Hélio Plapler

EFFECTS OF LOW-LEVEL LASER THERAPY ON COLLAGEN EXPRESSION AND NEUTROPHIL INFILTRATE IN 5-FLUOROURACIL-INDUCED ORAL MUCOSITIS IN HAMSTERS

Several studies have suggested that low‐level laser therapy (LLLT) can ameliorate oral mucositis; however, the mechanisms involved are not well understood. The aim of this study was to investigate the mechanisms of action of LLLT on chemotherapy‐induced oral mucositis, as related to effects on collagen expression and inflammation.

Effect of low-level laser therapy on bone repair: a randomized controlled experimental study

The aim of this study was to investigate the effect of low-level laser therapy (LLLT) on bone repair in femoral fractures. Sixty adult Wistar rats were randomly assigned into one of two groups: group A (ostectomy + LLLT) or group B (ostectomy + sham laser). An experimental model of complete bone fracture was surgically created by removing a 2-mm fragment from the middle third of the femoral shaft. Data were analyzed on days 8, 13, and 18 after the fracture (subgroups 1, 2, and 3). Samples were assessed for changes in inflammatory infiltration; trabecular bone matrix, periosteal, and new bone formations; and changes in the expression of particular osteogenic-related proteins (osteocalcin, osteopontin, and osteonectin). Microscopic analysis revealed a significant decrease in inflammatory infiltration, intense trabecular bone matrix and periosteal formation, and an increase in newly formed bone after laser irradiation. We also found an increase in the expression of bone matrix proteins with LLLT, with a significant difference measured for osteocalcin in the LLLT group at day 8 (p = 0.007). We show that LLLT plays an important role in augmenting bone tissue formation, which is relevant to fracture healing. LLLT may therefore be indicated as an adjunct therapeutic tool in clinical practice for the treatment or recovery of nonunion injuries.

Colonic fermentation and nutritional recovery in rats with massive small bowel resection

BACKGROUND/AIMS After massive small bowel resection, malabsorbed carbohydrates reach the colon and undergo fermentation. This study investigates the role of colonic fermentation in rats with 80% small bowel resection on weight gain, nitrogen balance, body composition, and intestinal adaptation. METHODS Resected or transected rats were fed a liquid diet enterally for 16 days with or without 30 mg/kg metronidazole to reduce fermentation. Weight gain was monitored until the rats were killed. Carcass composition, short-chain fatty acids in cecal content, total nitrogen output, and intestinal mucosal dry weight, protein, and DNA were measured. RESULTS Resected rats without metronidazole had a significantly better weight gain, carcass protein, nitrogen balance, and mucosal dry weight, protein, and DNA compared with that of resected rats receiving metronidazole. There were no significant differences between the two transected groups. CONCLUSIONS Decreasing colonic fermentation, measured by short-chain fatty acids in cecal content, reduced intestinal adaptation and nutritional recovery in rats with massive small bowel resection.

Graft-infiltrating cells in rats receiving orthotopic semiallogeneic small intestine transplantation with portal or systemic venous drainage.

The effect of alterations in venous drainage, from either ivc to portal vein (pv), along with peritransplant systemic (ivc) or portal (pv) venous alloimmunization with irradiated semiallogenic cells, on cell subset recovery in lymphoid organs of Lewis rats receiving orthoptic small bowel allografts (from LewisXBrown Norway) F1, LBNF1) was examined. Combined portal, venous drainage and alloimmunization has been reported to increase graft/recipient survival in this model. FACS analysis using monoclonal antibodies specific for different lymphocyte subsets was performed on cell suspensions of peripheral (P) and mesenteric (M) lymph node (LN), small bowel intraepithelial lymphocytes (SBIEL), and Peyers patch (PP) lymphocytes on days 2 and 8 posttransplantation. Donor cell contributions to these cellular analyses were estimated by comparison of FACS staining with polyclonal anti-Lewis or Lewis anti-LBNF1 antibodies. Control animals received syngeneic grafts. In both syngeneic and semi-allogenic transplants with pv or ivc drainage there was no consistent difference in cell subsets from in PLN compared with those of control nongrafted rats. Approximately 50% to 60% of these cells were alphabetaTcR+ with a CD4+/CD8+ ratio of 3-4:1 and a (CD4++CD8+)/alphabetaTcR+ ratio of 1:1. Some 5% to 12% ED3+ cells were also present. In IEL, MLN, and PP by contrast, there were significant differences in cells recovered from rats with ivc vs. pv drainage of grafts. The most striking changes reflected a decreased CD4+/CD8+ and alphabetaTcR+gammadeltaTcR+ cells in these tissues in rats predestined to show prolongation of allograft survival (ivc vs. pv injected IEL CD4/CD8+ ratios and alphabetaTcR+gammadeltaTcR+ ratios 1.0, 0.7 and 5.0, 1.0, respectively. These data are consistent with a proposed role for such gammadeltaTcR+ cells in the local regulation of graft rejection.

Single Session to Infrared Low Level Diode Laser on TNF-alpha. and IL-6 Cytokines Release by Mononuclear Spleen Cells in Mice: A Pilot Study

The results of low‐level infrared laser (LLL) systemic action on inflammatory modulation process, specifically diminishing pro‐inflammatory and producing anti‐inflammatory cytokines are extremely controversial in the literature. More studies are necessary to clarify the biomodulation process. The main objective was to investigate the effect of a single session of an AsGaAl laser on spleen cells interleukin‐6 (IL‐6) and tumor necrosis factor ‐ alpha (TNF‐α) release, in vivo, in mice.

Evaluation of the longitudinal musculature of segments of the distal colon interposed following extended jejunum-ileum resection.

Several morbid conditions may necessitate extensive intestinal resection, leading to short‐bowel syndrome. When clinical treatment becomes inefficient, a surgical approach is necessary. Distal colon interposition is one of the viable techniques. The interposition of colon segments between remnants of the small bowel improved lifestyle, increased transit time, and diminished diarrhea. The aim of this study is to observe the longitudinal muscular contractions after distal colon interposition. Sixteen male Wistar rats (EPM‐1) were submitted to an 80% small bowel resection associated with a partial colectomy of the distal colon immediately after the bifurcation of the middle colic artery followed by a 3‐cm isoperistaltic distal colon interposition. After 70 days, the animals were submitted to euthanasia and segments of the jejunum, ileum, remnant colon, and interposed colon were prepared for pharmacological tests. The isometric contractions were measured by a poligraph. After 30 minutes, the dose/effect curves were obtained for both metacholine and barium chloride stimulation through the extraluminal surface (serosa). After this period, we observed a significant increase in the length, diameter, and thickness of the intestinal wall. Regarding the sensibility (pD2), no difference was found (interposed colon = 7.21 ± 0.2; remnant colon = 7.65 ± 0.1; remnant jejunum 7.46 ± 0.1; and remnant ileum 7.57 ± 0.1), even though the animals were submitted to different procedures. In relation to the maximal effect (Emax), the longitudinal muscle contraction responses (interposed colon = 11.79 ± 0.1; remnant jejunum = 15.42 ± 0.2; and remnant ileum = 11.48 ± 0.2) were lower than those of the remnant colon (Emax = 22.42 ± 0.1). This means that there was a possible adaptation of colonic segments to their new location.

A study of actinic cheilitis treatment by two low-morbidity CO2 laser vaporization one-pass protocols

Therapeutic approaches to chronic actinic cheilitis focus on the removal or destruction of diseased epithelium. The CO2 laser has become an important therapeutic alternative, achieving clinical resolution in around 90% of patients. Although many laser physical parameters have been reported, some are known for their low potential for scar induction without compromising the success of the results. The aim of this clinicohistological study was to compare the therapeutic responses to two low-morbidity protocols involving a single laser pass. A total of 40 patients with chronic multicentric and microscopically proven disease were randomly submitted to two conservative CO2 laser protocols using a bilateral comparative model. The degree of histological atypia of the epithelium was determined in 26 patients both pre- and postoperatively for both protocols. Other histological phenomena were assessed in addition to this central analysis parameter. Clinical recurrence occurred in 12.5% of patients for each protocol, together with a significant reduction in the degree of epithelial atypia (p < 0.001), which was occasionally complete. However, no difference was found between the protocols (p > 0.05). Using these morphological parameters it was not possible to determine whether postoperative epithelial atypias in part of the sample were reactive or residual in nature. A few patients may show minor postoperative lesions. Due to their potential to achieve clinical and importantly microscopic resolution, the studied protocols may be used for mild through moderate dysplastic epithelium and clinically diffuse disease.

Phenotypic and functional assessment of intraepithelial lymphocytes (IEL) isolated from rat colon and small bowel

We have compared the proliferative potential of IELs isolated from rat colon (CIEL) and small bowel (SBIEL), and compared this with that observed using spleen lymphocytes. Unless additional irradiated spleen cells were added as a source of accessory cells, both IEL populations show poor proliferation in response to Con A stimulation. The CD4/CD8 ratio in spleen, SBIEL and CIEL was markedly different (3:1, 1:3, and 1:1, respectively). Cells expressing surface markers characteristic of macrophages were not routinely found in SBIELs. Both IEL preparations inhibited spleen cell proliferation in response to Con A or immobilized anti-CD3, and produced a soluble factor(s) capable of causing similar inhibition. For CIEL this inhibition was dependent upon a proliferation-independent but cell-cell contact dependent event.

Effects of ethanol on energy balance of rats and the inappropriateness of intraperitoneal injection.

Energy balance of female rats that were either injected daily with ethanol or received the alcohol by gavage was determined and the results compared with saline animals. Food intake, feces elimination, and body weight were recorded daily. After a 20-day period of treatment the animals were sacrificed and the energy content of the carcasses and feces was determined by bomb calorimetry. The results indicated that ethanol-injected animals underwent an impairment in the energy balance, with losses in body weight and body energy. Also, there was a decrease in metabolized energy intake. The results of a group of saline rats pair-fed to alcohol-injected rats showed that the impairment of the energy balance was not only a consequence of the decreased energy intake, because the ethanol-fed animals had an energy balance that was worse than the one of the pair-fed rats, even though both had eaten the same amount of food. Nevertheless, when alcohol was given by gavage, no alteration in the energy balance parameters was detected. Macroscopic observation of the abdominal cavity showed adherences in the gut of the alcohol-injected animals. It is concluded that the ethanol by itself does not alter the energy balance; however, depending on the route of administration it could indirectly impair the energy balance.

Aferição dos equipamentos de laser de baixa intensidade

Background: Despite the increase in the use of low-level laser therapy (LLLT), there is still a lack of consensus in the literature regarding how often the equipment must be calibrated. Objective: To evaluate the real average power of LLLT devices in the Greater Sao Paulo area. Methods: For the evaluation, a LaserCheck power meter designed to calibrate continuous equipment was used. The power meter was programmed with data related to the lasers wavelength to gauge the real average power being emitted. The LLLT devices were evaluated in two ways: first with the device cooled down and then with the device warmed up for 10 minutes. For each condition, three tests were performed. The laser probe was aligned with the power meter, which provided the real average power being emitted by the LLLT device. All of the data and information related to the laser application were collected with the use of a questionnaire filled in by the supervising therapists. Results: The 60 devices evaluated showed deficit in real average power in the cooled-down and warmed- up condition. The statistical analysis (ANOVA) showed a significant decrease (p<0.05) in the real average power measured in relation to the manufacturers average power. On average, the most common dose in the clinics was 4 J/cm², and the most desired effects were healing and anti-inflammatory effects. According to the World Association for Laser Therapy (WALT), 1 to 4 J of final energy are necessary to achieve these effects, however only one device was able to reach the recommended therapeutic window. Conclusion: The LLLT devices showed a deficit in real average power that emphasized a lack of order in the application of this tool. The present study also showed the need for periodical calibration of LLLT equipment and a better technical knowledge of the therapists involved.