Nanometre-level analysis demonstrates that lipid flow does not drive membrane glycoprotein movements

Nanometre-level analyses of the movements of membrane glycoproteins tagged with gold particles demonstrate that diffusing particles are not under the influence of a lipid flow, although a subset of particles which appear attached to the cytoskeleton are moving rearward.

[Pathologic analysis of lobular carcinoma of the breast--report of 36 cases]

Thirty-six cases of lobular carcinoma of the breast are reported. It comprised 11% of all the breast carcinomas. All patients were female. There were 6 cases of lobular carcinoma in situ (LCIS) with a mean age of 42 years and 30 cases of infiltrating lobular carcinoma (ILC) with a mean age of 51 years. LCIS was small, millet-size lesion which was usually accompanied with fibrocystic disease of the breast and often accidentally observed by pathologic examination. LCIS was prone to multicentricity, bilateral involvement and developing into ILC. Histologically, LCIS was characterized by intralobular proliferation of the cells lining the acini. The lumen became packed with these cells and progressively disappeared as the lobule became more and more distended. Pleomorphism of the cells was usually minimal. Necrosis was absent and mitosis was extremely rare. When the basement membrane of the acini was destroyed, two types of invasion were observed: first, the cells invaded into the stroma between the acini within the same lobule-so called LCIS with invasion, then the cells spread out of the boundary of the involved lobule and presented as threadlike strands or small nests infiltrated in a dense fibrous matrix. Sometimes the cells formed concentric rings around an apparently dilated duct. It should be pointed out that the mistakes made by pathologists in practics are overlooking LCIS and misinterpreting ILC.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell poking: quantitative analysis of indentation of thick viscoelastic layers

A recently introduced device, the cell poker, measures the force required to indent the exposed surface of a cell adherent to a rigid substratum. The cell poker has provided phenomenological information about the viscoelastic properties of several different types of cells, about mechanical changes triggered by external stimuli, and about the role of the cytoskeleton in these mechanical functions. Except in special cases, however, it has not been possible to extract quantitative estimates of viscosity and elasticity moduli from cell poker measurements. This paper presents cell poker measurements of well characterized viscoelastic polymeric materials, polydimethylsiloxanes of different degrees of polymerization, in a simple shape, a flat, thick layer, which for our purposes can be treated as a half space. Analysis of the measurements in terms of a linear viscoelasticity theory yields viscosity values for three polymer samples in agreement with those determined by measurements on a macroscopic scale. Theoretical analysis further indicates that the measured limiting static elasticity of the layers may result from the tension generated at the interface between the polymer and water. This work demonstrates the possibility of obtaining quantitative viscoelastic material properties from cell poker measurements and represents the first step in extending these quantitative studies to more complicated structures including cells.

Interpretation of fluorescence correlation spectroscopy and photobleaching recovery in terms of molecular interactions

The theoretical basis and experimental implementation of FCS and FPR measurements are now well established. Because of the requirements for system stability and long data acquisition times FCS is relatively rarely used. But FCS can provide unique information, especially about extents of aggregation or polymerization and therefore is a useful supplement to FPR for certain applications. FPR measurements are now carried out routinely in many laboratories in a variety of formats using different beam profiles, optical systems, and analytical schemes. A particular version may be better adapted to a specific application. The spot photobleaching approach, however, seems simplest and most versatile for cellular studies and is now most often used. Important experimental considerations in setting up a spot photobleaching instrument are discussed in detail in Chapter 10 by Wolf (this volume) and elsewhere (Petersen et al., 1986a). In interpreting FPR measurements it is also important to take into account the possibility of systematic errors from a number of sources. In Chapter 10 in this volume, Wolf discusses many factors that must be properly controlled in carrying out FPR measurements. Additional consideration of some of these points is presented by Petersen et al. (1986a). One potentially troublesome type of error arises from the possibility that chemical reactions initiated by the photobleaching pulse or during the measurement of recovery could significantly perturb the system. Evidence from a variety of sources [summarized, for example, in Petersen et al. (1986a)] indicates that photobleaching fluorophores can induce chemical cross-linking of cellular proteins under some conditions. But measurements in a number of different systems have demonstrated that, even if these types of reactions occur in FPR measurements, nevertheless they do not perturb the measured mobilities. If possible, however, this point should be checked for each new system because variations in structure or environmental conditions could enhance the chemical cross-linking reactions mediated by photogenerated free radicals. In practice, the principal difficulty in carrying out FPR measurements on cells is frequently the low intensity of the fluorescent signal which can be obtained from specifically labeled cell surface ligands or microinjected components. This low intensity results from the typically low capacity of an individual cell for the specifically labeled macromolecule. Even in the absence of systematic errors, low emission intensity will reduce the accuracy of measurements due to shot noise. This is an important practical limitation on measuring accuracy. Low measurement accuracy severely limits the extent to which the data can be interpreted mechanistically. Precision can be improved by averaging many recovery experiments.(ABSTRACT TRUNCATED AT 400 WORDS)

[Primary non-Hodgkin's lymphoma of the breast--report of 8 cases]

Eight cases of primary Non-Hodgkin's lymphoma (NHL) of the breast are reported. Almost all presented as a painless movable mass without nipple retraction, edema in the overlying skin, satellite skin nodules or bloody nipple discharge. Most of the cases belonged to B cell lymphoma. Wide local excision or simple mastectomy combined with chemotherapy or radiotherapy were adopted in the treatment of these patients. The average survival was 28 months. Since prognosis of NHL is worse than that of breast carcinoma and is easily misdiagnosed as breast cancer, it is important to take vigilance in the differential diagnosis.

[Midline malignant histiocytosis--diagnostic and prognostic study of 42 patients]

42 patients of midline malignant histiocytosis are reported. The differential diagnosis should be made carefully, for its clinical sign and pathologic picture are similar to some neoplasms, inflammatory or allergic diseases. The 3, 5 and 10 year survival rates are 52.4%, 38.1% and 21.4% respectively. The survival rate of those in the prodromal stage is the highest. The authors suggest that this disease probably belongs to the malignant tumor of mononuclear macrophage system and be a special type of malignant histiocytosis. It may be designated as the midline malignant histiocytosis.