Effects of low-intensity laser irradiation on hormonal responsiveness of patients with pulmonary tuberculosis

The method of proteinic catabolism degree estimation in potential renal transplant recipients was elaborated. It is based on the urea and creatinine level in blood determination and calculation of the metabolism index according to the formula. The substantiation of the patients treatment tactics and estimation of its efficacy was permitted by determination of predominational metabolism tendency.     

Effect of irradiation with a low-intensity diode laser on the metabolism of equine articular cartilage in vitro

OBJECTIVE: To determine whether irradiation with a low-intensity diode laser, which produces radiation at a wavelength of 810 nm, will induce nonthermal enhancement of chondrocyte metabolism. SAMPLE POPULATION: 144 grossly normal articular cartilage explants aseptically harvested from the femoral condyles of 6 adult horses. PROCEDURE: Treated cartilage explants were irradiated with a diode laser at 1 of 7 fluence levels that ranged from 8 to 1,600 J/cm2. Explants were incubated for 24 or 72 hours, labeled for 24 hours with [35S]Na2SO4, and assayed for newly synthesized sulfated glycosaminoglycan (GAG; measured incorporation of 35SO4) and endogenous GAG, chondroitin 6-sulfate (CS), and keratan sulfate (KS) content, using a dimethylmethylene blue assay. Laser-induced temperature changes were measured during irradiation with a diode laser and a neodymium:yttrium aluminum garnet (Nd:YAG) laser, which produces radiation at a wavelength of 1,064 nm, using conditions that were reported in previous studies to increase explant metabolism. RESULTS: After incubation for 24 or 72 hours, rate of 33SO4 uptake or endogenous GAG, CS, or KS content in irradiated explants was not significantly different than in nonirradiated explants. Cartilage temperature increased < 4.75 C during diode laser application. Cartilage temperature increased 5 to 12 C during Nd:YAG laser application. CONCLUSIONS: Minimal thermal increases in cartilage explants with use of a low-intensity diode laser resulted in no change in proteoglycan metabolism of chondrocytes. An increase in tissue temperature over a narrow range with use of a Nd:YAG laser may have contributed to the metabolic alteration of chondrocytes reported in previous studies.     

Effects of Nd:YAG laser irradiation on morphometry and lung function in elastase-induced emphysema in rats

BACKGROUND & OBJECTIVE: Although thoracoscopic laser ablation therapy has been hailed as an effective surgical treatment for diffuse emphysema, no one has as yet made an in-depth study of the efficacy of this treatment. This investigation was undertaken to research the effects of laser pneumoplasty on an animal model of emphysema. STUDY DESIGN/MATERIALS AND METHODS: Eight weeks after elastase treatment, the rats' left lungs were irradiated using contact Nd:YAG laser. Pulmonary function tests were performed 4 weeks after irradiation and the lungs were prepared for histologic examination. RESULTS: Dense fibrous scars beneath the pleura were observed at 4 weeks after irradiation. Although mean linear intercept values of irradiated lungs were not much lower than those in the non-irradiated elastase-treated group, laser irradiation caused a significant decrease in lung volume. While there was no significant difference in quasistatic compliance, elastic recoil pressure of the lung increased to control levels at total lung capacity volume. CONCLUSION: We conclude that laser therapy does not cause normalization of compliance, or improvement in the deeper part of the emphysematous lung, but rather a peripheral volume reduction and "encasement effect" on the lungs as a result of fibrotic scars.     

The action of low-intensity infrared laser radiation on skin afferents

Laser radiation modulates functional characteristics of mechanoreceptors. This inhibits impulse activity of the nerve endings from pain focus and reduces pain sensitivity of skin afferents, excitability of conductive nerve fibers. Changes in sensitivity become more pronounced with increasing duration of the exposure. By means of reflectory mechanism laser radiation may cause other general reactions of the body and enhance immune response of the skin.     

The effect of low-intensity laser radiation on functional potential of leukocytes

We examined whether X radiation induces a particular deletion in the mitochondrial DNA (mtDNA) of the cells of two human squamous cell carcinoma lines with different sensitivity to radiation and in a radiosensitive ataxia telangiectasia (AT) cell line. We used polymerase chain reaction (PCR) to quantify the accumulation of a particular 4977-bp deletion (delta mtDNA4977). PCR products of delta mtDNA4977 were detectable after exposure to 10 Gy in the radioresistant squamous cell carcinoma cells, 2 Gy in the radiosensitive squamous cell carcinoma cells and 1 Gy in the radiosensitive AT cells. These observations suggest that ionizing radiation induces the delta mtDNA4977 in human cells and that the radiation doses required to induce this deletion reflect the sensitivity of cells to radiation.     

Effects of ArF:excimer laser irradiation on human enamel and dentin

Round enamel and dentin surfaces of sound and carious extracted human teeth were irradiated by an ArF:excimer laser for up to 180 sec. Thermographic measurements indicated that the temperature rise due to heat accumulation caused by laser irradiation on these enamel and dentin surfaces was up to 19 degrees C (10 HZ with 540 J/cm2), and the temperature returned to the preirradiation value within 10 sec after the irradiation was stopped. Under light microscopy, no carbonization was evident on these surfaces, and a simple recess was formed by abrasion or vaporization in the irradiated regions. In the secondary SEM, uniformly distributed fine pores and prism structures appeared slightly on the enamel surfaces. Between the peritubular and the intertubular dentin, there appeared a distinct difference in the dissolved area. The laser almost completely removed carious regions of the enamel and the dentin, and penetration extended beyond the carious regions. In the backscattered electron SEM, highly mineralized layers were observed on the enamel and dentin surfaces dissolved by the laser.     

Effects of low-intensity ultrasound on the central nervous system of primates

The brains of anesthesized squirrel monkeys were exposed to 2.25 to 5 MHz ultrasound at low intensities (average power from 3 mW/cm2 to 0.9 W/cm2). The exposure produced evoked potentials recorded by EEG electrodes chronically implanted in the midline parietal region. Computer analysis of the waveforms showed that ultrasound produced a transient upward shift in both the peak frequency and in its amplitude. Complete adaptation occurred with 3 min of continuous exposure to either CW or pulsed irradiation.     

Effect of endurance training on pancreatic enzyme activity in rats

Immunoglobulin G (IgG) of Indian soft-furred rat, Millardia meltada, was purified by an immunoaffinity chromatography and antibodies against it was raised in rabbit. Using this rabbit anti-M. meltada IgG antibody, sensitivity of enzyme-linked immunosorbent assay (ELISA) to measure parasite-specific antibodies in the sera of M. meltada was markedly enhanced than the previous method using rabbit anti-mouse IgG and rabbit anti-rat IgG antibodies, which could cross-react to M. meltada IgG. Since M. meltada could effectively produce circulating antibodies against two intestinal helminths, Strongyloides venezuelensis and Nippostrongylus brasiliensis, the high susceptibility of this animal to an array of parasites seems to be not due to general immunological deficiency.     

Effects of right hemithoracic irradiation on ceftazidime penetration into the alveolar space in rats

We experienced with three patients with pulmonary dirofilariasis found in resected lungs. Two patients showed abnormal shadows on chest roentgenograms without symptoms. Another patients had chest discomfort. All patients underwent diagnostic thoracotomy. Histopathological examination showed necrotic granulomatous lesions surrounded by fibrous tissue and transverse section of Dirofilaria immits was found. It has been an increasing reported disease. It is important to keep in mind the possibility of dirofilariasis.     

Effect of low-intensity hippocampal stimulation on spatial versus working memory in rats.

Investigated differing predictions from the spatial mapping hypothesis of hippocampal function proposed by O'Keefe and Nadel (1978) and the working memory hypothesis proposed more recently by Olton and colleagues (Olton, Becker, & Handelmann, 1979). Each of 2 groups of rats was trained to use a different strategy to locate a submerged platform in opaque water. The MAP group used a spatial mapping strategy to reach a platform in a fixed location, whereas the CUE group used a guidance strategy, which involved following a cue that signaled the location of a randomly placed platform. Half of each group was given low-level unilateral electrical stimulation of the dentate gyrus and immediately tested on the water maze task. Results of Exp 1 show that both the MAP and CUE groups were impaired by stimulation. However, there was an inadvertent spatial element involved in the CUE task. When this element was eliminated in Exp 3, the same CUE Ss were unaffected by a 2nd series of stimulation trials, whereas the MAP Ss continued to show impairment. Results strongly support the cognitive mapping hypothesis and provide little support for the working memory hypothesis of hippocampal function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ambient temperature effects on thermoregulation and endurance in anticholinesterase-treated rats

In sedentary animals, physostigmine (PH) administration resulted in a decreased core temperature that is ambient temperature (Ta) dependent. PH administration in rats exercising on a treadmill (26 degrees C, 50% rh, 11m/min, 6 degrees incline) decremented endurance and increased rate of rise of core temperature (heating rate, HR). This study was undertaken to examine the effects of Ta on the endurance and thermoregulatory decrements of PH-treated running rats. Adult male rats (510-530g) were given either 0.2ml saline (C) or 100 ug/kg physostigmine salicylate in 0.2 ml saline via tail vein 15 min prior to the start of running to exhaustion at 10, 15, 26, or 30 degrees C. In both C- and PH-treated groups, endurance decreased and HR increased with increasing Ta from 15 to 30 degrees C. At 15 and 26 degrees C the C rats ran significantly (p < .05) longer and had significantly lower HR than the PH rats: C15 = 90 +/- 8 min, 0.022 +/- 0.006 degrees C/min; C26 = 67 +/- 6, 0.051 +/- 0.007; PH15 = 57 +/- 5, 0.052 +/- 0.008; and PH26 = 43 +/- 6, 0.092 +/- 0.007. At 10 and 30 degrees C there were no significant differences between C and PH-treated rats. A Ta of 30 degrees C was too high for effective cooling in either group, and at 10 degrees C both groups were able to dissipate heat despite the increased metabolic rate of the PH-treated rats. The PH-treated rat model of cholinergic drug effect is useful at a Ta of 15 and 26 degrees C.     

Anabolic-androgenic steroid increases running endurance in rats

The study was designed to determine whether treatment with an anabolic-androgenic steroid enhances running performance in rats by increasing their freely chosen training distance. Forty male Long-Evans rats were randomly divided into either a sedentary control group or an exercising group caged in specially designed running wheels in which the rats were able to run spontaneously. After 4 wk, both groups were further subdivided into two groups receiving either 0.5-mg Durabolin (nandrolone phenylpropionate) (im) or 0.5-mg saline, every second day. After 8 wk, running distance was similar in both exercising groups. Rats receiving the anabolic-androgenic steroid ran 41% longer during the test of submaximal running endurance compared to the trained rats receiving saline (P < 0.05). Submaximal running endurance was not increased in sedentary rats receiving the anabolic-androgenic steroid. After 4 wk of training, the maximal sprinting speed increased by 29% in trained rats. There was no further increase in maximal sprinting speed after an additional 4 wk of training and treatment with either anabolic-androgenic steroid or saline treatment. Therefore, rats that train spontaneously while being treated with an anabolic-androgenic steroid had increased submaximal running endurance compared with trained rats treated with saline, despite the similar voluntary training distance and skeletal muscle oxidative capacity between the two groups. The mechanism by which treatment with an anabolic-androgenic steroid, combined with training, enhances submaximal running performance could not be identified and needs to be addressed in future studies.     

Effect of endurance exercise training on muscle glycogen supercompensation in rats

The purpose of this study was to test the hypothesis that the rate and extent of glycogen supercompensation in skeletal muscle are increased by endurance exercise training. Rats were trained by using a 5-wk-long swimming program in which the duration of swimming was gradually increased to 6 h/day over 3 wk and then maintained at 6 h/day for an additional 2 wk. Glycogen repletion was measured in trained and untrained rats after a glycogen-depleting bout of exercise. The rats were given a rodent chow diet plus 5% sucrose in their drinking water and libitum during the recovery period. There were remarkable differences in both the rates of glycogen accumulation and the glycogen concentrations attained in the two groups. The concentration of glycogen in epitrochlearis muscle averaged 13.1 +/- 0.9 mg/g wet wt in the untrained group and 31.7 +/- 2.7 mg/g in the trained group (P < 0.001) 24 h after the exercise. This difference could not be explained by a training effect on glycogen synthase. The training induced approximately 50% increases in muscle GLUT-4 glucose transporter protein and in hexokinase activity in epitrochlearis muscles. We conclude that endurance exercise training results in increases in both the rate and magnitude of muscle glycogen supercompensation in rats.     

Skeletal muscle fatigue and physical endurance of young and old mice

In order to evaluate the role played by muscular and extramuscular factors in the development of fatigue in old age, the time course of fatigue in isolated skeletal muscles and spontaneous motor activity and endurance of whole animals were monitored using young (3-6 months) and old (34-36 months) CF57BL/6J mice. The isolated extensor digitorum longus (EDL) and soleus muscles from old mice had smaller (P < 0.05) mass and developed lower (P < 0.02) maximal tetanic tension at 100-Hz stimulation than the muscles of young mice. During stimulation at 30 Hz every 2.5 s, a 50% decline in original tetanic tension occurred by 109 s in young EDL and 129 s in old EDL, but by 482 s in young soleus and 1134 s (projected) in old soleus, indicating more (P < 0.05) resistance to fatigue in old than young soleus. However, the old mice showed significantly fewer (P < 0.002) spontaneous ambulatory movements than the young mice. On a treadmill with a belt speed of 10 m/min at an inclination of 0 degrees, the old mice could only run for 22 min compared to 39 min ran by young mice (P < 0.02). They took more rest periods (P< 0.02) than the young mice. In a quantitative swimming monitor, the old mice swam for a shorter (P < 0.05) time than young mice (20.4 min compared to 28.6 min). Integrated swimming activity at 20 min was smaller (P < 0.05) in old mice than in young mice (413 g/s compared to 628 g/s). Hence increased fatigue in old age is not caused by impairment of processes within the muscles, but by impairment of central or extramuscular processes.     

Dietary fatty acid profile affects endurance in rats

Typically athletes are advised to increase their consumption of carbohydrates for energy and, along with the general population, to reduce consumption of saturated fats. It is now recognized that fats are not identical in their influence on metabolism, and we argue that the composition of the polyunsaturated fat component should not be ignored. The aim of this study was to manipulate the dietary fatty acid profile in a high-carbohydrate diet in order to investigate the effect of dietary polyunsaturates on submaximal endurance performance in rats. Rats were fed one of three isoenergetic diets containing 22 energy percentage (E%) fat for 9 wk. The diets comprised an essential fatty acid-deficient diet (containing mainly saturated fatty acids); a diet high in n-6 fatty acids, High n-6; and a diet enriched with n-3 fatty acids, High n-3. Submaximal endurance in rats fed the High n-3 diet was 44% less than in rats fed the High n-6 diet (P < 0.02). All rats were then fed a standard commercial laboratory diet for a 6-wk recovery period, and their performances were reevaluated. Although endurance in all groups was lower then at 9 wk, it was again significantly 50% lower in the High n-3 group than the High n-6 group (P < 0.005). Although n-3 fats are considered beneficial for cardiovascular health, they appear to reduce endurance times, and their side effects need to be further investigated.     

The stress-limiting action of low-intensity laser radiation in patients with ischemic heart disease

In 20 patients with exercise-induced angina, the cold test brought about activated lipid peroxidation, modified the lipid phase of a red cell membrane, which correlated with systolic changes. Following a month laser therapy, it did not cause no activation of lipid peroxidative processes, significant changes in the organization of a cell membrane lipid bilayer, or any profound cardiac performance abnormalities, which gives grounds to state that laser radiation exerts membrane-stabilizing and antistress effects. The findings suggest that laser therapy should be used in coronary heart disease patients having a functional component of coronary insufficiency.     

Effects of irradiation on the biomechanics of osseointegration. An experimental in vivo study in rats

The present study reports on the late effects of increasing doses of radiation on the biomechanics of commercially pure titanium implants (fixtures) installed in the proximal tibia in 26 rats. Twelve weeks after various doses (10, 20, 30, and 35 Gy) of irradiation, the fixtures were inserted into rat tibiae, and after another eight weeks these were tested mechanically in vivo. Acute dose dependent skin reactions developed after all doses except 10 Gy, but most subsided within two to three weeks. There was a statistically significant reduction in torsion but the pull-out load was not significantly reduced for single doses up to 30 Gy. Histological analysis showed that bone remodelling was impaired. Shear stresses and shear moduli were estimated for the bone-implant interface and in the surrounding bone tissue. These estimated stresses and moduli were not found to be correlated to the dose of radiation.     

Classification of laser irradiation and safety measures

The use of lasers in medicine and especially surgery is rapidly expanding in many disciplines from clinical laboratory to the office practice and operating room. It is essential that users of this powerful tool have knowledge of their potential hazards and the measures to protect patients and personnel against injuries or undesired effects. Below, we have included information about the way lasers are classified; the development of protective standards; the current status of protection standards that apply to lasers, especially those used in medicine/surgery; the specific kinds of hazards associated with medical/surgical applications; and the measures by which hazards have been controlled. Since laser technology is still a young field, it is likely that problems unknown at present will occur and methodologies for controlling hazards will evolve. The American National Standards Committee produced the first consensus standard Z136.1 in 1973. The Standard was revised in 1976 to accommodate differences in biological effects for different wavelengths in the visible spectrum. The ANSI Standard has been revised again in 1980, and currently (1984) there are two additional standards in preparation, Z136.2 and 136.3, which treat the safe use of light-emitting diodes and the safe use of lasers in the health care environment, respectively. Most surgical and medical lasers are Class III or IV. Some lasers have a Class IV therapy level beam plus a Class I or II alignment beam. When using lasers, it is possible to generate incandescence or fluorescence in an irradiated object. This can occur even with protective eyewear, because the correlated radiations are usually of a different wavelength. Generally, this should not be a problem when beams are directed at biological material. However, hazard could be caused by lasers designed to produce fluorescence. Control of correlative radiation in a laser system is required in the federal regulations. Hazards of lasers may be grouped as those to the eye, skin and associated hazards, fire, x-rays, electrical, fumes, toxic materials, etc. Effects on tissue are governed by the following factors:--the energy or power density of the beam;--the absorption in tissue at the laser wavelength;--the time the beam is held at a given area.;--the protective effects of heat removal by thermal conduction and by circulation. Eye hazards include thermal burns or acoustical disruption (shock waves) from high-powered or high-energy beams in the visible and near infrared wavelengths. Direct beam exposure or specular or diffuse reflaction from these very high-power lasers can also cause injuries to other parts of the retina. For example, beams can directly penetrate through the sclera and cause retinal injury. Near ultraviolet (less than 400 hm) and far infrared (.3000 hm including CO2 lasers) can cause moderate to severe corneal burns. Far ultraviolet (200-315 nm), mid infrared (1400-3000 nanometers) can cause welders' flash or snow blindness and chronic exposure could cause cataract, and exposure to ultraviolet rays may be carcinogenic. For CO2 lasers, the far infrared radiation is attenuated by plastic goggles, or by glasses, or quartz. Other eyewear with special filters is used for different lasers. The whole personnel who may be exposed to direct beams, specular reflections, and many times diffuse reflections must wear protective eyewear. In all cases the surgeon and others viewing the procedure through the endoscope need glasses or suitable protective lenses installed in the endoscope. Persons who are not viewing the beam may not need to wear protective glasses with the same level of optical density. Glasses may be selected to provide protection for lasers operating in the visible wavelength to the point where the normal aversion response could protect the individual.     

Effect of low-power laser irradiation on impulse conduction in anesthetized rabbits

Low-power laser analgesic effect was generally accepted in clinical cases, whereas there was no direct evidence to indicate that low-power laser irradiation suppressed an impulse conduction within a peripheral nerve. The effect of low-power laser irradiation on electrically evoked responses within the sural nerve was electrophysiologically analyzed in anesthetized rabbits. High threshold evoked responses (conduction velocity was about 11 m/sec, unmyelinated A delta), which were induced by an electrical stimulation to the peripheral stump of the nerve, were significantly suppressed (9 to 19% inhibition) during low-power laser irradiation, which applied to the exposed sural nerve between the stimulus site and the recording site. The suppressive effect was reversible and recovered to the control level after the irradiation. Experimental evidence indicated that low-power laser irradiation suppressed the impulse conduction of unmyelinated A delta afferents in peripheral sensory nerve, which caused a pain sensation. Our data suggest that low-power laser acts as a reversible direct suppressor of neuronal activity.