949 resultados para low dose irradiation


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Introduction: CD103 is a specific integrin present on some CD4+ lymphocytes of the mucosal immune system. It has been hypothesized that most CD4+ lymphocytes in pulmonary sarcoidosis do not originate from mucosal sites but from redistribution from the peripheral blood, and therefore do not bear the CD103 integrin. Several studies have suggested that a low CD103+ percentage among bronchoalveolar lavage (BAL) CD4+ lymphocytes discriminates between sarcoidosis and other causes of lymphocytic alveolitis, but contradictory data exist. Methods: We reviewed 1151 consecutive patients with BAL lymphocytosis >10% and flow cytometry performed between 2006 and 2014. 944 cases were excluded due to poor BAL quality (n= 97), unavailable clinical data (n= 760), or unclear diagnosis (n= 87). The remaining 207 patients were grouped into 9 diagnostic categories. To assess the discriminative value of the CD103+CD4+/CD4+ ratio to distinguish sarcoidosis from the other entities, area under ROC curves (AUC) were determined. Results: Sarcoidosis patients (n=53) had a lower CD103+CD4+/CD4+ ratio than the other diagnostic categories. AUC was 62% for sarcoidosis compared to all other patients and 69% for sarcoidosis compared to other interstitial lung diseases. When combining CD103+CD4+/CD4+ and CD4+/CD8+ ratios, AUC increased to 76% and 78% respectively. When applying published cut-offs from 4 previous studies to our population, AUC varied between 54 and 73%. Conclusions: The CD103+CD4+/CD4+ ratio does not accurately discriminate between sarcoidosis and other causes of lymphocytic alveolitis, neither alone nor in combination with CD4+/CD8+ ratio, and is not a relevant marker for the diagnosis of sarcoidosis.

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Abstract Objective: To determine whether low-level laser therapy can prevent salivary hypofunction after radiotherapy and chemotherapy in head and neck cancer patients. Materials and Methods: We evaluated 23 head and neck cancer patients, of whom 13 received laser therapy and 10 received clinical care only. An InGaAlP laser was used intra-orally (at 660 nm and 40 mW) at a mean dose of 10.0 J/cm2 and extra-orally (at 780 nm and 15 mW) at a mean dose of 3.7 J/cm2, three times per week, on alternate days. Stimulated and unstimulated sialometry tests were performed before the first radiotherapy and chemotherapy sessions (N0) and at 30 days after the end of treatment (N30). Results: At N30, the mean salivary flow rates were significantly higher among the laser therapy patients than among the patients who received clinical care only, in the stimulated and unstimulated sialometry tests (p = 0.0131 and p = 0.0143, respectively). Conclusion: Low-level laser therapy, administered concomitantly with radiotherapy and chemotherapy, appears to mitigate treatment-induced salivary hypofunction in patients with head and neck cancer.

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OBJECTIVE: to compare the effects of low intensity laser therapy on in vitro bacterial growth and in vivo in infected wounds, and to analyze the effectiveness of the AsGa Laser technology in in vivo wound infections. METHODS: in vitro: Staphylococcus aureus were incubated on blood agar plates, half of them being irradiated with 904 nm wavelength laser and dose of 3J/cm2 daily for seven days. In vivo: 32 male Wistar rats were divided into control group (uninfected) and Experimental Group (Infected). Half of the animals had their wounds irradiated. RESULTS: in vitro: there was no statistically significant variation between the experimental groups as for the source plates and the derived ones (p>0.05). In vivo: there was a significant increase in the deposition of type I and III collagen in the wounds of the infected and irradiated animals when assessed on the fourth day of the experiment (p=0.034). CONCLUSION: low-intensity Laser Therapy applied with a wavelength of 904nm and dose 3J/cm2 did not alter the in vitro growth of S. aureus in experimental groups; in vivo, however, it showed significant increase in the deposition of type I and III collagen in the wound of infected and irradiated animals on the fourth day of the experiment.

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OBJECTIVE: To gather and clarify the actual effects of low-level laser therapy on wound healing and its most effective ways of application in human and veterinary medicine.METHODS: We searched original articles published in journals between the years 2000 and 2011, in Spanish, English, French and Portuguese languages, belonging to the following databases: Lilacs, Medline, PubMed and Bireme; Tey should contain the methodological description of the experimental design and parameters used.RESULTS: doses ranging from 3 to 6 J/cm2 appear to be more effective and doses 10 above J/cm2 are associated with deleterious effects. The wavelengths ranging from 632.8 to 1000 nm remain as those that provide more satisfactory results in the wound healing process.CONCLUSION: Low-level laser can be safely applied to accelerate the resolution of cutaneous wounds, although this fact is closely related to the election of parameters such as dose, time of exposure and wavelength.

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In the last growing seasons, goosegrass (Eleusine spp.) control failures have been observed following application of glyphosate on Roundup Ready® soybean in Rio Grande do Sul (RS) - Brazil, suggesting this species' resistance to the herbicide. Thus, the objectives of this study were to identify the occurrence of goosegrass resistance to the herbicide glyphosate in RS; and to determine the predominant species of the genus Eleusine, as well as the LD50 and GR50 of the suspected resistant biotypes. Two experiments were conducted under greenhouse conditions: one to identify the biotypes resistant to glyphosate, and the other, a dose-response curve experiment, as well as a study of the botanical characteristics of the species. In the first experiment, 39 biotypes were tested, mainly Eleusine indica, collected with suspected resistance to glyphosate. The glyphosate dose was 2,160 g e.a. ha-1, and the control was evaluated at 28 days after treatment. All biotypes were effectively controlled,with the biotypes from the municipality of Boa Vista do Incra showing greater tolerance. Two biotypes suspected of resistance (12.1 and 12.3) and a susceptible biotype in a dose-response experiment were tested at the following doses: 0, 135, 270, 540, 1,080, 1,620, and 2,160 g e.a. ha-1. The results of this experiment showed that biotype 12.1 does not present resistance to glyphosate and biotype 12.3 has a low level resistance since it is effectively controlled by the herbicide at the maximum dose.

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This study was designed to evaluate the thyroid and pituitary hormone levels in post-weaning rats whose dams were fed a low-protein diet during suckling (21 days). The dams and pups were divided into 2 groups: a control group fed a diet containing 22% protein that supplies the necessary amount of protein for the rat and is the usual content of protein in most commercial rat chow, and a diet group fed a low-protein (8%) diet in which the protein was substituted by an isocaloric amount of starch. After weaning all dams and pups received the 22% protein diet. Two hours before sacrifice of pups aged 21, 30 and 60 days, a tracer dose (0.6 µCi) of 125I was injected (ip) into each animal. Blood and thyroid glands of pups were collected for the determination of serum T4, T3 and TSH and radioiodine uptake. Low protein diet caused a slight decrease in radioiodine uptake at 21 days, and a significant decrease in T3 levels (128 ± 14 vs 74 ± 9 ng/dl, P<0.05), while T4 levels did not change and TSH was increased slightly. At 30 days, T3 and TSH did not change while there was a significant increase in both T4 levels (4.8 ± 0.3 vs 6.1 ± 0.2 µg/dl, P<0.05) and in radioiodine uptake levels (0.34 ± 0.02 vs 0.50 ± 0.03%/mg thyroid, P<0.05). At 60 days serum T3, T4 and TSH levels were normal, but radioiodine uptake was still significantly increased (0.33 ± 0.02 vs 0.41 ± 0.03%/mg thyroid, P<0.05). Thus, it seems that protein malnutrition of the dams during suckling causes hypothyroidism in the pups at 21 days that has a compensatory mechanism increasing thyroid function after refeeding with a 22% protein diet. The radioiodine uptake still remained altered at 60 days, when all the hormonal serum levels returned to the normal values, suggesting a permanent change in the thyroid function

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We examined the radioprotective effect of aminothiol 2-N-propylamine-cyclo-hexanethiol (20-PRA) on a human leukemic cell line (K562) following various radiation doses (5, 7.5 and 20 Gy) using a source of 60Co g-rays. At 5 Gy and 1 nM 20-PRA, a substantial protective effect (58%) was seen 24 h after irradiation, followed by a decrease at 48 h (11%). At the high radiation dose (20 Gy) a low protective effect was also seen (35%). In addition, the antitumorigenic potential of 10 nM 20-PRA was shown by the inhibition of crown gall formation induced by Agrobacterium tumefaciens. The radioprotective potency of 20-PRA is 105-106 times higher than that of the aminothiol WR-1065 (N-(2-mercaptoethyl)-1,3-diaminopropane) whose protective effect is in the 0.1 to 1.0 mM range.

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This study examined if leucine, arginine or glycine supplementation in adult obese patients (body mass index of 33 ± 4 kg/m²) consuming a Brazilian low energy and protein diet (4.2 MJ/day and 0.6 g protein/kg) affects protein and amino acid metabolism. After four weeks adaptation to this diet, each subject received supplements of these amino acids (equivalent to 0.2 g protein kg-1 day-1) in random order. On the seventh day of each amino acid supplementation, a single-dose 15N-glycine study was carried out. There were no significant differences in protein flux, synthesis or breakdown. The protein flux (grams of nitrogen, gN/9 h) was 55 ± 24 during the nonsupplemented diet intake and 39 ± 10, 44 ± 22 and 58 ± 35 during the leucine-, glycine- and arginine-supplemented diet intake, respectively; protein synthesis (gN/9 h) was 57 ± 24, 36 ± 10, 41 ± 22 and 56 ± 36, respectively; protein breakdown (gN/9 h) was 51 ± 24, 34 ± 10, 32 ± 28 and 53 ± 35, respectively; kinetic balance (gN/9 h) was 3.2 ± 1.8, 4.1 ± 1.7, 3.4 ± 2.9 and 3.9 ± 1.6. There was no difference in amino acid profiles due to leucine, arginine or glycine supplementation. The present results suggest that 0.6 g/kg of dietary protein is enough to maintain protein turnover in obese women consuming a reduced energy diet and that leucine, arginine or glycine supplementation does not change kinetic balance or protein synthesis.

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The prone position can be used for the planning of adjuvant radiotherapy after conservative breast surgery in order to deliver less irradiation to lung and cardiac tissue. In the present study, we compared the results of three-dimensional conformal radiotherapy planning for five patients irradiated in the supine and prone position. Tumor stage was T1N0M0 in four patients and T1N1M0 in one. All patients had been previously submitted to conservative breast surgery. Breast size was large in three patients and moderate in the other two. Irradiation in the prone position was performed using an immobilization foam pad with a hole cut into it to accommodate the breast so that it would hang down away from the chest wall. Dose-volume histograms showed that mean irradiation doses reaching the ipsilateral lung were 8.3 ± 3.6 Gy with the patient in the supine position and 1.4 ± 1.0 Gy with the patient in the prone position (P = 0.043). The values for the contralateral lung were 1.3 ± 0.7 and 0.3 ± 0.1 Gy (P = 0.043) and the values for cardiac tissue were 4.6 ± 1.6 and 3.0 ± 1.7 Gy (P = 0.079), respectively. Thus, the dose-volume histograms demonstrated that lung tissue irradiation was significantly lower with the patient in the prone position than in the supine position. Large-breasted women appeared to benefit most from irradiation in the prone position. Prone position breast irradiation appears to be a simple and effective alternative to the conventional supine position for patients with large breasts, since they are subjected to lower pulmonary doses which may cause less pulmonary side effects in the future.

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We determined the effect of the opiate receptor antagonist naloxone on aggression, emotion, feeder control, and eating behavior in high and low aggression female pigeons maintained at 80% of their normal weight and exposed to food competition interactions. Pigeons were divided into pairs by previously ranked high aggression (total time spent in offensive aggression exceeding 60 s/5 min; N = 6 pairs) and low aggression females (time spent in offensive aggression less than 10 s/5 min; N = 6 pairs). A pigeon in each pair received an sc dose of naloxone (1 mg kg-1 ml saline-1) and the other animal received the vehicle. Trials (10 min) were performed 30 min after the naloxone/vehicle administration. The naloxone group of high aggression pigeons showed lower scores of total time spent in offensive aggression (control: 98.6 ± 12.0; naloxone: 46.8 ± 6.6 s; P < 0.05) and higher scores of time spent in emotional responses (control: 3.5 ± 0.6; naloxone: 10.8 ± 2.4 s; P < 0.05) than controls. The other behaviors scored, feeder control and eating behavior, were not affected in this group. The naloxone group of low aggression pigeons, however, showed higher scores of offensive aggression than their controls (5.3 ± 1.3; naloxone: 28.7 ± 8.0 s; P < 0.05). The present results suggest that opiate receptor mechanisms are implicated in offensive aggression responses in high and low aggression pigeons. However, as reported for brain 5-hydroxytryptamine manipulation and GABA-A-benzodiazepine receptor manipulation, the effect of the opiate receptor antagonist on food competition aggression in pigeons was related to their pretreatment level of aggression.

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The healing of colorectal anastomoses after irradiation therapy continues to be a major concern. The authors evaluated the healing of rectal anastomoses in a rat model after a preoperative 500-cGy dose of cobalt60 irradiation. Thirty-six male Wistar rats were divided into two equal groups: control (group A), and irradiation group (group B). Group B received a single 500-cGy dose of irradiation, and a rectal resection and end-to-end anastomosis was performed in both groups on the 7th day after irradiation. Parameters of the healing process included bursting pressure and collagen content on the 5th, 7th, and 14th days after surgery. In the irradiation group, the mean bursting pressure on the 5th, 7th, and 14th days was 116, 218, and 273 mmHg, respectively. The collagen content assessed by histomorphometry was 9.0, 20.8, and 32%, respectively. In contrast, the control group had a mean bursting pressure of 175, 225 and 263 mmHg, and a collagen content of 17.8, 28.1, and 32.1%, respectively. The adverse effect of irradiation on healing was detectable only on the 5th postoperative day, as demonstrated by lower bursting pressure (P < 0.013) and collagen content (P < 0.008). However, there was no failure of anastomotic healing such as leakage or dehiscence due to irradiation. We conclude that a single preoperative 500-cGy dose of irradiation delays the healing of rectal anastomosis in rats.

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We evaluated the prevalence of low bone mineral density (BMD) and osteoporotic fractures in kidney transplantation (KT) patients and determined risk factors associated with osteoporotic fractures. The study was conducted on 191 patients (94 men and 97 women) with first KT for 3 years or more presenting stable and preserved renal function (serum creatinine levels lower than 2.5 mg/dl). KT patients were on immunosuppressive therapy and the cumulative doses of these drugs were also evaluated. BMD was determined by dual-energy X-ray absorptiometry at multiple sites (spine, femur and total body). Quantitative ultrasound of the calcaneus (broadband ultrasound attenuation, speed of sound, and stiffness index, SI) was also performed. Twenty-four percent (46) of all patients had either vertebral (29/46) or appendicular (17/46) fractures. We found osteoporosis and osteopenia in 8.5-13.4 and 30.9-35.1% of KT patients, respectively. Women had more fractures than men. In women, prevalent fractures were associated with diabetes mellitus [OR = 11.5, 95% CI (2.4-55.7)], time since menopause [OR = 3.7, 95% CI (1.2-11.9)], femoral neck BMD [OR = 1.99, 95% CI (1.4-2.8)], cumulative dose of steroids [OR = 1.1, 95% CI (1.02-1.12)] and low SI [OR = 1.1, 95% CI (1.0-1.2)]. In men, fractures were associated with lower lumbar spine BMD [OR = 1.75, 95% CI (1.1-2.7)], lower SI [OR = 1.1, 95% CI (1.03-1.13)], duration of dialysis [OR = 1.3, 95% CI (1.13-2.7)], and lower body mass index [OR = 1.24, 95% CI (1.1-1.4). Our results demonstrate high prevalence of low BMD and osteoporotic fractures in patients receiving a successful kidney transplant and indicate the need for specific intervention to prevent osteoporosis in this population.

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Over the last decades, the incidence of ultraviolet B (UVB)-related skin problems has been increasing. Damages induced by UVB radiation are related to mutations that occur as a result of direct DNA damage and/or the production of reactive oxygen species. We investigated the anti-oxidant effects of a Polygonum multiflorum thumb extract against skin damage induced by UVB irradiation. Female SKH-1 hairless mice were divided into three groups: control (N = 7), distilled water- (N = 10), and P. multiflorum extract-treated (PM, N = 10) groups. The PM (10 g) was extracted with 100 mL distilled water, cryo-dried and 9.8 g was obtained. The animals received a topical application of 500 µL distilled water or PM extract (1, 2, 4, 8, and 16%, w/v, dissolved in distilled water) for 30 min after UVB irradiation (wavelength 280-320 nm, 300 mJ/cm²; 3 min) of the dorsal kin for 14 days, and skin immunohistochemistry and Cu,Zn-superoxide dismutase (SOD1) activity were determined. SOD1 immunoreactivity, its protein levels and activities in the skin were significantly reduced by 70% in the distilled water-treated group after UVB irradiation compared to control. However, in the PM extract-treated groups, SOD1 immunoreactivity and its protein and activity levels increased in a dose-dependent manner (1-16%, w/v, PM extract) compared to the distilled water-treated group. SOD1 protein levels and activities in the groups treated with 8 and 16%, w/v, PM extract recovered to 80-90% of the control group levels after UVB. These results suggest that PM extract strongly inhibits the destruction of SOD1 by UV radiation and probably contains anti-skin photoaging agents.

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We investigated the day-night differences in intestinal oxidative-injury and the inflammatory response following total body (TB) or abdominopelvic (AP) irradiation, and the influence of melatonin administration on tissue injury induced by radiation. Rats (male Wistar, weighing 220-280 g) in the irradiated groups were exposed to a dose of 8 Gy to the TB or AP region in the morning (resting period - 1 h after light onset) or evening (activity span - 13 h after light onset). Vehicle or melatonin was administered immediately before, immediately after and 24 h after irradiation (10, 2.0 and 10 mg/kg, ip, respectively) to the irradiated rats. AP (P < 0.05) and TB (P < 0.05) irradiation applied in the morning caused a significant increase in thiobarbituric acid reactive substance (TBARS) levels. Melatonin treatment in the morning (P < 0.05) or evening (P < 0.05) decreased TBARS levels after TB irradiation. After AP irradiation, melatonin treatment only in the morning caused a significant decrease in TBARS levels (P < 0.05). Although we have confirmed the development of inflammation after radiotherapy by histological findings, neither AP nor TB irradiation caused any marked changes in myeloperoxidase activity in the morning or evening. Our results indicate that oxidative damage is more prominent in rats receiving TB and AP irradiation in the morning and melatonin appears to have beneficial effects on oxidative damage irrespective of the time of administration. Increased neutrophil accumulation indicates that melatonin administration exerts a protective effect on AP irradiation-induced tissue oxidative injury, especially in the morning.

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The effect of ionizing irradiation on testes and the protective effects of melatonin were investigated by immunohistochemical and electron microscopic methods. Eighty-two adult male Wistar rats were divided into 10 groups. The rats in the irradiated groups were exposed to a sublethal irradiation dose of 8 Gy, either to the total body or abdominopelvic region using a 60Co source at a focus of 80 cm away from the skin in the morning or evening together with vehicle (20% ethanol) or melatonin administered 24 h before (10 mg/kg), immediately before (20 mg/kg) and 24 h after irradiation (10 mg/kg), all ip. Caspace-3 immunoreactivity was increased in the irradiated group compared to control (P < 0.05). Melatonin-treated groups showed less apoptosis as indicated by a considerable decrease in caspace-3 immunoreactivity (P < 0.05). Electron microscopic examination showed that all spermatogenic cells, especially primary spermatocytes, displayed prominent degeneration in the groups submitted to total body and abdominopelvic irradiation. However, melatonin administration considerably inhibited these degenerative changes, especially in rats who received abdominopelvic irradiation. Total body and abdominopelvic irradiation induced identical apoptosis and testicular damage. Chronobiological assessment revealed that biologic rhythm does not alter the inductive effect of irradiation. These data indicate that melatonin protects against total body and abdominopelvic irradiation. Melatonin was more effective in the evening abdominopelvic irradiation and melatonin-treated group than in the total body irradiation and melatonin-treated group.