Antimicrobial Photodynamic Therapy (aPDT) for decontamination of high-speed handpieces: A comparative study.

BACKGROUND: Cross-transmission is a major concern in dental offices. Various disinfection methods have been frequently used to reduce its incidence. Standard procedures include decontamination and sterilization. Traditional decontamination methods include: Alcohol 70 % and chlorhexidine digluconate, however, antimicrobial photodynamic therapy (aPDT) could be added as an option. The objective was to evaluate the effectiveness of aPDT on decontamination of high-speed handpieces, contaminated by Staphylococcus aureus (SA) and Escherichia coli (EC), and compare it to autoclave sterilized and to conventional chemical decontamination methods. METHODS: Sterilized, SA and EC contaminated high-speed handpieces were divided in 7 groups: G1- sterilized in an autoclave. G2- contaminated untreated control. G3- contaminated and decontaminated using Alcohol 70 %. G4- contaminated and decontaminated using chlorhexidine digluconate 2%. G5- contaminated and laser treated. G6- contaminated and photosensitizer treated. G7- contaminated and photodynamic therapy. RESULTS: The groups G3, G4, G7 did not show bacterial growth, G5 and G6 showed bacterial growth similar to G2. The study did not find SA or EC sensible to laser irradiation only, differently from some authors and did not consider biofilm in our experiments. CONCLUSION: Our experiment showed that, laser and photosensitizer isolated were not effective to inhibit Staphylococcus aureus (SA) and Escherichia coli (EC) growth, but when associated in aPDT technique, can be compared to chemical disinfection agents that are traditionally used and effective against this pathogen.

Proinflammatory effects of photoactivated methylene blue on rat model of Walker 256 carcinosarcoma.

BACKGROUND: Photodynamic therapy (PDT) is an anticancer therapy that associates the photosensitizer (PS), oxygen and light to destroy cancer cells. Methylene blue (MB) is considered a second generation phenothiazine dye with excellent photochemical properties. AIM: To evaluate whether MB-mediated PDT can induce oxidative stress and inflammation, therefore, interfering tumor growth. MATERIALS AND METHODS: The study was conducted on Wistar rats transplanted with Walker 256 carcinosarcoma (W256). The proinflammatory interleukins levels (IL-1ß, IL-6, IL-10, TNF-α) were determined by ELISA, mRNA expression of COX-1, COX-2, iNOS and eNOS by RT-PCR, lipid peroxidation was measured by the TBARS method. Moreover, myeloperoxidase (MPO) activity in neutrophils was determined by MPO activity assay. All indices mentioned above were determined in tumor tissue. Kaplan - Meier and Gehan - Breslow - Wilcoxon tests were used for survival analysis. RESULTS: We found that the treatment of W256 with 0.1% MB + 1 J/cm2 provoked a significant increase in the interleukins levels (IL-1ß, IL-6, IL-10, TNF-α), prostaglandin E2, the mRNA expression of COX-2, iNOS, lipid peroxidation and MPO activity in tumor tissue, which were statistically different (p < 0.05) compared to other experimental and control groups. The results of the estimation of survival curves show a greater probability of survival in 0.1% MB + 1 J/cm2 (total energy dose =142.8 J/cm2) treated group. CONCLUSION: Our results suggest that treatment of W256 with 0.1% MB + 1 J/cm2 was able to promote cytotoxic effects in tumor tissue by the generation of reactive oxygen species causing inflammation and thus interfering in the tumor growth.

Proinflammatory effects of photoactivated methylene blue on rat model of Walker 256 carcinosarcoma

Photodynamic therapy (PDT) is an anticancer therapy that associates the photosensitizer (PS), oxygen and light to destroy cancer cells. Methylene blue (MB) is considered a second generation phenothiazine dye with excellent photochemical properties. Aim: To evaluate whether MB-mediated PDT can induce oxidative stress and inflammation, therefore, interfering tumor growth. Materials and Methods: The study was conducted on Wistar rats transplanted with Walker 256 carcinosarcoma (W256). The proinflammatory interleukins levels (IL-1ß, IL-6, IL-10, TNF-a) were determined by ELISA, mRNA expression of COX-1, COX-2, iNOS and eNOS by RT-PCR, lipid peroxidation was measured by the TBARS method. Moreover, myeloperoxidase (MPO) activity in neutrophils was determined by MPO activity assay. All indices mentioned above were determined in tumor tissue. Kaplan — Meier and Gehan — Breslow — Wilcoxon tests were used for survival analysis. Results: We found that the treatment of W256 with 0.1% MB + 1 J/cm2 provoked a significant increase in the interleukins levels (IL-1ß, IL-6, IL-10, TNF-a), prostaglandin E2, the mRNA expression of COX-2, iNOS, lipid peroxidation and MPO activity in tumor tissue, which were statistically different (p < 0.05) compared to other experimental and control groups. The results of the estimation of survival curves show a greater probability of survival in 0.1% MB + 1 J/cm2 (total energy dose =142.8 J/cm2 ) treated group. Conclusion: Our results suggest that treatment of W256 with 0.1% MB + 1 J/cm2 was able to promote cytotoxic effects in tumor tissue by the generation of reactive oxygen species causing inflammation and thus interfering in the tumor growth

Proinflammatory effects of photoactivated methylene blue on rat model of Walker 256 carcinosarcoma

Photodynamic therapy (PDT) is an anticancer therapy that associates the photosensitizer (PS), oxygen and light to destroy cancer cells. Methylene blue (MB) is considered a second generation phenothiazine dye with excellent photochemical properties. Aim: To evaluate whether MB-mediated PDT can induce oxidative stress and inflammation, therefore, interfering tumor growth. Materials and Methods: The study was conducted on Wistar rats transplanted with Walker 256 carcinosarcoma (W256). The proinflammatory interleukins levels (IL-1ß, IL-6, IL-10, TNF-a) were determined by ELISA, mRNA expression of COX-1, COX-2, iNOS and eNOS by RT-PCR, lipid peroxidation was measured by the TBARS method. Moreover, myeloperoxidase (MPO) activity in neutrophils was determined by MPO activity assay. All indices mentioned above were determined in tumor tissue. Kaplan — Meier and Gehan — Breslow — Wilcoxon tests were used for survival analysis. Results: We found that the treatment of W256 with 0.1% MB + 1 J/cm2 provoked a significant increase in the interleukins levels (IL-1ß, IL-6, IL-10, TNF-a), prostaglandin E2, the mRNA expression of COX-2, iNOS, lipid peroxidation and MPO activity in tumor tissue, which were statistically different (p < 0.05) compared to other experimental and control groups. The results of the estimation of survival curves show a greater probability of survival in 0.1% MB + 1 J/cm2 (total energy dose =142.8 J/cm2 ) treated group. Conclusion: Our results suggest that treatment of W256 with 0.1% MB + 1 J/cm2 was able to promote cytotoxic effects in tumor tissue by the generation of reactive oxygen species causing inflammation and thus interfering in the tumor growth

Low level laser therapy partially restores trachea muscle relaxation response in rats with tumor necrosis factor alpha-mediated smooth airway muscle dysfunction.

BACKGROUND AND OBJECTIVE: It is unknown if the decreased ability to relax airway smooth muscles in asthma and other inflammatory airways disorders can be influenced by low level laser therapy (LLLT) irradiation. To investigate if LLLT could reduce impairment in inflamed trachea smooth muscles (TSM) in rats. STUDY DESIGN/MATERIALS AND METHODS: Controlled rat study where trachea was dissected and mounted in an organ bath apparatus with or without a TNF-alpha solution. RESULTS: Low level laser therapy administered perpendicularly to a point in the middle of the dissected trachea with a wavelength of 655 nm and a dose of 2.6 J/cm(2), partially restored TSM relaxation response to isoproterenol. Tension reduction was 47.0 % (+/-2.85) in the laser-irradiated group compared to 22.0% (+/-2.21) in the control group (P < 0.01). Accumulation of cAMP was almost normalized after LLLT at 22.3 pmol/mg (+/-2.1) compared to 17.6 pmol/mg (+/-2.1) in the non-irradiated control group (P < 0.01). CONCLUSION: Low level laser therapy partially restores the normal relaxation response in inflamed TSM and normalizes accumulation of cAMP in the presence of isoproterenol.

Analgesic effect of He-Ne (632.8 nm) low-level laser therapy on acute inflammatory pain.

OBJECTIVE: The aim of this study was to evaluate the analgesic effect of the low level laser therapy (LLLT) with a He-Ne laser on acute inflammatory pain, verifying the contribution of the peripheral opioid receptors and the action of LLLT on the hyperalgesia produced by the release of hyperalgesic mediators of inflammation. BACKGROUND DATA: All analgesic drugs have undesired effects. Because of that, other therapies are being investigated for treatment of the inflammatory pain. Among those, LLLT seems to be very promising. MATERIAL AND METHODS: Male Wistar rats were used. Three complementary experiments were done. (1) The inflammatory reaction was induced by the injection of carrageenin into one of the hind paws. Pain threshold and volume increase of the edema were measured by a pressure gauge and plethysmography, respectively. (2) The involvement of peripheral opioid receptors on the analgesic effect of the laser was evaluated by simultaneous injection of carrageenin and naloxone into one hind paw. (3) Hyperalgesia was induced by injecting PGE2 for the study of the effect of the laser on the sensitization increase of nociceptors. A He-Ne laser (632.8 nm) of 2.5 J/cm2 was used for irradiation. RESULTS: We found that He-Ne stimulation increased the pain threshold by a factor between 68% and 95% depending on the injected drug. We also observed a 54% reduction on the volume increase of the edema when it was irradiated. CONCLUSION: He-Ne LLLT inhibits the sensitization increase of nociceptors on the inflammatory process. The analgesic effect seems to involve hyperalgesic mediators instead of peripheral opioid receptors.

Distribution of melanin-concentrating hormone neurons projecting to the medial mammillary nucleus.

The melanin-concentrating hormone and neuropeptide glutamic acid-isoleucine are expressed in neurons located mainly in the hypothalamus that project widely throughout the CNS. One of the melanin-concentrating hormone main targets is the medial mammillary nucleus, but the exact origin of these fibers is unknown. We observed melanin-concentrating hormone and neuropeptide glutamic acid-isoleucine immunoreactive fibers coursing throughout the mammillary complex, showing higher density in the pars lateralis of the medial mammillary nucleus, while the lateral mammillary nucleus showed sparse melanin-concentrating hormone innervation. The origins of these afferents were determined by using implant of the retrograde tracer True Blue in the medial mammillary nucleus. Double-labeled neurons were observed in the lateral hypothalamic area, rostromedial zona incerta and dorsal tuberomammillary nucleus. A considerable population of retrogradely labeled melanin-concentrating hormone perikaryal profiles was also immunoreactive to neuropeptide glutamic acid-isoleucine (74+/-15% to 85+/-15%). The afferents from the lateral hypothalamic area, rostromedial zona incerta and dorsal tuberomammillary nucleus to the medial mammillary nucleus were confirmed using implant of the anterograde tracer Phaseolus vulgaris leucoagglutinin. In addition, using double-labeled immunohistochemistry, we found no co-localization between neurons expressing melanin-concentrating hormone and adenosine deaminase (histaminergic marker) in the dorsal tuberomammillary nucleus. We hypothesize that these melanin-concentrating hormone projections participate in spatial memory process mediated by the medial mammillary nucleus. These pathways would enable the animal to look for food during the initial moments of appetite stimulation.

Revelation without presentation: counterfeit study list yields robust revelation effect.

This study explores the revelation effect, a recognition memory phenomenon that occurs when test items (or related items) are specially processed before recognition judgment. These revealed items, whether targets or lures, receive a positive response bias. Although the effect occurs across various conditions, it has not been shown to occur when participants make judgments unrelated to episodic memory. We investigated whether the effect would occur when a recognition decision was nominally one of episodic memory, but when a complete episodic event had not occurred. Specifically, participants listened to noise that allegedly masked a list of words (in fact, no words existed). A revelation effect occurred with this pseudo-subliminal procedure, suggesting that the revelation effect need not rely on stimuli recalled through episodic memory but only a specific event to recall. The effect did not occur when participants simply guessed whether words were on an unheard list or made semantic judgments.

Origin of sensory and autonomic innervation of the rat temporomandibular joint: a retrograde axonal tracing study with the fluorescent dye fast blue.

Previous studies that have used retrograde axonal tracers (horseradish peroxidase alone or conjugated with wheat germ agglutinin) have shown that the temporomandibular joint (TMJ) is supplied with nerve fibers originating mainly from the trigeminal ganglion, in addition to other sensory and sympathetic ganglia. The existence of nerve fibers in the TMJ originating from the trigeminal mesencephalic nucleus is unclear, and the possible innervation by parasympathetic nerve fibers has not been determined. In the present work, the retrograde axonal tracer, fast blue, was used to elucidate these questions and re-evaluated the literature data. The tracer was deposited in the supradiscal articular space of the rat TMJ, and an extensive morphometric analysis was performed of the labeled perikaryal profiles located in sensory and autonomic ganglia. This methodology permitted us to observe labeled small perikaryal profiles in the trigeminal ganglion, clustered mainly in the posterior-lateral region of the dorsal, medial, and ventral thirds of horizontal sections, with some located in the anterior-lateral region of the ventral third. Sensory perikarya were also labeled in the dorsal root ganglia from C2 to C5. No labeled perikaryal profiles were found in the trigeminal mesencephalic nucleus. On the other hand, autonomic labeled perikaryal profiles were distributed in the sympathetic superior cervical and stellate ganglia, and parasympathetic otic ganglion. Our results confirmed those of previous studies and also demonstrated that: (i) there is a distribution pattern of labeled perikaryal profiles in the trigeminal ganglion; (ii) some perikaryal profiles located in the otic ganglion were labeled; and (iii) the trigeminal mesencephalic nucleus did not show any retrogradely labeled perikaryal profiles.

The distribution of melanin-concentrating hormone in the monkey brain (Cebus apella).

Melanin-concentrating hormone was identified in the brain of Cebus monkey using immunohistochemical and in situ hybridization. MCH-immunoreactive neurons were found in the lateral hypothalamus and dorsolateral zona incerta. MCH-ir fibers were seen in the medial mammillary nucleus, and in the median eminence, and very few fibers in the globus pallidus. This is the first report describing the MCH-ir cell and fiber distribution in the monkey brain.

LET spectra measurements on LDEF: variations with shielding and location.

LET spectra measurements made with passive plastic nuclear track detectors (PNTDs) were found to depend on detector orientation, shielding and experiment location. LET spectra were measured at several locations on LDEF as part of the P0006 LETSME experiment (Benton and Parnell, 1984), the P0004 Seeds in Space experiment (Parks and Alston, 1984), the A00l5 Free Flyer Biostacks and the M0004 Fiber Optics Data Link experiment (Taylor, 1984). Locations included the east, west and Earth sides of the LDEF satellite. The LET spectra measured with PNTDs deviated significantly from calculations, especially for high LET particles (LET infinity H2O > or = 100 keV/micrometer). At high LETs, short-range inelastic secondary particles produced by trapped proton interactions with the nuclei of the detector were found to be the principal contributor to LET spectra. At lower LETs, the spectra appeared to be due to short-range, inelastic and stopping primary protons, with primary GCR particles making a smaller contribution. The dependence of LET spectra on detector orientation and shielding was studied using the four orthogonal stacks in the P0006 experiment. Both measurements of total track density and LET spectra showed a greater number of particles arriving from the direction of space than from Earth. Measurements of LET spectra in CR-39 PNTD on the east (leading) and west (trailing) sides of LDEF showed a higher rate of production at the west side. This was caused by a larger flux of trapped protons on the west side as predicted by the east/west trapped proton anisotropy in the South Atlantic Anomaly (SAA). Track density measured in CR-39 PNTDs increased as a function of shielding depth in the detector stack. A similar measurement made in a thick stack of CR-39 interspersed with layers of Al and exposed to 154 MeV protons at a ground-based accelerator showed a similar result, indicating that a significant fraction of the particle events counted were from secondaries and that the total cross-section for production of proton-induced secondaries increased as the energy of primary protons attenuated. Little change was seen in either total differential or integral LET spectra as a function of shielding depth, indicating that the increase in cross section with decreasing proton energy affected mostly the shorter range secondary components. Similarity in the slopes of LET spectra from ground-based proton exposures and the A00l5 LET spectra showed that modeling of a monoenergetic proton beam transported through a 1-D geometry was a useful first step in modeling the production of secondary particles by trapped protons in the SAA.

Secondary particle contribution to LET spectra on LDEF.

Four experiments utilizing passive detectors (P0006, P0004, A0015, M0004) were flown on LDEF to study the radiation environment. These experiments have been summarized in a companion paper (Benton et al., 1996). One of the experimental goals was to measure LET spectra at different locations and shielding depths with plastic nuclear track detectors (PNTD). It was found that the LET spectra extended well above the LET cutoff imposed by the geomagnetic field on GCR particle penetration into LEO. The high LET particles detected were mostly short-range (range < 2000 m), indicating that they were secondaries produced locally within the PNTD. The presence of these high LET particle fluences is important for the determination of dose equivalent because of the high Quality Factors (Q) involved. A relatively small fraction of particle fluence can contribute a large fraction of dose equivalent. Short-range, inelastic secondary particles produced by trapped protons in the South Atlantic Anomaly (SAA) were found to be a major contributor to the LET spectra above 100 keV/micrometer. The LET spectra were found to extend beyond the approximately 137 keV/micrometer relativistic GCR Fe peak to over 1000 keV/micrometer. The high LET tail of the LET spectra was measured in CR-39 and polycarbonate PNTDs using different techniques. GCR made a relatively modest contribution to the LET spectra as compared to the contributions from short-range secondary particles and stopping protons. LET spectra intercomparisons were made between LDEF measurements and exposures to 154 MeV accelerated proton beams. The similarities support the role of nuclear interactions by trapped protons as the major source of secondary particles in the PNTDs. Also techniques were employed to reduce the range cutoff for detection of the short-range secondaries to approximately 1 micrometer, so that essentially all secondary particles were included in the LET spectra. This has allowed a more realistic assessment of secondary contribution to dose equivalent. Comparisons of measured and calculated LET spectra have been made that demonstrate the need for more accurate modeling of secondary particles in radiation transport codes. Comparisons include preliminary calculations in which attempts have been made to include secondary particles.

Particle directionality and trapped proton fluences on LDEF.

Directionality of incident space radiation is a significant factor in spacecraft shielding and astronaut dosimetry in low Earth orbit (LEO). Particle directionality of GCR and trapped protons were measured on LDEF with plastic nuclear track detectors (PNTD) from the P0006 west-side experiment. This experiment consisted of a thick detector stack and is described more fully in a companion article (Benton et al., 1996). The anisotropy of the trapped protons produced maximum intensity for protons arriving from the west. The fluences of the eastward directed trapped protons have been measured by selection of the particles on the basis of range in the PNTDs. The measured fluences are compared with the model calculations of Armstrong and Colborn (1993).

Intercomparison of radiation measurements on STS-63.

A joint NASA Russia study of the radiation environment inside the Space Shuttle was performed on STS-63. This was the second flight under the Shuttle-Mir Science Program (Phase 1). The Shuttle was launched on 2 February 1995, in a 51.65 degrees inclination orbit and landed at Kennedy Space Center on 11 February 1995, for a total flight duration of 8.27 days. The Shuttle carried a complement of both passive and active detectors distributed throughout the Shuttle volume. The crew exposure varied from 1962 to 2790 microGy with an average of 2265.8 microGy or 273.98 microGy/day. Crew exposures varied by a factor of 1.4, which is higher than usual for STS mission. The flight altitude varied from 314 to 395 km and provided a unique opportunity to obtain dose variation with altitude. Measurements of the average east-west dose variation were made using two active solid state detectors. The dose rate in the Spacehab locker, measured using a tissue equivalent proportional counter (TEPC), was 413.3 microGy/day, consistent with measurements made using thermoluminescent detectors (TLDs) in the same locker. The average quality factor was 2.33, and although it was higher than model calculations, it was consistent with values derived from high temperature peaks in TLDs. The dose rate due to galactic cosmic radiation was 110.6 microGy/day and agreed with model calculations. The dose rate from trapped particles was 302.7 microGy/day, nearly a factor of 2 lower than the prediction of the AP8 model. The neutrons in the intermediate energy range of 1-20 MeV contributed 13 microGy/day and 156 microSv/day, respectively. Analysis of data from the charged particle spectrometer has not yet been completed.

In-flight radiation measurements on STS-60.

A joint investigation between the United States and Russia to study the radiation environment inside the Space Shuttle flight STS-60 was carried out as part of the Shuttle-Mir Science Program (Phase 1). This is the first direct comparison of a number of different dosimetric measurement techniques between the two countries. STS-60 was launched on 3 February 1994 in a nearly circular 57 degrees x 353 km orbit with five U.S. astronauts and one Russian cosmonaut for 8.3 days. A variety of instruments provided crew radiation exposure, absorbed doses at fixed locations, neutron fluence and dose equivalent, linear energy transfer (LET) spectra of trapped and galactic cosmic radiation, and energy spectra and angular distribution of trapped protons. In general, there is good agreement between the U.S. and Russian measurements. The AP8 Min trapped proton model predicts an average of 1.8 times the measured absorbed dose. The average quality factor determined from measured lineal energy, y, spectra using a tissue equivalent proportional counter (TEPC), is in good agreement with that derived from the high temperature peak in the 6LiF thermoluminescent detectors (TLDs). The radiation exposure in the mid-deck locker from neutrons below 1 MeV was 2.53 +/- 1.33 microSv/day. The absorbed dose rates measured using a tissue equivalent proportional counter, were 171.1 +/- 0.4 and 127.4 +/- 0.4 microGy/day for trapped particles and galactic cosmic rays, respectively. The combined dose rate of 298.5 +/- 0.82 microGy/day is about a factor of 1.4 higher than that measured using TLDs. The westward longitude drift of the South Atlantic Anomaly (SAA) is estimated to be 0.22 +/- 0.02 degrees/y. We evaluated the effects of spacecraft attitudes on TEPC dose rates due to the highly anisotropic low-earth orbit proton environment. Changes in spacecraft attitude resulted in dose-rate variations by factors of up to 2 at the location of the TEPC.

Development, implementation, and results of a successful multidisciplinary adverse drug reaction reporting program in a university teaching hospital.

The development and implementation of an active adverse drug reaction reporting program in a university teaching hospital is described. The progression from a solely voluntary system to a multidisciplinary program consisting of both voluntary and involuntary components is discussed. A total of 1,011 adverse reactions were reported between July 1, 1988 and July 22, 1992. The most common reaction reported was rash. Antibiotics were most commonly implicated in the reactions reported. As a single agent, digoxin was involved most frequently. Voluntary reporting by physicians, nurses, and pharmacists accounted for approximately 24% of the adverse reactions reported. Occurrence screening by the Quality Assurance department produced approximately 76% of the reports.

Alcohol consumption, smoking habits and body fat distribution in Italian men and women aged 20-60 years.

The study was performed on 601 patients (294 males and 307 females) of a general practitioner. Alcohol intake and smoking habits were compared with other anthropometric measurements including waist-to-hip girth ratio. Patients were divided into non-smokers and smokers (subdivided into three groups according to the number of cigarettes smoked per day) and into non-drinkers and drinkers (subdivided into three groups with different alcohol intakes). Ex-smokers were excluded from the study. Analysis of covariance using age, body mass index, physical activity and menopausal status as covariates, showed that: (1) cigarette smoking is not accompanied by a specific pattern for body fat distribution; (2) waist-to-hip ratio was significantly different for the four classes of alcohol intake for women (non-drinkers: 0.809, < 11 g: 0.805, 11-20 g: 0.809, > 20 g: 0.826; F = 2.8, P < 0.05) but not for men (non-drinkers: 0.944, < 20 g: 0.934, 21-40 g: 0.940, > 40 g: 0.943; F = 0.9); (3) increased alcohol intake corresponds to an increased lipid and energy supply.