Mutans streptococci oral colonization in 12-30-month-old Brazilian children over a one-year follow-up period

OBJECTIVES: The infection levels of mutans streptococci were investigated during a one-year follow-up in children aged 12 to 30 months attending school nurseries where a sucrose-rich diet was provided. METHODS: Oral levels of mutans streptococci obtained from 101 children at baseline and after a one-year follow-up were compared by age, number of teeth, feeding habits, and presence of visible plaque at baseline. Baseline predictors and changes in mutans streptococci levels during the study were compared to caries incidence after one year. RESULTS: Fluctuations in mutans streptococci levels during the follow-up period were not related to feeding habits or presence of visible plaque. Mutans streptococci levels increased after one year among children aged 12 to 24 months, while a significantly higher proportion of those aged 25-30 months showed a decrease in mutans streptococci levels during the study. Multiple logistic regression analysis suggested that high levels of mutans streptococci (> or = 100 cfu) at baseline were associated with a higher caries increment, while reduction in mutans streptococci was negatively associated with caries incidence. CONCLUSIONS: Our data suggest that despite early mutans streptococci infection and high exposure to sucrose, mutans streptococci may achieve relatively stable levels after 2 years of age. Heavy colonization by mutans streptococci in an early age was related to an extremely high caries incidence during childhood, while decreasing levels of mutans streptococci can be associated to the decrease in caries activity.     

Management of the oral mucosal lesions seen in association with HIV infection

Oral lesions cause considerable morbidity in association with HIV infection. Their successful management depends upon accurate diagnosis and the use of appropriate therapy. Various treatment approaches are described for some of the common oral lesions including Kaposi's sarcoma, oral candidiasis, hairy leukoplakia and recurrent oral ulcers associated with HIV disease. This paper will discuss the therapies available in the USA and UK. In other countries some of the drugs discussed will be available in different doses and preparations. In addition other drugs may be available in other parts of the world that are not licensed for use in the USA or UK, and their availability may vary.     

Chironomus sancticaroli (Diptera: Chironomidae) in ecotoxicology: laboratory cultures and tests

Chironomus sancticaroli is a tropical species, easy to grow and to maintain in laboratory cultures. It has a fast reproduction cycle, under adequate conditions, around 30 days, allowing it to have many generations per year, an important criterion for selecting a test organism in ecotoxicology. Its life stages include: eggs, four larval instars (one planktonic and three benthic), pupa and adult (midges) This study aimed to: (1) review the methods for C. sancticaroli cultivation and its use in ecotoxicological tests, (2) establish a laboratory culture of C. sancticaroli, presenting the difficulties and discussing the ways to overcome them. Early 4th instar larvae was the most used in acute studies, while the 1st instar larvae (early 1st instar) was the most used in chronic studies; 96?h and 28 days were the most frequent durations in acute and chronic studies, respectively. The most common endpoints evaluated were organisms’ survival and development, and most of the ecotoxicological studies using C. sancticaroli were performed in laboratory. Most of the tested contaminants were pesticides and these had the most adverse effects on organisms. Most mesocosms with environmental contaminated samples did not show adverse effects on C. sancticaroli. Chronic and field studies as well as those testing the effects of the mixture contaminants on C. sancticaroli were still deficient. Keeping the laboratory environment and equipment effectively sanitized was important as well as maintaining stabilized conditions of temperature, photoperiod, physical, chemical and biological water quality in cultures.

     

alpha(1)-Adrenoceptors in the lateral septal area modulate food intake behaviour in rats

Background and purpose:

Control of food intake is a complex behaviour which involves many interconnected brain structures. The present work assessed if the noradrenergic system in the lateral septum (LS) was involved in the feeding behaviour of rats.

Experimental approach:

In the first protocol, the food intake of rats was measured. Then non-food-deprived animals received either 100 nL of 21 nmol of noradrenaline or vehicle unilaterally in the LS 10 min after local 10 nmol of WB4101, an α₁-adrenoceptor antagonist, or vehicle. In the second protocol, different doses of WB4101 (1, 10 or 20 nmol in 100 nL) were microinjected bilaterally into the LS of rats, deprived of food for 18 h and food intake was compared to that of satiated animals.

Key results:

One-sided microinjection of noradrenaline into the LS of normal-fed rats evoked food intake, compared with vehicle-injected control animals, which was significantly reduced by α₁-adrenoceptor antagonism. In a further investigation, food intake was significantly higher in food-deprived animals, compared to satiated controls. Pretreatment of the LS with WB4101 reduced food intake in only food-deprived animals in a dose-related manner, suggesting that the LS noradrenergic system was involved in the control of food intake.

Conclusion and implications:

Activation by local microinjection of noradrenaline of α₁-adrenoceptors in the LS evoked food intake behaviour in rats. In addition, blockade of the LS α₁-adrenoceptors inhibited food intake in food-deprived animals, suggesting that the LS noradrenergic system modulated food intake behaviour and satiation.     

In vitro cytotoxicity,genotoxicity and antigenotoxicity assessment of Solanum lycocarpum hydroalcoholic extract

Context: Solanum lycocarpum A. St.-Hil. (Solanaceae), popularly known as ‘fruta-do-lobo’ (wolf fruit), ‘lobeira’ and ‘jurubebão’, is commonly used by native people of Central Brazil in powder form or as a hydroalcoholic extract for the management of diabetes and obesity and to decrease cholesterol levels. Objective: The present study determines the possible cytotoxic, genotoxic and antigenotoxic activities of hydroalcoholic extract of the S. lycocarpum fruits (SL).

Materials and methods: The clonogenic efficiency assay was used to determine the cytotoxicity. Three concentrations of SL (16, 32 and 64?μg/mL) were used for the evaluation of its genotoxic and antigenotoxic potential on V79 cells using the micronucleus and comet assays. In the antigenotoxicity assays, the cells were treated simultaneously with SL and the alkylating agent methyl methanesulphonate (MMS, 44?μg/mL for the micronucleus assay and 22?μg/mL for the comet assay) as an inducer of micronuclei and DNA damage.

Results: The results showed that SL was cytotoxic at concentrations up to 64?μg/mL. No significant differences in the rate of chromosome or DNA damage were observed between cultures treated with SL and the control group. In addition, the frequencies of micronuclei and DNA damage induced by MMS were significantly reduced after treatment with SL. The damage reduction percentage ranged from 68.1% to 79.2% and 12.1% to 16.5% for micronucleus and comet assays, respectively.

Discussion and conclusion: SL exerted no genotoxic effect and exhibited chemopreventive activity against both genomic and chromosome damage induced by MMS.     

Photobiomodulation as an adjunctive therapy for alveolar socket preservation: a preliminary study in humans

Lasers in Medical Science - Bone remodeling results in loss of alveolar bone height and thickness. Photobiomodulation (PBM) based on photochemical stimulation by low-intensity lasers emerges as an...     

Endogenous peptides of a soluble major histocompatibility complex class I molecule, H-2Lds: sequence motif, quantitative binding, and molecular modeling of the complex.

To gain insight into the rules that govern the binding of endogenous and viral peptides to a given major histocompatibility complex (MHC) class I molecule, we characterized the amino acid sequences of a set of self peptides bound by a soluble analogue of murine H-2Ld, H-2Lds. We tested corresponding synthetic peptides quantitatively for binding in several different assays, and built three-dimensional computer models of eight peptide/H-2Lds complexes, based on the crystallographic structure of the human HLA-B27/peptide complex. Comparison of primary and tertiary structures of bound self and antigenic peptides revealed that residues 2 and 9 were not only restricted in sequence and tolerant of conservative substitutions, but were spatially constrained in the three-dimensional models. The degree of sequence variability of specific residues in MHC-restricted peptides reflected the lack of structural constraint on those amino acids. Thus, amino acid residues that define a peptide motif represent side chains required or preferred for a close fit with the MHC class I heavy chain.