RESUMO
OBJECTIVES: The aim of this review is to highlight recent progress in the field of biomaterials-mediated dental pulp tissue engineering. Specifically, we aim to underscore the critical design criteria of biomaterial platforms that are advantageous for pulp tissue engineering, discuss models for preclinical evaluation, and present new and innovative multifunctional strategies that hold promise for clinical translation. MATERIALS AND METHODS: The current article is a comprehensive overview of recent progress over the last 5 years. In detail, we surveyed the literature in regenerative pulp biology, including novel biologic and biomaterials approaches, and those that combined multiple strategies, towards more clinically relevant models. PubMed searches were performed using the keywords: "regenerative dentistry," "dental pulp regeneration," "regenerative endodontics," and "dental pulp therapy." RESULTS: Significant contributions to the field of regenerative dentistry have been made in the last 5 years, as evidenced by a significant body of publications. We chose exemplary studies that we believe are progressive towards clinically translatable solutions. We close this review with an outlook towards the future of pulp regeneration strategies and their clinical translation. CONCLUSIONS: Current clinical treatments lack functional and predictable pulp regeneration and are more focused on the treatment of the consequences of pulp exposure, rather than the restoration of healthy dental pulp. CLINICAL RELEVANCE: Clinically, there is great demand for bioinspired biomaterial strategies that are safe, efficacious, and easy to use, and clinicians are eager for their clinical translation. In particular, we place emphasis on strategies that combine favorable angiogenesis, mineralization, and functional tissue formation, while limiting immune reaction, risk of microbial infection, and pulp necrosis.
Assuntos
Endodontia , Endodontia Regenerativa , Materiais Biocompatíveis , Polpa Dentária , Humanos , Dispositivos Lab-On-A-Chip , Regeneração , Engenharia TecidualRESUMO
The objective of this study was to evaluate the effects of different captive housing conditions on reproductive cyclicity and adrenocortical activity in adult females of two small-sized felid species, the tigrina (Leopardus tigrinus; n = 3) and margay (Leopardus wiedii; n = 2). Females were housed as singletons and subjected to three enclosure conditions over successive time periods: Phase I-large, enriched enclosures for 3 months; Phase II-small, empty enclosures for 5.5 months; Phase III-the same small enclosures enriched with branches and nest boxes for 6.5 months. Fecal samples were collected five times weekly throughout the study for analysis of progestagen, estrogen, and corticoid metabolites. On the basis of observed behaviors, stereotypic pacing was more frequent before feeding for all cats, regardless of enclosure conditions. Both species displayed a bimodal activity pattern, with peaks occurring at nightfall and dawn. All animals exhibited agitated behavior, characterized by a high frequency and duration of stereotypic pacing, primarily during the first 3 days after moving to the small empty enclosures. On the basis of hormonal analyses, ovarian follicular activity decreased and corticoid concentrations increased in tigrinas after transfer to the small barren cages compared to the patterns observed in the initial large, enriched enclosures. Corticoid concentrations in tigrinas then declined after small cage enrichment. Margay females exhibited increased corticoid excretion during Phases II and III, but in contrast to tigrinas, concentrations remained high even after cage enrichment. It was further showed that enriching the small enclosures was insufficient to reestablish normal ovarian activity within the time frame of the study for both species. In summary, margay and tigrina females exhibited distinct elevations in corticoid concentrations after transfer from large enriched enclosures to smaller barren cages that corresponded with agitated behavior, especially immediately after transfer. Fecal corticoid concentrations were reduced after cage enrichment in tigrinas, but not in margays. Although only a few individuals were evaluated, data suggest there may be species differences in response to captive environmental conditions. Overall results emphasize the importance of enclosure dimensions and enrichment when designing species appropriate environments for improving the health and reproductive fitness of threatened species. Zool Biol 26:441-460, 2007. (c) 2007 Wiley-Liss, Inc.
RESUMO
Captive adult male ocelots (Leopardus pardalis, n = 3), margays (L. wiedii, n = 3) and tigrinas (L. tigrinus, n = 4) in two locations in southern Brazil were studied for 14 consecutive months to evaluate the effect of season on testicular function. Reproductive evaluations, including testicular measurements, electroejaculation and blood collection were conducted monthly. Fecal samples were collected weekly for androgen metabolite analysis to assess testicular steroidogenic activity. Ocelots had the highest number of motile spermatozoa in the ejaculate (114.7+/-15.8 x 10(6); P < 0.05), the highest percentage of morphologically normal spermatozoa (82.4+/-1.2%; P < 0.05) and the highest concentration of fecal androgens (1.71 vs. 0.14 microg/g; P < 0.05). Margays and tigrinas had lower numbers of motile spermatozoa (23.4+/-2.8 x 10(6), 74.2+/-8.9 x 10(6), respectively), lower percentages of morphologically normal spermatozoa (57.4+/-2.8, 59.2+/-3.5%, respectively), and lower fecal androgen concentrations (0.15+/-0.01, 0.23+/-0.01 microg/g, respectively). Serum testosterone concentrations were similar among the three species. Fecal androgen concentrations were not affected by season, with the exception of the ocelot where concentrations were higher (P < 0.05) in the summer. Ejaculates were collected throughout the year; however, peaks in average sperm production were observed during the summer for all species. In summary, this study has identified several species differences in male testicular traits among ocelots, margays and tigrinas. Results of longitudinal reproductive assessments suggest males of each species are capable of breeding throughout the year.
Assuntos
Androgênios/análise , Carnívoros/fisiologia , Fezes/química , Estações do Ano , Sêmen/fisiologia , Testosterona/sangue , Animais , Carnívoros/anatomia & histologia , Masculino , Pênis/anatomia & histologia , Fotoperíodo , Contagem de Espermatozoides , Motilidade dos Espermatozoides , Temperatura , Testículo/anatomia & histologiaRESUMO
Reproductive endocrine patterns were characterized in female ocelots (Leopardus pardalis; n = 3), tigrinas (Leopardus tigrinus; n = 2), and margays (Leopardus wiedii; n = 2) housed in captivity in southern Brazil. Females were maintained as singletons and exposed to natural fluctuations in photoperiod. Cyclic changes in ovarian steroids were monitored by analyzing estrogen and progestogen metabolites in fecal samples collected five times weekly for 14 to 18 months. Based on intervals between fecal estrogen peaks, mean (+/- SEM) duration of the estrous cycle was 18.4 +/- 1.6 days for the ocelots (range, 7-31 days; n = 75 cycles), 16.7 +/- 1.3 days for the tigrinas (range, 11-27 days; n = 23 cycles), and 17.6 +/- 1.5 days for the margays (range, 11-25 days; n = 32 cycles). Fecal progestogen analyses combined with two laparoscopic observations of the ovaries confirmed that ocelots and tigrinas did not ovulate spontaneously. In contrast, non-mating-induced luteal phases of 40.1 +/- 6.3 days in duration (range, 30-60 days) were observed frequently in both margays. There was no evidence of gonadal seasonality in margays in either follicular or luteal activity. In ocelots, cyclic changes in estrogen excretion were observed during each month of the year; however, only one female cycled continuously. In the other two ocelots, periods of acyclicity of several months' duration were observed. It was not possible to conclude whether tigrinas were aseasonal because estrous cyclicity was observed in only one of two individuals. In the female that cycled, a 3-month period of acyclicity was observed in the late fall/early winter. These data demonstrate similarities among three felid species of the genus Leopardus, including evidence they are polyestrous but experience unexplained periods of ovarian inactivity. Only the margays differed by exhibiting occasional spontaneous, non-mating-induced ovulations. Historically, these species have not bred well in captivity. However, it is hoped that understanding the biological similarities and differences among them could lead to improved management strategies that may one day result in increased reproductive success. Zoo Biol 20:103-116, 2001. Copyright 2001 Wiley-Liss, Inc.
RESUMO
Tissue specimens from four species of Neotropical small cats (Oncifelis geoffroyi, N = 38; O. guigna, N = 6; Leopardus tigrinus, N = 32; Lynchailurus colocolo, N = 22) collected from throughout their distribution were examined for patterns of DNA sequence variation using three mitochondrial genes, 16S rRNA, ATP8, and NADH-5. Patterns between and among O. guigna and O. geoffroyi individuals were assessed further from size variation at 20 microsatellite loci. Phylogenetic analyses using mitochondrial DNA sequences revealed monophyletic clustering of the four species, plus evidence of natural hybridization between L. tigrinus and L. colocolo in areas of range overlap and discrete population subdivisions reflecting geographical isolation. Several commonly accepted subspecies partitions were affirmed for L. colocolo, but not for O. geoffroyi. The lack of geographical substructure in O. geoffroyi was recapitulated with the microsatellite data, as was the monophyletic clustering of O. guigna and O. geoffroyi individuals. L. tigrinus forms two phylogeographic clusters which correspond to L.t. oncilla (from Costa Rica) and L.t. guttula (from Brazil) and which have mitochondrial DNA (mtDNA) genetic distance estimates comparable to interspecific values between other ocelot lineage species. Using feline-specific calibration rates for mitochondrial DNA mutation rates, we estimated that extant lineages of O. guigna diverged 0.4 million years ago (Ma), compared with 1.7 Ma for L. colocolo, 2.0 Ma for O. geoffroyi, and 3.7 Ma for L. tigrinus.
Assuntos
Carnívoros/genética , Filogenia , Alelos , Animais , Carnívoros/classificação , Conservação dos Recursos Naturais , DNA Mitocondrial/genética , Ecossistema , Evolução Molecular , Feminino , Variação Genética , Genética Populacional , Masculino , Reação em Cadeia da Polimerase , América do Sul , Especificidade da Espécie , Fatores de TempoRESUMO
Considerable variation in the frequency of the clinical manifestations of onchocerciasis was seen in the individual endemic foci of the disease in province of Esmeraldas, Ecuador. In hypoendemic areas, 84.6% of all microfilaria-positive inhabitants were found to be free of any clinical manifestations of the disease, whereas in the hyperendemic area clinical manifestations were present in 57.9% of those infected. Ocular keratitis, macular papular rash of the skin and subcutaneous onchocercal nodules of varying frequency were the major clinical variants. Long-standing onchodermatitis and hypertrophy of the skin were rarely seen. Clinical evidence of prolonged ocular and skin invasion by microfilariae was seen only in the hyperendemic area. Of the 26.1% of the microfilaria-positive inhabitants who had onchocercal nodules, 91.7% lived in the hyperendemic area. 41.1% of all nodules occurred in the region of the iliac crest. Clinical conditions associated with high microfilarial density, i.e., elephantiasis of the legs and scrotum, lymphadenopathy, hanging groin, hydrocele and inguinal hernia were seen only in the hyperendemic area. The clinical features were similar to those seen in Africa, but the low incidence of the clinical presentation and severity of the disease suggested a recent infestation of the province.
Assuntos
Oncocercose/patologia , Equador , Olho/patologia , Humanos , Ceratite/etiologia , Linfonodos/patologia , Oncocercose/complicações , Oncocercose/epidemiologia , Pele/patologiaRESUMO
The frequency, intensity and clinical features of onchocerciasis in the two ethnic groups (Blacks and Chachilla--an indigenous tribe) in the endemic foci of the disease in Esmeraldas province (Ecuador) were evaluated. The incidence of infection and intensity of the disease seen in both groups were directly related to the frequency of man-vector contact and not to racial factors. Both groups showed the same rate of positivity in both the hyperendemic and hypoendemic areas. Males of both groups had a consistently higher positivity rate than did females. The Chachilla were found to have a higher mean microfilarial density than Blacks in both types of endemic areas. Certain clinical features of the disease analogous to those seen in the African form were present only in Blacks. No lymphatic involvement or hypertrophic scarring was seen in the Chachilla, suggesting that in the Blacks there may be a generaically related predisposition to lymphatic complications of microfilarial infections.
Assuntos
Etnicidade , Oncocercose/epidemiologia , Adolescente , Adulto , Negro ou Afro-Americano , Fatores Etários , População Negra , Criança , Pré-Escolar , Equador , Feminino , Humanos , Lactente , Masculino , Microfilárias , Pessoa de Meia-Idade , Oncocercose/parasitologia , Oncocercose/patologia , Fatores Sexuais , Pele/parasitologiaRESUMO
In the province of Esmeraldas in Ecuador, 11 endemic foci of onchocerciasis were identified. The major focus, located on Rio Cayapas, consisted of 65 contiguous positive communities with an average infection rate of 51.1%. A distance-dependent characteristic of the onchocerciasis infection suggested that the transmission was centered principally in the areas near the head-waters of the river. This area, inhabited primarily by the indigenous tribe, Chachi, with an infection rate of 85%, was considered an area of hyperendemicity. Towards the river's mouth, where the majority of the inhabitants were Blacks, the rate of infection was 7%. The endemic focus located on Rio Santiago, populated entirely by Blacks and consisting of 17 contiguous positive communities, had an average infection rate of 18.8%. Again, the highest rate of infection, 33%, occurred in the upper reaches of the river. Resulting from the transient and migratory activity of some microfilariae-positive persons, 9 other isolated foci were found dispersed throughout the province. The infection rate of each focus was distinct, reflecting geographical location and ethnic composition. All foci other than the interior regions of Rio Cayapas were areas of hypoendemicity.
Assuntos
Ectoparasitoses/epidemiologia , Oncocercose/epidemiologia , Adolescente , Adulto , Fatores Etários , Animais , População Negra , Criança , Pré-Escolar , Ectoparasitoses/parasitologia , Equador , Feminino , Água Doce , Humanos , Indígenas Sul-Americanos , Lactente , Masculino , Pessoa de Meia-Idade , Onchocerca/isolamento & purificação , Oncocercose/parasitologia , Densidade Demográfica , Saúde da População Rural , Fatores Sexuais , Pele/parasitologia , MigrantesRESUMO
The epidemiology of infection was studied in all endemic foci of onchocerciasis in the province of Esmeraldas in Ecuador. The incidence of infection and the density of microfilariae in the skin, both greater in males than females, increased with age, reaching highest levels at 40-45 years in males and at 60 years and older in females. In the hyperendemic area males and females had the same rate of infection, but the microfilarial density in males exceeded that in females. In the hypoendemic areas males had a higher infection rate than females, but females registered a higher density of microfilariae in the skin. The incidence and location of the onchocercal nodules correlated closely with the density of microfilariae. Adults, aged 50-54 had the highest prevalence of onchocercal nodules, which occurred primarily in the thorax and pelvic regions. Children aged 0-14 years showed a low prevalence of nodules, the head region being the primary site. Of the two diagnostic methods used to detect the presence of microfilariae, most of the diagnoses (85.6%) were made by skin biopsies as compared to those made by the Mazzotti test (14.4%).