A modified technique for the impregnation of lanthanum tracer to study the integrity of tight junctions on cells grown on a permeable substrate

2006 ◽  
Vol 69 (10) ◽  
pp. 776-783 ◽  
Author(s):  
Harriet Nilsson ◽  
Anca Dragomir ◽  
Anders Ahlander ◽  
Marianne Ljungkvist ◽  
Godfried M. Roomans
Keyword(s):  
Tight Junctions ◽  
Modified Technique ◽  
Lanthanum Tracer

scholarly journals A modified technique to obtain uniform precipitation of lanthanum tracer in the extracellular space.

1977 ◽  
Vol 25 (8) ◽  
pp. 1013-1015 ◽  
Author(s):  
M Shaklai ◽  
M Tavassoli
Keyword(s):  
Bone Marrow ◽  
Low Temperature ◽  
Extracellular Space ◽  
Lanthanum Nitrate ◽  
Modified Technique ◽  
Lanthanum Tracer

A method for obtaining a uniform, dense precipitate of lanthanum nitrate to delineate extracellular space is described. Improvement of the previous technique is achieved by phosphate precipitation of lanthanum in the tissue carried out at low temperature. This method has been successfully applied to bone marrow.

scholarly journals A freeze-fracture and lanthanum tracer study of the complex junction between Sertoli cells of the canine testis.

1978 ◽  
Vol 76 (1) ◽  
pp. 57-75 ◽  
Author(s):  
C J Connell
Keyword(s):  
Tight Junctions ◽  
Sertoli Cells ◽  
Freeze Fracture ◽  
Intercellular Junctions ◽  
Septate Junction ◽  
Septate Junctions ◽  
Thin Sections ◽  
En Face ◽  
Lanthanum Tracer ◽  
Complex Junction

What appear to be true septate junctions by all techniques currently available for the cytological identification of intercellular junctions are part of a complex junction that interconnects the Sertoli cells of the canine testis. In the seminiferous epithelium, septate junctions are located basal to belts of tight junctions. In thin sections, septate junctions appear as double, parallel, transverse connections or septa spanning an approximately 90-A intercellular space between adjacent Sertoli cells. In en face sections of lanthanum-aldehyde-perfused specimens, the septa themselves exclude lanthanum and appear as electron-lucent lines arranged in a series of double, parallel rows on a background of electron-dense lanthanum. In freeze-fracture replicas this vertebrate septate junction appears as double, parallel rows of individual or fused particles which conform to the distribution of the intercellular septa. Septate junctions can be clearly distinguished from tight junctions as tight junctions prevent the movement of lanthanum tracer toward the lumen, appear as single rows of individual or fused particles in interlacing patterns within freeze-fracture replicas, and are seen as areas of close membrane apposition in thin sections. Both the septate junction and the tight junction are associated with specializations of the Sertoli cell cytoplasm. This is the first demonstration in a vertebrate tissue of a true septate junction.

Intercellular Junctions in the Differentiating Rat Otocyst

1979 ◽  
Vol 88 (4) ◽  
pp. 540-544 ◽  
Author(s):  
Khalid M. Khan ◽  
William F. Marovitz
Keyword(s):  
Gap Junctions ◽  
Tight Junctions ◽  
Intercellular Space ◽  
Early Stage ◽  
Freeze Fracture ◽  
Intercellular Junctions ◽  
Junctional Complex ◽  
Luminal Surface ◽  
Lanthanum Tracer

Intercellular junctions between cells of the rat otocyst on the 12th day of gestation were studied using lanthanum tracer and freeze-fracture techniques. At the luminal surface, the intercellular space is closed by a series of tight junctions. Gap junctions are also present between cells both within and below the luminal junctional complex. The presence of tight and gap junctions at this early stage in the differentiating otocyst is probably essential for the development of a normally functioning adult ear.

Microanatomy of the Periplasm of Bacillus Licheniformis

1971 ◽  
Vol 29 ◽  
pp. 262-263
Author(s):  
B.K. Ghosh
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Bacillus Licheniformis ◽  
External Environment ◽  
Permeability Barrier ◽  
Periplasmic Space ◽  
Modified Technique ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Periplasm of bacteria is the space outside the permeability barrier of plasma membrane but enclosed by the cell wall. The contents of this special milieu exterior could be regulated by the plasma membrane from the internal, and by the cell wall from the external environment of the cell. Unlike the gram-negative organism, the presence of this space in gram-positive bacteria is still controversial because it cannot be clearly demonstrated. We have shown the importance of some periplasmic bodies in the secretion of penicillinase from Bacillus licheniformis.In negatively stained specimens prepared by a modified technique (Figs. 1 and 2), periplasmic space (PS) contained two kinds of structures: (i) fibrils (F, 100 Å) running perpendicular to the cell wall from the protoplast and (ii) an array of vesicles of various sizes (V), which seem to have evaginated from the protoplast.

Ultrastructure of melanocyte-keratinocyte interactions and pigment transfer in vitro

1978 ◽  
Vol 36 (2) ◽  
pp. 650-651
Author(s):  
Raul I. Garcia ◽  
Evelyn A. Flynn ◽  
George Szabo
Keyword(s):  
Direct Injection ◽  
Skin Pigmentation ◽  
Freeze Fracture ◽  
Pigment Granule ◽  
Time Lapse ◽  
Ultrastructural Level ◽  
Lanthanum Tracer ◽  
A Cell

Skin pigmentation in mammals involves the interaction of epidermal melanocytes and keratinocytes in the structural and functional unit known as the Epidermal Melanin Unit. Melanocytes(M) synthesize melanin within specialized membrane-bound organelles, the melanosome or pigment granule. These are subsequently transferred by way of M dendrites to keratinocytes(K) by a mechanism still to be clearly defined. Three different, though not necessarily mutually exclusive, mechanisms of melanosome transfer have been proposed: cytophagocytosis by K of M dendrite tips containing melanosomes, direct injection of melanosomes into the K cytoplasm through a cell-to-cell pore or communicating channel formed by localized fusion of M and K cell membranes, release of melanosomes into the extracellular space(ECS) by exocytosis followed by K uptake using conventional phagocytosis. Variability in methods of transfer has been noted both in vivo and in vitro and there is evidence in support of each transfer mechanism. We Have previously studied M-K interactions in vitro using time-lapse cinemicrography and in vivo at the ultrastructural level using lanthanum tracer and freeze-fracture.

Freeze-etch observations on the tight junctions of sertoli cells grown in organ culture with FSH

1978 ◽  
Vol 36 (2) ◽  
pp. 340-341
Author(s):  
Rita Meyer ◽  
Zoltan Posalaky ◽  
Dennis Mcginley
Keyword(s):  
Organ Culture ◽  
Tight Junctions ◽  
Sertoli Cell ◽  
Germ Cells ◽  
Sertoli Cells ◽  
Barrier Function ◽  
Cell Junction ◽  
Intramembranous Particles ◽  
Junctional Complexes ◽  
Oriented Parallel

The Sertoli cell tight junctional complexes have been shown to be the most important structural counterpart of the physiological blood-testis barrier. In freeze etch replicas they consist of extensive rows of intramembranous particles which are not only oriented parallel to one another, but to the myoid layer as well. Thus the occluding complex has both an internal and an overall orientation. However, this overall orientation to the myoid layer does not seem to be necessary to its barrier function. The 20 day old rat has extensive parallel tight junctions which are not oriented with respect to the myoid layer, and yet they are inpenetrable by lanthanum. The mechanism(s) for the control of Sertoli cell junction development and orientation has not been established, although such factors as the presence or absence of germ cells, and/or hormones, especially FSH have been implicated.

How I Do It: Modified Technique for Vein Preparation Using the SaphLITE Retractor and PAS-Port System

2007 ◽  
Vol 10 (2) ◽  
pp. E141-E142
Author(s):  
Tamotsu Yasuda ◽  
Go Watanabe ◽  
Kenji Kawachi
Keyword(s):  
Modified Technique ◽  
Port System

MODIFIED LAMINOPLASTY AFTER EXCISION OF CERVICAL SCHWANNOMA WITH LARGE EXTRAVERTEBRAL EXTENSION

2018 ◽  
Vol 1 (1) ◽  
pp. 9
Author(s):  
Muhammad Faris ◽  
Abdul Hafid Bajamal ◽  
Zaky Bajamal ◽  
Krisna Tsaniadi Prihastomo
Keyword(s):  
Surgical Treatment ◽  
Spinal Canal ◽  
Conventional Technique ◽  
Modified Technique ◽  
Younger Patients ◽  
Knowing That ◽  
Anteroposterior Diameter ◽  
Intradural Extramedullary ◽  
Intradural Extramedullary Tumour

Tumour excision and laminoplasty are commonly performed as surgical treatment of extra vertebral extension of cervical schwannoma. It is worth knowing that the conventional technique of multilevel laminectomy may hinder younger patients in the long-term. This article reports a 30-year old man with an intradural-extramedullary tumour which extended from C4 to T1 that underwent modified laminoplasty.  This modified technique is preferable in maintaining the anteroposterior diameter of spinal canal as well as reducing the displacement of guttered laminae

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