Combining laser-irradiation and glycerol immersion of skeletal muscles to improve their optical transparency

We have evaluated the state of the skeletal muscles, thymus, and bone marrow before and after laser irradiation of the rats and following the physical load on the irradiated animals. In the first experiment, both hind limbs of each rat in the region of projection of gastrocnemius muscles were subjected to 5 sessions of infrared laser irradiation at a dose of 11.70-12.60 J/sq.cm during 12 days with the use of a He-Ne laser. In the second experiment, the similarly irradiated rats were subjected to physical load in the form of swimming during 30 minutes. The histological, morphometric, cytological, and cytogenetic analysis have demonstrated that the muscle mass of the animals involved in the two experiments did not change. At the same time, laser irradiation caused the impairment of the function of the thymus and bone marrow. This effect was even more pronounced when the animals underwent the combined influence of laser irradiation and physical load. The ana-telophase assay revealed a rise in the number of cells with aberrant mitoses in the two organs of the immune system. It is concluded that in order to reduce the possible unfavourable consequences of laser therapy for the skeletal muscles preceding the physical load/training, it is necessary to choose the optimal dose of radiation and develop a sparing regime of laser irradiation taking into consideration the initial state of the organism.

Download Full-text

Chronic Laser Exposure Effects on Rabbit Retina

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100093523 ◽

1972 ◽

Vol 30 ◽

pp. 54-55

Author(s):

Burton B. Silver ◽

Theodore Lawwill

Keyword(s):

Laser Irradiation ◽

Laser Light ◽

Broad Band ◽

Argon Laser ◽

Atropine Sulfate ◽

Ultrastructural Changes ◽

Laser Exposure ◽

Rabbit Retina ◽

Histological Changes ◽

Threshold Doses

Dutch-belted 1 to 2.5 kg anesthetized rabbits were exposed to either xenon or argon laser light administered in a broad band, designed to cover large areas of the retina. For laser exposure, the pupil was dilated with atropine sulfate 1% and pheny lephrine 10%. All of the laser generated power was within a band centered at 5145.0 Anstroms. Established threshold for 4 hour exposures to laser irradiation are in the order of 25-35 microwatts/cm2. Animals examined for ultrastructural changes received 4 hour threshold doses. These animals exhibited ERG, opthalmascopic, and histological changes consistent with threshold damage.One month following exposure the rabbits were killed with pentobarbitol. The eyes were immediately enucleated and dissected while bathed in 3% phosphate buffered gluteraldehyde.

Download Full-text

Distribution of c-protein isoforms in sarcomeres of developing chick skeletal muscle

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010010319x ◽

1988 ◽

Vol 46 ◽

pp. 226-227

Author(s):

D. A. Fischman ◽

J. E. Dennis ◽

T. Obinata ◽

H. Takano-Ohmuro

Keyword(s):

Skeletal Muscles ◽

Thick Filament ◽

Protein Isoforms ◽

Actin Binding ◽

Striated Muscles ◽

C Protein ◽

Sarcomeric Protein ◽

Thick Filaments ◽

Cross Bridges ◽

Bridge Bearing

C-protein is a 150 kDa protein found within the A bands of all vertebrate cross-striated muscles. By immunoelectron microscopy, it has been demonstrated that C-protein is distributed along a series of 7-9 transverse stripes in the medial, cross-bridge bearing zone of each A band. This zone is now termed the C-zone of the sarcomere. Interest in this protein has been sparked by its striking distribution in the sarcomere: the transverse repeat between C-protein stripes is 43 nm, almost exactly 3 times the 14.3 nm axial repeat of myosin cross-bridges along the thick filaments. The precise packing of C-protein in the thick filament is still unknown. It is the only sarcomeric protein which binds to both myosin and actin, and the actin-binding is Ca-sensitive. In cardiac and slow, but not fast, skeletal muscles C-protein is phosphorylated. Amino acid composition suggests a protein of little or no αhelical content. Variant forms (isoforms) of C-protein have been identified in cardiac, slow and embryonic muscles.

Download Full-text

The effect of ionophore A23178 on the α-actinin crosslinks in the z-band of frog skeletal muscle: An EM study

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100142396 ◽

1986 ◽

Vol 44 ◽

pp. 154-155

Author(s):

F.T. Llados ◽

V. Krlho ◽

G.D. Pappas

Keyword(s):

Muscle Damage ◽

Transmitter Release ◽

Skeletal Muscles ◽

Calcium Uptake ◽

Muscle Membrane ◽

Frog Skeletal Muscle ◽

Ach Release ◽

Sustained Action ◽

Calcium Deposits ◽

Intense Stimulation

It Is known that Ca++ enters the muscle fiber at the junctional area during the action of the neurotransmitter, acetylcholine (ACh). Pappas and Rose demonstrated that following Intense stimulation, calcium deposits are found In the postsynaptic muscle membrane, Indicating the existence of calcium uptake In the postsynaptic area following ACh release. In addition to this calcium uptake, when mammal Ian skeletal muscles are exposed to a sustained action of the neurotransmitter, muscle damage develops. These same effects, l.e., Increased transmitter release, calcium uptake and finally muscle damage, can be obtained by Incubating the muscle with lonophore A23178.

Download Full-text

Microstructural changes of Aluminum Nitride after laser irradiation and electroless copper deposition

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100170918 ◽

1994 ◽

Vol 52 ◽

pp. 636-637

Author(s):

S. Cao ◽

A. J. Pedraza ◽

L. F. Allard

Keyword(s):

Aluminum Nitride ◽

Laser Irradiation ◽

Electroless Deposition ◽

Thermal Evaporation ◽

Surface Region ◽

Near Surface ◽

Laser Patterning ◽

Electroless Copper ◽

Excimer Laser Irradiation ◽

Laser Effect

Excimer-laser irradiation strongly modifies the near-surface region of aluminum nitride (AIN) substrates. The surface acquires a distinctive metallic appearance and the electrical resistivity of the near-surface region drastically decreases after laser irradiation. These results indicate that Al forms at the surface as a result of the decomposition of the Al (which has been confirmed by XPS). A computer model that incorporates two opposing phenomena, decomposition of the AIN that leaves a metallic Al film on the surface, and thermal evaporation of the Al, demonstrated that saturation of film thickness and, hence, of electrical resistance is reached when the rate of Al evaporation equals the rate of AIN decomposition. In an electroless copper bath, Cu is only deposited in laser-irradiated areas. This laser effect has been designated laser activation for electroless deposition. Laser activation eliminates the need of seeding for nucleating the initial layer of electroless Cu. Thus, AIN metallization can be achieved by laser patterning followed by electroless deposition.

Download Full-text