Intracellular motility of mitochondria: role of the inner compartment in migration and shape changes of mitochondria in XTH-cells

1978 ◽  
Vol 30 (1) ◽  
pp. 99-115
Author(s):  
J. Bereiter-Hahn
Keyword(s):  
Phase Contrast ◽  
Heart Cells ◽  
Underlying Principle ◽  
Good Accord ◽  
Contrast Microscopy ◽  
Mitochondrial Motility ◽  
Time Required ◽  
Shape Changes ◽  
Intracellular Motility

Mitochondrial movements have been followed by phase-contrast microscopy in living XTH-cells (Xenopus laevis tadpole-heart cells) in tissue culture. The same organelles have been viewed subsequently in electron micrographs. Locomotion of mitochondria proceeds at velocities up to 100 micrometer/min. Formation of branches of mitochondria and other shape changes may occur with the same speed. Mitochondrial motility can be classified into 4 types: (I) Alternating extension and contraction at the two ends of rod-shaped mitochondria. (2) Lateral branching. (3) Alternate stretching and contraction of arbitrary parts of a mitochondrion amounting to a kind of peristaltic action. (4) Transverse wave propagation along the organelle. Types I to 3 can be reduced to the same underlying principle; they cause locomotion. Formation of mitochondrial extensions is due to elongation of cristae. The observations are discussed in terms of 4 specific proposals. (I) Intracellular locomotion of mitochondria is caused by local enlargements and contractions of the organelles. (2) The shape changes are correlated with alterations in the arrangement of the cristae. (3) Such arrangements are not associated with overall swelling or shrinkage of the mitochondrion; they are local features. (4) Estimates of the time required for rearrangement of the inner compartment amount to less than 0.3 s for single crista arrangements during the fastest shape changes, and less than 1–3 s during slower alterations. This high velocity is in good accord with the hypothesis of energy conservation by conformational events during oxidative phosphorylation.

scholarly journals Rough Dental Implant Surfaces and Peri-Implantitis: Role of Phase-Contrast Microscopy, Laser Protocols, and Modified Home Oral Hygiene in Maintenance. A 10-Year Retrospective Study

2021 ◽  
Vol 11 (11) ◽  
pp. 4985
Author(s):  
Gianluigi Caccianiga ◽  
Gérard Rey ◽  
Paolo Caccianiga ◽  
Alessandro Leonida ◽  
Marco Baldoni ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Phase Contrast ◽  
Vertical Movement ◽  
Subgingival Plaque ◽  
Phase Contrast Microscopy ◽  
Implant Surface ◽  
Total Percentage ◽  
Contrast Microscopy

The aim of this study was to evaluate two different kinds of rough implant surface and to assess their tendency to peri-implantitis disease, with a follow-up of more than 10 years. Data were obtained from a cluster of 500 implants with Ti-Unite surface and 1000 implants with Ossean surface, with a minimum follow-up of 10 years. Implants had been inserted both in pristine bone and regenerated bone. We registered incidence of peri-implantitis and other causes of implant loss. All patients agreed with the following maintenance protocol: sonic brush with vertical movement (Broxo), interdental brushes, and oral irrigators (Broxo) at least two times every day. For all patients with implants, we evaluated subgingival plaque samples by phase-contrast microscopy every 4 months for a period of more than 10-years. Ti-Unite surface implants underwent peri-implantitis in 1.6% of the total number of implants inserted and Ossean surface implants showed peri-implantitis in 1.5% of the total number of implants. The total percentage of implant lost was 4% for Ti-Unite surfaces and 3.6% for Ossean surfaces. Strict control of implants leads to low percentage of peri-implantitis even for rough surfaces dental implants.

scholarly journals A CYTOCHEMICAL DESCRIPTION OF THE MULTIPLICATION OF MENGOVIRUS IN L-929 CELLS

1962 ◽  
Vol 12 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Richard M. Franklin
Keyword(s):  
Phase Contrast ◽  
Basic Protein ◽  
Virus Production ◽  
Cytological Change ◽  
Virus Particles ◽  
Contrast Microscopy ◽  
Infected Cells ◽  
Cytological Changes ◽  
Perinuclear Area

A correlation of cytochemical changes with virus production has been studied in L cells infected with Mengovirus. After a latent period of about 2 hours, virus was produced rapidly, reaching maximum titers of up to 12,000 particles per cell in 6 to 8 hours. The earliest cytological change was in the nucleus and consisted of a slight condensation of chromatin. There is no evidence, however, for the multiplication of either the viral RNA or protein in the nucleus. RNA, of high molecular weight, accumulated in the perinuclear area of the cytoplasm and was later found in inclusions. The perinuclear RNA was digestible with RNase and may be located in or on ribosomes. The inclusion RNA was resistant to RNase but could be removed by pepsin or potassium permanganate; it is probably in completed virus particles. Viral antigen was first observed in a perinuclear location and later in the above-mentioned inclusions. Although the viral protein contains appreciable amounts of arginine and lysine, it is not a basic protein of the histone type. Phase-contrast microscopy of living cells clearly demonstrated the role of the inclusions in release of virus from infected cells. A comparison is made between these cytological changes in Mengo-infected cells and those which have been found by other workers in polio-infected cells. There are many very similar changes.

Role Of Surface Negative Charge In Platelet Aggregation

1981 ◽  
Author(s):  
K Tanoue ◽  
S M Jung ◽  
I Isohisa ◽  
C Sakakibara ◽  
S Ariga ◽  
...  
Keyword(s):  
Phase Contrast ◽  
Negative Charge ◽  
Human Platelets ◽  
Platelet Surface ◽  
Rabbit Platelets ◽  
Contrast Microscopy ◽  
Physiologic Saline ◽  
And Control ◽  
The Relationship

The relationship between aggregability and electrophoretic mobility (EPM) was studied to clarify the role of surface negative charge in platelet function. 1. Human platelets were washed 3 times with Phillip’s buffer (pH 7.4), resuspended to 107 platelets/ml in modified Zeiller and Hannig’s buffer with 1 mM EDTA and incubated with various concentrations of ADP, adrenaline, thrombin and ristocetin at 37°C for 3 min. Without further washing, mean EPM of about 700 platelets was determined by the automatic Laser Zee System 3000 with good reproducibility with less than 1 % variation coefficient for 5 measurements. In all experiments, aggregating agents were dissolved in physiologic saline to obtain the same solution conductance both in test and control platelet suspensions to which saline alone was added. Neither 1-100 uM ADP nor 5-500 μM adrenaline had any effect on platelet EPM. Thrombin decreased EPM with dose response relation with -1.692±0.014 μm/sec/V/cm without thrombin, -1.580±0.084 with o725 , -1.578±0.001 with 1.0, -1.454±0.018 with 2.0 and -1.289±0.004 with 5.0 U/ml of thrombin. Ristocetin had decreasing effect on EPM at 0.2 mg/ml or less. After addition of above aggregating agents, the washed platelets did not aggregate under phase contrast microscopy. 2. EPM of washed platelets were compared with aggregability in the PRP collected from 33 clinical cases with various degrees of aggregation. There was no correlation between EPM and secondary and maximum aggregation induced by any of these four agents. However, intensity of primary aggregation by adrenaline correlated with EPM (r= 0.485, P<0.01). The same tendency was observed in primary aggregation by ADP. 3. Treatment of washed rabbit platelets with increasing doses of neuraminidase resulted in increasing aggregation by ADP and collagen associated with decrease in EPM. These findings suggested that platelet surface negative charge may be regulatory role in initiation of platelet activation.

The Morphology and Origin of the Golgi Bodies and their Role in the Secretion of the Acrosome in the Spermatogenesis of Pulmonate Gastropods as Determined in the Living Material by Phase-contrast Microscopy

1956 ◽  
Vol s3-97 (39) ◽  
pp. 369-377
Author(s):  
VISHWA NATH ◽  
BRIJ L. GUPTA
Keyword(s):  
Phase Contrast ◽  
Duplex Structure ◽  
Golgi Bodies ◽  
Golgi Region ◽  
Contrast Microscope ◽  
Contrast Microscopy ◽  
Spermatid Nucleus ◽  
Living Material ◽  
Dark Contrast

In this paper are embodied our observations on the morphology, origin, and role of the Golgi bodies in the spermatogenesis of the slug, Anadenus altivagus, and the snail, Euaustenia cassida. Living cells have been studied under the phase-contrast microscope and photomicrographed. In the juxta-nuclear Golgi region in primary spermatocytes the Golgi bodies exist in the form of (1) granules and rods of dark contrast, (2) spheres of pale contrast, and (3) spheroids showing a duplex structure, each consisting of a sphere of pale contrast and an incomplete or complete cortex or sheath of dark contrast. The Golgi spheroids have been shown to arise three times in the course of spermatogenesis from the mitochondrial granules by a process of alignment. The acrosome is formed from a cap of tiny acrosomal granules, which are deposited in front of the spermatid nucleus by the Golgi bodies (acroblasts).

On the Mechanism of Primary Hemostasis

1979 ◽  
Author(s):  
H.K. Breddin ◽  
N. Bender ◽  
K. Kirchmaier ◽  
M. Ziemen
Keyword(s):  
Phase Contrast ◽  
Thrombus Formation ◽  
Vascular Lesion ◽  
Phase Contrast Microscopy ◽  
New Techniques ◽  
Primary Hemostasis ◽  
Contrast Microscopy ◽  
Subcutaneous Tissues ◽  
Citrate Blood

The sticking of platelets to basal membranes and to collagen fibers followed by subsequent aggregation are thought to be the first steps in hemostasis. During the first seconds after a vascular lesion platelets are stimulated outside the vessel and are transformed by forming pseudopodes and by sphering. Subcutaneous tissues of different species [human, Pig, dog, rat) as well as other tissues contain a lipoprotein with low tnrombo-plastic activity that stimulates platelets very rapidly. The action of this hemostasis activating factor (HaF) can be evaluated in fresh citrate blood by phase contrast microscopy and less specifically by the enhancement of platelet retention and the acceleration but not induction of platelet aggregation.HaF may play an important part in the activation of primary hemostasis. The proteins defective in v.-Willebrand’s syndrome are probably catalysing the stimulating effect of HaF on platelets. With new techniques the mechanism of the first steps in hemostasis can be further elucidated as well as the role of these mechanisms in thrombus formation.

Phase Contrast Morphology of Coagulation Clot Maturation and Fibrinolysis

1965 ◽  
Vol 13 (01) ◽  
pp. 047-059 ◽  
Author(s):  
J. R Jannach
Keyword(s):  
Refractive Index ◽  
Phase Contrast ◽  
Positive Phase ◽  
Phase Contrast Microscopy ◽  
Clot Retraction ◽  
Fibrin Formation ◽  
Contrast Microscopy

SummaryMorphologic observations of coagulation, clot maturation and fibrinolysis in thin standardized clots were presented using negative and positive phase contrast microscopy. The study described the beginning of fibrin formation in centers away from platelets and platelet clumps but usually associated with platelet fragments. Although the preparations failed to reveal clot retraction, the fibrin strands did show a change in refractive index. Intact clot preparations were demonstrated several weeks after incubation at 37° 0.The observation of greatest significance, in the light of recent studies accentuating the role of platelets in hemostasis, was the lysis of platelets and platelet clumps which had undergone viscous metamorphosis. This action of plasmin on platelets may be of great importance in the prevention of hemostasis in the fibrinolytic syndrome and the destruction of damaged platelets in the normal circulation.

Elucidation of block boundaries as the dissolution channels in hydrated cement

1978 ◽  
Vol 36 (1) ◽  
pp. 484-485
Author(s):  
N.V. Belov ◽  
U.I. Papiashwili ◽  
B.E. Yudovich
Keyword(s):  
Liquid Phase ◽  
Grain Boundaries ◽  
Benzoyl Peroxide ◽  
Phase Contrast ◽  
Active Role ◽  
Point Of View ◽  
Hardened Cement ◽  
Hydrated Cement ◽  
Hardened Cement Paste

It has been almost universally adopted that dissolution of solids proceeds with development of uniform, continuous frontiers of reaction.However this point of view is doubtful / 1 /. E.g. we have proved the active role of the block (grain) boundaries in the main phases of cement, these boundaries being the areas of hydrate phases' nucleation / 2 /. It has brought to the supposition that the dissolution frontier of cement particles in water is discrete. It seems also probable that the dissolution proceeds through the channels, which serve both for the liquid phase movement and for the drainage of the incongruant solution products. These channels can be appeared along the block boundaries.In order to demonsrate it, we have offered the method of phase-contrast impregnation of the hardened cement paste with the solution of methyl metacrylahe and benzoyl peroxide. The viscosity of this solution is equal to that of water.

The role of differential phase contrast in electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 176-177
Author(s):  
E.M. Waddell ◽  
J.N. Chapman ◽  
R.P. Ferrier
Keyword(s):  
Phase Contrast ◽  
Practical Method ◽  
Position Vector ◽  
Differential Phase ◽  
Pure Phase ◽  
Differential Phase Contrast ◽  
The Difference ◽  
Image Position ◽  
First Moment

Dekkers and de Lang (1977) have discussed a practical method of realising differential phase contrast in a STEM. The method involves taking the difference signal from two semi-circular detectors placed symmetrically about the optic axis and subtending the same angle (2α) at the specimen as that of the cone of illumination. Such a system, or an obvious generalisation of it, namely a quadrant detector, has the characteristic of responding to the gradient of the phase of the specimen transmittance. In this paper we shall compare the performance of this type of system with that of a first moment detector (Waddell et al.1977).For a first moment detector the response function R(k) is of the form R(k) = ck where c is a constant, k is a position vector in the detector plane and the vector nature of R(k)indicates that two signals are produced. This type of system would produce an image signal given bywhere the specimen transmittance is given by a (r) exp (iϕ (r), r is a position vector in object space, ro the position of the probe, ⊛ represents a convolution integral and it has been assumed that we have a coherent probe, with a complex disturbance of the form b(r-ro) exp (iζ (r-ro)). Thus the image signal for a pure phase object imaged in a STEM using a first moment detector is b2 ⊛ ▽ø. Note that this puts no restrictions on the magnitude of the variation of the phase function, but does assume an infinite detector.

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