Mauro Geller

Effect of laser therapy on DNA damage

Whereas the biostimulative effect on tissues using low intensity laser therapy for treating many diseases has been described, the photobiological basis and adverse effects are not well understood. The aim of this study, using experimental models, is to observe the combined effect of physical damage (laser) and a chemical agent (hydrogen peroxide) on Escherichia coli cultures and bacterial plasmids.

Low-level infrared laser effect on plasmid DNA

Low-level laser therapy is used in the treatment of many diseases based on its biostimulative effect. However, the photobiological basis for its mechanism of action and adverse effects are not well understood. The aim of this study, using experimental models, was to evaluate the effects of laser on bacterial plasmids in alkaline agarose gel electrophoresis and Escherichia coli cultures. The electrophoretic profile of bacterial plasmids in alkaline agarose gels were used for studying lesions in DNA exposed to infrared laser. Transformation efficiency and survival of Escherichia coli AB1157 (wild-type), BH20 (fpg/mutM-), BW9091 (xth-), and DH5αF’Iq (recA-) cells harboring pBSK plasmids were used as experimental models to assess the effect of laser on plasmid DNA outside and inside of cells. Data indicate low-level laser: (1) altered the electrophoretic profile of plasmids in alkaline gels at 2,500-Hz pulsed-emission mode but did not alter at continuous wave, 2.5- and 250-Hz pulsed-emission mode; (2) altered the transformation efficiency of plasmids in wild-type and fpg/mutM-E. coli cells; (3) altered the survival fpg/mutM-, xthA- and recA-E. coli cultures harboring pBSK plasmids. Low-level infrared laser with therapeutic fluencies at high frequency in pulsed-emission modes have effects on bacterial plasmids. Infrared laser action can differently affect the survival of plasmids in E. coli cells proficient and deficient in DNA repair mechanisms, therefore, laser therapy protocol should take into account fluencies, frequencies and wavelength of laser, as well as tissue conditions and genetic characteristics of cells before beginning treatment.

Diclofenac plus B vitamins versus diclofenac monotherapy in lumbago: the DOLOR study.

Abstract Objectives: To assess the influence of vitamins B1, B6 and B12 on the analgesia success achieved by diclofenac in subjects with acute lumbago. Research design and methods: A randomised, double blind controlled clinical study in parallel groups, in which subjects received twice-daily oral administration of either the combination therapy, Group DB (50 mg diclofenac plus 50 mg thiamine, 50 mg pyridoxine and 1 mg cyanocobalamin) or diclofenac monotherapy, Group D (50mg diclofenac). The study period lasted a maximum of 7 days. If sufficient pain reduction was achieved (defined as Visual Analogue Scale <20 mm and patients satisfaction), subjects could withdraw from the treatment after 3 or 5 days. All subjects gave written informed consent to participate in the study. Main outcome measures: The primary confirmatory study objective was to determine the number of patients with sufficient pain reduction after 3 days of treatment. Results: Three hundred and seventy-two subjects were allocated at random to either treatment group: Group DB – 187 subjects and Group D – 185 subjects. After 3 days of treatment, a statistically significant higher proportion of subjects in Group DB (n = 87; 46.5%) than in Group D (n = 55; 29%) terminated the study due to treatment success (χ2: 12.06; p = 0.0005). Furthermore, the combination therapy yielded superior results in pain reduction, improvement of mobility and functionality. Drug safety monitoring profile throughout the trial was within the expected safety profile of diclofenac. Conclusions: The combination of diclofenac with B vitamins was superior to diclofenac monotherapy in lumbago relief after 3 days of treatment. As a study drawback, daily VAS measurements were only recorded until subject withdrawal from treatment, whether after 3, 5, or 7 days. There were no differences in safety profile between the two study groups.

Prevalence of plexiform neurofibroma in children and adolescents with type i neurofibromatosis

OBJECTIVE To assess prevalence of plexiform neurofibroma in children and adolescents with type I neurofibromatosis and its malignant potential. METHODS A retrospective study was conducted through analysis of the database at Centro Nacional de Neurofibromatose [Brazilian Neurofibromatosis Center], collected from the following reference services between 1996 and 2004: Instituto de Dermatologia Prof. Rubem David Azulay da Santa Casa de Misericórdia do Rio de Janeiro, Instituto de Pediatria e Puericultura Martagão Gesteira da Universidade Federal do Rio de Janeiro and Department of Immunology and Microbiology at Faculdade de Medicina de Teresópolis. RESULTS Over that period, 104 patients aged between 1-17 years were admitted with clinical diagnosis of type I neurofibromatosis. Of these, 53 were male and 51 were female, and 28 patients (15 male and 13 female) had plexiform neurofibroma (26.9%). Division by age group resulted in 21.42% (six) between 1-5 years; 35.71% (10) between 6-12 years and 42.85% (12) between 13-17 years. Of the 104 patients, two developed a malignant peripheral nerve sheath tumor (1.92%). CONCLUSIONS Plexiform neurofibromas are relatively common manifestations in patients with type I neurofibromatosis and may be a cause of significant increase in morbidity and mortality among patients. In this study, we conclude that frequency of plexiform neurofibroma and its malignant potential in the population studied is in agreement with data from the international literature.

Validation of tissue microarray technology in malignant peripheral nerve sheath tumours

Background: It has been suggested that the donor tissue cores used in tissue microarrays (TMAs) may not be representative of the whole tissue section. Aim: To validate the use of TMA technology in the study of malignant peripheral nerve sheath tumours (MPNSTs). Methods: A TMA was constructed containing five independent core biopsy samples of 14 formalin-fixed, paraffin-embedded MPNSTs. The immunohistochemical (IHC) results of the five cores from the same tissue block on TMA were compared with readings from whole sections using two antibodies: anti-Ki-67 and anti-S-100. Digital image analysis was performed to calculate the percentage of positive stain areas. The agreement between IHC results obtained with TMA cores and whole sections was assessed using the κ statistic. Results: There was good to very good agreement between IHC results for whole and TMA sections from MPNSTs. In relation to S-100, very good agreement (92% agreement; κ = 0.77) was observed using a minimum of four TMA cores. Staining results for Ki-67 from at least four readable TMA cores were the same as those for the whole section in 86% of cases, with good agreement, using weighted κ statistics (κ = 0.63). Conclusions: This study indicates that the TMA technique can be used in the IHC study of MPNSTs, even with the use of heterogeneous markers such as S-100 protein.

Low-intensity infrared laser increases plasma proteins and induces oxidative stress in vitro.

Low-intensity laser therapy is based on the excitation of endogenous chromophores in biotissues and free-radical generation could be involved in its biological effects. In this work, the effects of the low-intensity infrared laser on plasma protein content and oxidative stress in blood from Wistar rats were studied. Blood samples from Wistar rats were exposed to low-intensity infrared laser in continuous wave and pulsed-emission modes at different fluencies. Plasma protein content and two oxidative stress markers (thiobarbituric acid-reactive species formation and myeloperoxidase activity) were carried out to assess the effects of laser irradiation on blood samples. Low-intensity infrared laser exposure increases plasma protein content, induces lipid peroxidation, and increases myeloperoxidase activity in a dose- and frequency-dependent way in blood samples. The low-intensity infrared laser increases plasma protein content and oxidative stress in blood samples, suggesting that laser therapy protocols should take into account fluencies, frequencies, and wavelengths of the laser before beginning treatment.

Low intensity infrared laser induces filamentation in Escherichia coli cells

Low intensity continuous wave and pulsed emission modes laser is used in treating many diseases and the resulting biostimulative effect on tissues has been described, yet the photobiological basis is not well understood. The aim of this wok was to evaluate, using bacterial filamentation assay, effects of laser on Escherichia coli cultures in exponential and stationary growth phase. E. coli cultures, proficient and deficient on DNA repair, in exponential and stationary growth phase, were exposed to low intensity infrared laser, aliquots were spread onto microscopic slides, stained by Gram method, visualized by optical microscopy, photographed and percentage of bacterial filamentation were determined. Low intensity infrared laser with therapeutic fluencies and different emission modes can induce bacterial filamentation in cultures of E. coli wild type, fpg/mutM, endonuclease III and exonuclease III mutants in exponential and stationary growth phase. This study showed induction of bacterial, filamentation in E. coli cultures expose to low intensity infrared laser and attention to laser therapy protocols, which should take into account fluencies, wavelengths, tissue conditions, and genetic characteristics of cells before beginning treatment.

Laser for treatment of aphthous ulcers on bacteria cultures and DNA

Low-intensity red lasers are proposed for treatment of oral aphthous ulcers based on biostimulative effects. However, effects of low-intensity lasers at fluences used in clinical protocols on DNA are controversial. The aim of this work was to evaluate the effects of low-intensity red laser on survival and induction of filamentation of Escherichia coli cells, and induction of DNA lesions in bacterial plasmids. Escherichia coli cultures were exposed to laser (660 nm, 100 mW, 25 and 45 J cm(-2)) to study bacterial survival and filamentation. Also, bacterial plasmids were exposed to laser to study DNA lesions by electrophoretic profile and action of DNA repair enzymes. Data indicate that low-intensity red laser: (i) had no effect on survival of E. coli wild type, exonuclease III and formamidopyrimidine DNA glycosylase/MutM protein but decreased the survival of endonuclease III deficient cultures; (ii) induced bacterial filamentation, (iii) there was no alteration in the electrophoretic profile of plasmids in agarose gels, (iv) there was no alteration in the electrophoretic profile of plasmids incubated with formamidopyrimidine DNA glycosylase/MutM protein and endonuclease III enzymes, but it altered the electrophoretic profile of plasmids incubated with exonuclease III. Low-intensity red laser at therapeutic fluences has an effect on the survival of E. coli endonuclease III deficient cells, induces bacterial filamentation in E. coli cultures and DNA lesions targeted by exonuclease III.

Prevalência de neurofibromas plexiformes em crianças e adolescentes com neurofibromatose tipo 1

OBJECTIVE: To assess prevalence of plexiform neurofibroma in children and adolescents with type I neurofibromatosis and its malignant potential. METHODS: A retrospective study was conducted through analysis of the database at Centro Nacional de Neurofibromatose [Brazilian Neurofibromatosis Center], collected from the following reference services between 1996 and 2004: Instituto de Dermatologia Prof. Rubem David Azulay da Santa Casa de Misericordia do Rio de Janeiro, Instituto de Pediatria e Puericultura Martagao Gesteira da Universidade Federal do Rio de Janeiro and Department of Immunology and Microbiology at Faculdade de Medicina de Teresopolis. RESULTS: Over that period, 104 patients aged between 1-17 years were admitted with clinical diagnosis of type I neurofibromatosis. Of these, 53 were male and 51 were female, and 28 patients (15 male and 13 female) had plexiform neurofibroma (26.9%). Division by age group resulted in 21.42% (six) between 1-5 years; 35.71% (10) between 6-12 years and 42.85% (12) between 13-17 years. Of the 104 patients, two developed a malignant peripheral nerve sheath tumor (1.92%). CONCLUSIONS: Plexiform neurofibromas are relatively common manifestations in patients with type I neurofibromatosis and may be a cause of significant increase in morbidity and mortality among patients. In this study, we conclude that frequency of plexiform neurofibroma and its malignant potential in the population studied is in agreement with data from the international literature.

Neurofibromatoses: part 1 ? diagnosis and differential diagnosis

Neurofibromatoses (NF) are a group of genetic multiple tumor growing predisposition diseases: neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2) and schwannomatosis (SCH), which have in common the neural origin of tumors and cutaneous signs. They affect nearly 80 thousand of Brazilians. In recent years, the increased scientific knowledge on NF has allowed better clinical management and reduced complication morbidity, resulting in higher quality of life for NF patients. In most cases, neurology, psychiatry, dermatology, clinical geneticists, oncology and internal medicine specialists are able to make the differential diagnosis between NF and other diseases and to identify major NF complications. Nevertheless, due to its great variability in phenotype expression, progressive course, multiple organs involvement and unpredictable natural evolution, NF often requires the support of neurofibromatoses specialists for proper treatment and genetic counseling. This Part 1 offers step-by-step guidelines for NF differential diagnosis. Part 2 will present the NF clinical management.