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PubMed2000

Hypothermia inhibits pentylenetetrazol kindling and prevents kindling-induced deficit in shuttle-box avoidance.

In this study, we evaluated the effects of hypothermic exposure on pentylenetetrazol (PTZ) kindling and the resulting deficit of shuttle-box avoidance learning in rats. Additionally, to acknowledge neuronal cell loss, we estimated the number of toluidine blue-positive cells in different brain regions after PTZ kindling and hypothermia exposure in comparison to different normothermic and hypothermic controls. To obtain hypothermic conditions over a period of up to about 3 h, 30 min after PTZ application the animals were treated with 5 mg/kg chlorpromazine (CP) and 25 min later exposed to 15 degrees C cold water for 5 min. Under these conditions the rectal and the striatal temperature were reduced up to a maximum of 5 degrees C. The additional injection of CP did not influence the development of PTZ kindling. Animals treated with PTZ/CP and exposed to hypothermia did not reach the criterion for kindling. Furthermore, this group of animals did not demonstrate any learning deficit. Forty-eight hours after the last kindling application the number of toluidine blue-stained cells was decreased in the investigated brain regions (hippocampal CA1 and CA3 sector, hilus, and cingular cortex) of kindled rats. Hypothermia protected from cell damage in the hippocampal CA3 sector and in the hilus. Results suggest that the inhibiting effect of hypothermia on the development of kindling and the following learning deficit possibly resulted from the suppression of cell damage in distinct brain structures on PTZ-kindled rats.

Animals↗
PubMed2002

Factors influencing the susceptibility of Gram-negative bacteria to toluidine blue O-mediated lethal photosensitization.

AIMS: Bacteria can be killed by red light in the presence of a photosensitizer. The purpose of this study was to evaluate the effect of physiological and environmental factors on the susceptibility of some bacteria associated with oral infections in immunocompromised patients to killing by the photosensitizer toluidine blue O (TBO). METHODS AND RESULTS: Suspensions of Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae in human saliva, horse serum or saline were exposed to light from a helium/ neon laser in the presence of TBO. Additional suspensions at various growth phases and pHs were treated in an identical manner. Survivors were enumerated by viable counting. All three species were susceptible to lethal photosensitization under all of the conditions tested. The presence of serum and, to a lesser extent, saliva decreased the level of kill attained. The bactericidal effect was reduced at acid pHs but was unaffected by the growth phase of the organism. CONCLUSIONS: The composition and pH of the fluid in which bacteria are suspended influenced the effectiveness of TBO-mediated lethal photosensitization, whereas killing was unaffected by the growth phase of the organism. SIGNIFICANCE AND IMPACT OF THE STUDY: Environmental factors operating in the mouths of patients with mucositis could reduce the effectiveness of TBO-mediated lethal photosensitization of bacteria associated with this condition.

Animals↗
PubMed2004

Photo-activated disinfection of the root canal: a new role for lasers in endodontics.

Because micro-organisms play a crucial role in the development of pulpal and periapical disease, the prognosis of endodontic therapy is intimately related to the presence of bacteria within the root canal system. Micro-organisms may persist in the apical region of the root canal system despite chemomechanical preparation. The usefulness of Class IV lasers (such as Nd:YAG, diode, KTP and Er:YAG) for photo-thermal disinfection of the root canal has been demonstrated in numerous studies. An alternative approach to microbial killing in the root canal system by laser light involves the use of low-power lasers to drive a photochemical reaction that produces reactive oxygen species, a technique termed photo-activated disinfection (PAD). By using exogenous photosensitisers such as tolonium chloride, killing of all types of bacteria can be achieved. In vitro studies of PAD have demonstrated its ability to kill photosensitised oral bacteria (such as E. faecalis), and more recently microbial killing in vivo in the root canal system has been demonstrated. While PAD can be undertaken as part of the routine disinfection of the root canal system, it also has potential use for eradicating persistent endodontic infections for which conventional methods have been unsuccessful.

Bacteria↗
PubMed1993

[Biopsy technics in oral oncology: excisional or incisional biopsy? A critical review of the literature and the authors' personal contribution].

The authors review the literature regarding bioptic techniques which are used in oral oncology, particularly referring to the dispute about incisional and excisional biopsy in cases of neoplastic or suspected lesions. As a matter of fact, though incisional biopsy at the oral cavity level is an easily executed technique, some clinicians found that an incision of a neoplasia could help its spreading or could help its spreading or could even increase its malignancy. Nevertheless, analyzing the literature, it can't be found, at present, the existence of data based on real clinical survey, which could prove a worse prognosis subsequent to a certain bioptic approach, even if some experimental studies on animal models, pointed out the potential danger caused by a neoplasia's incision. But, according to the authors, the oncological risk of metastasis' formation or of a local insemination is irrelevant if the operator follows the general rules of oncological surgery. To conclude, the authors present their diagnostic operative protocol, based on the principle that the diagnosis must always precede the treatment of the pathology. Therefore, when the size and site of the lesions allow it, incisional biopsy (simple or multiple) must always be chosen and, if necessary, must be preceded by the tolonium chloride stain.

Artifacts↗
PubMed1998

Morphologic effects of glycerol on the mental nerve.

OBJECTIVES: In recent years, injection of pure glycerol has been used successfully for the treatment of trigeminal neuralgia. However, the mode of action of this therapy remains unclear. The present experiment was undertaken to examine histologically the morphologic changes produced by extraneural injections of pure glycerol into the dog mental nerve. STUDY DESIGN: Under direct vision, glycerol was injected extraneurally into the mental foramen on one side of the lower jaw of each of nine dogs. Physiologic saline solution was the control on the contralateral side of each animal. Animals were killed at 1, 3, and 7 days after the application of glycerol, and the mental nerve specimens were examined by light microscopy. RESULTS: Results showed that extraneural application of pure glycerol in the vicinity of the dog mental nerve is not associated with structural changes. No signs of nerve degeneration or other morphologic changes were observed for any of the experimental and control specimens in any of the time intervals studied. CONCLUSIONS: It can be concluded that despite the encouraging clinical results related to extraneural application of pure glycerol for treatment of trigeminal neuralgia, glycerol produces its effect without inducing any morphologic or destructive changes in the peripheral nerve. A probable explanation of the temporary clinical effectiveness of glycerol in relieving trigeminal neuralgia is discussed.

Animals↗
PubMed1989

Human cutaneous mast cells--a study of fixative and staining reactions in normal skin.

Routinely used formal saline fixation reduces the number of demonstrable mast cells in human skin by up to 30% compared with paired specimens fixed in Carnoys medium. Using metachromatic (toluidene blue), orthochromatic (alcian blue/safranin), enzymatic (chloroacetate esterase reaction) and immunofluorescence (berberine and fluorescein conjugated avidin) staining techniques, mast cells were demonstrated and quantified. Alcian blue/safranin and fluorescein-conjugated avidin were both superior to the other staining methods used. We recommend the use of Carnoys medium fixed tissue stained with either alcian blue/safranin or conjugated avidin for optimal visualization and assessment of mast cells in human skin.

Acetates↗
PubMed1998

Preservation and staining of myelinated nerve fibers.

Six procedures are given for preservation of myelinated nerve fibers for light or electron microscopic studies. These procedures fall into two main categories: those with and those without aldehyde fixation. Essentially different effects are attained by application of tannic acid, saline, microwave or conventional heating, or a decreased temperature. All procedures end in osmication. Three main aspects of myelinated fiber morphology are taken into account when judging the quality of their preservation: axon, myelin sheath, and axon/myelin coherence. Each aspect can be preserved excellently, but always in combination with a less superior quality of the other two aspects. Superior myelin quality is attained using microwave irradiation, either with aldehydes to which tannic acid is added or without aldehyde fixatives. Superior axon quality is attained with aldehydes and (conventional) heating. Axon/myelin coherence is best preserved by decreasing the temperature during the rinse with saline. Another two procedures provide good, though less superior, preservation of both axon and axon/myelin coherence. Next, the fixed tissue is embedded in plastic blocks from which semithin and ultrathin plastic sections are cut for light and electron microscopy, respectively. In addition to the standard procedure for toluidine blue staining on semithin sections, two microwave-supported procedures are described, which can be used as alternatives if the staining result is unsatisfactory. Furthermore, a toluidine blue staining procedure is described for glycol methacrylate (GMA)-embedded material, which can be used if larger sections are needed.

Aldehydes↗
PubMed1989

Critical electrolyte concentration of the heterochromatin and euchromatin of Triatoma infestans.

The binding of toluidine blue molecules under Mg2+ competitive staining conditions was investigated in chromocentres and the euchromatin of single- and multi-chromocentred nuclei of Triatoma infestans Malpighian tubule cells. It was demonstrated that the chromocentre of single-chromocentred nuclei exhibited the largest critical electrolyte concentration (CEC) value (0.4 M), followed by the chromocentres of multi-chromocentred nuclei (0.3 M) and the euchromatin (0.2 M). The differences in CEC values were assumed to be due to differences in availability of free DNA phosphates and in packing states of the DNA-protein complexes of these chromatin types. Differences in chromatin supra-organization were evident for the chromocentral heterochromatin of single vs multi-chromocentred nuclei. This was also valid for the chromocentral heterochromatin in some multi-chromocentred nuclei, when one of the heterochromatic bodies was especially larger than the others.

Animals↗
PubMed2001

Administration of osteocalcin accelerates orthodontic tooth movement induced by a closed coil spring in rats.

The effect of local administration of osteocalcin (OC) on experimental tooth movement was examined in the rat. The maxillary first molar was first moved mesially with an initial tipping force of 30 g with a closed-coil spring anchored to the incisor for 10 days (n = 48). Three experimental groups (n = 8) were injected with purified rat OC at doses of 0.1, 1, and 10 micrograms, respectively. The injection into the palatal bifurcation site of the first molar was repeated daily. The control groups (n = 8) were injected with rat serum albumin (10 micrograms), phosphate buffered saline (PBS), or were not injected. Tooth movement was evaluated daily by measuring the inter-cuspal distance between the first and the second molars on a precise plaster model. The cumulative tooth movement (mm) in the 1-microgram OC-injected groups was significantly more than that in all of the control groups on day 9. The rate of tooth movement (mm/day) showed periodical elevation, with high values on days 1, 4, 7, and 9. Acceleration of tooth movement by OC was significant in the early experimental period. Subsequently, acceleration of early tooth movement by OC was histologically evaluated (n = 40). Each of four animals from the control (PBS, n = 20) and the experimental (1 microgram OC, n = 20) groups was killed daily up to 5 days. A significantly larger number of osteoclasts accumulated on the mesial alveolar bone surface in the 1-microgram OC-injected group on day 3 than that observed in control group. These results suggest that administration of OC accelerates orthodontic tooth movement due to enhancement of osteoclastogenesis on the pressure side, primarily in the early experimental period.

Acid Phosphatase↗
PubMed1988

Toxicity and ultrastructural localization of mercuric chloride in cultured murine macrophages.

The effects of mercuric chloride on cell survival, phagocytosis and cell migration were examined in cultured mouse peritoneal macrophages, and the accumulation of mercuric chloride in the cells was visualized by autometallography and evaluated by light and electron microscopy. Macrophages exposed to mercury concentrations from 1.25 microM to 10 microM mercuric chloride showed a concentration- and time-dependent increase in mercuric chloride accumulation, while cells exposed to 20 microM and 40 microM mercury showed an inverse relationship between mercury concentration and the accumulation of mercury. Mercury concentrations above these levels caused cell necrosis. Electron microscopy revealed that mercury was located primarily within lysosomes but also in the nucleus and cytoplasm. Mercury increased the death rate of macrophages in a concentration-dependent manner when cells were treated with mercury concentrations not causing cell necrosis. Further, we found that mercury clearly impaired macrophage random migration and possibly the capability for phagocytosis.

Animals↗
PubMed2006

Effect of Ca+ on the photobactericidal efficacy of methylene blue and toluidine blue against gram-negative bacteria and the dye affinity for lipopolysaccharides.

BACKGROUND AND OBJECTIVES: Methylene blue (MB) and toluidine blue (TB) form metachromatic complexes with lipopolysaccharides (LPS). The greater photobactericidal efficacy of TB may be explained by its affinity for LPS. This study aims to elucidate the difference in photobactericidal efficacies between the dyes using Ca(2+) as a competitor for dye-binding sites on the bacterial outer membrane. STUDY DESIGN/MATERIALS AND METHODS: Fixed dye concentration solutions with gram-negative bacteria and increasing concentrations of CaCl(2) were exposed to red laser light. Bacterial survival and spectrophotometry were used to describe the effect of Ca(2+) on dye interaction with bacteria and LPS. RESULTS: MB-mediated photokilling was inhibited more significantly than that of TB. CaCl(2) inhibited dye photobleaching and suppressed the metachromatic reaction between the dyes and LPS, in particular TB. CONCLUSIONS: CaCl(2) inhibits bacterial photokilling by binding with LPS, as well as other anionic polymers including outer membrane proteins. LPS is chiefly involved in TB-mediated photokilling, whereas outer membrane proteins probably are more involved in MB-mediated photokilling.

Calcium Chloride↗
PubMed1991

A morphological study on glutamate-induced swelling of cultured astrocytes: involvement of calcium and chloride ion mechanisms.

Morphological changes in cultured astrocytes exposed to L-glutamate (Glu) were examined light and electron microscopically. The treatment with 0.1 mM Glu for 60 min caused marked swelling of the cells, which was characterized by reduction in staining of cytoplasm with Toluidine blue, disappearance of the cytoplasmic granular ground substances, swollen mitochondrion and nucleus, and dispersed chromatin. The above changes were prevented by the removal of Na+, Ca2+ or Cl- from the incubation medium for Glu treatment. However, the Glu treatment in a Cl(-)-free medium caused conspicuous aggregation of 10 nm filaments.

Animals↗