Fine structural studies on differentiation and dedifferentiation in the higher plant

The storage cells in the cotyledons of air-dried Phaseolus vulgaris seeds contain large quantities of polysaccharides, protein and to a lesser extent, lipids. A single multilobed nucleus occurs in the centre of each storage cell surrounded by large starch grains, small plastids and mitochondria whilst the cytoplasm occupies the narrow channels between the various organelles. The cell walls are composed of two layers, the outer, cellulosic, and inner, non-cellulosic, and the latter serves as a polysaccharide store. After hydration for 24 hours the storage cells respond to in vitro culturing, on solid medium (Murashige and Skoog, 1962) containing 2,4-D, kinetin and coconut milk, by producing a callus tissue which, when routinely subcultured, continues to grow for a potentially indefinite period. No organogenesis was observed in the callus cultures during the one year of cultivation. The callus appears on the adarial side of the cotyledon (which is in contact with the medium) and, initially, mainly developes from the storage cells in the vicinity of the adaxial provascular strands and progressively spreads towards the abaxial surface. The nuclear divisions observed are mainly amitotic with mitoses apparently being confined to storage cells which have already undergone nuclear fragmentation. Free-wall formation occurs frequently in automatically dividing cells and plays an active role in nuclear fragmentation. Large labyrinthine wall bodies are abundant in the dedifferentiating storage cells, sometim.es apparently free in the cytoplasm or more often forming on the cell walls. Wall bodies also occur, along with freely-forming walls, in the established callus. A comparison is also made between in vivo and in vitro development of the cotyledon; vitro food digestion proceeds slowly and it is faster on the adaxial side, in comparison to relatively fast food digestion when vivo which occurs more uniformly in the storage tissue. Neither-cell division for organelle replication occur during germination The air-dried Linum usitatissimum hypocotyl serves as food store (along with the rest of the embryo) during seed dormancy, with the main food stores being lipid, protein and polysaccharides; during germination protein bodies are digested and give rise to vacuoles. The hypocotyl reaches its full height at about Day 10; by that time stomata are fully differentiated and in addition to the normal epidermal cells and guard cells, "swollen" cells occur at various sites in the epidermis; all .epidermal cells contain a spindle-shaped nuclear inclusion. Decapitation of the Day 10 hypocotyl results in the appearance of 5-20 novo developed adventitious buds which become macroscopically visible at the upper end of this organ by about Day 10. The majority become dormant but one bud eventually becomes dominant and grows into a replacement shoot. The initiation of a bud is characterised by several transverse divisions in the axially elongated, normal- type epidermal cell, followed by radial and tangential longitudinal ones. The cortical cells, in the case of a non-dormant bud, appear to dedifferentiate more-or-less contemporaneously with the epidermal cells and a provascular connection becomes established between the bud and the axial vascular tissue of the hypocotyl. In the dormant bud this connection appears to occur later when leaf primordia are already visible and only some discontinuous tracheary elements differentiate in contrast to continuous strands in the non-dormant bud. Dedifferentiation of epidermal and cortical cells is apparently accompanied by the appearence of some highly irregular chloroplast profiles indicating some kind of chloroplast replication. After decapitation the hypocotyl becomes greener, its top swells, the cell walls of cortical cells become thicker, cortical chloroplasts develop massive starch grains and transfer cells appear in the vascular tissue connecting the adventitious bud with the axial vascular tissue as well as in the latter itself

Postinfarct Ventricular Septal Defect after Coronary Covered Stent Implantation

We report a case of a postinfarction ventricular septal defect caused by an acute recurrent occlusion after the implantation of a covered stent, which was performed as a rescue procedure for the ruptured left anterior descending artery during a percutaneous coronary intervention. Although the emergent implantation of a covered stent for the ruptured coronary arteries such as the left main coronary artery or the origins of the left anterior descending artery can be performed during a percutaneous coronary intervention, and a coronary bypass surgery should be considered in order to decrease the risk of complete occlusion, thus providing a superior long term patency

A Splicing Mutation in the Novel Mitochondrial Protein DNAJC11 Causes Motor Neuron Pathology Associated with Cristae Disorganization, and Lymphoid Abnormalities in Mice

Mitochondrial structure and function is emerging as a major contributor to neuromuscular disease, highlighting the need for the complete elucidation of the underlying molecular and pathophysiological mechanisms. Following a forward genetics approach with N-ethyl-N-nitrosourea (ENU)-mediated random mutagenesis, we identified a novel mouse model of autosomal recessive neuromuscular disease caused by a splice-site hypomorphic mutation in a novel gene of unknown function, DnaJC11. Recent findings have demonstrated that DNAJC11 protein co-immunoprecipitates with proteins of the mitochondrial contact site (MICOS) complex involved in the formation of mitochondrial cristae and cristae junctions. Homozygous mutant mice developed locomotion defects, muscle weakness, spasticity, limb tremor, leucopenia, thymic and splenic hypoplasia, general wasting and early lethality. Neuropathological analysis showed severe vacuolation of the motor neurons in the spinal cord, originating from dilatations of the endoplasmic reticulum and notably from mitochondria that had lost their proper inner membrane organization. The causal role of the identified mutation in DnaJC11 was verified in rescue experiments by overexpressing the human ortholog. The full length 63 kDa isoform of human DNAJC11 was shown to localize in the periphery of the mitochondrial outer membrane whereas putative additional isoforms displayed differential submitochondrial localization. Moreover, we showed that DNAJC11 is assembled in a high molecular weight complex, similarly to mitofilin and that downregulation of mitofilin or SAM50 affected the levels of DNAJC11 in HeLa cells. Our findings provide the first mouse mutant for a putative MICOS protein and establish a link between DNAJC11 and neuromuscular diseases

Distal protection devices during percutaneous coronary and carotid interventions

Distal embolization of particulate matter complicates percutaneous coronary and peripheral interventions more often than had been recognized until recently. A number of distal protection devices are under development. The PercuSurge GuardWire™ is a balloon occlusion thrombectomy device approved by the United States Food and Drug Administration for saphenous vein graft intervention. A number of filter devices utilize an expandable filter mounted on the angioplasty guidewire to facilitate entrapment of particles and safe removal. The Parodi Anti-Emboli System™ is an example of a catheter occlusion device that establishes protection by reversing blood flow in the target vessel

Chemosensory Neurons Modulate the Response to Oomycete Recognition in Caenorhabditis elegans

Understanding how animals detect and respond to pathogen threats is central to dissecting mechanisms of host immunity. The oomycetes represent a diverse eukaryotic group infecting various hosts from nematodes to humans. We have previously shown that Caenorhabditis elegans mounts a defense response consisting of the induction of chitinase-like (chil) genes in the epidermis to combat infection by its natural oomycete pathogen Myzocytiopsis humicola. We provide here evidence that C. elegans can sense the oomycete by detecting an innocuous extract derived from animals infected with M. humicola. The oomycete recognition response (ORR) leads to changes in the cuticle and reduction in pathogen attachment, thereby increasing animal survival. We also show that TAX-2/TAX-4 function in chemosensory neurons is required for the induction of chil-27 in the epidermis in response to extract exposure. Our findings highlight that neuron-to-epidermis communication may shape responses to oomycete recognition in animal hosts

Coronary artery perforations after contemporary percutaneous coronary interventions: Evaluation of incidence, risk factors, outcomes, and predictors of mortality

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137603/1/ccd26917_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137603/2/ccd26917.pd

Anabolic androgenic steroids reverse the beneficial effect of exercise on tendon biomechanics: An experimental study

Background The effect of anabolic androgenic steroids on tendons has not yet been fully elucidated. Aim of the present study was the evaluation of the impact of anabolic androgenic steroids on the biomechanical and histological characteristics of Achilles tendons. Methods Twenty-four male Wistar rats were randomized into four groups with exercise and anabolic steroids (nandrolone decanoate) serving as variables. Protocol duration was 12 weeks. Following euthanasia, tendons’ biomechanical properties were tested with the use of a modified clamping configuration. Histological examination with light and electron microscopy were also performed. Results In the group of anabolic steroids and exercise the lowest fracture stress values were observed, while in the exercise group the highest ones. Histological examination by light and electron microscopy revealed areas of collagen dysplasia and an increased epitendon in the groups receiving anabolic steroids and exercise. Conclusions These findings suggest that anabolic androgenic steroids reverse the beneficial effect of exercise, thus resulting in inferior maximal stress values

Structural modification of bacterial cellulose fibrils under ultrasonic irradiation

Ιn the present study we investigated ultrasounds as a pretreatment process for bacterial cellulose (BC) aqueous suspensions. BC suspensions (0.1–1% wt) subjected to an ultrasonic treatment for different time intervals. Untreated BC presented an extensively entangled fibril network. When a sonication time of 1 min was applied BC fibrils appeared less bundled and dropped in width from 110 nm to 60 nm. For a longer treatment (3–5 min) the width of the fibrils increased again to 100 nm attributed to an entanglement of their structure. The water holding capacity (WHC) and ζ-potnential of the suspensions was proportional to the sonication time. Their viscosity and stability were also affected; an increase could be seen at short treatments, while a decrease was obvious at longer ones. Concluding, a long ultrasonic irradiation led to similar BC characteristics as the untreated, but a short treatment may be a pre-handling method for improving BC properties

Fatal Delayed Coronary Artery Perforation After Coronary Stent Implantation

Most type I and II perforations are predominately caused by hydrophilic and stiff wires, often presented in the delayed form, and do not require pericardial drainage or surgical interventions. However, we report a type III delayed coronary artery perforation at the site of stent implantation after intervention without any evidence of immediate perforations. To the best of our knowledge, this is the first case report of angiographic documentation and treatment of delayed coronary perforation at the site of stent, presented as a cardiac arrest