Comparative effects of wavelengths of low-power laser in regeneration of sciatic nerve in rats following crushing lesion

Peripheral nerves are structures that, when damaged, can result in significant motor and sensory disabilities. Several studies have used therapeutic resources with the aim of promoting early nerve regeneration, such as the use of low-power laser. However, this laser therapy does not represent a consensus regarding the methodology, thus yielding controversial conclusions. The objective of our study was to investigate, by functional evaluation, the comparative effects of low-power laser (660 nm and 830 nm) on sciatic nerve regeneration following crushing injuries. Twenty-seven Wistar rats subjected to sciatic nerve injury were divided into three groups: group sham, consisting of rats undergoing simulated irradiation; a group consisting of rats subjected to gallium-aluminum-arsenide (GaAlAs) laser at 660 nm (10 J/cm(2), 30 mW and 0.06 cm(2) beam), and another one consisting of rats subjected to GaAlAs laser at 830 nm (10 J/cm(2), 30 mW and 0.116 cm(2)). Laser was applied to the lesion for 21 days. A sciatic functional index (SFI) was used for functional evaluation prior to surgery and on days 7, 14, and 21 after surgery. Differences in SFI were found between group 660 nm and the other ones at the 14th day. One can observe that laser application at 660 nm with the parameters and methods utilised was effective in promoting early functional recovery, as indicated by the SFI, over the period evaluated.

LOCAL LOW POWER LASER IRRADIATION ACCELERATES THE REGENERATION OF THE FIBULAR NERVE IN RATS

Objective: To study the influence of low power GaAsAl laser irradiation on the regeneration of a peripheral nerve, following a controlled crush injury. Material and methods: The right common fibular nerve of 30 Wistar rats was submitted to a crush injury with an adjustable load forceps (5 000 g, 10 minutes of application). The animals were divided into three groups (n=10), according to the postoperative procedure (no irradiation; sham irradiation; effective irradiation). Laser irradiation (830 nm wave-length; 100 mW emission power; continuous mode; 140 J/cm(2)) was started on the first postoperative day and continued over 21 consecutive days. Body mass, time spent on the walking track and functional peroneal index (PFI) were analyzed based on the hind footprints, both preoperatively and on the 21st postoperative day. Results: Walking time and PFI significantly improved in the group that received effective laser irradiation, despite the significant gain in body mass between the pre- and post-operative periods. Conclusion: Low Power GaAsAl laser irradiation, with the parameters used in our study, accelerated and improved fibular nerve regeneration in rats.

Gastrointestinal transit, appetite, and energy balance in gastrectomized patients

Background: Alterations in gastrointestinal tract physiology after gastrectomy may affect appetite and energy balance. Objective: The objective of this study was to examine energy balance, appetite, and gastrointestinal transit in subjects with gastrectomy. Design: Seven subjects with total gastrectomy (TG) and 14 subjects with partial gastrectomy (PG), who were free from signs of recurrent disease, and 10 healthy control subjects were studied. Resting energy expenditure (REE) was measured by indirect calorimetry and compared with REE predicted by the Harris-Benedict equation (mREE/pREE%). Gastrointestinal transit was measured by scintigraphy. Habitual food intake was assessed, and appetite was measured during scintigraphy after ingestion of a test meal (361 kcal). Results: Body mass index was not different among the groups. mREE/pREE% was higher in patients with PG (P < 0.01) than in control subjects. The TG group showed higher energy intake (P < 0.05) than the PG group and control subjects. Gastric emptying was faster in the PG group than in control subjects, and gastrointestinal transit was accelerated in both PG and TG groups. An intense, precocious postprandial fullness and a relatively early recovery of hunger and prospective consumption sensations were seen in these patients. Conclusions: Patients with PG or TG have higher than predicted energy expenditure, which in TG seems to be compensated for by increased energy intake. These patients have preserved postprandial appetite responses and precocious postprandial fullness, which seem to be associated with disturbances in gastrointestinal transit of the ingested meal and are likely to be independent of vagal fiber integrity or stomach-released ghrelin. Am J Clin Nutr 2009; 89: 231-9.

Oral and pharyngeal transit of a paste bolus in Chagas` disease

We measured the oral and pharyngeal transit of a paste bolus in 20 patients with Chagas` disease and 21 controls. Each subject swallowed of a 10-ml paste bolus prepared with 50 ml of water and 4.5 g of instant food thickener labeled with 55.5 MBq of 99(m) technetium phytate. After the scintigraphic recording of the transit, we delineated regions of interest (ROI) corresponding to mouth, pharynx, and proximal esophagus. Time-activity curves were generated for each ROI. There was no difference between patients with Chagas` disease and controls with respect to the duration of oral and pharyngeal transit, amount of pharyngeal residue, or flux of bolus entry into the proximal esophagus. The amount of oral residue was higher in patients with Chagas` disease (median = 0.71 ml) than in controls (median = 0.45 ml). The pharyngeal clearance duration was longer in patients with Chagas` disease (median = 0.85 s) than in controls (median = 0.60 s). The oral transit duration of the patients with Chagas` disease and dysphagia (median = 0.55 s, n = 14) was shorter than the oral transit duration of chagasic patients without dysphagia (median = 0.80 s, n = 6). We conclude that when swallowing a paste bolus, patients with Chagas` disease may have an increased amount of oral residue and a longer pharyngeal clearance duration than asymptomatic volunteers.

The Essential Oil of Eucalyptus tereticornis and its Constituents, alpha- and beta-Pinene, Show Accelerative Properties on Rat Gastrointestinal Transit

The essential oil of Eucalyptus tereticornis (EOET) has pharmacological activities but their effects on the gastrointestinal tract are yet unknown. It possesses alpha- and beta-pinene as minor constituents, isomers largely used as food or drink additives. In this work, we studied their actions on gut motility. After feeding with a liquid test meal, conscious rats received perorally EOET, alpha-, or beta-pinene, and the fractional dye retention was determined. EOET and its constituents decreased the gastric retention. In anesthetized rats, pinenes increased gastric tonus, while enhancing the meal progression in the small intestine of conscious rats. Both alpha- and beta-pinene contracted gastric strips in vitro but relaxed the duodenum. Conversely, EOET relaxed both the gastric and duodenal strips. In conclusion, EOET accelerates the gastric emptying of liquid, and part of its action is attributed to the contrasting effects induced by alpha- and beta-pinene on the gut.