Oral microbiome characterization in oral mucositis patients-A systematic review.

BACKGROUND: Oral mucositis (OM) is a severe and common adverse effect of cancer treatment. The oral microbiome appears to play a role on the onset and severity of OM. Therefore, this systematic review aims to characterize the oral dysbiosis associated with OM. METHODS: The PRISMA checklist was followed and PubMed, Web of Science, and Scopus were screened for clinical studies characterizing the oral microbiome alterations in patients with OM. RESULTS: From a total of 2500 articles retrieved, we included nine articles in this systematic review. Certain types of bacteria, as Fusobacterium, were recognized as predictors of the onset of OM. In addition, it was reported that patients with severe OM presented a reduction in alpha-diversity, an increase in beta-diversity. The abundance of some taxa significantly changed with OM severity, with Bacillota phylum and genera Leptotrichia, Actinomyces, and Prevotella decreasing and Treponema increasing with disease progression. Additionally, during cancer treatment, changes in the oral microbiome have been observed in OM patients, with an increase in Candida and nosocomial pathogens, including Staphylococcus species. CONCLUSION: Our review indicates that cancer treatment can significantly alter the oral microbiome, with more pronounced changes observed in patients with severe OM in all relevant oral phyla, but more pronounced in Bacillota phylum.

Cardiovascular risk factors during pregnancy impact the postpartum cardiac and vascular reverse remodeling.

Pregnant women with cardiovascular risk (CVR) factors are highly prone to develop cardiovascular disease later in life. Thus, recent guidelines suggest extending the follow-up period to 1 yr after delivery. We aimed to evaluate cardiovascular remodeling during pregnancy and determine which CVR factors and potential biomarkers predict postpartum cardiac and vascular reverse remodeling (RR). Our study included a prospective cohort of 76 healthy and 54 obese and/or hypertensive and/or with gestational diabetes pregnant women who underwent transthoracic echocardiography, pulse-wave velocity (PWV), and blood collection at the 1st trimester (1T) and 3rd trimester (3T) of pregnancy as well as at the 1st/6th/12th mo after delivery. Generalized linear mixed-effects models was used to evaluate the extent of RR and its potential predictors. Pregnant women develop cardiac hypertrophy, as confirmed by a significant increase in left ventricular mass (LVM). Moreover, ventricular filling pressure (E/e') and atrial volume increased significantly during gestation. Significant regression of left ventricular (LV) volume, LVM, and filling pressures was observed as soon as 1 mo postpartum. The LV global longitudinal strain worsened slightly and recovered at 6 mo postpartum. PWV decreased significantly from 1T to 3T and normalized at 1 mo postpartum. We found that arterial hypertension, smoking habits, and obesity were independent predictors of increased LVM during pregnancy and postpartum. High C-reactive protein (CRP) and low ST2/IL33-receptor levels are potential circulatory biomarkers of worse LVM regression. Arterial hypertension, age, and gestational diabetes positively correlated with PWV. Altogether, our findings pinpoint arterial hypertension as a critical risk factor for worse RR and CRP, and ST2/IL33 receptors as potential biomarkers of postpartum hypertrophy reversal.NEW & NOTEWORTHY This study describes the impact of cardiovascular risk factors (CVR) in pregnancy-induced remodeling and postpartum reverse remodeling (up to 1 yr) by applying advanced statistic methods (multivariate generalized linear mixed-effects models) to a prospective cohort of pregnant women. Aiming to extrapolate to pathological conditions, this invaluable "human model" allowed us to demonstrate that arterial hypertension is a critical CVR for worse RR and that ST2/IL33-receptors and CRP are potential biomarkers of postpartum hypertrophy reversal.

The Role of Biotics as a Therapeutic Strategy for Oral Mucositis - A Systematic Review.

OBJECTIVES: Oral mucositis (OM) is an acute and highly prevalent side effect of cancer treatments. Currently, there is no effective strategy for its prevention or treatment. This systematic review aimed to assess the effectiveness of biotics used as a therapeutic strategy for the management of OM. MATERIALS AND METHODS: The PRISMA checklist was followed and PubMed, Web of Science, and Scopus were screened for clinical and pre-clinical studies assessing the potential effects of biotics in OM. Inclusion criteria included in vivo studies related to oral mucositis evaluating the effect of biotics, and written in Portuguese, English, French, Spanish, or Dutch. The following exclusion criteria were used: systematic reviews and meta-analyses, reviews, case reports, opinion papers or comments, conference papers, letters without results, articles not related to oral therapy-induced mucositis or biotics, or in vitro articles that do not simulate oral mucositis. RESULTS: From a total of 1250 articles retrieved, 9 were included in this systematic review. Four clinical studies reported a reduction in oral mucositis occurrence with Lactobacillus species (Lactobacillus casei and Lactobacillus brevis CD2) and Bacillus clausii UBBC07. In pre-clinical studies, Lactococcus lactis genetically modified and Lactobacillus reuteri reduced the severity of OM and Streptococcus salivarius K12 also decreased the size of the ulcers. CONCLUSION: The findings of this systematic review suggest that probiotic supplementation may potentially reduce the incidence of therapy-induced OM and decrease its severity in patients undergoing cancer treatment. However, the available evidence is marred by significant heterogeneity across studies.

Effect of uremic state in intestine through a co-culture in vitro intestinal epithelial model.

The progressive loss of renal function in chronic kidney disease (CKD) leads to the accumulation of uremic toxins. Recent studies related uremic plasma as well dysbiotic gut microbiome to impaired intestinal barrier function, allowing the translocation of microorganisms or by-products from the intestinal lumen to systemic circulation, contributing to systemic inflammation, cardiovascular risk and progression of CKD. Our main goal was to evaluate the impact of different uremic conditions on an improved in vitro intestinal Caco-2/HT29-MTX/Raji B triple co-culture model. For that, the impact of CKD patients' plasma and elevated urea concentration and its by-products on the triple model was assessed. The results showed that uremic conditions did not potentiate the Escherichia coli (E. coli) translocation, although may interfere with the integrity and the permeability of the intestinal barrier. Also, results showed that E. coli translocation was higher in Caco-2 monoculture than in Caco-2/HT29-MTX/Raji B triple model, suggesting that the triple model creates a more effective intestinal barrier. This study allowed to conclude that the uremic state influences the integrity of the intestinal barrier, but this influence could not be directly translated in an increase on the E. coli translocation through the intestinal epithelium, at least in Caco-2/HT29-MTX/Raji B intestinal epithelial barrier model.

Influence of dialysis therapies on oral health: a pilot study.

OBJECTIVES: Chronic kidney disease (CKD) is a public health problem worldwide. Currently, the link between oral health status, dialysis modality, and dialysis vintage is still not clear. The aim of this study was to evaluate periodontal disease, dental caries, and Candida colonization among patients under hemodialysis (HD) therapy, peritoneal dialysis (PD) therapy, and PD with previous history of HD (HD/PD). METHOD AND MATERIALS: The clinical history, smoking, and oral hygiene habits were recorded. Decayed, missing, or filled teeth (DMFT) index, Visible Plaque Index (VPI), clinical attachment level (CAL), bleeding on probing, saliva flow rate, saliva pH, and oral yeast colonization were assessed. RESULTS: HD/PD patients were generally submitted to longer periods of dialysis therapy than the other groups. The number of decayed and filled teeth did not differ between groups; HD patients presented a higher number of teeth, but poor periodontal status. Among the three groups, HD patients presented higher VPI, CAL, and oral Candida colonization, independently of the time under dialysis therapy. Candida albicans (HD and PD), Candida krusei (HD), and Candida carpophila (PD) were isolated in these patients. CONCLUSION: HD presented a more adverse impact on oral health than PD, particularly periodontal disease and oral Candida colonization; however, this impact on oral health appears to be reduced or ameliorated when patients change from HD to PD therapy.

Determination of Azole Resistance and TR34/L98H Mutations in Isolates of Aspergillus Section Fumigati from Turkish Cystic Fibrosis Patients.

BACKGROUND: Aspergillus fumigatus is the species section Fumigati most frequently isolated from the respiratory tract of cystic fibrosis (CF) patients. Recent studies suggest that mutations in the Cyp51 gene, particularly TR34/L98H, are responsible for azole resistance. OBJECTIVES AND METHODS: The focus of this study was on section Fumigati isolates isolated from the respiratory tract samples of CF patients. More specifically, the goal was to detect A. fumigatus isolates, test their antifungal susceptibility to itraconazole, voriconazole and posaconazole, and finally determine the presence of TR34/L98H and other mutations in the isolates Cyp51A gene. RESULTS AND CONCLUSIONS: A set of 31 isolates of Aspergillus section Fumigati were obtained from the sputum samples of 6 CF patients and subsequently identified to species level by microsatellite genotyping. All isolates were determined as A. fumigatus and involved 14 different genotypes. The minimal inhibitory concentrations to the three azoles were determined by the E-test method, and the Cyp51A gene was sequenced. One of the genotypes was found to be resistant to all azoles but no mutations were detected in the Cyp51A gene, especially the TR34/L98H mutation. Therefore, mutations in genes other than Cyp51A or other distinct mechanisms may be responsible for this reported multiazole resistance found in a Turkish CF patient.

Oral manifestations in children with mucopolysaccharidosis / Manifestações orais de mucopolissacaridose em crianças

BACKGROUND: Patients with mucopolysaccharidosis have several changes of the stomatognathic complex, representing a challenge for dentists. OBJECTIVE: The study aimed to evaluate and characterize oral health in patients with mucopolysaccharidosis in a reference center of Portugal. METHOD: The sample consisted of twelve participants with mucopolysaccharidosis followed in Metabolic Diseases Unit of the S. João Hospital Centre and twelve healthy participants followed at Faculty of Dental Medicine, University of Porto. The clinical oral evaluation was performed by a complete extra-oral and intra-oral examination to assess the presence of oral pathologies, gingival index and occlusion status. RESULTS: Mucoplysaccaridosis patients and controls presented similar age ranges and sex distribution. In comparison to controls, children with mucopolysaccharidosis presented a higher prevalence of tooth decay, gingival bleeding, macroglossia, dental hypoplasia, lingual interposition, delayed tooth eruption, anterior open bite, right and left posterior cross-bite, limitation of mouth opening, alteration on the size and shape of the teeth, diastemata and maxillary compression. CONCLUSIONS: Patients with mucopolysaccharidosis have a high prevalence eruption delay, teeth morphology alterations, occlusal problems, dental caries and bleeding gums, highlighting the need of oral health care providers to improve diagnostics and preventive protocols to overcome the factors that limit the oral health of these patients and promote together with parent/caregiver efficient oral care strategies.

INFORMAÇÕES GERAIS: Os pacientes com mucopolissacaridose apresentam diversas alterações do complexo estomatognático, representando um desafio para os médicos dentistas. OBJETIVO: O estudo pretendeu avaliar e caracterizar a saúde oral em pacientes com mucopolissacaridose num centro de referência em Portugal. MÉTODO: A amostra foi constituída por doze pacientes com mucopolissacaridose (MPS) seguidos na Unidade de Doenças Metabólicas do Centro Hospitalar de São João e doze participantes saudáveis seguidos na Faculdade de Medicina Dentária da Universidade do Porto. A avaliação clínica oral consistiu num completo exame extra-oral e intra-oral para avaliação de patologias orais, índice gengival e perfil oclusal. RESULTADOS: Pacientes com MPS e controlos apresentaram médias similares de idade e de distribuição de género. Em comparação com os controlos, crianças com mucopolissacaridose apresentam maior prevalência de dentes cariados, sangramento gengival, macroglossia, hipoplasia dentária, interposição lingual, erupção dentária atrasada, mordida aberta anterior, mordida cruzada posterior direita e esquerda, limitação da abertura da boca, alteração do tamanho e forma dentária, diastemas e compressão maxilar. CONCLUSÃO: Pacientes com mucopolissacaridose apresentam maior prevalência de erupção dentária atrasada, alterações morfológicas dentárias, problemas oclusais, cáries dentárias e gengivas inflamadas, reforçando a necessidade de prestadores de saúde oral para melhorar diagnósticos e protocolos preventivos para ultrapassar os fatores que limitam a saúde oral destes pacientes e promover em conjunto com pais/cuidadores estratégias de saúde oral eficientes.

Asymptomatic Effluent Protozoa Colonization in Peritoneal Dialysis Patients.

Currently, chronic kidney disease (CKD) is a global health problem. Considering the impaired immunity of CKD patients, the relevance of infection in peritoneal dialysis (PD), and the increased prevalence of parasites in CKD patients, protozoa colonization was evaluated in PD effluent from CKD patients undergoing PD. Overnight PD effluent was obtained from 49 asymptomatic stable PD patients. Protozoa analysis was performed microscopically by searching cysts and trophozoites in direct wet mount of PD effluent and after staining smears. Protozoa were found in PD effluent of 10.2% of evaluated PD patients, namely Blastocystis hominis, in 2 patients, and Entamoeba sp., Giardia sp., and Endolimax nana in the other 3 patients, respectively. None of these patients presented clinical signs or symptoms of peritonitis at the time of protozoa screening. Our results demonstrate that PD effluent may be susceptible to asymptomatic protozoa colonization. The clinical impact of this finding should be further investigated.

Low prevalence of oral protozoa colonization in Portuguese healthy and end-stage renal disease patients undergoing peritoneal dialysis / Baja prevalencia de la colonización oral de protozoos en Portugueses saludables y o pacientes renales del último estadio de enfermedad y que necesitan de diálisis del peritoneo

Infections are a major complication in end-stage renal disease (ESRD) patients undergoing peritoneal dialysis (PD). Because the oral cavity may act as a source of systemic pathogens, some authors advocated specific measures when these patients are submitted to oral interventions, such as the administration of prophylactic antibiotics. Oral protozoa colonization may vary significantly with geographic distribution and to our knowledge no studies were performed in Portugal. The aim of the present study was to evaluate protozoa colonization in the saliva of ESRD patients undergoing PD and of their family members, living in the north of Portugal. Saliva was collected from 39 PD patients with a mean time on PD therapy of 12.7 - 15.9 months, and from 18 healthy volunteers (ESRD family members) for microscopic evaluation of protozoa by Lugols’ direct smear and specific staining techniques (Giemsa, Trichrome and Kinyoun). After the analysis of 456 smears obtained from 57 participants, only one PD patient (2.6%) presented an amoeba trophozoite in saliva. In conclusion, very low oral protozoa colonization was found, both on PD patients and family controls, suggesting that the oral protozoa colonization of Portuguese population is low and not significantly modified by the presence of end-stage chronic kidney disease. Further studies are required to address this issue.

Las infecciones son la principal complicación en pacientes renales del último estadio (ESRD) y que necesitan de diálisis del peritoneo (PD). Como la cavidad oral puede funcionar como una fuente de patógenos sistémicos, algunos autores indican medidas específicas cuando esos pacientes son sometidos a intervenciones orales, como la administración de antibióticos profilácticos. La colonización oral puede variar significativamente con la distribución geográfica. Según nuestros conocimientos, no han sido realizados estudios similares en Portugal. El principal objetivo fue evaluar la colonización de protozoos en saliva de pacientes ESRD del Norte de Portugal que hacían PD y, también, de sus familiares. Muestras de saliva fueron recogidas de 39 pacientes PD, con tiempo medio de terapia de PD de 12,7-15,9 meses y, también de 18 voluntarios saludables (familiares de ESRD). Las mismas utilizadas para evaluación microscópica de protozoos en laminas con lugol y tinciones especificas (Giemsa, Trichrome and Kinyoun). Después del análisis de 456 laminas, obtenidas de los 57 participantes, solamente en un paciente PD (2.6%) se observó un trofozoíto del ameba. En conclusión, se encontró una baja prevalencia de colonización oral de protozoos en el grupo estudiado. Así, la colonización oral de la población Portuguesa por protozoos es baja y no se cambia con la evolución de la enfermedad. Para mejor analizar esta situación, futuros estudios son necesarios.

The biochemistry of saliva throughout pregnancy / O efeito da gravidez sobre a bioquímica salivar

BACKGROUND & OBJECTIVE: Sialometric and sialochemical analyses during pregnancy are not consistent, and frequently contradictory in terms of salivary flow rate, pH, and concentration of calcium, phosphorous, sodium, potassium, chloride, glucose and α-amylase. We, therefore, measured the evolution of these parameters throughout pregnancy. METHOD: A cross-sectional study compared sialometric and sialochemical analyses of 30 pregnant women vs. 30 age-matched non-pregnant women, and a longitudinal study evaluated the pregnant women in the first and third trimester of pregnancy. RESULTS: Pregnant women presented acidic non-stimulated saliva, but neutral stimulated saliva pH, and no relevant changes in salivary flow rate. Scialochemical analysis showed decreased calcium levels, increased phosphate levels, and a progressive decrease in glucose levels throughout pregnancy. CONCLUSION: Pregnancy significantly changes the oral biochemical milieu, creating a favorable environment for the development of oral pathology, in particular, dental caries.

OBJETIVO: Os achados relativos às análises sialométricas e sialoquímicas durante a gravidez não são consistentes, e por vezes são mesmo contraditórias. Assim, fizemos uma revisão da literatura e comparamos os níveis salivares de cálcio, fósforo, sódio, potássio, cloreto, glucose, α-amilase, pH e a taxa de fluxo salivar entre mulheres grávidas e não grávidas, bem como, avaliamos a evolução desses parâmetros ao longo da gravidez. MÉTODO: Realizamos um estudo transversal comparando a bioquímica salivar de um grupo inicial de 30 mulheres grávidas com um grupo inicial de 30 mulheres não gestantes da mesma idade seguido de um estudo longitudinal avaliando as mulheres grávidas no primeiro e terceiro trimestre de gravidez. RESULTADO: As mulheres grávidas apresentaram um pH da saliva não estimulada ácido, mas um pH da saliva estimulada neutro, assim como diminuição dos níveis salivares de cálcio, aumento dos níveis salivares de fosfato, e uma diminuição progressiva nos níveis de glicose na saliva ao longo da gravidez. CONCLUSÃO: A gravidez muda significativamente o ambiente bioquímico oral, criando condições favoráveis para o desenvolvimento de patologia oral, em particular da cárie dentária.

Hyposalivation, acidic saliva, decayed teeth and oral yeast prevalence in children with mucopolysaccharidosis / Hiposalivação, saliva acídica, dentes cariados e prevalência oral de levedura em crianças com mucopolisacaridose

OBJECTIVE: Patients with mucopolysaccharidosis present several alterations of the stomatognathic complex, however, no data is available on saliva biochemistry and yeast colonization. The aim of the study was to evaluate caries experience as well as saliva biochemistry and microbiology parameters in patients with mucopolysaccharidosis. METHOD: The sample consisted of twelve participants with mucopolysaccharidosis followed in the Metabolic Disease Unit of the Centro Hospitalar de S. João and twelve healthy participants followed at the Faculty of Dental Medicine, University of Porto. To all participants, Decayed, Missing, Filled Teeth (DMFT) index was evaluated. In addition, saliva was collected to evaluate biochemical parameters (flow rate, pH, sodium, potassium, chloride, calcium, phosphate, α-amylase and IgA) and the microbiological profile (total microorganisms, mutans streptococci and yeasts) of all participants. RESULTS: In comparison to controls, the mucoplysacharidosis patients presented a higher prevalence of decayed teeth, lower salivary flow and pH values. They also presented also lower calcium and higher phosphate ions in saliva. No differences were found between groups regarding oral microbial load for total microorganisms, mutans streptococci and yeasts as well as oral prevalence of mutans streptococci. However, MPS patients presented higher prevalence of oral Candida in comparison to controls. CONCLUSION: The higher prevalence of decayed teeth and higher oral yeast colonization in MPS patients may be related to the lower saliva calcium concentration, pH and flow.

OBJETIVO: Pacientes portadores de mucopolissacaridose apresentam várias alterações do complexo estomatognático; no entanto, não existem dados disponíveis sobre a bioquímica da saliva e ou sobre a colonização por fungos. O objetivo deste estudo foi avaliar a prevalência de cárie dentária bem como parâmetros bioquímicos e microbiológicos em pacientes com mucopolissacaridose. MÉTODOS: A amostra foi constituída por doze participantes com mucopolissacaridose, acompanhados na Unidade de Doenças Metabólicas do Centro Hospitalar de S. João do Porto e por doze participantes saudáveis acompanhados na Faculdade de Medicina Dentária da Universidade do Porto. Para todos os participantes, o índice de dentes cariados, perdidos ou obturados foi avaliado. Além disso, foram recolhidas amostras de saliva de todos os participantes para avaliar os parâmetros bioquímicos (fluxo salivar, pH, sódio, potássio, cloreto, cálcio, fosfato, α-amilase e IgA) e microorganismos tais como Streptococcus mutans e leveduras. RESULTADOS: Em comparação aos controles, os pacientes com MPS apresentam maior prevalência de dentes cariados assim como fluxo salivar e pH reduzido. Os pacientes com MPS apresentaram também taxas menores de íons de cálcio e maiores de íons de fosfato. Não foram encontradas diferenças entre os grupos quanto à carga microbiana oral por microrganismos totais, Streptococcus mutans e leveduras, bem como quanto à prevalência oral de Streptococcus mutans. No entanto, os pacientes com MPS apresentaram maior prevalência de candidíase oral em comparação com os controlos. CONCLUSÃO: A maior prevalência de dentes cariados e a maior colonização oral por leveduras em pacientes com MPS pode estar relacionada com a baixa concentração de cálcio salivar, com o pH ácido e com a hiposalivação.

Plasma and urine renalase levels and activity during the recovery of renal function in kidney transplant recipients.

Renalase is a recently described enzyme secreted by the kidney into both plasma and urine, where it was suggested to degrade catecholamines contributing to blood pressure control. While there is a controversy regarding the relationship between renal function and plasma renalase levels, there is virtually no data in humans on plasma renalase activity as well as on both urine renalase levels and activity. We prospectively examined the time course of plasma and urine renalase levels and activity in 26 end-stage renal disease (ESRD) patients receiving a cadaver kidney transplant (cadaver kidney recipients [CKR]) before surgery and during the recovery of renal function up to day 90 post transplant. The relationship with sympathetic and renal dopaminergic activities was also evaluated. The recovery of renal function in CKR closely predicted decreases in plasma renalase levels (r = 0.88; P < 0.0001), urine renalase levels (r = 0.75; P < 0.0001) and urine renalase activity (r = 0.56; P < 0.03), but did not predict changes in plasma renalase activity (r = -0.02; NS). Plasma norepinephrine levels positively correlated with plasma renalase levels (r = 0.64, P < 0.002) as well as with urine renalase levels and activity (r = 0.47 P < 0.02; r = 0.71, P < 0.0005, respectively) and negatively correlated with plasma renalase activity (r = -0.57, P < 0.002). By contrast, plasma epinephrine levels positively correlated with plasma renalase activity (r = 0.67, P < 0.0001) and negatively correlated with plasma renalase levels (r = -0.62, P < 0.003). A significant negative relationship was observed between urine dopamine output and urine renalase levels (r = -0.48; P < 0.03) but not with urine renalase activity (r = -0.33, NS). We conclude that plasma and urine renalase levels closely depend on renal function and sympathetic nervous system activity. It is suggested that epinephrine-mediated activation of circulating renalase may occur in renal transplant recipients with good recovery of renal function. The increase in plasma renalase activity observed in ESRD patients and renal transplant recipients can be explained on the basis of reduced inhibition of the circulating enzyme.

Characterization of the oral fungal microbiota in smokers and non-smokers.

This study aimed to assess the effect of smoking on the biodiversity of the oral fungal microbiota of healthy young subjects, using an improved culture method that assesses both total and pathogenic viable fungi. Forty individuals (20 smokers and 20 non-smokers) were selected. All individuals presented fungal growth (100% for molds and 92.5% for yeasts), a prevalence higher than previously reported. The most commonly occurring molds were Penicillium sp., Aspergillus sp., and Cladosporium sp. Smokers presented significantly higher levels of yeasts and pathogenic molds than did non-smokers. No differences in fungal prevalence and diversity were observed in smokers and non-smokers following a 30-wk observation period. In conclusion, tobacco smoking may alter the oral mycobiota and facilitate colonization of the oral cavity with yeasts and pathogenic molds. The effect of chronic fungal colonization on the oral health of tobacco smokers cannot be neglected.

Reduced salivary flow and colonization by mutans streptococci in children with Down syndrome

OBJECTIVES: Although individuals with Down syndrome have considerable oral disease, the prevalence of dental caries in this group is low. The present study aimed to compare known risk factors for dental caries development in children with Down syndrome and a matched population (siblings). In both populations, the number of acidogenic microorganisms, such as mutans streptococci, lactobacilli and Candida species, and the paraffin-stimulated pH, flow rate and IgA concentration in whole saliva were evaluated and compared. METHOD: Saliva was collected, and the caries index was evaluated in 45 sibling pairs aged between 6 and 18 years old. The salivary IgA concentration was determined by immunoturbidimetry. Salivary mutans streptococci, lactobacilli and Candida species were quantified on mitis salivarius agar containing bacitracin and 20% sucrose, rogosa agar supplemented with glacial acetic acid and sabouraud agar supplemented with chloramphenicol, respectively. RESULTS: Down syndrome children had a higher caries-free rate (p<0.05) and lower salivary mutans streptococci counts (p<0.03) compared to their siblings. Similar numbers of lactobacilli and Candida species were found in both groups. Salivary flow rates were 36% lower in Down syndrome children compared to their siblings (p<0.05). The salivary pH did not differ between Down syndrome children and controls. The Down syndrome children had an IgA secretion rate 29% lower than that of their siblings, but this difference was not statistically significant. CONCLUSIONS: In conclusion, the lower number of mutans streptococci in the saliva may be one of the factors contributing to the lower caries rate observed in Down syndrome children, despite evidence of hyposalivation.

Caries in Portuguese children with Down syndrome

OBJECTIVES: Oral health in Down syndrome children has some peculiar aspects that must be considered in the follow-up of these patients. This study focuses on characterizing the environmental and host factors associated with dental caries in Portuguese children with and without Down syndrome. METHODS: A sibling-matched, population-based, cross-sectional survey was performed. RESULTS: Down syndrome children presented a significantly greater percentage of children without caries, 78 percent vs. 58 percent of non-Down syndrome siblings. This difference in the DMFT index (number of decayed, missing and filled teeth) essentially reflects data obtained from treated teeth, for which 91 percent of children with Down syndrome had never had a tooth treated vs. 67 percent of siblings. This result was statistically significant, whereas results for decayed and lost teeth did not differ between Down syndrome children and their unaffected siblings. Additionally, in Down syndrome children, a delayed eruption of the second molar occurs. Down syndrome children and their siblings have similar oral hygiene habits, but a higher percentage of Down syndrome children visit a dentist before the age of three years, in comparison to their siblings. Bruxism was also more common in Down syndrome children compared to their siblings. CONCLUSIONS: Our results show that Portuguese children with Down syndrome have lower caries rates than children without Down syndrome. This reduced prevalence may be associated with the parents' greater concern about oral health care in Down syndrome children, resulting in their taking them sooner to visit a dentist, as well as to a higher bruxism prevalence and delayed tooth eruption.

Glycaemic control with insulin prevents the reduced renal dopamine D1 receptor expression and function in streptozotocin-induced diabetes.

BACKGROUND: It was demonstrated in streptozotocin (STZ)-induced diabetic rats that the D(1) receptor agonist failed to promote sodium excretion as a result of reduced renal D(1) receptor expression and decreased receptor G protein coupling. The present study examined the influence of glycaemic control with insulin on the renal D(1) receptor dysfunction in STZ-induced type 1 diabetes. METHODS: Renal function, blood pressure, the natriuretic response to 5% volume expansion (VE) and the effects of the D(1) receptor agonist fenoldopam on natriuresis and on Na(+)/K(+)-ATPase activity in renal tubules were evaluated in uninephrectomized and sham-operated Wistar rats treated with STZ and compared with controls and STZ-treated rats made euglycaemic with insulin. D(1) receptor immunohistochemistry and protein abundance by western blot were also determined in all groups. RESULTS: Treatment of sham and uninephrectomized rats with STZ caused a 4-fold increase in glucose plasma levels compared to controls and euglycaemic diabetic rats. A blunted natriuretic response to VE was observed in both sham and uninephrectomized hyperglycaemic diabetic rats, and this was accompanied by failure of fenoldopam to increase natriuresis and to inhibit renal Na(+)/K(+)-ATPase activity. In contrast, in both sham and uninephrectomized euglycaemic diabetic rats, the natriuretic response to VE, the fenoldopam-induced natriuresis and the accompanied inhibition of Na(+)/K(+)-ATPase activity were similar to those of the corresponding controls. D(1) receptor immunodetection and protein abundance were reduced in hyperglycaemic diabetic rats, but not in euglycaemic diabetic animals. CONCLUSIONS: We conclude that the renal expression and natriuretic response to D(1) receptor activation is compromised in both sham and uninephrectomized rats with STZ-induced diabetes. These abnormalities were prevented by lowering glucose blood levels with insulin, thus providing evidence for the involvement of hyperglycaemia in the disturbances that underlie the compromised dopamine-sensitive natriuresis and increase of blood pressure in type 1 diabetes.

Local modulation of the natriuretic peptide system in the rat remnant kidney.

BACKGROUND: The natriuretic peptide (NP) system plays a central role in the renal adaptations to acute volume expansion. However, the modulation of the NP system in chronic renal insufficiency (CRI) remains to be elucidated. In the present study, we evaluated cardiac haemodynamics, plasma type-B natriuretic peptide (BNP) levels and the expression of natriuretic peptide receptor A (NPR-A) and NPR-C in the renal cortex (RC) and medulla (RM) of Sham and (3/4) nephrectomized ((3/4)nx) rats, up to 26 weeks after surgery. METHODS: Male Wistar-Han rats (190-220 g; n = 49) were randomly assigned to (3/4)nx or Sham surgery. Two, 10 and 26 weeks after surgery, non-invasive blood pressure (BP) and left ventricular (LV) haemodynamics were performed, and urine and blood were collected for metabolic studies and plasma BNP determination. In addition, tissue samples from RC and RM were obtained for NPR-A and NPR-C quantification (RT-PCR and western blotting) as well as NPR-A immunodetection. RESULTS: In (3/4)nx rats, the progressive interstitial fibrosis and tubular atrophy were accompanied by a time-dependent increase of BP and impaired natriuretic response to volume expansion (VE). This was accompanied in (3/4)nx rats by an early and time-dependent elevation of BNP circulating levels that was not associated with cardiac dysfunction or increased myocardial BNP gene expression. In (3/4)nx rats, NPR-A expression in the remnant RM was consistently reduced at 2, 10 and 26 weeks, and this was accompanied by an increase in NPR-C expression in the remnant RC from (3/4)nx rats. CONCLUSIONS: BP elevation and compromised natriuretic response to VE in (3/4)nx rats is associated with increased circulating BNP levels in the absence of cardiac dysfunction. This is accompanied in (3/4)nx rats by both impaired NPR-A expression in the RM and upregulation of NPR-C in the RC suggesting a novel mechanism for NP resistance in CRI.

Jejunal dopamine and Na,K-ATPase activity in early chronic renal insufficiency.

AIM: The uninephrectomised and three-quarter nephrectomised (3/4nx) rats present dopamine-sensitive enhanced natriuresis. This is accompanied in uninephrectomised rats by a reduced jejunal Na(+),K(+)-ATPase activity with recovered sensitivity to inhibition by dopamine. The present study examined the jejunal Na(+),K(+)-ATPase activity and the role of dopamine in 3/4nx animals. METHODS: Fourteen days after surgery, the L-amino acid decarboxylase activity (AADC) activity, the enzyme responsible for the synthesis of dopamine, and the Na(+),K(+)-ATPase activity, were determined in jejunal epithelial cells from 3/4nx and Sham rats. In addition, the effect of dopamine (1 micromol/L) on jejunal Na(+),K(+)-ATPase activity was evaluated in both groups. RESULTS: The 3/4nx rats presented a reduced AADC activity in jejunal epithelial cells (V(max) in nmol/mg prot/15 min, 142 +/- 6 vs 190 +/- 10, P < 0.05). In addition, the jejunal Na(+),K(+)-ATPase activity was increased in 3/4nx rats (Pi release in nmol/mg prot/min, 137 +/- 1 vs 122 +/- 2, P < 0.05). However, dopamine was unable to inhibit the Na(+),K(+)-ATPase activity in jejunal epithelial cells from both 3/4nx and Sham animals. CONCLUSIONS: In contrast to uninephrectomy, the jejunal Na(+),K(+)-ATPase activity is increased in 3/4nx rats and is not sensitive to inhibition by dopamine.