarcoma, melanoma, cervical carcinoma, choriocarcinoma, or other breast adenocarcinoma (SW613, MDA, BT20) did not affect collagen synthesis of fibroblasts. Although to a lesser extent, this stimulating effect was reproduced by using the conditioned medium (CM) of the active cells but not with CM of the other cell types. A slight stimulation was also obtained when tumoral MCF7 cells and fibroblasts shared the same medium but were physically separated, suggesting that close contact was required for optimal stimulation of collagen synthesis. The collagen synthesis stimulating activity was not related to a modification of fibroblast proliferation rate. The production of collagen types I, III, and VI and fibronectin were increased in cocultures of fibroblasts with MCF7 cells. The increased synthesis of collagen types I and III and fibronectin was paralleled by similar changes in the steady-state level of their mRNAs. On the contrary, the increased production of collagen type VI appeared regulated at a post-transcriptional level.

Determination by latex immunoassay of protein 1 in normal and pathological urine

A sensitive latex particle assay has been developed to study the occurrence of protein 1 in human urine. The coefficients of variation (CVs) of the method which is fully automated vary between 3 and 11.5%. The assayable concentration range is 0.3 to 40 micrograms/l. Protein 1 is clearly a sex-dependent protein. In contrast to urinary retinol-binding protein (RBP) which shows no variation with age or sex, protein 1 is excreted in greater amounts in males from the puberty. In adults, the mean concentration of protein 1 in urine of men is approximately 5 times that of women. In the urine from both sexes, protein 1 occurs as a single component with a Mr around 21,000 and an pI of about 4.8. Protein 1 is correlated with RBP in the urine from female or male patients with impaired proximal tubular function, which suggests that it is handled by the kidney in a similar manner as RBP. Diabetics, however, show elevations of urinary protein 1 which do not correlate with the RBP excretion but with the albuminuria. A competition between albumin and protein 1 for renal tubular uptake might explain this paradoxical behaviour of protein 1 in the course of diabetic nephropathy.

[Evaluation of radiation doses during radiological tests]

The purpose of this document is to provide radiologists with a simple, but realistic means of determining the individual dose delivered to a patient during a radiological examination both in the region under investigation and at any other particularly sensitive organs. Fourteen types of examinations were considered corresponding to those most frequently carried out in France. The choice of examinations and methods of taking the films approaches as closely as possible, the average situations, and the frequency of different techniques is influenced by the results of a national study of radiodiagnostic examinations carried out in France in 1982. In the first section, the influence on the radiation dose of varying different physical parameters and techniques is analysed, with an aim of defining the limits of validity of the presented dosimetric values and the possible adaptation of these values to any individual situation, which is slightly different from these considered in this study. The second section describes the model used for determining the absorbed dose presented in the tables, concerning each type of examination, as well as bibliographic references referring to methods and results of determining the dose. The suggested calculation model may be used as a base for dose estimation for other types of examination.

Development of an acellular pertussis vaccine and its administration as a booster in healthy adults

An acellular pertussis vaccine which contains highly purified pertussis toxoid (PT) and filamentous haemagglutinin (FHA) has been developed. These proteins have been shown to be stable, with essentially no significant reversion of the pertussis toxoid after a new detoxification procedure. Two clinical trials using this vaccine as a booster in 45 healthy adults have been performed. Results show that the vaccine was well tolerated, causing essentially mild, transient symptoms after administration. It induced an increase in anti-PT and anti-FHA antibody titres in all vaccinees.

Antagonistic effects of laminin and fibronectin in cell-to-cell and cell-to-matrix interactions in MCF-7 cultures

During morphogenesis, tumor progression and metastasis, cell adhesion, dissociation, and migration result from a complex balance between cell-to-cell and cell-to-matrix interactions. Two different organization patterns of MCF-7 cells were induced by different extracellular matrix proteins. When plated on plastic or polymeric type I collagen gel used as a model of interstitial matrix, MCF-7 cells spread and grew in monolayer. When cultured on a solid gel of basement membrane (BM) proteins (85% laminin) used as a model of BM, cells formed clusters attached to the matrix. Matrix proteins regulated these two types of cell organization by preferentially promoting cell-to-cell or cell-support interactions. On plastic in the presence of soluble laminin or on laminin-coated dishes, cells also formed clusters. Addition of soluble fibronectin induced spreading of the cells, suggesting that laminin and fibronectin have competitive antagonistic effects on MCF-7 cell morphology. Antilaminin antibodies inhibited cluster formation and attachment, emphasizing the important role of this glycoprotein not only in promoting cluster attachment but also in cell-to-cell contact formation. Such effects of extracellular matrix proteins could play significant roles in tumor progression and metastasis.

Fibroblasts induce the assembly of the macromolecules of the basement membrane

The mechanism regulating the deposition of basement membrane components (BMCs) in a polymeric structure at the junction with the connective tissues is not yet understood. Cultures and cocultures of epithelial BMC-producing cells (L2 or PER cells) and fibroblasts were prepared in several experimental conditions and the organization of BMCs was studied by immunofluorescence. The pattern of BMCs in pure cultures of L2 or pulmonary epithelial rat (PER) cells consisted of intra- and extracellular granular deposits. At very high density, the cell contours were also underlined by a disrupted network of BMC deposits. A different fibrillar plexus--containing laminin, collagen type IV, and heparan-sulfate proteoglycan resistant to deoxycholate treatment and distant from the cell membrane--was observed in cocultures of L2 or PER cells with fibroblasts. Fibrils of fibronectin and/or collagen type I were most often dissociated from this plexus of BMCs. Similar results were obtained by adding a conditioned medium of L2 or PER cells to confluent fibroblasts, even when the cells were killed. Pure laminin also bound to the fibroblast layer. A coated film of fibronectin or polymeric collagen type I was unable to bind BMC provided by a conditioned medium. It is suggested that molecule(s) synthesized by fibroblasts and deposited in the pericellular matrix are involved in the assembly of BMCs.

Interactions between fibroblasts and a reconstituted basement membrane matrix

A gel-like reconstituted basement membrane matrix containing type IV collagen, laminin, entactin, nidogen, and heparan sulfate proteoglycan was used to examine the interactions between normal calf skin fibroblasts and basement membranes. Within 6 h after seeding, fibroblasts initiated a migration that resulted in the formation of a cellular network after 1 day of culture on top of the gel. Electron microscopy revealed that fibroblasts were able to remodel the basement membrane matrix by penetrating into the gel (from day 3), depositing fibronectin and collagen fibers, and retracting this extracellular matrix. Fibroblasts cultured on the Engelbreth-Holm-Swarm reconstituted basement membrane matrix displayed ultrastructural features characterized by a poor synthetic apparatus (rough endoplasmic reticulum and Golgi vesicles), a large cytoskeleton, and intracytoplasmic vesicles containing laminin. Thus the reconstituted basement membrane matrix is remodeled by skin fibroblasts, and reciprocally their ultrastructural morphologic features are affected by this matrix.

Splenic simulation by left hepatic lobe following splenectomy

Remodeling of the liver following splenectomy may simulate hypertrophy of an accessory spleen on sulfur colloid scans. Two patients are reported. In one case splenic simulation is attributed to unusual hepatic scarring confirmed at autopsy. In the second the unusual configuration appears to have been caused by molding of the liver. The clinician should be aware of possible splenic simulation in postsplenectomy patients suspected of hypersplenism.

Fluorescein angiography after retinal detachment microsurgery

The eyes of 78 patients who underwent retinal detachment microsurgery (82 eyes) were prospectively evaluated postoperatively with fluorescein angiography. Of these 14.6% showed angiographic evidence of cystoid macular oedema (CMO.). A significantly greater risk of developing cmo was discovered in aphakic eyes (30% CMO.) as compared to phakic eyes (7% CMO.) and in eyes where the maculae were detached pre-operatively (23% CMO.), as compared to eyes where the maculae were attached pre-operatively (5% CMO.). Eyes which had undergone several surgical procedures for retinal reattachment (38% CMO.) were compared to eyes which had undergone only one surgical procedure (6.5% CMO.). It was found that 4.9% of the 82 eyes showed cellophane premacular membrane without dye leakage. A further 6% of the eyes showed premacular membranes associated with dye leakage. No statistically significant risk factor associated with the development of macular pucker was disclosed in this series.

Longitudinal study of asymptomatic meningococcal carriage in two Belgian populations of schoolchildren

In Brussels, a 15-month longitudinal survey was conducted in two primary schools, from March 1975 to May 1976, in order to analyse the dynamic of asymptomatic meningococcal carriage, during an epidemic mainly caused by serogroup B, serotype 2 Neisseria meningitidis. In the first school, which is situated in a suburban area with upper-middle socio-economic status of residents, a mean prevalence of carriers of 10 per cent, an acquisition rate of eight per 1000 months, and a mean duration of carriage of 12.4 months were observed among 158 schoolchildren aged six to 11 years old. In the second school, which is situated in a densely populated area with low socio-economic status of residents, a mean prevalence of carriers of 33 per cent, an acquisition rate of 28 per 1000 months, and a mean duration of carriage of 11.7 months were observed among 203 schoolchildren aged three to 14 years old. For both schools, the median duration of carriage was estimated at 9.4 months. The differences of prevalence and incidence of acquisition between the two schools cannot be explained by age, sex or ethnic factors and are probably related to socio familial variables. The theoretical relationship between prevalence, incidence and duration of meningococcal carriage was for the first time demonstrated in this study. The results also suggest that populations of low socio-economic status and living in densely populated areas constitute a target population for meningococcal disease prevention.

Computed tomography with geometrical enlargement

Third generation CT scanners perform examinations of small objects without employing all the detectors. Geometrical enlargement solves this problem by moving the tube-detector assembly according to the size of the object to be scanned; this improves spatial resolution, reducing both the tube current and the skin dose. Such an application for pediatric CT and small objects is of particular interest.

Atypical transmission of ABO blood groups in a French family

A group AB mother (Mrs P.D.) gave birth to a group O female baby (C.D.). Extensive study of the blood group genetic markers in both the parents and the child, carried out on several occasions, showed nothing unusual outside the ABO system. Mrs P.D. then, gave birth to a second female baby who was also group O. Mrs P.D. had normal amounts of A, B, H and Lewis antigens in her saliva. The H, A and B agglutinability of her red cells was in the range of normal A2B group. This A2B blood group was characterized by very low A gene-specified glycosyltransferase activity in serum. Moreover this activity was undetectable in red blood cell membranes. These results are discussed in the light of various hypotheses in order to explain this unusual transmission of ABO blood group.

Cardiac catheterization: dosimetry on patients

Our study was made on 49 patients and we used capsules of lithium fluoride. The average fluoroscopy time was 32 min. and the average cinema film length was 76.5 metres. The relationship between the entry dose, the fluoroscopy time and the length of cinema film allowed us to calculate a fluoroscopy equivalent time (F.E.T) for each patient which was of 51 min. (32 min. + 76/4) as radiation dose of one minute fluoroscopy equal radiation dose of 4 metres of cinema film. The average heart dose was 0.70 X 10(-3) X FET (GY) or 70 mr/min. There was an absence of relation of the exit dosage to the diameter of the patient and a proportionality of the heart dose to the exit dose. Furthermore the maximum eye dose recorded was 200 mrads and the maximum gonadal dose was 350 mrads.