Life Sciences Commons^™

Imaging The Electrocyte Of Torpedo Marmorata By Scanning Force Microscopy, L. I. Pietrasanta, A. Schaper, G. Q. Fox, F. J. Barrantes, T. M. Jovin

Scanning Microscopy

Scanning force microscopy (SFM) and scanning electron microscopy (SEM) were used to examine the tissue structure of the electric organ of Torpedo marmorata in air and in liquid after applying fracturing and cryosectioning techniques and chemical fixation. The electric organ is organized in columns of stacked electrocytes, arranged in a honeycomb pattern. The columns were cut along a plane normal to the cell stack and thin sections were transferred to polylysine coated glass coverslips. The polarity of the electrocytes was made apparent by immunofluorescence microscopy directed to different domains of the acetylcholine receptor (AChR), thus revealing the innervated face of …

Influence Of Bleeding On Post-Mortem Tenderization Of Fish Muscle During Chilled Storage, M. Ando, A. Nishiyabu, T. Nakagawa, Y. Makinodan

Scanning Microscopy

The influence of bleeding on post-mortem tenderization of fish muscle during storage was studied. Six fish species were used for the present study. Among them, delay of post-mortem tenderization of muscle by bleeding was shown in the pelagic fishes: yellowtail, horse mackerel, and striped jack. On the other hand, bleeding had no influence on the muscle firmness of the bottom fishes: red sea bream, flatfish, and rudder-fish. According to transmission electron microscopy, degradation of pericellular collagen fibrils was delayed in bled yellowtail and horse mackerel. In the case of striped jack, though, collagen fibril degradation could not be observed; slower …

The Nucleation And Growth Of Calcium Phosphate Crystals At Protein And Phosphatidylserine Liposome Surfaces, G. H. Nancollas, A. Tsortos, A. Zieba

Scanning Microscopy

The kinetics of calcium phosphate crystal growth at the surfaces of proteins and phospholipids has been investigated using free drift and constant composition methods in supersaturated calcium phosphate solutions (relative supersaturations: with respect to hydroxyapatite, HAP, σHAP = 15.0, and with respect to octacalcium phosphate, OCP, σOCP = 1. 9). Fibrinogen and collagen molecules adsorbed at hydrophobic surfaces as well as uncross-linked collagen fibrils induce ion binding and subsequent nucleation of calcium phosphate. The formation of OCP on phosphatidylserine vesicles introduced to highly supersaturated calcium phosphate solutions probably involves the interaction of the calcium ions with the ionized carboxylic groups …

Hydration-Scanning Tunneling Microscopy As A Reliable Method For Imaging Biological Specimens And Hydrophilic Insulators, M. Heim, R. Eschrich, A. Hillebrand, H. F. Knapp, G. Cevc, R. Guckenberger

Scanning Microscopy

The recently discovered high lateral conductivity of molecularly thin adsorbed water films enables investigation of biological specimens, and even of surfaces of hydrophilic insulators by scanning tunneling microscopy (STM). Here we demonstrate the capabilities of this method, which we call hydration-STM (HSTM), with images of various specimens taken in humid atmosphere: We obtained images of a glass coverslip, collagen molecules, tobacco mosaic virus, lipid bilayers and cryosectioned bovine achilles tendon on mica. To elucidate the physical mechanism of this conduction phenomenon we recorded current-voltage curves on hydrated mica. This revealed a basically ohmic behavior of the J-V curves without a …

Ultrastructure Of Dentin Matrix In Heritable Dentin Defects, J. Waltimo, H. Ranta, P. -L. Lukinmaa

Scanning Microscopy

Heritable dentin defects form a group of diseases which exclusively affect dentin among the various dental tissues. While one type is associated with the generalized connective tissue disorder, osteogenesis imperfecta, other types occur as single traits. The clinical manifestations of the dentin defects vary from insignificant to severe enough to cause aesthetical and functional failure of the teeth. Scanning and transmission electron microscopic studies, reviewed in this paper, have markedly clarified the ultrastructure of the aberrant dentin matrix. Both similar and different changes seem to occur in the various forms of heritable dentin defects. Abnormalities in the appearance and organization …

Scanning Electron Microscopic Study Of The Collagen Sheath Of The Human Thyroid Gland And Its Disorders, Masao Morita, Takuro Ogata, Keijiro Araki

Scanning Microscopy

A cell-maceration/scanning electron microscope (SEM) method was employed to demonstrate the collagen sheath around follicles (perifollicular sheath) of the human thyroid gland and its disorders. In the normal thyroid gland, the follicles were surrounded by spherical collagen sheaths composed of a framework of thick collagen bands 1-5 μm in width and fine solitary collagen fibrils 50-70 nm in diameter. In benign thyroid diseases (Graves' disease, Hashimoto's thyroiditis and adenomatous goiter), the perifollicular sheaths differed in size and in shape according to the disease, but they were always composed of thick collagen bands and fine fibrils as in the normal thyroid. …

Scanning Electron Microscopic Study Of The Three-Dimensional Structure Of The Collagen Networks Of Gastric Cancer, Masuki Iyoki, Keijiro Araki, Takuro Ogata

Scanning Microscopy

The three-dimensional structure of the collagen networks in human gastric carcinoma was examined by scanning electron microscopy (SEM) after treatment with the cell-maceration method using a low temperature NaOH solution. Based on stromal content, the poorly differentiated adenocarcinoma can be divided into the medullary carcinoma area and the scirrhous carcinoma area. In the medullary carcinoma, the collagen sheath around the small tumor cell acinus formed spherical chambers (20-30 μm in diameter) with fenestrations (about 5 μm in diameter) connecting the chambers. The collagen sheath was composed of fine collagen fibrils (about 50 nm in diameter). In the scirrhous area, there …

Radiation-Induced Fibrosis: The Structure/Function Relationship, J. C. Murray

Scanning Microscopy

Fibrosis is a frequent complication of therapeutic radiation delivered to organ sites such as the thorax and pelvic region. We investigated the relationship between function, and biochemical and structural changes in the lung and colon of CBA mice irradiated with 240 kV X-rays. Progressive changes in lung function, as evidenced by increased breathing rates were observed out to 6 months post-irradiation. Biochemical studies demonstrated increased metabolism (synthesis and breakdown) of collagen around 6 months after irradiation, but provided no evidence of net collagen accumulation. Analysis of collagen isotypes revealed a slight increase in the ratio of types I and Ill. …

Contributions Of Electron Microscopy To The Study Of The Hypertrophic Scar And Related Lesions, C. Ward Kischer

Scanning Microscopy

Prior to 1969, only one study of the hypertrophic scar had been done using electron microscopy, and that one used electron diffraction. Since that time, studies using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) have been integral in establishing not only the characteristics of this lesion but in formulating the reasons why the scar develops and how it resolves. The first SEM studies demonstrated a homogeneous, dense dermal matrix which supported the conclusion that the hypertrophic scar and keloid reflected excess collagen. These same studies were integral in identifying the collagen nodule as the basic anatomical unit of …

Calcium Pyrophosphate Crystal Deposition: A Kinetic Study Using A Type I Collagen Gel Model, Gretchen S. Mandel, Paul B. Halverson, Melisa Rathburn, Neil S. Mandel

Scanning Microscopy

Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease is characterized by deposits of triclinic (t) and monoclinic (m) CPPD crystals in articular and fibrocartilage. Many investigators have attempted to model CPPD crystal growth using both solution and a variety of gel systems. We have investigated the effect of type I collagen fibrils on CPPD crystal nucleation and growth using an ionic diffusion model. Collagen was isolated from porcine menisci using a pepsin solubilization procedure and gelled in three layers, with one containing 10 mM pyrophosphate (PPi) plus physiologic ions, the middle containing only the ions, while the third contained 25 mM …

Achilles Tendon Replacement By A Collagen Fiber Prosthesis: Morphological Evaluation Of Neotendon Formation., Arthur J. Wasserman, Y. Pedro Kato, David Christiansen, Michael G. Dunn, Frederick H. Silver

Scanning Microscopy

Reconstituted type I collagen was processed into fibers which were subsequently severely dehydrated and cyanamide cross-linked. Fibers prepared by this method were stronger and more resistant to degradation than uncrosslinked fibers. When used as a tendon replacement prosthesis, morphological events occurred which were observed by light, scanning, transmission electron microscopy and electron histochemistry.

Resorption was the initial host response to the prosthesis and involved gradual biodegradation. Formation of a host-replacement tendon was the second response. Increased collagen fibril diameters and a transition in the proteoglycan/collagen fibril interactions occurred in the newly developing connective tissue between 3 and 10 weeks post-implantation. …

Stimulation Of Collagen Formation In The Intestinal Anastomosis By Low Dose He-Ne Laser, David T. Yew, Winnie W. Y. Li, K. M. Pang, Y. C. Mok, C. Au

Scanning Microscopy

The effect of low dose He-Ne laser on the healing of intestinal anastomosis was studied in the albino rat. A small piece of jejunum was removed from each rat and the ends sutured back with a simple interrupted pattern. In the experimental animal, the anastomosis was Irradiated through an optic fiber with a He-Ne laser (1 mW) for 15 minutes whereas in the control animal, the anastomosis was not irradiated. The differences between the two groups were compared by histology, transmission electron microscopy, scanning electron microscopy and autoradiography 3 and 7 days after operation. The laser treated experimental animals demonstrated …

Extracellular Matrix Production By Osteoblasts On Bioactive Substrata In Vitro, J. E. Davies, T. Matsuda

Scanning Microscopy

Some bone-substitute biomaterials have been classified as bioactive since they allow direct biological bonding to their surface in vivo. Using in vitro techniques, we have re-created the first stages of this biological bonding phenomenon and compared the initial, fibrillar, extracellular matrices produced by migrated primary osteoblast cell populations in contact with both dense and macroporous calcium phosphate substrata, apatite/bioactive glass composite (ABC) and 45S5 bioactive glass (BAG). The first formed fibrils in contact with these materials may be identified as collagen from their morphology as observed by scanning electron microscopy (SEM). However, the organization of this fibrillar material is …

An Electron Microscopic Study Of Microfibrils Of Bone Marrow, Ferrell R. Campbell

Scanning Microscopy

After fixation of bone marrow with glutaraldehyde, tannic acid and saponin, a delicate network of microfibrils (10 nm) was observed in the extracellular space. Masses of microfibrils were most frequently observed between the endothelial cells of the sinusoidal wall and adventitial reticular cells, but were also observed at other sites throughout the marrow stroma. Microfibrils are an important component of the extracellular material of bone marrow and appear to provide an anchoring substrate for the endothelium.

Contribution Of Scanning Electron Microscopy And Associated Analytical Techniques To The Study Of Atherosclerotic Disease, R. Laschi

Scanning Electron Microscopy

Human carotid atheroma has been examined by scanning electron microscopy (SEM) utilizing both secondary and backscattered electron detectors and transmission electron microscopy (TEM) both at conventional and high voltage.

Different cytochemical techniques have been used to map elastic fibers, proteoglycans, calcium, non esterified cholesterol. By immunocytochemistry the distribution of factor VIII related antigen and actin has been studied.

With SEM it was possible to detect aspects of carotid plaques not appreciated when using other conventional techniques. With TEM some modifications of the structural and/or functional features of connective tissue macromolecules have been observed. The occurrence of anomalous collagen has been …

Implantation Failure Of Peritoneal Dialysis Catheters: A Scanning Electron Microscopical Study, D. W. Gregory, G. G. Youngson, D. Marshall

Scanning Electron Microscopy

Patients with end stage renal failure may be treated by continuous ambulatory peritoneal dialysis. The transcutaneous portion of the catheters used in this treatment is covered with porous expanded polytetrafluoroethylene (PTFE) to provide a surface suitable for tissue infiltration. Following some instances where catheters failed to become fixed in the abdominal wall, a scanning electron microscopical study was carried out to compare the infiltration of catheters having successful or unsuccessful implantation.

The porous layer of a well-fixed catheter, removed after successful renal transplantation, was infiltrated with collagen fibrils and overlain by layered connective tissue composed of fibroblasts and collagen fibre …

Collagen Deposition During Wound Repair, Charles J. Doillon, Michael G. Dunn, Richard A. Berg, Frederick H. Silver

Scanning Electron Microscopy

Collagen fiber diameters, amount of birefringent collagen (brightness) and birefringence retardation were measured in implanted collagen-based sponges containing hyaluronic acid (HA) and fibronectin (FN). In the presence of HA and FN, increased number of fibroblasts and brightness were observed 6 days after wounding. Increased brightness in the presence of HA and FN reflected increased deposition of oriented collagen fibers. From days 9 to 12, increased fiber diameters were similar in implanted collagen-based sponges with or without HA and FN. Increased birefringence retardation in sponges containing HA and FN was consistent with increased packing density of collagen fibers observed by scanning …

Demonstrable Fixative Interactions, Keith M. Meek, John A. Chapman

Scanning Electron Microscopy

Electron-optical examination of reconstituted collagen fibrils fixed with tannic acid and/or glutaraldehyde and positively stained with heavy metal anions and cations reveals distinct changes in the high resolution staining patterns seen in TEM. Correlation with the known sequence data demonstrates that these changes are caused by (a) interaction of the fixative with certain charged groups in the collagen and (b) localized stain-exclusion effects following fixation. We have analysed the positive and negative staining patterns from glutaraldehyde-treated collagen in detail. In positive staining, uptake of staining ions is shown to be inhibited not only at residues known to interact with glutaraldehyde …

Wave-Length Dispersive Microprobe Analysis Of Coated Samples Of Bulk Tissues, C. Ward Kischer, Thomas M. Teska

Scanning Electron Microscopy

Hypertrophic scars contain highly pleomorphic cells, including many from the erythrocytic series which have been extravasated. The conventional visual mode of SEM cannot distinguish the cell types with certainty except in the case of typical biconcave disc-shaped erythrocytes. Microprobe elemental analysis might be used to differentiate one type from another on the basis of iron and possibly phosphorus (for nucleated cells). Using coated specimens (gold or gold-palladium) precludes simultaneous visual mode SEM with EDX because of energy line interference with phosphorus and other elements. However, wave-length dispersive analysis offers minimal or no interference, and a coated specimen offers the use …