scholarly journals Shift in collagen type as an early response to induction of the metanephric mesenchyme.

1981 ◽  
Vol 89 (2) ◽  
pp. 276-283 ◽  
Author(s):  
P Ekblom ◽  
E Lehtonen ◽  
L Saxén ◽  
R Timpl

Conversion of the nephrogenic mesenchyme into epithelial tubules requires an inductive stimulus from the ureter bud. Here we show with immunofluorescence techniques that the undifferentiated mesenchyme before induction expresses uniformly type I and type III collagens. Induction both in vivo and in vitro leads to a loss of these proteins and to the appearance of basement membrane components including type IV collagen. This change correlates both spatially and temporally with the determination of the mesenchyme and precedes and morphological events. During morphogenesis, type IV collagen concentrates at the borders of the developing tubular structures where, by electron microscopy, a thin, often discontinuous basal lamina was seen to cover the first pretubular cell aggregates. Subsequently, the differentiating tubules were surrounded by a well-developed basal lamina. No loss of the interstitial collagens was seen in the metanephric mesenchyme when brought into contact with noninducing tissues or when cultured alone. Similar observations were made with nonnephrogenic mesenchyme (salivary, lung) when exposed to various heterotypic tissues known to induce tubules in the nephrogenic mesenchyme. The sequential shift in the composition of the extracellular matrix from an interstitial, mesenchymal type to a differentiated, epithelial type is so far the first detectable response of the nephrogenic mesenchyme to the tubule-inducing signal.

1985 ◽  
Vol 73 (1) ◽  
pp. 19-32
Author(s):  
W.C. Young ◽  
I.M. Herman

We utilized fluorescence microscopy and affinity-purified antibodies to probe the form and function of cytoplasmic actin in endothelial cells (EC) recovering from injury and grown on extracellular matrices in vitro. Bovine aortic EC were seeded onto glass microscope coverslips that had been coated with either BSA, fibronectin, type I and III (interstitial) collagens, type IV (basement membrane) collagen or gelatin. After EC that had been grown on glass, glass-BSA or extracellular matrix-coated coverslips reached confluence, a 300–400 micron zone of cells was mechanically removed to stimulate EC migration and proliferation. Post-injury EC movements were monitored with time-lapse, phase-contrast videomicrography before fixation for actin localization with fluorescence microscopy using affinity-purified antibodies. We found that the number of stress fibres within EC was inversely proportional to the rate of movement; and, the rates of movement for EC grown on glass or glass-BSA were approximately eight times faster than EC grown on gelatin or type IV collagen (X velocity = 0.5 micron/min versus 0.06 micron/min). EC movements on fibronectin and interstitial collagens were similar (X velocity = 0.2 micron/min). These results suggest that extracellular matrix molecules modulate EC stress fibre expression, thereby producing alterations in the cytoskeleton and the resultant EC movements that follow injury in vitro. Moreover, the induction of stress fibres in the presence of basement membrane (type IV) collagen may explain the failure of aortic EC to migrate and repopulate wounded regions of intima during atherogenesis in vivo.


1986 ◽  
Vol 102 (3) ◽  
pp. 740-747 ◽  
Author(s):  
R D Sanderson ◽  
J M Fitch ◽  
T R Linsenmayer ◽  
R Mayne

Analyses were made of the requirements for the formation of a continuous basal lamina during myogenesis of quail muscle in vitro. A culture system was developed in which mass cultures of differentiating muscle cells were embedded in a native gel of rat tail collagen. Fibroblastic cells, which were also present in the cultures, migrated into the gel and within a few days surrounded the newly formed myotubes. In this environment, a continuous basal lamina was formed at the surface of the myotubes as demonstrated by immunofluorescent staining with monoclonal antibodies against type IV collagen, laminin, and heparan sulfate, as well as by electron microscopic immunolocalization. To distinguish between the role of the fibroblasts and the collagen gel in promoting basal lamina formation, clones of quail muscle cells lacking fibroblasts were subsequently embedded in a native rat tail collagen gel. Under these conditions, only very limited fluorescent staining for basement membrane components was observed associated with the myotubes. However, the introduction of chick muscle or skin fibroblasts into the clonal cultures just before gel formation resulted in the formation of an extensive basal lamina on the surface of the myotubes. Conditioned medium from fibroblast cultures by itself was not effective in promoting basal lamina formation. These results clearly show that during myogenesis in vitro fibroblasts must be in close proximity to the myotubes for a continuous basal lamina to form. These results probably relate closely to the interactions that must occur during myogenesis in vivo between the muscle cells and the surrounding connective tissue including the developing tendons.


1985 ◽  
Vol 79 (1) ◽  
pp. 119-136
Author(s):  
J.D. Aplin ◽  
S. Campbell ◽  
T.D. Allen

Ultrastructural comparisons have been made between human amnion extracellular matrix in tissue and cell culture. Immunochemical analysis of matrix deposited by monolayers of cultured amnion epithelial cells has also been undertaken. The basal cell surfaces are highly invaginated with an associated basal lamina that is more electron dense at the distal tips of basal cell processes where hemidesmosomes are frequent. Immediately below the lamina densa is a zone rich in collagen bundles. In the underlying stroma two types of fibril predominate, one striated of 50 nm diameter and one of 18 nm diameter. The observations suggest that at gestational term the epithelial cells are still active in the production of matrix. Secretion appears to occur into invaginations in the basal cell surface where a loosely organized mixture of stromal-type and basal laminal-type aggregates is formed. In culture on plastic, cells also deposit a mixture of basal laminal (type IV collagen + laminin) and stromal (collagens type I + III) components as well as fibronectin. However, segregation into a true basal lamina with underlying stroma does not occur in vitro, suggesting the need for an organized subcellular template to complete matrix morphogenesis. The in vitro and in vivo evidence suggest that the epithelium contributes to the subjacent dense collagenous zone as well as to the basal lamina.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yakkanti Akul Sudhakar ◽  
Raj Kumar Verma ◽  
Smita C. Pawar
Keyword(s):  

Editor's Note: this Article has been retracted; the Retraction Note is available at https://www.nature.com/articles/s41598-020-76500-9


Medicina ◽  
2020 ◽  
Vol 56 (5) ◽  
pp. 232
Author(s):  
Francesca Mori ◽  
Francesca Saretta ◽  
Annamaria Bianchi ◽  
Giuseppe Crisafulli ◽  
Silvia Caimmi ◽  
...  

Biologic drugs are widely used in pediatric medicine. Monoclonal antibodies (mAbs) in particular are a therapeutic option for rheumatic, autoinflammatory and oncologic diseases. Adverse drug reactions and hypersensitivity reactions (HSR) to mAbs may occur in children. Clinical presentation of HSRs to mAbs can be classified according to phenotypes in infusion-related reactions, cytokine release syndrome, both alpha type reactions and type I (IgE/non-IgE), type III, and type IV reactions, all beta-type reactions. The aim of this review is to focus on HSRs associated with the most frequent mAbs in childhood, with particular attention to beta-type reactions. When a reaction to mAbs is suspected a diagnostic work-up including in-vivo and in-vitro testing should be performed. A drug provocation test is recommended only when no alternative drugs are available. In selected patients with immediate IgE-mediated drug allergy a desensitization protocol is indicated. Despite the heavy use of mAbs in childhood, studies evaluating the reliability of diagnostic test are lacking. Although desensitization may be effective in reducing the risk of reactions in children, standardized pediatric protocols are still not available.


1996 ◽  
Vol 271 (5) ◽  
pp. L844-L853 ◽  
Author(s):  
C. Garat ◽  
F. Kheradmand ◽  
K. H. Albertine ◽  
H. G. Folkesson ◽  
M. A. Matthay

Adhesive interactions between cells and extracellular matrix proteins are important in cell attachment, migration, and proliferation. The present work defines the role of fibronectin (soluble and insoluble) compared with type I and type IV collagen on in vitro alveolar epithelial wound healing. Repeated video microscopy experiments demonstrated that the half-time of wound closure was decreased in the presence of soluble fibronectin (6.6 +/- 2.1 vs. 17.4 +/- 0.8 h in serum-free medium, P < 0.05). Video microscopy, electron microscopy, and vinculin distribution demonstrated the contribution of two main events during the repair process: the migration of epithelial cell sheets and the spreading of the cells. During the wound healing, the internuclear distance between two adjacent cells at the migrating edge of the wound was significantly increased 10 h after wounding in the presence of soluble fibronectin (67 +/- 3.0 vs. 45 +/- 1.5 microns in serum-free medium, P < 0.05), indicating that cell spreading is involved as part of the mechanism for wound closure. Compared with type I and type IV collagen, insoluble fibronectin was the most potent stimulus for alveolar type II cell motility and wound healing in the absence of other serum factors. These results demonstrate that alveolar epithelial wound healing can be modulated in vitro by the composition of the extracellular matrix, an effect that may be mediated by changes in cell shape.


2014 ◽  
Vol 191 (4S) ◽  
Author(s):  
Laurence A. Levine ◽  
Tom M. Schmid ◽  
Susan G. Emeigh Hart ◽  
Thomas Tittelbach ◽  
Michael P. McLane ◽  
...  

2021 ◽  
Vol 16 (2) ◽  
pp. 19-26
Author(s):  
Leelavathi Muthupalaniappen ◽  
Adawiyah Jamil

This article provides information on allergy testing and serves as a simple guide for physicians who are considering using allergy testing as a step in patient management. Basic principles of allergy testing, indications for testing, and how and when to choose a suitable allergy test are discussed. Allergy testing in general refers to evaluation of either type I or type IV hypersensitivity reactions. The type I (immediate) reaction is evaluated using the skin prick test (in vivo) or serum IgE (in vitro) test methods, while the type IV (delayed) reaction is determined via the skin patch test method. The allergens responsible for a specific reaction can be identified from allergy testing, and this information is useful in administering avoidance measures. Appropriate treatment of allergic reactions along with allergen avoidance ensure a successful treatment outcome and prevent future reactions.


1985 ◽  
Vol 33 (7) ◽  
pp. 655-664 ◽  
Author(s):  
S Berrih ◽  
W Savino ◽  
S Cohen

The immunohistochemical detection of elements of the human thymic extracellular matrix in situ and in vitro is described. In the normal thymus, the intracapsular and intraseptal fibers were strongly labeled by anti-type I collagen antiserum. Basement membranes bordering the capsule, septae, and perivascular spaces were intensely stained by anti-type IV collagen, anti-fibronectin, and anti-laminin sera. In hyperplastic myasthenia gravis thymuses, the major changes consisted of discontinuities of the basement membrane adjacent to clusters of epithelial (keratin-containing) cells, among which an unusual connective framework (densely labeled by all the antisera) was observed. In vitro, most epithelial cells were strongly labeled by antifibronectin serum and to a lesser extent by the anti-type IV collagen and anti-laminin sera. In addition, fibronectin, laminin, and type IV collagen were detected in the intercellular spaces bordering the epithelial cells in culture. Results show that thymic epithelial cells participate in the synthesis of extracellular matrix elements, which as a result of their localization and influence on epithelial cell growth, should be regarded as constitutive components of the thymic microenvironment.


Plant Disease ◽  
2020 ◽  
Vol 104 (8) ◽  
pp. 2210-2216
Author(s):  
Xuan Gong ◽  
Xinyao He ◽  
Yuhui Zhang ◽  
Lei Li ◽  
Zhengxi Sun ◽  
...  

Fusarium head blight (FHB) caused by Fusarium species is a globally important wheat disease. Host resistance to FHB is composed of multiple mechanisms, including resistance to initial infection (type I), disease spread (type II), toxin accumulation (type III), kernel infection (type IV), and yield loss (type V), of which the last three have been less studied. Traditionally, the Fusarium-damaged kernel rate (FDK; percentage of Fusarium-infected grains) from point- or spray-inoculated experiments was used as the parameter for type IV resistance, which may be problematic because of the influence of type II resistance. Here we propose a new definition for type IV resistance: that is, the resistance against Fusarium infection expressed in wheat grains that have the same chance in contact with the pathogen, under favorable temperature and humidity for infection. Fhb1 confers strong type II resistance, leading to significantly reduced FHB severity and FDK. To investigate the role of Fhb1 in type IV resistance, a pair of near-isogenic lines, R22W (Fhb1 carrier, resistant in terms of type II resistance) and S22V (non-Fhb1, susceptible), along with eight wheat genotypes differing at Fhb1 were inoculated at different grain development stages with Fusarium macrospores both in vivo and in vitro. The in vivo experiments with all florets inoculated demonstrated a significant reduction in thousand kernel weight (TKW) in inoculated grains, regardless of their Fhb1 status and developmental stages. Surprisingly, R22W showed more TKW reduction than S22V, which was supported by the scanning electron microscopy observation that confirmed the more severe degradation of starch granules in R22W grains. The in vitro experiments demonstrated that grains from both R22W and S22V promoted fungal colonization, but no significant difference was found between the two lines. In summary, our results indicated that the proposed type IV evaluation system is effective in determining different grain resistance levels, providing novel tools for FHB resistance breeding. The finding that Fhb1 is not associated with type IV resistance enriches our understanding of this gene.


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