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The mdx mouse, although a genetic and biochemical homologue of human Duchenne muscular dystrophy (DMD), presents a comparatively mild histopathological and clinical phenotype. These differences are partially attributable to the greater efficacy of regeneration in the mdx mouse than in DMD muscle. To lessen this disparity, we have used a single dose of X-irradiation (16 Gy) to inhibit regeneration in one leg of mdx mice. The result is an almost complete block of muscle fiber regeneration leading to progressive loss of muscle fibers and their replacement by loose connective tissue. Surviving fibers are mainly peripherally nucleated and, surprisingly, of large diameter. Thus, X-irradiation converts mdx muscle to a model system in which the degenerative process can be studied in isolation from the complicating effect of myofiber regeneration. This system should be of use for testing methods of alleviating the myofiber degeneration which is common to mdx and DMD.

This paper presents surface temperature responses of various tissue phantoms and in vitro and in vivo biological materials in air to non-ablative pulsed CO2 laser irradiation, measured with a thermocamera. We studied cooling off behavior of the materials after a laser pulse, to come to an understanding of heat accumulation and related thermal damage during (super) pulsed CO2 laser irradiation. The experiments show a very slow decay of temperatures in the longer time regime. This behavior is well predicted by a simple model for one-dimensional heat flow that considers the CO2 laser radiation as producing a heat flux on the material surface. The critical pulse repetition frequency for which temperature accumulation is sufficiently low is estimated at about 5 Hz. Although we have not investigated the ablative situation, our results suggest that very low pulse frequencies in microsurgical procedures may be recommended.

Collagen metabolism was investigated in the fibrotic tissue which developed in pig thigh muscle 6 to 15 months after acute gamma irradiation. During this period, total collagen deposits in the fibrotic tissue increased 10-fold compared to the healthy muscle tissue. These deposits were composed mainly of type I and III collagen, and the type I/type III ratio was lower in the fibrotic than in the muscle tissue. Small pieces of both fibrotic and muscle tissue were incubated with [14C]proline. The [14C]hydroxyproline content of the fibrotic tissue reflected large concomitant increases in the synthesis of total collagen, mainly of types I and III, which rose 14- and 17-fold, respectively. Similarly, the level of type I and type III procollagen mRNAs rose 9- and 5-fold, respectively, in the fibrotic tissue versus the muscle tissue. These results suggest that procollagen gene transcription or RNA maturation in the cell nuclei is activated in the fibrotic tissue. The possibility that such activation is due to the long-term inflammatory state of this tissue is discussed.

Dystrophin deficiency in skeletal muscle of the x-linked dystrophic (mdx) mouse can be partially remedied by implantation of normal muscle precursor cells (mpc) (Partridge, T. A., J. E. Morgan, G. R. Coulton, E. P. Hoffman, and L. M. Kunkel. 1989. Nature (Lond.). 337:176-179). However, it is difficult to determine whether this biochemical "rescue" results in any improvement in the structure or function of the treated muscle, because the vigorous regeneration of mdx muscle more than compensates for the degeneration (Coulton, G. R., N. A. Curtin, J. E. Morgan, and T. A. Partridge. 1988. Neuropathol. Appl. Neurobiol. 14:299-314). By using x-ray irradiation to prevent mpc proliferation, it is possible to study loss of mdx muscle fibers without the complicating effect of simultaneous fiber regeneration. Thus, improvements in fiber survival resulting from any potential therapy can be detected easily (Wakeford, S., D. J. Watt, and T. A. Patridge. 1990. Muscle & Nerve.) Here, we have implanted normal mpc, obtained from newborn mice, into such preirradiated mdx muscles, finding that it is far more extensively permeated and replaced by implanted mpc than is nonirradiated mdx muscle; this is evident both from analysis of glucose-6-phosphate isomerase isoenzyme markers and from immunoblots and immunostaining of dystrophin in the treated muscles. Incorporation of normal mpc markedly reduces the loss of muscle fibers and the deterioration of muscle structure which otherwise occurs in irradiated mdx muscles. Surprisingly, the regenerated fibers are largely peripherally nucleated, whereas regenerated mouse skeletal muscle fibers are normally centrally nucleated. We attribute this regeneration of apparently normal muscle to the tendency of newborn mouse mpc to recapitulate their neonatal ontogeny, even when grafted into 3-wk-old degenerating muscle.

A hyaluronan binding protein (HABP), extracted from cartilage, was biotin-labelled and used for histochemical localization of hyaluronan (HA) in tissue sections. Various tissues were fixed for a mixture of formaldehyde and glutaraldehyde during microwave irradiation. The microwave oven when set at 700 W and 45 degrees C yielded an intense and specific staining of HA. Under these conditions the relative proportion of the two aldehydes did not influence the staining intensity. Aldehyde fixation during microwave irradiation for HA histochemistry, (1) save time, (2) eliminates the use of cetylpyridinium chloride (CPC), and (3) improves the reproducibility.

This study evaluated the width of tissue necrosis lateral to carbon dioxide laser incisions on human intraoral excisional biopsy specimens. Measurements were made on specimens including epithelium, muscle, dense and loose connective tissue, and salivary gland. Results showed a mean width of tissue necrosis of 86 microns in epithelium, 85 microns in muscle, 51 microns in loose connective tissue, 96 microns in dense connective tissue, and 41 microns in salivary gland. The range of thermal necrosis in different tissue types is probably based on the water content within each type. A cellular partially homogenized zone of reversible thermal damage up to 500 microns in width was visible adjacent to the zone of thermal necrosis. The relatively narrow width of tissue necrosis with this technique may account for the claimed superior properties of laser-induced wounds compared with those created by electrosurgery.

A comparative histological investigation of posttraumatic regeneration in irradiated with 30 or 40 Gy and cross-sectioned musculus gastrocnemius of rats after autotransplantation into muscle defect of non-irradiated minced muscle tissue and laser therapy of hind limb in post-operative period was conducted. The obtained results showed that in irradiated with 30 Gy sectioned muscle (control series) the inflammatory reaction, resorption of fibrin in the area of trauma were inhibited and proliferation of muscle tissue from proximal and distal stump was suppressed. The rough connective tissue scar was formed. In experimental series for stimulation of regeneration the method of autografting minced muscle tissue into the defect of irradiated (30 or 40 Gy) cross-sectioned muscle and combination of this method with helium-neon laser rays exposition was used. The more marked recovery was obtained in irradiated with 30 Gy operated muscle after a 10-day treatment of limb with laser rays.

We have recently demonstrated by dielectric relaxation studies in the radio-frequency range that there is a sharp decrease in the conductivity and permittivity of the membranes of chick embryo myoblasts in vitro at the time of fusion (60 h) (Bonincontro et al. 1987). This sharp fall in membrane electrical parameters was subsequently shown to be due to changes in ionic flux, particularly of the Na+/K+ equilibrium (Santini et al. 1988). Ionizing radiation induces a wide variety of effects on biological membranes, including variations in membrane ionic transport. We wished to investigate if sublethal doses of gamma-irradiation could affect membrane electrical parameters and thus myoblast membrane fusion. Consequently, chick embryo myoblast aggregate cultures were irradiated with 3.25, 5.15 or 6.35 Gy at 24 h of culture. We found that the lower dose delays membrane fusion by about 10 h while the two higher doses block fusion up to 120 h of culture. Aggregates showed a very high cell viability. The possible mechanisms by which ionizing radiation causes these variations in myoblast membrane electrical properties and fusion are discussed.

Fresh chicken breast and beef incubated in water were found to contain no o-Tyr at the current levels of detection (0.1 ppm) by capillary gas chromatography/mass spectrometry and selective ion monitoring. In contrast, samples incubated at 37 degrees C in the presence of ethanol, benzene, or carbon tetrachloride (used in fat extraction) contained large quantities (2.5-5.1 ppm) of o-Tyr. No o-Tyr was detected in the water-insoluble fraction of meat treated with carbon tetrachloride after triple extraction by water. However, reaction of radiation generated .OH in gamma-irradiated fresh chicken tissue with endogenous phenylalanine yields o-Tyr with a linear yield-dose response in both water-soluble and -insoluble tissue fractions. Nonradiolytically generated .OH is suggested to be formed through a mitochondrion-mediated Haber-Weiss reaction in association with water-soluble proteins since the yields of o-Tyr in beef, a tissue with a higher mitochondrial content, are four times greater than in the chicken breast tissue.

The effect of microwaves of 2355 MHz and 50 microW/cm2 on rat respiratory system has been investigated. On the basis of the experimental results and a priori suggestions a mathematical model has been developed to describe the process observed. Its structural and functional block-diagram is proposed permitting to define the mechanism of action of SHF field.

It is established that a decrease in the Ca2(+)-ATPase activity in the sarcoplasmic reticulum membranes 1 and 24 hours after the local X-ray irradiation of rabbit hind limb by a dose of 0.21 Cl/kg is caused mainly by a change in the enzymic microenvironment and a damage of native protein-lipid interactions essential for the functional activity of Ca2(+)-ATPase.

Combined methods of tumor therapy including electromagnetic hyperthermia are used nowadays in many countries of the world. Ordinary control of temperature at several points of a heated volume by invasive temperature sensitive elements gives approximate evaluation of a temperature profile during a session of hyperthermia. The authors have proposed methods for the calculation of temperature distributions in tissues taking account of the correlation of the blood flow and temperature and its contribution to heat transfer processes in body tissues. It is assumed that the vessels are equally distributed in the body volume sparing a necessity to record each one individually. The rated temperature profiles by the depth of a heated body zone corresponding to different variants of a UHF radiator and a tumor are given. Some conclusions as to the peculiarities of electromagnetic heating of body tissues have been drawn.

Early (1 and 24 h) after X-irradiation with a dose of 0.21 C/kg changes occurred in the acceptability of the polypeptide chain parts of sarcoplasmic reticulum Ca-ATPase for the effect of trypsin. The analysis of the results of studying the structural and functional properties of a hydrophobic fragment of this enzyme in the control and after irradiation permitted to define the part of the Ca-ATPase polypeptide chain that provided ion selectivity of the fragment.

The aim of our work was to establish the influence of the HgCl2 poisoning (various doses) on the Fe distribution in the rat organism. 175 Wistar rats were divided into 5 groups: I--control group, II--intoxicated with HgCl2 in the dose of 1 mg/kg of body weight, in the III group the HgCl2 dose was 6 mg/kg, in the IV group--12 mg/kg, in the V--12 mg/kg but rats of this group were given afterwards BAL (2.3-dimercaptopropanol). All rats were given 0.2 ml of 59FeCl3, radioactivity 3.7 kBq. The animals were put to sleep with chloroform after 3 and 6 hours, and 1, 2, 4, 8, 14 days after the isotope administration. For the radiometric assays the following organs or tissues were taken: stomach, small and large intestine, liver, kidneys, lungs, heart, muscles, spleen, blood, brain, testicles. The results are given in the percent of Fe dose in 1 g of wet tissue. The statistical analysis (Students' t test) was performed. The results indicate that in poisoned animals the Fe distribution was different than in controls. Increased concentration of 59Fe was noted after 3 and 6 hours in stomach and after 1 day in large intestine, whereas in other organs the Fe concentration was lower, correlating usually with the Hg dose. One interesting thing was noted: the Fe concentration in almost all organs was higher in rats intoxicated with the 12 mg/kg dose of HgCl2 and given afterwards BAL (IV group), than in rats that were not given BAL. Present results can have some practical significance in therapeutic procedure in mercury poisoning and during the convalescence.

Increased MR signal intensity was observed on T2-weighted, STIR, and Gadolinium-DTPA-enhanced T1-weighted images of subcutaneous and muscular soft tissue in 9 of 10 children treated with combination chemotherapy and radiation therapy (RT) for malignancy in the pelvis or an extremity. Total radiation doses ranged from 59.5 to 65 Gy. Eight of the patients with these changes received hyperfractionated RT (seven for Ewing sarcoma and one for perineal rhabdomyosarcoma); one was treated for pelvic hemangiopericytoma with once-daily fractions. Evidence of soft tissue damage became apparent as early as the sixth week of RT and was seen for up to 69 wk post-RT. There was no clear MR evidence of RT-induced soft tissue damage in one patient, who underwent hyperfractionated RT for pelvic rhabdomyosarcoma. Other MR findings in this group included evidence of bladder wall thickening in three of the seven patients given pelvic RT and increased T1-weighted signal of irradiated marrow in nine patients. All patients had clinical evidence of skin, soft tissue, or epithelial radiation effects. Increased MR signal intensity secondary to RT-induced damage can be differentiated from widespread tumor by geometric borders that conform to the margins of the radiation field.

Using polarized ultraviolet (UV) fluorescence microscopy, it was shown that the local damage of muscle fibres causes in their morphologically unchanged parts the alternation of regions, being in different functional states referred to as "pseudocontraction" and "superrelaxation". The pattern of UV fluorescence anisotropy suggests that conformation of contractile proteins by "pseudocontraction" is similar to that at contraction, though changes in sarcomere length do not occur. The "superrelaxation" is characterized by a desorganization of myofilaments. During the spreading of Zenker's necrosis, the "pseudocontraction" is seen transferred first into "superrelaxation", and then into irreversible contracture and rigor. "The boundary of Zenker's necrosis" overlaps with the boundary of the self-propagating irreversible contracture. There is no proper boundary of Zenker's necrosis, because the destructive changes are observed over all the muscle fibre. Contraction nodules arise in the regions of "superrelaxation" and follow the changes of the contractile system, peculiar of contracture. The study of the influence of medium ionic composition on the development of Zenker's necrosis suggests that the arising and spreading of destruction are inseparably associated with the irreverrsible changes of intracellular membrane structures, and with the possibility of propogation of the damage signal by these structures along muscle fibres.

The effect of the muscle tissue, ground into a fine chyme, to restoration of the m. gastrocnemius ability to posttraumatic regeneration after x-ray radiation in the doses 20--30 Gy, has been studied in 64 non-inbred white male rats with the body mass about 200 g. The ground muscle is a viscous mass, consisting of finest scraps of muscle fibers, pieces of sarcolemmal tubules with 2--3 nuclei and separate cells. The great destruction of the muscle stroma relieves metabolites to get out and to diffuse. As demonstrate the histological investigations carried out for 1 month, an essential part of the muscle autotransplant, put into the irradiated extremity, regenerates up to formation of differentiated muscle fibers and promotes to restore the regenerative activity in the irradiated m. gastrocnemius.

Male rats of the Wistar strain were fasted overnight prior to exposure to single total-body X-ray dose of 2.39 Gy (250 R). Irradiated and sham-irradiated rats were pair-fed for 5 days, in the next period they were fed ad libitum. The levels of corticosterone and immunoreactive insulin in serum, glucose in blood, glycogen in liver, heart and skeletal muscle were determined 1 and 6 h, 1, 2, 3, 7, 14, 28, and 38 days after irradiation and sham-irradiation. Irradiation of rats resulted, at one hour, in a decrease and, at two days, in an icrease in level of blood glucose. A marked increase in liver glycogen persisted from 6 h to 21 days after irradiation. The level of glycogen in the skeletal muscle was reduced at 6 h and increased on days 3 and 14. Heart muscle glycogen declined within the first 24 h and rose at 14 days after exposure. The kinetics of changes in the heart and skeletal muscle glycogen following non-lethal irradiation was similar and indicated an overlap of changes produced by fasting with those brought about by irradiation, particularly during the first week. Corticosterone in serum was markedly increased in rats at 24 and 72 h after irradiation compared to pair-fed controls. The serum insulin concentration did not change after irradiation, except for a single increase on day 21. Irradiation with non-lethal doses produced changes in the parameters of the carbohydrate metabolism studied, except for serum insulin, which reflected the changes in the nutrition regimen upon pair-feeding rather than the effect of ionizing irradiation.

Three series of experiments were conducted on the gastrocnemius muscle of rats. In the first series the entire muscles were autografted. In the second series autografting of the muscles was preceeded by irradiation of both hind limbs at a dose of 1000 R. In the third series x-ray irradiation at the limbs with helium-neon laser whereupon the muscles were autografted. The transplantation regeneration was studied histologically after 2 weeks, one and two months. It was established that exposure to laser stimulates cell reparation in the skeletal muscle tissues and makes post-traumatic regeneration depressed by x-rays return to normal.

The effect of ultrahigh-frequency energy of electromagnetic field of low intensity on certain morphometric indices of intracellular organoids and on cellular ultrastructure were studied in the developing skeletal muscular tissue of chick embryos. In the skeletal muscles of irradiated embryos a limited cellular destruction, structural disorders in myonic organoids were revealed. Reactive-recovery processes manifested themselves in hyperplasy and hypertrophy of organoids, in activation of protein synthesis, in increasing amount of myosatellites. At early stages after irradiation peripheral mitochondria are subjected to greater changes. After hatching, central mitochondria in myons suffer more. Quantitative changes in myonic organoids and degree of their destruction seem to depend on.a peculiar differentiation of the muscular tissue, blood supply and innervation of the muscle as an organ.

The functional status of rat skeletal muscles was studied at dormancy and during the intensive muscular work under conditions of repeated administration of iodine 131 in doses causing reversible and irreversible damages to thyroid gland (the absorbed doses were from 0.27 to 266 Gy). The biochemical changes in muscles were transient; they correlated with the thyroid gland status and lifetime of animals and were displayed during the first 15 days and 2-12 months after the start of the isotope injection.

During irradiation with an Ar+-and Kr+-laser the temperature rise in living and dead tissue was measured in various depths. The contribution of the blood flow to the heat transport during irradiation was found to be small. The influence of the different depths of penetration and backscattering at the blue-green Ar+-and the red Kr+-radiation was investigated. The measurements compared with theory show reasonable agreement for an one-dimensional model below 100 degrees C. The results are discussed with respect to laser application in medicine.

Procedure is presented for studying the coefficient of biological tissue absorption of radiation with the wavelength lambda = 1.06 mkm. The absorption coefficient is determined by the temperature values of biological tissue experimentally measured with thermopairs. The coherent radiation current falls on the surface of biological tissue. A mathematical model is formulated for biological tissue heating with radiation. Solution of Furier equation obtained by means of Green function is given. Using the relationship found, the energy absorbed by the biological tissue was calculated and the absorption coefficient of radiation with lambda - 1.06 mkm was determined. The results were analysed and the error of the obtained values of absorption coefficients of biological tissues under study were determined.

To adequately plan and administer localized hyperthermia with interstitial microwave antennas, the thermal distribution patterns generated by such antennas must be characterized. This study evaluated the performance of single node 915 MHz antennas operating either alone or as a 2 cm square array of four parallel antennas using both muscle-equivalent phantoms and canine thigh muscle. Two types of measurements were compared. Specific absorption rate (SAR), where temperature increases resulting from short duration microwave pulses were used to define power distribution, and temperature gradients during simulated hyperthermia treatments. SAR measurements in phantoms were comparable to those obtained in non-perfused canine muscle demonstrating the usefulness of the phantom for these measurements. For a single antenna there was a rapid decrease in power radially which resulted in a steep thermal gradient at distances within 0.5 cm. However, the power generated by a four-antenna array was highest along its central axis and declined to approximately 50% near the antennas at the array periphery. Along the central axis of the array power decreased most rapidly distal to the antenna nodes. The distribution of temperature measured during simulated hyperthermia treatments in phantoms paralleled the SAR distribution and was comparable to the temperature gradient observed in perfused canine muscle, suggesting that phantoms could be used to predict temperature distributions in resting muscle tissue.

Observations are reported indicating that CO2 laser radiation induces the appearance of strong primary fluorescence in the tissues surrounding the incidence zone of the beam. The characteristics of this emission were studied by means of cytofluorometric techniques on rat muscles and compared with the fluorescence obtained by a heating procedure or by storage of tissue slices. Laser-induced primary fluorescence was found to be related to the thermal effect of CO2 laser radiation. Moreover, evidence is provided that the processes occurring during heating and those occurring during tissue decomposition most probably produce the same fluorescent products, albeit with different rates. From the results obtained, it is suggested that primary fluorescence can be used as a marker of the damage suffered by the irradiated tissues.

The authors condensed their knowledge of physical injuries of skeletal muscle, particularly injuries caused by mechanical energy, atmospheric pressure, radiation, extremes of temperature and electricity. The possible perils, outcomes and consequences are discussed. Special attention is given to the military medical projections.

Frogs Rana pipiens maintained under constant laboratory environmental conditions were subjected daily to chronic microwave exposure with pulsed microwave (2.88 GHZ) at a power density of 10 mW/cm2, during 0.1 hour, for periods up to 100 days. The whole body Specific Absorption Rate (SAR) was of 1.5 mW/g per 1 mW/cm2. The passive and dynamic electrical parameters of sartorius muscle cells from control and irradiated frogs as a function of temperature in the range from 10 C to 30 C, have been analyzed. This temperature dependence analysis, presented in another work, was planned to be used in this paper for detecting those possible "masked" chronic microwave effects in complex membrane mechanisms highly temperature sensitive, and tightly related to the excitation and propagation of bioelectrical responses. The temperature dependence of the passive (Vr, Gm, Cm, and tau) and the active cell electrical parameters (theta, V*, Vs, VNa, Vn, V+, V-, kr, kNa, kK, tau Na, tau K, -gNa, gNa, gK, INa, and IK) was not altered by chronic microwave exposure. The striking observation reported in another work, about the presence of two groups of cell electrical parameters, characterized by their dependence with temperature, was reproduced on the irradiated muscle cells. Results have indicated that there was not muscle cell cumulative bioeffects resulting from microwave exposure to 10 mW/cm2, over a 0.1 hour period.

Experiments were carried out on phantoms imitating muscular and fatty tissues which were exposed to a single action of microwave hyperthermia in microwave set "Volna-2" (460 MHz installation with a modified antenna. The temperature in the phantoms was measured by copper-constant thermocouples in periods of automatic switching off the microwave power. Temperature distribution in the phantoms was found to depend on the depth, exposure time and power.

This work concerns the electrical properties of waveguide applicators consisting of flanged rectangular waveguides filled with a dielectric, used in medical applications (microwave thermography and local hyperthermia). The reflection coefficient and the near field configuration in lossy materials were obtained in some cases analytically and in some other cases numerically. The validity of these methods was verified experimentally. The study shows that the matching of the applicator and the penetration depth in a lossy material, such as a living tissue, depend not only on the tissue characteristics but also on the characteristics of the applicator itself.

A sparse neutrophilic leukocytic infiltrate was found in the gingival sulcus, both in the flight and the control animals, while no changes were observed in the palate. Mitoses in gingival and palatal tissues were in approximately equal numbers in all animal groups. The tongues of flight mice and controls contained areas characterized by vascular dilatation, separation of muscle bundles, and regressive and degenerative changes in muscle fibers. Mucous glands in the posterior part of the tongue of flight and control animals exhibited acinar distension. Also examined were the vertebral column; femur, knee joint, tibia and fibula of the right hindlimb; and the tracheal cartilages. No evidence of cosmic ray particle effects was found in any of these tissues.

Irradiation of rabbits with decimetre waves (regions of adrenal glands, liver and lower part of thigh) was accompanied by an increased content of free, biologically active corticosteroids in blood plasma due to liberation of the substances from a complex with transcortine. This phenomenon correlated with activation of the electron transport in respiratory chain of liver tissue mitochondria. The irradiation of the liver region caused distinct alteration in mitochondrial functions apparently due to intensified effect of the decimetre waves directly on the liver tissue.