White spot lesions: diagnosis and treatment - a systematic review

BACKGROUND

White spot lesions represent the first stage of caries and their prevalence has been increasing in recent years, particularly in patients undergoing orthodontic treatment. DIferential diagnosis and lesion activity are essential to decide on the clinical approaches to treatment. The aim of this study is to understand if the new diagnostic tools such as fluorescence, microradiography and computed microtomography have the potential to change the conventional treatment of white spots".

METHODS

A systematic search of available studies in the literature was carried out, using PRISMA guidelines, in Pubmed and Scopus electronic databases and manually to identify relevant articles to answer the PICO question: "Do the new diagnostic tools have the potential to change the conventional treatment of white spots?". This systematic review included randomized controlled trials (RCT), cross-sectional and longitudinal studies complying with the following inclusion criteria: (i) studies in humans, (ii) studies about white spot lesions, (iii) studies published between 2012 and 2023, (iv) studies having both diagnosis and treatment and (v) studies with full text available. In this review we excluded other systematic reviews of clinical trials and in vitro studies. The RoB tool was used to assess the risk of bias.

RESULTS

The systematic literature search identified 143 potentially relevant references, which after applying the exclusion criteria, resulted in 20 articles. Regarding diagnostic methods, most articles found were based on conventional methods of visual examination (n:10) or fluorescence (n:7). The least referenced diagnostic techniques were based on the use of clinical photographs (n:2), cross-sectional microradiography (n:1) and computed microtomography (n:1). The use of DIAGNOdent was reported by 3 in vitro studies. With regard to therapies, most studies reported the use of infiltrating resin (n:7) and fluoride-based products (n:5). Other studies have reported the use of self-assembling peptide P11-4 (n:1), home care (n:1), casein phosphopeptide-amorphous calcium phosphate (n:2) and hydrochloric acid (n:1). Combination therapies were also considered.

CONCLUSION

Diagnostic tool does not have the potential to change the form of treatment, whether it is a conventional method or a more differentiated one.

Oral Health Strategies: Surveying the Present to Plan the Future of Community-Based Learning

Introduction: Oral health literacy relates to the capacity of individuals to acquire, understand and to act upon oral health information to make appropriate health decisions. This scientific review's main goal is to analyze the strategies that improve oral health literacy within the community, specifically oriented to a community-based learning model focused on the most vulnerable risk groups in society. Materials and Methods: The current review is based on the literature on oral health literacy within community-based learning strategies. The present review selected scientific studies by searching MEDLINE and related databases, such as Web of Science and PUBMED, and by consulting existing bibliographies. Results: Based on the application of the inclusion criteria to the abstracts, 45 publications were retrieved which explicitly dealt with the definitions of oral health literacy, community-based learning, and service learning. Several studies have demonstrated that health consumers with low health literacy fail to understand the available health information. Therefore, innovative oral health literacy strategies should be undertaken. Service learning is an example of an educational approach where the student learns specific soft skills in the classroom and collaborates directly with an agency or institution and engages in reflection activities to deepen their understanding of what is being taught. Conclusions: One of the main strategies used to incorporate the oral health professional in social responsibility and direct contact in the community is through experiencing community-based learning projects. The future graduate must be an educator capable of educating patients in order to themselves acquire high-level skills in oral health literacy.

Is oral microbiota associated with overweight and obesity in children and adolescents? A systematic review

This article aims to verify the relationship between the composition and diversity of oral microbiota with overweight and obese children and adolescents. This systematic review was registered in PROSPERO, followed PRISMA 2020, and included an electronic search until March 2022, in PubMed/MEDLINE, Web of Science, Scopus, and The Cochrane Library databases. Studies were eligible if they compared the oral microbiota according to nutrition status among children and adolescents. Independent peers using JBI Critical Appraisal Checklists assessed the quality of studies. Eleven studies were eligible to be included in this review, with a total of 1,695 children and adolescents, 224 were obese, 190 were overweight, 1,154 were eutrophics and 127 were underweight. The most frequent phyla in overweight and obese children and adolescents, in comparison to their counterparts were Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria and Fusobacteria. It was identified that nine of the eleven articles selected showed an association between oral microbiota and overweight and obesity in children and adolescents. We observed that there is an important association between oral bacterial composition diversity and overweight and obesity. This finding indicates the relevance of the evaluation and surveillance in oral health to control cases of overweight and obesity in children and adolescents.

The influence of overweight and obesity in the oral health of a sample of portuguese adults

Background

Overweight and obesity may lead to different problems in various body systems and in the oral cavity. Dental caries and periodontal disease have been related with overweight. The aim of this study was to assess how overweight and obesity have impact on the lifestyle, oral habits and oral pathologies.

Methods

We conducted an observational cross-sectional study where we applied a questionnaire to 140 individuals from Lisbon and Viseu, Portugal., which 70 had a normal Body Mass Index (BMI) (control group) and 70 had an excessive BMI. We also made an oral observation in each individual to record the permanent teeth decayed, missing and filled index (DMFT), the Community Periodontal Index and the oral hygiene status.

Results

From the final sample, 30% of the subjects with overweight brushed their teeth once a day or less, while the majority (62.9%) of the control group brushed twice a day. In the oral examination, 70% had calculus, while in the control group only 22.5% presented calcified plaque. The DMFT was higher among the obesity group in comparison with the control group. Regarding periodontal disease, the participants with overweight need more dental intervention (81.4%) in contrast with the control group (14%).

Conclusions

Most overweight and obese individuals present precarious oral hygiene habits, higher prevalence of dental caries, and worse periods of periodontal health. They are not aware of the repercussions of the association between their cariogenic diet, oral health and overweight.

Key messages

• Oral health behaviors are related with other health conditions, namely obesity and this is a fundamental public health issue.

• Primary preventive strategies should be established having in consideration the oral health status of adults in treatment for obesity and in weight control programs.

Validity and reliability of the Portuguese version of the rapid estimate of adult literacy in dentistry: REALD-29 PT

BACKGROUND

Health literacy is a main factor in health for its improvement, allowing the individuals to have a greater capacity to engage and participate in collective health promotion actions. The evaluation of functional health literacy is essential to determine the ability that each individual has to understand basic health information. The present study aimed to perform the translation and cross-cultural adaptation of the Rapid Estimate of Adult Literacy in Dentistry-30 to the Portuguese language and test the reliability and validity of this version.

METHODS

After translation and cultural adaptation, the instrument was applied to a group of individuals that participate in the program Atividade Senior, developed by the municipality of Viseu, Portugal. The final sample was composed by 206 participants that accepted responding to the translated version of the instrument. Statistical validation was accomplished to complete the process and obtain the final instrument. One question was removed for the creation of the final instrument with 29 questions, therefore being named Rapid Estimate of Adult Literacy in Dentistry-29 PT.

RESULTS

The Rapid Estimate of Adult Literacy in Dentistry-29 PT presented good internal reliability. Cronbach's alpha ranged from 0.89 to 0.90 when words were deleted individually. The analysis of test-retest reliability revealed excellent reproducibility. We can verify that the Rapid Estimate of Adult Literacy in Dentistry-29 PT scale for assessment of oral health literacy among older adults presents an acceptable internal consistency, with a global Cronbach´s alpha of 0.894.

CONCLUSIONS

The new scale can be applied to assess oral health literacy among older Portuguese adults, presenting an acceptable internal consistency and is validated to assess oral health literacy and is crucial in epidemiological studies.

Population wide testing pooling strategy for SARS-CoV-2 detection using saliva

SARS-CoV-2 pandemic has forced frequent testing of populations. It is necessary to identify the most cost-effective strategies for the detection of COVID-19 outbreaks. Nasopharyngeal samples have been used for SARS-CoV-2 detection but require a healthcare professional to collect the sample and cause discomfort and pain to the individual. Saliva has been suggested as an appropriate fluid for the diagnosis of COVID-19. We have investigated the possibility of using pools of saliva samples to detect SARS-CoV-2 in symptomatic and asymptomatic patients. Two hundred and seventy-nine saliva samples were analyzed through RT-PCR of Envelope, Nucleocapsid and Open Reading Frame 1ab genes. Reproducibility assays showed an almost perfect agreement as well as high sensitivity (96.6%), specificity (96.8%), positive predicted value (96.6%), and negative predicted value (96.8%). The average Cycle Threshold of the genes detected was 29.7. No significant differences (p > 0.05) were detected when comparing the cycle threshold average of two consecutive reactions on the same positive saliva samples. Saliva samples have a higher median viral load (32.6) than in nasopharyngeal samples (28.9), although no significant differences were detected (p > 0.05). Saliva-pool samples allowed effective SARS-CoV-2 screening, with a higher sensibility (96.9%) on 10-sample pools than in 20-sample pools (87.5%). Regardless of pools size specificity was high (99.9%) and an almost perfect agreement was observed. Our strategy was successfully applied in population wide testing of more than 2000 individuals, showing that it is possible to use pooled saliva as diagnostic fluid for SARS-CoV-2 infection.

Pharmacological blockage of the AHR-CYP1A1 axis: a call for in vivo evidence

The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that can be activated by structurally diverse compounds arising from the environment and the microbiota and host metabolism. Expanding evidence has been shown that the modulation of the canonical pathway of AHR occurs during several chronic diseases and that its abrogation might be of clinical interest for metabolic and inflammatory pathological processes. However, most of the evidence on the pharmacological abrogation of the AHR-CYP1A1 axis has been reported in vitro, and therefore, guidance for in vivo studies is needed. In this review, we cover the state-of-the-art of the pharmacodynamic and pharmacokinetic properties of AHR antagonists and CYP1A1 inhibitors in different in vivo rodent (mouse or rat) models of disease. This review will serve as a road map for those researchers embracing this emerging therapeutic area targeting the AHR. Moreover, it is a timely opportunity as the first AHR antagonists have recently entered the clinical stage of drug development.

Self-perception of childrenś oral health by their parents

Background

Neglecting oral hygiene can lead to early tooth loss, pain, discomfort and, consequently, a great monetary investment to repair the damage caused in the stomatognathic system, whether of masticatory, phonetic or aesthetic origin. The aim of the present study consists in the characterization of oral health perception and oral hygiene habits of the children by their own parents and the creation of a scale to classify children's oral health perception by their parents.

Methods

A cross-sectional observational epidemiological study was performed. The population of this study was made up of 422 parents whose children are between five and eleven years of age and who attend schools in the districts of Viseu and Lisbon. The data collection was achieved through the application of a self-administered questionnaire in order to characterize the parentś perception of the oral health of their own children.

Results

Through the analysis of the questionnaires, 54.8% of the sample considered that their own children present inadequate oral health behaviors; 40.3% sufficient and only 4.8% consider that their children have good and adequate oral health behaviors. Regarding oral hygiene, most of the children did it one to five times a day, 44.7% took ‘2 minutes' to perform this activity, 70.3% did not use dental floss, 77.9% do not brush their teeth after lunch, 49.3% only use toothbrush for oral hygiene, 13.6% never went to the dentist, 26.9% are afraid, 38.1% have already suffered from toothache, 28.8% had gingival hemorrhage and 12.6% had gingival inflammation.

Conclusions

Oral health is a determining factor for a good quality of life. To this end, it is essential to implement oral health education and promotion strategies with all members of the household, in order to guarantee better oral health indexes in the community.

Key messages

Oral health literacy and knowledge is essential in order to improve oral health indexes in the community. The characterization of the oral health of children and adolescents is crucial to improve oral health behaviors and establish the correct oral health promotion programs.

Oral health behaviour perception scale applied among a sample of Portuguese adolescents

Introduction: The application of a scale can be particularly useful for the epidemiological studies comparing different populations and for analysis of the influence of distinct aspects of oral health on the development of certain health conditions. The aim of this study consists in the creation of a scale to classify the level of perception of the oral health behaviors applicable to a sample of Portuguese adolescents. Material and Methods: An observational cross-sectional study was designed with a total of 649 adolescents between the ages of 12 and 18 years old from five public schools in the Viseu and Guarda districts, in Portugal. Data was collected by the application of a self-administered questionnaire and, after analysis of data collection, the newly Universidade Católica Portuguesa (UCP) oral health perception scale was created. Statistical analysis was performed using SPSS-IBM software version 24.0 (IBM SPSS, Chicago, Il., USA). In the descriptive statistical analysis, absolute and descriptive frequencies were used for variables with nominal measurement level, mean as a measure of central tendency and standard deviation as a measure of dispersion for interval variables. Results: Oral health behaviors perception respecting the assumptions defined by the present scale has been elaborated. The result showed that 67% of the sample presented a poor perception of their oral health behaviors, 23.9% intermediate/sufficient, while 8.2% refer having good perception, respecting the assumptions defined for the elaboration of the present scale. Conclusion: For this purpose, through the scale to classify the level of oral health behaviors applicable to the sample of portuguese adolescents, it is possible to compare the data of several samples and understand what are the most frequent oral or eating habits among adolescents.

Dental caries and oral health behavior assessments among portuguese adolescents

Introduction: Adolescents have a high risk of developing caries in Portugal. The present study is designed to assess dental caries experience among the adolescents by the application of DMFT index, characterize the oral health risk factors and to determine the association between caries experience and socio-demographic variables. The characterization of the oral health behaviors of adolescents of the central region of Portugal will help in the development of specific oral health education strategies to improve oral health among the local communities. Material and methods: A cross-sectional study was conducted among a convenient sample of 694 adolescents aged 12 to 18 years attending public schools in two Portuguese districts using a structured questionnaire designed to investigate oral health and behavior of participants. In addition, a clinical examination was carried out noting the decayed, missing and filled teeth. A descriptive analysis of the variables was performed using the Chi-square, Mann-Whitney and Kruskal-Wallis tests (p<0.05). A multivariate analysis was applied for analysis of the association between variables. Results: The mean DMFT index score of 2.91±2.9 was obtained. Of the total sample, 73% consumed sugary food daily, 50.1% considered having good oral health and 70.8% did not report pain in the last 12 months. Most adolescents (79.4%) brushed their teeth daily and 60% did not use dental floss. Of the total sample, 96.4% had a dental appointment in the last 12 months, 46.4% of which was for preventive purposes. Applying the Chi-square statistical test, we verified that the adolescents who brush their teeth daily presented a good perception about their oral health (p<0.001), the DMFT index scores were associated with the residence area (p=0.01) and the presence of dental caries was associated with the perception of oral health (p=0.049) and sugary food intake (p=0.029).Conclusion: Portuguese adolescents presented a low DMFT index. The DMFT index was associated with residence area, perception of oral health and sugary food intake. Daily toothbrushing was associated with self-perception of oral health. It is suggested that oral health promotion and prevention programs should aim to reduce the risks of oral disease development.

Tracking the functional meaning of the human oral-microbiome protein-protein interactions

The interactome - the network of protein-protein interactions (PPIs) within a cell or organism - is technically difficult to assess. Bioinformatic tools can, not only, identify potential PPIs that can be later experimentally validated, but also be used to assign functional meaning to PPIs. Saliva's potential as a non-invasive diagnostic fluid is currently being explored by several research groups. But, in order to fully attain its potential, it is necessary to achieve the full characterization of the mechanisms that take place within this ecosystem. The onset of omics technologies, and specifically of proteomics, delivered a huge set of data that is largely underexplored. Quantitative information relative to proteins within a given context (for example a given disease) can be used by computational algorithms to generate information regarding PPIs. These PPIs can be further analyzed concerning their functional meaning and used to identify potential biomarkers, therapeutic targets, defense and pathogenicity mechanisms. We describe a computational pipeline that can be used to identify and analyze PPIs between human and microbial proteins. The pipeline was tested within the scenario of human PPIs of systemic (Zika Virus infection) and of oral conditions (Periodontal disease) and also in the context of microbial interactions (Candida-Streptococcus) and showed to successfully predict functionally relevant PPIs. The pipeline can be applied to different scientific areas, such as pharmacological research, since a functional meaningful PPI network can provide insights on potential drug targets, and even new uses for existing drugs on the market.

A method for the rapid evaluation of leather biodegradability during the production phase

Advances in technological-industrial processes have led to the development of new materials that generate different impacts on the environment when presented as waste. The application of sustainable manufacturing practices in order to improve the environmental behaviour of materials, including in the waste stage, is now an important industry responsibility. This study developed a new method for the rapid evaluation of leather biodegradability that can easily be operated by the tannery industry during the production phase. The method uses the OxiTop® system within which a solid sample is suspended in a liquid medium with no nutritional limitations at a constant temperature and stirring conditions. Ten leather samples were tested based on the existing methodology for determining aerobic biological activity (EN 16087-1: 2011), ultimate aerobic biodegradability of plastic materials in an aqueous medium (ISO 14851: 2004), and OECD 301F guidelines for testing of chemicals. The developed method has been shown to reliably distinguish (over 7 days) between samples produced using different manufacturing processes/treatments. Starch proved to be a better standard reference material for checking inoculum activity and the proper functioning of the measurement system than cellulose. Skin without treatment was shown to be a suitable reference material for defining the maximum biodegradation of leather materials. Double exponential and Gompertz mathematical models closely described the biodegradation of the tested samples. This method offers a way for industry to test and produce leather materials with higher levels of biodegradability, thus reducing the adverse environmental impacts of the final products when presented as solid waste.

Chemical profile and antioxidant potential of four table grape (Vitis vinifera) cultivars grown in Douro region, Portugal

The aim of this work was to improve the knowledge about the potential of Douro region (North of Portugal) to produce table grapes of superior quality. Skin, pulp, and seeds of four table grapes ‘Alphonse Lavallée’, ‘Cardinal’, ‘Dona Maria’ and ‘Muscat Hamburgo’ produced in Dour region, collected at commercial maturity stage, were evaluated. Phenolic compounds, organic acids and sugars were determined in each cultivar and in the different parts of the grape by HPLC-DAD, while the antioxidant properties were evaluated by DPPH, Cuprac and lipid peroxidation assays. Phenolics from different classes were found: four anthocyanins (delphynidin, cyanidin, petunidin and malvidin), two hydroxibenzoic acids (gallic acid and protocatechuic acid), three hydroxycinnamic acids (caffeic, chlorogenic and coumaric acids), one flavonol (rutin), three flavan-3-ols ((+)-catechin, (-)-epicatechin, and (-)-epicagallocatechin)), one oligomer (procyanidin B2) and one stilbene (resveratrol). In addition, three organic acids (tartaric, malic and citric acids) and two types of sugars (glucose and fructose) were detected in all samples. Differences were found between cultivars (p<0.001) and sample material type (p<0.001). Skins presented the higher content in anthocyanins, seeds in flavan-3-ols and pulps in phenolic acids, organic acids and free-sugars. The cultivar ‘Cardinal’ showed the highest content in phytochemicals, while ‘Dona Maria’ was the cultivar with the lowest content. Nonetheless, the content of flavan-3-ols and organic acids in ‘Dona Maria’, associated with its higher antioxidant capacity, makes it an interesting choice as table grape from healthier point of view. According to our results, Douro region have proper environmental conditions to produce these table grapes.

Women generating narratives after an unwanted prenatal diagnosis result: randomized controlled trial

We have defined a psychological intervention based on cognitive narrative therapy and the Ottawa decision framework to reduce adjustment problems following a termination of pregnancy (TOP) after a positive prenatal diagnosis (PND). The intervention is composed of four sessions: decision, subjectivation, metaphorization, and projecting. This study aims to assess the effectiveness of a cognitive narrative intervention to prevent depression and anxiety symptoms after TOP. The intervention was accepted by 24 participants. The outcome is compared with a control group of 67 women who also terminated a pregnancy after PND. Participants were from several Portuguese institutions; 64.4% had a genetic and 35.6% had ultrasound diagnosis; the mean age was 30.0 years and the mean gestational age was 19 weeks. There are two evaluations: a baseline at the 15th day and a sixth month follow-up after TOP, using Beck Depression Inventory, Zung Anxiety Scale, Perinatal Grief Scale, and an instrument capturing participant satisfaction. Six months after TOP, there is a lower mean of anxiety and depression (p < 0.05), between groups, with effect sizes on the follow-up of 0.54 for depression, 0.41 for anxiety, and 0.23 for perinatal grief. This intervention has very positive effects on women mental health, and we emphasize the importance of the meaning-making process in the context of terminating a wanted pregnancy.

Materiais Psicopedagógicos: Os desafios da sua construção na Educação para a Saúde

A cidadania constitui um processo ativo, no qual o indivíduo e a sociedade interagem para o alcance de objetivos e de superação de dificuldades comuns. O contexto escolar, é assim considerado um dos meios mais privilegiados para que a aprendizagem se consolide, dado ser um local integrador, das várias áreas do saber, e de preocupações transversais à sociedade. Como tal, a aposta na educação para a cidadania e a sua inserção no currículo escolar torna-se importante desde os níveis de ensino mais precoces. A elaboração de projetos que permitam concretizar os objetivos que norteiam esta área de conhecimento deve ter em linha de conta não só as necessidades e fragilidades específicas da comunidade escolar, na qual se desenvolverá uma determinada ação, mas também possibilitar a extensão destas ações aos restantes contextos onde o indivíduo se encontra inserido. Uma das áreas de abordagem da educação para a cidadania diz respeito à Educação para a Saúde. Tornar os jovens mais conscientes e auto-eficientes quanto a comportamentos e tomadas de decisão para a sua saúde global envolve o fornecimento de informação válida, coerente e sistemática sobre a prevenção e proteção da saúde. Não obstante o papel da família nesta educação, a escola ao tornar-se um contexto seguro, está a incentivar a adoção de comportamentos mais benéficos e vantajosos, encontrando-se numa posição ideal para a promoção e manutenção da saúde da comunidade educativa e comunidade envolvente. Dada a existência de alguns relatos por parte dos educadores responsáveis pela área curricular em apreço, nomeadamente face à escassez de material psicopedagógico avaliável e planificável nas áreas de abordagem na unidade curricular de Cidadania, pretende-se conhecer até que ponto a carência destes materiais é geral na comunidade educativa, e que necessidades são apontadas pelos educadores face a essa carência. Deste modo, desenvolveu-se o instrumento “Fomentar a Cidadania: a contribuição da docência no futuro da unidade curricular” tendo como propósito averiguar a existência ou inexistência de materiais pedagógicos que auxiliem os professores nestas aulas. A par da averiguação da inexistência de materiais, pretende-se construir instrumentos que auxiliem os educadores nas aulas de Cidadania. Todavia, verificando-se a existência de poucos recursos psicopedagógicos que auxiliem os educadores, objetiva-se complementar os já existentes, sendo destinados a crianças com idades compreendidas entre os 6 e os 9 anos de idade, do 1º ciclo do Ensino Básico. A construção destes materiais psicopedagógicos nas áreas que contemplam a Educação para a Saúde, nomeadamente a Alimentação Saudável, Substâncias Psicoativas e Sexualidade e afetos, contemplam um conjunto de exercícios práticos para as crianças e são acompanhados por um manual destinado aos educadores como forma de orientá-los nas aulas de Cidadania, como também para envolver e motivar as crianças a desenvolver noções básicas e uma tomada de consciência de alguns aspetos importantes a esta educação.

Colloid centrifugation of fresh stallion semen before cryopreservation decreased microorganism load of frozen-thawed semen without affecting seminal kinetics

Freezability of equine semen may be influenced by microorganism population of semen. The objective of this study was to verify the effect of single-layer density gradient centrifugation (SLC) of fresh semen before cryopreservation on semen's microbial load (ML) and sperm cells kinetics after freezing-thawing. For that, one ejaculate was collected from 20 healthy stallions and split into control (C) samples (cryopreserved without previous SLC) and SLC samples (subjected to SLC). Semen cryopreservation was performed according to the same protocol in both groups. Microbial load of each microorganism species and total microbial load (TML) expressed in colony-forming units (CFU/mL) as well as frozen-thawed sperm kinetics were assessed in both groups. Additional analysis of the TML was performed, subdividing the frozen-thawed samples in "suitable" (total motility ≥ 30%) and "unsuitable" (total motility < 30%) semen for freezing programs, and comparing the C and SLC groups within these subpopulations. After thawing, SLC samples had less (P < 0.05) TML (88.65 × 10(2) ± 83.8 × 10(2) CFU/mL) than C samples (155.69 × 10(2) ± 48.85 × 10(2) CFU/mL), mainly due to a reduction of Enterococcus spp. and Bacillus spp. A relationship between post-thaw motility and SLC effect on ML was noted, as only in samples with more than 30% total motility was ML reduced (P < 0.05) by SLC (from 51.33 × 10(2) ± 33.26 × 10(2) CFU/mL to 26.68 × 10(2) ± 12.39 × 10(2) CFU/mL in "suitable" frozen-thawed semen vs. 240.90 × 10(2) ± 498.20 × 10(2) to 139.30 × 10(2) ± 290.30 × 10(2) CFU/mL in "unsuitable" frozen-thawed semen). The effect of SLC on kinetics of frozen-thawed sperm cells was negligible.

Effect of breeding activity on the microflora of the external genitalia and in the semen of stallions, and the relationship between micro-organisms on the skin and on the external genitalia

A possible role of breeding activities in the composition of the microbial population in stallions' external genitalia (EG) and the relationship between micro-organisms colonizing the skin of the abdomen and the ones colonizing the EG have not been studied. In experiment 1, EG microbiological samples were collected from 41 stallions used for both natural cover and semen collection (BST) and from 18 non-breeding stallions (NBST). A higher (p < 0.05) frequency of isolation of potentially pathogenic species was found for BST. Age did not influence number of micro-organism species isolated both in BST and NBST. In experiment 2, the microbial content of the EG and semen was compared in 23 BST. Most micro-organisms isolated from the EG were present in semen, albeit with a numerically lower prevalence. In 7 stallions, six microbial species isolated from semen were absent from the EG cultures, suggesting contamination by the operator. In experiment 3, a numerically higher number of micro-organism species was isolated from the EG of 31 stallions, than from their skin of the ventral abdomen in contact with the penis or from the skin of the thorax. With the sole exception of Escherichia coli, potentially pathogenic bacteria were only isolated from the EG but not from the skin. Results suggest that breeding activity increased the number of species colonizing the EG; most species isolated from the EG were also found in semen even if with a lower frequency, and additional semen contamination seemed to occur during its manipulation. Many micro-organism species of the skin were also isolated from the penis, but independently of being or not in contact with the penis, skin did not seem to provide an adequate environment for the growth of potentially pathogenic bacteria that were isolated from EG, with the sole exception for E. coli.

Effective energy barrier distributions for random and aligned magnetic nanoparticles

Isothermal magnetic relaxation measurements are widely used to probe energy barriers in systems of magnetic nanoparticles. Here we show that the result of such an experiment can differ greatly for aligned and randomly oriented nanoparticles. For randomly oriented cobalt-doped magnetite nanoparticles we observe a prominent low-energy tail in the energy barrier distribution that is greatly attenuated when the particles are magnetically aligned. Monte Carlo simulations show that this behaviour arises for nanoparticles with both cubic and uniaxial magnetic anisotropy energy terms even though for cubic or uniaxial anisotropy alone the energy barrier distribution is independent of nanoparticle orientation.

Reversible catecholamine-induced cardiomyopathy due to pheochromocytoma: case report

Pheochromocytoma is a tumor originating from chromaffin tissue. It commonly presents with symptoms and signs of catecholamine excess, such as hypertension, tachycardia, headache and sweating. Cardiovascular manifestations include catecholamine-induced cardiomyopathy, which may present as severe left ventricular dysfunction and congestive heart failure. We report a case of pheochromocytoma which was diagnosed following investigation of dilated cardiomyopathy. We highlight the dramatic symptomatic improvement and reversal of cardiomyopathy, with recovery of left ventricular function after treatment.

Computational prediction of the human-microbial oral interactome

BACKGROUND

The oral cavity is a complex ecosystem where human chemical compounds coexist with a particular microbiota. However, shifts in the normal composition of this microbiota may result in the onset of oral ailments, such as periodontitis and dental caries. In addition, it is known that the microbial colonization of the oral cavity is mediated by protein-protein interactions (PPIs) between the host and microorganisms. Nevertheless, this kind of PPIs is still largely undisclosed. To elucidate these interactions, we have created a computational prediction method that allows us to obtain a first model of the Human-Microbial oral interactome.

RESULTS

We collected high-quality experimental PPIs from five major human databases. The obtained PPIs were used to create our positive dataset and, indirectly, our negative dataset. The positive and negative datasets were merged and used for training and validation of a naïve Bayes classifier. For the final prediction model, we used an ensemble methodology combining five distinct PPI prediction techniques, namely: literature mining, primary protein sequences, orthologous profiles, biological process similarity, and domain interactions. Performance evaluation of our method revealed an area under the ROC-curve (AUC) value greater than 0.926, supporting our primary hypothesis, as no single set of features reached an AUC greater than 0.877. After subjecting our dataset to the prediction model, the classified result was filtered for very high confidence PPIs (probability ≥ 1-10-7), leading to a set of 46,579 PPIs to be further explored.

CONCLUSIONS

We believe this dataset holds not only important pathways involved in the onset of infectious oral diseases, but also potential drug-targets and biomarkers. The dataset used for training and validation, the predictions obtained and the network final network are available at http://bioinformatics.ua.pt/software/oralint.

Effects of body condition and leptin on the reproductive performance of Lusitano mares on extensive systems

The aim of this study was to investigate the effects of body condition (BC), BC changes, and plasma leptin concentrations on the reproductive performance of Lusitano broodmares on extensive systems. Data from 119 mares (ranging from 4 to 22 years of age) were collected over a period of four consecutive breeding seasons. Each case was considered as one foaled mare bred in 1 year. Body condition changes at conception (ΔBCScon) showed a strong effect on fertility at the first two postpartum estrous cycles and a significant interaction with body condition score at conception (BCScon) was observed (P < 0.01). The best fertility results were obtained with positive and greater ΔBCScon. The best predictive value of fertility (91%) was achieved when the BCScon was 3.0 and ΔBCScon was 0.375. Global foaling rate for the 4-year period was 74.5%. Mean foaling interval and gestation length were, respectively, 368.0 ± 2.8 and 340.3 ± 1.0 days. Gestation length was influenced by the month of foaling (P < 0.05) and decreased as mares got older (P < 0.01). The number of estimated estrous cycles per live foal was 1.78 ± 0.12, including foal heat ovulation. Leptin was correlated with BCS (0.41; P < 0.001), but in the present study, plasma leptin concentrations on late gestation and early lactation did not influence fertility results. At 90 days of age, lower growth performances were obtained in foals which dams presented negative BCS changes on the first 3 months of lactation (P < 0.05). In conclusion, BC changes at early postpartum period influence the reproductive efficiency of broodmares and the growth of their suckling foals. These findings are important to help breeders on management options concerning feeding strategies in the Lusitano production systems and others under similar conditions.

Coronary artery vasospasm and acute myocarditis: a rare association

Coronary vasospasm is one cause of chest pain in patients with acute myocarditis. This is a rare association, with few cases reported in the literature. The authors describe a case of acute myocarditis in which presentation mimicked acute myocardial infarction. During hospitalization severe angina recurred twice, accompanied by transient ST-segment elevation in different locations. The hypothesis of coronary vasospasm is discussed. The role of cardiac magnetic resonance imaging in this context is highlighted.

[Cardiomyopathy: first clinical manifestation of a pheochromocytoma--case report]

Stress cardiomyopathy clinical presentation mimics an acute coronary syndrome. It is characterized by left ventricular multi-segmental commitment, absence of significant coronary artery disease and by the complete resolution of all the findings. Its pathophysiology is not yet clear, but the main theory suggests a catecholamine-mediated cardiotoxicity mechanism. Pheochromocytoma is a neuroendocrine tumor producer of catecholamines with several cardiovascular manifestations. We report a case of stress cardiomyopathy that was the first clinical manifestation of an unknown pheochromocytoma.

Electrical storm induced by H1N1 A influenza infection

Pandemic H1N1 influenza A virus is spreading worldwide. We report a case of electrical storm during H1N1 influenza A infection in a patient with congenital long-QT syndrome (LQTS) that was previously stable on beta-blocker therapy. Possible causes for the association of A flu and LQTS recurrent ventricular arrhythmias are discussed.

Pharmacogenetics and anticoagulant therapy: two cases of genetically determined response to warfarin

Inter- and intra-individual variability of response to warfarin means that its anticoagulant effect must be monitored, given the risk of thromboembolic complications and bleeding. This variability is influenced by gender, age, body mass index, smoking, diet, comorbid conditions, drug interactions and genetic factors. Pharmacogenetics refers to the study of genetic background to predict drug response, effectiveness and risk of adverse effects in a given patient. The authors illustrate its relevance in two case reports. A 40-year-old woman admitted for massive pulmonary thromboembolism underwent anticoagulant and fibrinolytic therapy, following which warfarin was needed in unusually high doses to achieve effective anticoagulation. The genetic variants c.430CC and c.1075AA of the CYP2C9 gene were identified, predisposing to rapid warfarin metabolism, as well as the c.-1639GG variant of the VKORC1 gene, associated with low sensitivity to the drug. Together, these variants give high resistance to warfarin. In the second case, a 76-year-old man with permanent atrial fibrillation developed excessive prolongation of prothrombin time after being treated with 5 mg/day warfarin for 5 days. The genetic variants c.430CC and c.1075AC of the CYP2C9 gene and 1639AA of the VKORC1 gene were identified. Together, these polymorphisms confer high sensitivity to warfarin, necessitating smaller doses to maintain therapeutic anticoagulation levels. The authors review the relevance of the study of genetic polymorphisms related to anticoagulant therapy and discuss its potential usefulness in clinical practice.

Portuguese study of familial dilated cardiomyopathy: the FATIMA study

Dilated cardiomyopathy (DCM) is a myocardial disease, characterized by ventricular dilatation and impaired systolic function, that in more than 30% of cases has a familial or genetic origin. Given its age-dependent penetrance, DCM frequently manifests in adults by signs or symptoms of heart failure, arrhythmias or sudden death. The predominant mode of inheritance is autosomal dominant, and in these cases mutations are identified in genes coding for cytoskeletal, sarcomeric or nuclear envelope proteins. To date, most studies aimed at molecular diagnosis of DCM have been in selected families, or in larger groups of patients, but screening for mutations in a limited number of genes. Consequently, the epidemiology of mutations in familial DCM remains unknown. There is thus a need for multicenter studies, involving screening for a wide range of mutations in several families and in cases of idiopathic DCM. The present article describes the methodology of a multicenter study, aimed at clinical and molecular characterization of familial DCM patients in the Portuguese population.

Elementary properties of Kir2.1, a strong inwardly rectifying K(+) channel expressed by pigeon vestibular type II hair cells

By using the patch-clamp technique in the cell-attached configuration, we have investigated the single-channel properties of an inward rectifier potassium channel (Kir) expressed by pigeon vestibular type II hair cells in situ. In high-K(+) external solution with 2 mM Mg(2+), Kir inward current showed openings to at least four amplitude levels. The two most frequent open states (L2 and L3) had a mean slope conductance of 13 and 28 pS, respectively. L1 (7 pS) and L4 (36 pS) together accounted for less than 6% of the conductive state. Closed time distributions were fitted well using four exponential functions, of which the slowest time constant (tau(C4)) was clearly voltage-dependent. Open time distributions were fitted well with two or three exponential functions depending on voltage. The mean open probability (P(O)) decreased with hyperpolarization (0.13 at -50 mV and 0.03 at -120 mV). During pulse-voltage protocols, the Kir current-decay process (inactivation) accelerated and increased in extent with hyperpolarization. This phenomenon was associated with a progressive increase of the relative importance of tau(C4). Kir inactivation almost disappeared when Mg(2+) was omitted from the pipette solution. At the same time, P(O) increased at all membrane voltages and the relative importance of L4 increased to a mean value of 47%. The relative importance of tau(C4) decreased for all open states, while L4 only showed a significantly longer open time constant. The present work provides the first detailed quantitative description of the elementary properties of the Kir inward rectifier in pigeon vestibular type II hair cells and specifically describes the Kir gating properties and the molecule's sensitivity to extracellular Mg(2+) for all subconductance levels. The present results are consistent with the Kir2.1 protein sustaining a strong inwardly rectifying K(+) current in native hair cells, characterized by rapid activation time course and slow partial inactivation. The longest closed state (tau(C4)) appears as the main parameter involved in time- and Mg(2+)-dependent decay. Finally, in contrast to Kir2.1 results described so far for mammalian cells, external Mg(2+) had no effect on channel conductance.

Kvbeta1.1 associates with Kvalpha1.4 in Chinese hamster ovary cells and pigeon type II vestibular hair cells and enhances the amplitude, inactivation and negatively shifts the steady-state inactivation range

Although A-type potassium currents are found in type II hair cells in the inner ear of most species, the molecular mechanisms for activation and inactivation of the A-type potassium current (I(A)) remain unknown. In frog semicircular canal hair cells, for example, there appear to be two classes of currents having either fast or slow inactivation [Norris CH, Ricci AJ, Housley GD, Guth PS (1992) The inactivating potassium currents of hair cells isolated from the crista ampullaris of the frog. J Neurophysiol 68:1642-1653; Russo G, Calzi D, Martini M, Rossi ML, Fesce R, Prigioni I (2007) Potassium currents in the hair cells of vestibular epithelium: position-dependent expression of two types of A channels. Eur J Neurosci 25:695-704]. It has been suggested that somehow the "ball and chain" mechanism (NH(3) (N) terminus motif) is modified by alternative splicing to account for the two classes of inactivation. To examine other possibilities, we cloned alpha and beta subunits that comprise the A-type potassium channel complex in adult and embryonic pigeon brain, cochlea and labyrinth. By sequence homology, we concluded that the subunits present were Kvalpha1.4 and Kvbeta1.1. The sequence of the open reading frame for Kvalpha1.4 contained the N-terminus, pore and COOH (C) terminus motifs for N-and C-type inactivation. The sequence for Kvbeta1.1 displayed amino acids consistent with assembly and association with Kvalpha1.4 alpha subunits. Kvalpha1.4 and Kvbeta1.1 were transfected either singly or in combination into Chinese hamster ovary (CHO) cells. These cells and native hair cells from the pigeon utricle were patch clamped and the inactivation properties of the A-type current were studied. In the native hair cells, the A-type current was identified by its pharmacological (4-aminopyridine (4-AP); IC(50)=11 microM) and voltage dependent inactivation properties. A comparison of the mean time constants from best-fitted single exponential and sum of two exponential equations to the ionic current inactivation revealed the following. In CHO cells when Kvalpha1.4 was expressed alone, the mean time constant (tau(1)=107 ms+/-19, N=32) was significantly (P<0.001) longer and the mean peak amplitude (2.28 nA+/-0.39, N=32) was smaller than when Kvalpha1.4 and Kvbeta1.1 were expressed in CHO cells. Moreover, the co-transfection of Kvalpha1.4 and Kvbeta1.1 into CHO cells caused a shift in the steady state inactivation curve parameter Vo 30 mV in the hyperpolarized direction relative to CHO cells expressing only Kvalpha1.4. Similarly, Kvalpha1.4-transfected CHO cells produced longer time constants and smaller amplitudes than those found for native utricular hair cells. These data lead us to conclude that while the amino acid motifs are present in Kvalpha1.4 and Kvbeta1.1 to suggest N-and C-type inactivation, co-assembly and association of Kvalpha1.4 and Kvbeta1.1 may also produce changes in the time dependent inactivation properties of vestibular hair cells.

Na+ currents in vestibular type I and type II hair cells of the embryo and adult chicken

In birds, type I and type II hair cells differentiate before birth. Here we describe that chick hair cells, from the semicircular canals, begin expressing a voltage-dependent Na current (INa) from embryonic day 14 (E14) and continue to express the current up to hatching (E21). During this period, INa was present in most (31/43) type I hair cells irrespective of their position in the crista, in most type II hair cells located far from the planum semilunatum (48/63), but only occasionally in type II hair cells close to the planum semilunatum (2/35). INa activated close to -60 mV, showed fast time- and voltage-dependent activation and inactivation, and was completely, and reversibly, blocked by submicromolar concentrations of tetrodotoxin (Kd = 17 nM). One peculiar property of INa concerns its steady-state inactivation, which is complete at -60 mV (half-inactivating voltage = -96 mV). INa was found in type I and type II hair cells from the adult chicken as well, where it had similar, although possibly not identical, properties and regional distribution. Current-clamp experiments showed that INa could contribute to the voltage response provided that the cell membrane was depolarized from holding potentials more negative than -80 mV. When recruited, INa produced a significant acceleration of the cell membrane depolarization, which occasionally elicited a large rapid depolarization followed by a rapid repolarization (action-potential-like response). Possible physiological roles for INa in the embryo and adult chicken are discussed.

Return of potassium ion channels in regenerated hair cells: possible pathways and the role of intracellular calcium signaling

Recent electrophysiological studies in pigeon have demonstrated that potassium channels are completely functional in regenerated type II hair cells at 21 days post-treatment (PT) with ototoxic doses of streptomycin. The currents return in the order they appear during development. The mixture of ionic currents in a regenerated type II hair cell in a particular region of the neuroepithelium is the same as in its ancestor in that region. The return of currents in regenerated type I hair cells is more complicated. The dominant conductance gKI is not present until after 70 days PT. Before 70 days, the ionic currents in type I hair cells resemble those of regenerated type II hair cells, suggesting that the ionic currents in type II hair cells might be precursors of the ionic currents in regenerated type I hair cells. New data show that at one year PT, the kinetics and drug sensitivity of the dominant K+ conductance in type I hair cells are identical to gKI. Supporting cells, believed to be the precursors of regenerated type II hair cells, have effectively no voltage-gated outward potassium channels, suggesting that regenerated type II hair cells must develop these channels de novo. The next step is to understand the mechanisms by which the potassium channel protein is synthesized, migrates through the cytosol, and is inserted into the plasmalemma of regenerating hair cells. These mechanisms are unknown. We propose that intracellular calcium is involved in this process, as well as in the differentiation, proliferation, and gene regulation of precursor cells fated to become hair cells.

Response to seasonal drought in three cultivars of Ceratonia siliqua: leaf growth and water relations

Responses of leaf growth and leaf water relations to seasonal drought were monitored during two successive years in three cultivars (Galhosa, Espargal and Mulata) of Ceratonia siliqua L. growing in the field in southern Portugal. Leaf water relations of fully expanded leaves were characterized by pressureâ volume analysis, and morphometric measurements of petiolar xylem were made. The three cultivars differed with respect to onset of leaf initiation. In Galhosa, there was a sharp peak of leaf initiation in June that was immediately followed by a period when leaf expansion rates were highest. The onset of leaf growth occurred earlier in Espargal and Mulata than in Galhosa, and both cultivars continued producing new leaves throughout the summer period. The diurnal pattern of water relations in recently expanded leaves indicated that, during midsummer, Galhosa was the only cultivar in which leaf water potential did not fall below the turgor loss point and leaf relative water content remained above 90%. The occurrence of osmotic adjustment in recently expanded leaves of Galhosa was not demonstrated conclusively. However, during the dry season following leaf formation, a seasonal decrease in osmotic potential sufficient to maintain turgor was detected in 1-year-old leaves of Galhosa but not in 1-year-old leaves of the other cultivars. Among cultivars, Galhosa petioles had the widest xylem conduits, which may partly explain why midday leaf water potential in Galhosa never decreased below -2.0 MPa even at the end of the summer drought.

[Can blood homocysteine explain the family history of vascular diseases?]

INTRODUCTION AND AIMS

Family history of vascular disease is an important risk factor for vascular disease, independent of conventional risk factors. Homocysteinemia, a newly defined risk factor, is caused by genetics, such as cystathionine beta synthase deficiencies, and metabolic deficiencies. With the present work we intend to study the influence of family history of vascular disease in homocysteinemia.

METHODS

We studied 204 normal persons (153 males), average age 38.7 +/- 10.9 years, in terms of family history of vascular disease (death due to myocardial infarction or a stroke), conventional risk factors, routine laboratory tests, fasting homocysteinemia and after oral methionine loading (0.1 g/Kg body weight). We compared laboratory results, conventional risk factors and homocysteinemia levels in persons with and without a family history of vascular disease. We performed covariance analysis to evaluate, in a multivariate model, factors that were related to basal or after methionine loading homocysteinemia.

RESULTS

35% of persons presented a family history of vascular disease (FHVD). Persons with FHVD presented higher age (45.6 +/- 8.9 versus 35.0 +/- 10.1, p < 0.001), and higher prevalence of hypertension (p = 0.002), dyslipidemia (p = 0.001), obesity (p = 0.03), and physical inactivity (p = 0.03). They presented a tendency, without statistical significance, to have a higher prevalence of diabetes and of hyperhomocysteinemia, and to present higher levels of basal and afterload homocysteinemia. Performing covariance analysis, basal homocysteinemia did not present any relation to FHVD. After methionine load homocysteinemia was strongly influenced by basal homocysteinemia (p = 0.0000), and significantly related to FHVD (p = 0.039).

CONCLUSIONS

Homocysteinemia cannot explain most of the risk of family history of vascular disease, not explained by conventional risk factors. The only significant relationship between homocysteinemia and FHVD was observed with afterload homocysteinemia in the multivariate model. FHVD is clearly related to conventional risk factors.

[Secondary prevention in acute myocardial infarction]

Myocardial infarction is still one of the main causes of mortality and morbidity in Western countries. The advances made in the last 30 years have made it possible to reduce mortality significantly (which is currently below two digits) as well as morbidity. The subject of secondary prevention of myocardial infarction gains particular significance in this context since 10 to 15% of the patients who survive the hospital phase of myocardial infarction die during the first year following discharge and, of these deaths, half occur in the first three months. Therefore, it is necessary to make an early definition of the risk of another coronary event, that is, to make a risk stratification. This should occur throughout hospitalization and should be complete at the time of discharge, never beyond the first weeks of evolution. Bearing in mind the age, sex, coronary risk factors, ischemia persistence, the degree of left ventricular dysfunction and the presence of malignant disrhythmias, there are three risk levels: high; intermediate; and low. An overall approach to secondary prevention of infarction should take into account that, apart from the factors of such high prognostic value (Chapter II) assessed in the definition of risk groups, the measures to reduce reinfarction and sudden death (Chapter III) and the control of the risk factors for heart disease (Chapter IV) should also be considered. The principal late complications of infarction with significant prognostic influence are described in Chapter III: left ventricular dysfunction; rhythm disturbances and residual ischemia. The diagnostic criteria and therapeutic objectives are considered in each of the groups with relevance to consolidated advances according to the modern concept of evidence based medicine, according to international regulations. The grading of scientific evidence into three distinct categories (A, B and C), based on five levels of evidence classified from I to V, is presented accordingly in relation to the therapeutic proposals. Chapter III deals with a set of therapeutic interventions used in secondary prevention because they reduce reinfarction and sudden death: platelet antiaggregants; anticoagulants; Beta blockers; calcium channel blockers; antioxidants and nitrates. A concept of particular clinical significance is presented for each of these groups of drugs. The last part contains an eminently clinical overall review of the principal advances in coronary risk factor control, new therapeutic acquisitions in atherosclerotic disease with natural relevance to hypolipidemic agents and statins, which apart from controlling the plasmatic levels of cholesterol, also stabilize the atherosclerotic plaque and reduce acute coronary events significantly. Apart from dyslipidemia, the classic risk factors are: smoking; hypertension; obesity; diabetes and sedentary life. In each case, reference is made to the general measures and specific approaches, as well as the pharmacological therapy according to evidence based medicine. The recommended attitudes are pointed out. The role of cardiac rehabilitation and postmenopausal hormone replacement therapy are also discussed in the last part of these recommendations, in which the on-going controversy regarding hormone replacement therapy is pointed out in view of the results of more recent clinical trials.

Effects of KCNQ channel blockers on K(+) currents in vestibular hair cells

Linopirdine and XE991, selective blockers of K(+) channels belonging to the KCNQ family, were applied to hair cells isolated from gerbil vestibular system and to hair cells in slices of pigeon crista. In type II hair cells, both compounds inhibited a slowly activating, slowly inactivating component of the macroscopic current recruited at potentials above -60 mV. The dissociation constants for linopirdine and XE991 block were <5 microM. A similar component of the current was also blocked by 50 microM capsaicin in gerbil type II hair cells. All three drugs blocked a current component that showed steady-state inactivation and a biexponential inactivation with time constants of approximately 300 ms and 4 s. Linopirdine (10 microM) reduced inward currents through the low-voltage-activated K(+) current in type I hair cells, but concentrations up to 200 microM had little effect on steady-state outward K(+) current in these cells. These results suggest that KCNQ channels may be present in amniote vestibular hair cells.

Hair cell and supporting cell density and distribution in the normal and regenerating posterior crista ampullaris of the pigeon

The numbers of supporting cells and the numbers and types of hair cells in three distinct longitudinal regions through the posterior canal cristae of control and streptomycin-treated pigeons were determined using stereological techniques. For control cristae, type I (3758) and type II (3517) hair cells occurred in approximately equal numbers. However, the proportions varied in different longitudinal zones: Zone I (peripheral region) had four times more type II hair cells (2083) than type I (483), while Zone II (intermediate region) had almost seven times more type I (2517) than type II (367) hair cells and Zone III (central region) had relatively equal numbers of type I (758) and type II (1067) hair cells. Novel findings included the following: (1) immediately after the post-injection sequence (PIS) of streptomycin, there was a significant reduction in both hair cells (-93%) and supporting cells (-45%); (2) by 70 days after the PIS, the population of type I hair cells returned to control values (however, the normal complement of complex calyces took 1 year to recover); (3) during the first 143 days after the PIS, the number of type I and type II hair cells across all zones returned linearly with about the same slope (46 and 43 cells per day, respectively), although the rate of return differed significantly in different zones; (4) there was a massive overproduction of hair cells (+150%) and supporting cells (+120%) during the first 5 months of recovery; and (5) during the first year after the PIS, both hair cells and supporting cells increased and their increases in numbers were correlated (r = 0.88, P < 0.01). Knowledge of the sequence and numbers of regenerating hair cells may help elucidate common modes of cell survival, recovery, and compensation from neural insult.