ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01287.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYCultivated cells form a valuable model system for studies on the effects of various preparative protocols for scanning electron microscopy (SEM). The various effects of each preparative step can be followed in detail in the light microscope and no diffusion gradients complicate the fixation and other procedures as in the case of solid tissues.Studies on cultivated cells indicate that the glutaraldehyde component of a glutaraldehyde‐based fixative does not contribute to the effective osmotic pressure of the fixative and thus the osmolarity of the buffer, and other components, must be equalized to that of the medium in which the cells grow. Even small deviations from this ideal effective osmotic pressure will result in osmotically induced artefacts.Disturbances of pH and temperature of the cultures prior to and during fixation will result in changes in the appearance of many cellular structures such as microspikes and ruffles.We find that osmium fixation is advisable in most instances for best possible membrane preservation and that even long periods of glutaraldehyde fixation do not compensate for osmium fixation.Dehydration always results in shrinkage. Freeze drying (FD) and critical point drying (CPD) also give rise to shrinkage, the former to a lesser degree than the latter.A gold‐palladium alloy gives a less granular coating that does gold alone. When cultured cells are studied, a metal thickness of between 5 and 15 nm is usually sufficient to give rise to an adequate secondary electron production and to avoid charging even at accelerating voltages of 30–40 kV. Without treatment with OsO4a thicker metal coating is req

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01288.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYScanning electron microscopy (SEM) is a valuable tool for the analysis of morphogenetic events. The role of extracellular materials in primary neural induction in the early stage 5 chick embryo may be analysed by SEM as well as by histochemical techniques.During primary neural induction, extracellular materials in the early stage 5 chick embryo form a fan‐shaped region on the ectoderm anterior to Hensen's node. Fibronectin and sulphated glycosaminoglycans are present anterior to Hensen's node on the ventral ectoderm layer. It is proposed that the fanshape of extracellular materials has a dual function; as a chemical substrate to form close contacts between the inducing cells and the target ectoderm cells, and to serve as a contact guidance system for the pre‐notochordal ce

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01289.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYAfter 15 years of development, scanning electron microscopy now plays a major role in biomedical science. This brief review highlights some aspects of the contribution of SEM to the teaching of morphology, to experimental scientific research and to pathological diagnosis.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01290.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYExamination of autolysed control mouse small intestine using scanning electron microscopy has revealed details of the connective tissue components of the mucosa. The cores of the villi are seen collapsed across the intervillous basin. Crypts of Lieberkuhn are seen as tubular channels stretching down from the intervillous basin. Sometimes the crypts are split in two by a connective tissue septum. The mouths of the crypts of Lieberkuhn are, in general, arranged in double rows between the single rows of villi. The ratio of number of crypts to numbers of villi was calculated as 5.01:1. This is close to the figure of 4.53:1, as quoted by Smith&Jarvis (1980) who used differential interference contrast microscopy to investigate the crypt to villus ratio. After radiation, the severe drop in the number of crypt mouths can be clearly seen by the combination of autolysis and scanning electron microscopy: the rows of crypt mouths between the villi have been lost, and many crypt mouths have been occluded by stromal tissue. The arrangement of the crypt mouths and the observation of mucosal abnormalities after irradiation have led to the postulation that cells leaving the crypt mouths move in a spiral manner towards and then up the villous surface: this postulated movement might imply an asymmetry in some properties of enterocytes. The use of scanning electron microscopy in conjugation with autolysis and irradiation has thus forced a critical re‐examination of the relationships between crypts and vill

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01291.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYScanning electron microscopy of the small intestine of the mouse 5 days after X‐ or neutron irradiation has revealed the formation of giant cells on the villus surface.Correlative light microscopy and transmission electron microscopy have shown that these giant cells are syncytial in nature.Characteristic features of lipid inclusions and apical microvilli suggest that these syncytia are giant enterocytes. It has also been shown that these giant cells are in contact with the connective tissue core of the villus and have a close contact with the normal enterocytes, thus maintaining mucosal integrity. It is postulated that radiation damage has caused incomplete separation during mitosis and that attempted division occurs outside the crypts of Lieberkuh

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01292.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYThis report reviews the contribution of scanning electron microscopy (SEM) in haematology. Important observations regarding red cell shape and deformities are referred to and contributions in the definition and classification erythrocyte disorders are stressed. In this field there is no doubt that SEM has contributed much to the three‐dimensional visualization of RBC disorders.As far as leucocyte pathology is concerned the situation is less clear. SEM has contributed much to current knowledge and understanding of the surface properties of white blood cells. Normal leucocytes have different surface features and can be distinguished under the SEM. However, some overlap does occur, making individual distinction on the basis of surface architecture alone extremely difficult. The difficulties in this regard are discussed in this review and factors influencing the variability of surface microprojections are reviewed briefly.Leukaemic cells of different origins may also be distinguished under the SEM. However, while ‘hairy’ cells have typical surface features and non‐lymphoid leukaemic cells, in particular monocytes, are readily distinguished from lymphoid leukaemic cells, there is much overlap of surface topography. Undifferentiated cells and early myeloblasts and lymphoblasts have similar surface features and cannot be distinguished under the SEM. While SEM adds a valuable third dimension to morphology and ultrastructure, it cannot be used alone in the definition of difficult cases of acute le

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01293.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYIn this study scanning immuno‐electron microscopic (SIEM) techniques were used to identify human leukaemia‐lymphoma cells. Monodispersed polystyrene (latex) beads were conjugated to specific antisera using glutaraldehyde, in an attempt to detect surface antigenic components on a variety of cells of known origin. Antisera, mostly immunoglobulin fractions, against human thymus (T) derived cells, common type acute lymphoblastic leukaemia cells (C/ALL) and surface immunoglobulin (sIg) bearing cells were used to coat latex spheres, while rabbit anti‐mouse Thy‐1 antiserum or whole human‐IgG (γ‐globulin) bound to latex were used as controls in some experiments. The use of SIEM techniques in the direct mode as a simple and sensitive method for labelling surface antigens is described. The disadvantages of the SIEM methodology are also summarized while the requirements for optimal cell preparation using this technique are stressed. The experiments were designed to ascertain whether prolonged fixation of cells could be used prior to incubation of the cells with the marker. In this respect, repeated neutralization of the glutaraldehyde with glycine is essential. SIEM labelling of cells is random and unreliable without adequate quenching with glycine. The heteroantisera used in this study proved to be adequate and insignificant non‐specific attachment and cross reactivity were seen. SIEM adds a further dimension to ultrastructural aspects of immunology and is a potentially useful tool in the study and identification of leukaemia and

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01294.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYColloidal gold can be used as an electron‐dense cytochemical probe for direct or indirect labelling techniques. Gold markers can be prepared in a size range of 5–150 nm, and show size‐dependent shape characteristics and absorption spectra. Size and shape distribution increases with mean particle diameter, with appreciable overlapping between populations of different mean size. Using radio isotope‐binding assays, spectrophotometric analysis and an innovative rapid microtitration technique, the effect of pH, ionic strength and protein concentration on gold‐protein interaction has been studied. Efficient adsorption of protein to gold occurs at, or near, the pI of the protein. The amount of protein needed to effect stabilization is both a function of pH and of ionic strength, but does not reflect the amount of protein binding for all proteins. There is evidence for multilamellar adsorption of proteins to gold, which is discussed in context of the bioactivity, and stability of the probe. A working protocol for the routine reproducible manufacture of protein‐gold probes is given, making use of the microtitr

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01295.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYProcedures for preparing gold colloid particles stabilized with either avidin or protein A are described. Methods of using these general utility tracers for localizing biotinylated and fc bearing immunoglobulins are outlined and, as examples of the way in which these methods can be applied, procedures for identifying epidermal growth factor receptors and surface fibronectin on ovarian granulosa cells are described.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01296.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY