Microwave radiation and thermal effects on the bioenergetics of isolated mitochondria.

AIMS: This study proposes to investigate the effects of microwave radiation and its thermal effects, compared to thermal effects alone, on the bioenergetics of mitochondria isolated from mouse liver. METHODS: The main parameters investigated in this study are mitochondrial respiration (coupled states: S3 and S4; uncoupled state), using a high-resolution respirometer, and swelling, using a spectrophotometer. RESULTS: Mitochondria irradiated at 2.45 GHz microwave with doses 0.085, 0.113 and 0.141 kJ/g, presented a decrease in S3 and uncoupled state, but an increase in S4. Conversely, mitochondria thermally treated at 40, 44 and 50 °C presented an increasing in S3 and S4, while uncoupled state was unaltered. Mitochondrial swelling increases as a function of the dose or temperature, indicating membrane damages in both cases. CONCLUSION: Microwave radiation and thermal effect alone indicated different bioenergetics mitochondria response. These results imply that the effects due to microwave in medical treatment are not exclusively due to the increase in temperature, but a combination of electromagnetic and thermal effects.

Effect of photobiomodulation therapy on performance and running economy in runners: A randomized double-blinded placebo-controlled trial.

The objective of this study was to evaluate effects of photobiomodulation therapy (PBMT) on the 3000 m running performance (primary outcome), running economy (RE), metabolic cost and ratings of perceived exertion during running (secondary outcomes). Twenty male endurance athletes performed 4-min treadmill rectangular test at 12 km.h-1 monitored by a gas analyser. After that, PBMT or placebo in each lower limb was applied, followed performed a maximum test of 3000 m. Immediately after 3000 m test, the athletes repeated the treadmill test. Another application of PBMT/placebo was done after the treadmill test, and athletes went back to the laboratory 24 h later to repeat the treadmill test. After a 72 h interval, athletes repeated all procedures with another treatment intervention (PBMT/placebo). Athletes performed the 3000 m running test ~7s faster when treated with PBMT with similar effort score compared placebo condition. The RE remains unchanged immediately post 3000 m running test, nonetheless RE measured post-24 h improved by 5% with PBMT application without changes in metabolic cost. The PBMT pre- and post-conditioning enhanced the 3000 m running performance and improved RE 24 h following the 3000 m test. However, no changes on ratings of perceived exertion and metabolic cost with the application of PBMT.

Repetitive transcranial magnetic stimulation improve tinnitus in normal hearing patients: a double-blind controlled, clinical and neuroimaging outcome study.

BACKGROUND AND PURPOSE: Tinnitus is a frequent disorder which is very difficult to treat and there is compelling evidence that tinnitus is associated with functional alterations in the central nervous system. Targeted modulation of tinnitus-related cortical activity has been proposed as a promising new treatment approach. We aimed to investigate both immediate and long-term effects of low frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) in patients with tinnitus and normal hearing. METHODS: Using a parallel design, 20 patients were randomized to receive either active or placebo stimulation over the left temporoparietal cortex for five consecutive days. Treatment results were assessed by using the Tinnitus Handicap Inventory. Ethyl cysteinate dimmer-single photon emission computed tomography (SPECT) imaging was performed before and 14 days after rTMS. RESULTS: After active rTMS there was significant improvement of the tinnitus score as compared to sham rTMS for up to 6 months after stimulation. SPECT measurements demonstrated a reduction of metabolic activity in the inferior left temporal lobe after active rTMS. CONCLUSION: These results support the potential of rTMS as a new therapeutic tool for the treatment of chronic tinnitus, by demonstrating a significant reduction of tinnitus complaints over a period of at least 6 months and significant reduction of neural activity in the inferior temporal cortex, despite the stimulation applied on the superior temporal cortex.

Light/dark cycle-dependent metabolic changes in adipose tissue of pinealectomized rats.

We investigated the effects of pinealectomy on adipose tissue metabolism at different times of day. Adult male Wistar rats were divided into two groups: pinealectomized and control (sham-operated). Eight weeks after surgery, the animals were killed at three different times (at 8.00 a.m., at 4.00 p.m. and 11.00 p.m.). We collected blood samples for glucose, insulin, corticosterone, and leptin determinations, and periepididymal adipocytes for in vitro insulin-stimulated glucose uptake, oxidation, and incorporation into lipids. Pinealectomy caused insulin resistance as measured by 2-deoxyglucose uptake (a fall of approximately 40 % in the maximally insulin-stimulated rates) accompanied by hypercorticosteronemia at the three time points investigated without changes in plasma insulin an or leptin levels. Furthermore, pinealectomy increased the insulin-induced glucose incorporation into lipids (77 %) at 4.00 p.m. and insulin-induced glucose oxidation in the morning and in the afternoon, while higher rates were observed in the evening and in the morning in control rats. In conclusion, cell responsiveness to insulin was differentially affected by pineal ablation and time of day, and persistent insulin resistance was obtained in pinealectomized rats. We hypothesize that pinealectomy exposes the animal to an inadequate match between energy requirements and fuel mobilization.

Long-term nutritional and digestive consequences of pelvic radiation.

OBJECTIVE: To study long-term changes in nutritional status and gastrointestinal (GI) functions of 15 women previously treated with radiotherapy for gynecological cancer. Two years prior to this research, these patients had been assessed twice: before external radiotherapy and 5 weeks later, at the completion of the external dose (45-50 Gy). METHODS: Each patient was given complete clinical evaluation, consisting of dietary, physical activity and digestive symptoms questionnaires. Blood was drawn for routine clinical laboratory tests (hemoglobin, white blood cell count, creatinine, lipoproteins, glucose, total proteins, albumin, and C reactive protein). Body composition was assessed by classical anthropometric indicators and double beam X-ray absorptiometry (DEXA), while muscle strength was measured through a hand dynamometer. Resting energy expenditure (REE), obtained by indirect calorimetry, was subtracted from energy ingestion, derived from dietary records, to calculate energy balance. RESULTS: This third evaluation included fifteen patients. A significant increase in body mass index (BMI), % body fat and waist circumference were observed in comparison to earlier evaluations. The lean compartment decreased significantly, and REE descended in parallel. Meanwhile, total energy, fat and protein intake increased, compared to previous measurements. The changes in bowel habits observed during radiotherapy persisted at this third evaluation, with the exception of diarrhea, which was less reported. Abdominal bloating and rectal symptoms were the most prevalent complaints. CONCLUSIONS: After radiation treatment for gynecological cancer, patients gained more body fat than expected in Chilean women around menopause. In spite of high protein ingestion, the loss of fat-free mass observed during radiation treatment was not recovered along with weight increase. This is probably associated with infrequent physical activity, both during and after treatment, and hyperphagia.

Alteraçöes nutricionais e do metabolismo energético na irradiaçäo abdominal: estudo experimental / Nutritional and energy metabolism changes in abdominal irradiation: experimental study

Estudaram-se os efeitos da irradiaçäo sobre o estado nutricional e o metabolismo energético do hospedeiro. Utilizaram-se 48 ratos adultos machos Wistar, mantidos em gaiolas metabólicas, e divididos em grupos controle (C) e irradiado (R). No período 1, pré-irradiaçäo, os ratos foram submetidos a calorimetria indireta no dia 4 (calorimetria 1) que forneceu as variáveis gasto energético (GE), quociente respiratório (QR), substrato total oxidado (STO) e proteínas (PO), glicides (GO) e lípides oxidadas (LO). A seguir transcorreu o período 2, de irradiaçäo, quando os ratos R receberam 300 cGy/ diários de irradiaçäo abdominal, por cinco dias, sob restriçäo em molde acrílico. Cada rato do grupo C passou a receber alimentaçäo pareada e foi submetido a irradiaçäo simulada. Calorimetrias foram realizadas durante esse período (II e III) e após o seu final (IV). No sacrifício (dia 14), dosou-se hemoglobina, hermatócrito, albumina e transferrina. A análise estatística dos resultados foi feita com significância de 0,05 e 0,01. No período 1, näo houve diferenças entre os grupos em relaçäo às variáveis analisadas. No período 2 ocorreu reduçäo da ingestäo de dieta e perda percentual de peso corpóreo nos dois grupos. Apesar da ingestäo semelhante, a reduçäo ponderal foi maior no grupo R que no C. A incorporaçäo de nitrogênio decresceu significantemente no período 2. Apenas a média de albumina sérica apresentou-se menor no grupo R. O QR reduziu-se na avaliaçäo calorimétrica III, mantendo-se mais baixo em IV no grupo R, sem retornar aos níveis iniciais. Houve reduçäo significante do GE apenas no grupo R, em III. No grupo R o STO diminuiu com a irradiaçäo. Em ambos houve reduçäo da PO e GO, que no grupo R se manteve reduzida em IV, mantendo menor PO. Nas condiçöes do presente estudo, a irradiaçäo abdominal determinaou reduçäo de ingestäo alimentar, perda ponderal corporal, hipoalbuminemia, reduçäo de incorporaçäo de nitrogênio e promoveu queda do gasto energético e do quociente respiratório, levando ainda a uma alteraçäo do perfil de consumo de substratos. Conclui-se que a irradiaçäo pode conduzir a desnutriçäo protéico-calórico, näo decorrente exclusivamente da anorexia a ela associada

[Nutritional and energy metabolism changes in abdominal irradiation--experimental study]. / Alterações nutricionais e do metabolismo anergético na irradiação abdominal-estudo experimental.

In this study the effects on nutritional status and energetic metabolism due to abdominal irradiation were analysed. Adult male Wistar rats (48), were divided in two groups Control (C) and Radiated (R). The rats were maintained all time in metabolic cages. The study was done in two periods: Period 1 begun at 0 day, where rats adapted to cages and oral diet, had food and water "ad libitum". At the day 4 indirect calorimetric measurements were performed (calorimetry I). At Period 2, group R rats abdominal radiation at a 300cGy/day rate, for 5 consecutive days, and group C started a pair feeding process linked individually to R rats and suffered application of simulated-radiation. Two other calorimetric measurements (II,III) were performed during Period 2. After radiation the last calorimetry was performed (IV). At sacrifice (day 14) blood was collected for determination of hemoglobin, haematocrit, albumin and transferrin. There were no statistical differences among groups C and R during Period 1 (p < 0.05). Great reduction in food intake and weight variation were found in Period 2, but weight loss was significantly higher in R rats. Nitrogen balance decreased in Period 2, but without difference among the groups (p < 0.05). Serum albumin was significantly lower in R rats. Respiratory quotient decreased in both groups during Period 2, but R rats kept it lower (p < 0.05). The energy expenditure level decreased after radiation in Group R. During Period 2 total substrate oxidation decreased in R rats. Radiation decreased glucose and protein oxidation.(ABSTRACT TRUNCATED AT 250 WORDS)

Different lethal effects by enzyme-generated triplet indole-3-aldehyde in different Escherichia coli strains.

Strains of Escherichia coli which lack 4-thiouridine (S4U) exhibit a higher survival rate than their wild-type parents which contain S4U after treatment with enzyme-generated triplet indole-3-aldehyde. In a similar manner to results obtained with monochromatic 334 nm UV light, the survival is related to single-strand breakage of DNA in E. coli containing the pBR 322 plasmid. The effects of the excited states generated by an enzymatic system suggest that S4U is an important chromophore in the lethal effects observed. The results also suggest that the energy transferred from triplet indole-3-aldehyde to S4U may also be passed from S4U of t-RNA to DNA, possibly through a singlet oxygen intermediate generated by excited S4U, resulting in a decrease in the survival rate of E. coli containing S4U. These results emphasize the importance of excited states in biological systems.