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1.
Ultrasound Obstet Gynecol ; 62(5): 644-652, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37161550

RESUMO

OBJECTIVES: To identify all prediction models for fetal and neonatal outcomes in pregnancies with preterm manifestations of placental insufficiency (gestational hypertension, pre-eclampsia, HELLP syndrome or fetal growth restriction with its onset before 37 weeks' gestation) and to assess the quality of the models and their performance on external validation. METHODS: A systematic literature search was performed in PubMed, Web of Science and EMBASE. Studies describing prediction models for fetal/neonatal mortality or significant neonatal morbidity in patients with preterm placental insufficiency disorders were included. Data extraction was performed using the CHARMS checklist. Risk of bias was assessed using PROBAST. Literature selection and data extraction were performed by two researchers independently. RESULTS: Our literature search yielded 22 491 unique publications. Fourteen were included after full-text screening of 218 articles that remained after initial exclusions. The studies derived a total of 41 prediction models, including four models in the setting of pre-eclampsia or HELLP, two models in the setting of fetal growth restriction and/or pre-eclampsia and 35 models in the setting of fetal growth restriction. None of the models was validated externally, and internal validation was performed in only two studies. The final models contained mainly ultrasound (Doppler) markers as predictors of fetal/neonatal mortality and neonatal morbidity. Discriminative properties were reported for 27/41 models (c-statistic between 0.6 and 0.9). Only two studies presented a calibration plot. The risk of bias was assessed as unclear in one model and high for all other models, mainly owing to the use of inappropriate statistical methods. CONCLUSIONS: We identified 41 prediction models for fetal and neonatal outcomes in pregnancies with preterm manifestations of placental insufficiency. All models were considered to be of low methodological quality, apart from one that had unclear methodological quality. Higher-quality models and external validation studies are needed to inform clinical decision-making based on prediction models. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.


Assuntos
Insuficiência Placentária , Pré-Eclâmpsia , Recém-Nascido , Gravidez , Humanos , Feminino , Retardo do Crescimento Fetal/diagnóstico por imagem , Pré-Eclâmpsia/prevenção & controle , Insuficiência Placentária/diagnóstico por imagem , Placenta , Cuidado Pré-Natal
2.
Avian Pathol ; 50(1): 52-60, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33016771

RESUMO

Almost two decades ago, in addition to a compulsory M. gallisepticum (Mg) monitoring programme of breeding stock based on European Union regulations, the Dutch poultry industry added national regulations to further reduce the Mg prevalence in Dutch commercial poultry. Currently, all commercial chicken and turkey flocks except broilers are monitored for Mg. All breeding flocks on a farm where one or more flocks tested Mg positive are culled. Mg positive layer pullets are channelled and layer pullets placed on Mg positive multi-age farms are vaccinated. The monitoring data obtained were analysed covering a period of 17 years. Moreover, 31 Dutch Mg isolates from the same period were analysed by multilocus sequence typing (MLST) and compared to available PubMLST data. The results show that in breeding stock the seroprevalence decreased from 1.6% to 0.0%, in commercial layers from 6.3% to 1.9%, and in meat turkeys from 17.6% to 2.4%. The MLST results showed the presence of closely related and identical sequence types (STs) within the different Dutch poultry types. Similar STs were found in Northern and Southern Europe only. The results show a fast decline in the Mg prevalence since 2001, although in layers the Mg prevalence has stabilized and suggests backyard poultry might pose a risk for commercial poultry. The need for Mg control across poultry sectors and in trade was confirmed by the similarity in STs found in different types of poultry and regions. These results from the Dutch poultry industry can be extrapolated to Mg control in general.


Assuntos
Galinhas/microbiologia , Infecções por Mycoplasma/veterinária , Mycoplasma gallisepticum/imunologia , Doenças das Aves Domésticas/microbiologia , Perus/microbiologia , Animais , Técnicas de Tipagem Bacteriana/veterinária , Fazendas , Feminino , Genótipo , Masculino , Tipagem de Sequências Multilocus/veterinária , Infecções por Mycoplasma/epidemiologia , Infecções por Mycoplasma/microbiologia , Infecções por Mycoplasma/prevenção & controle , Mycoplasma gallisepticum/genética , Mycoplasma gallisepticum/isolamento & purificação , Países Baixos/epidemiologia , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/prevenção & controle , Estudos Soroepidemiológicos
3.
Commun Earth Environ ; 1(1): 31, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33184615

RESUMO

Icebergs represent nearly half of the mass loss from the Greenland Ice Sheet and provide a distributed source of freshwater along fjords which can alter fjord circulation, nutrient levels, and ultimately the Meridional Overturning Circulation. Here we present analyses of high resolution optical satellite imagery using convolutional neural networks to accurately delineate iceberg edges in two East Greenland fjords. We find that a significant portion of icebergs in fjords are comprised of small icebergs that were not detected in previously-available coarser resolution satellite images. We show that the preponderance of small icebergs results in high freshwater delivery, as well as a short life span of icebergs in fjords. We conclude that an inability to identify small icebergs leads to inaccurate frequency-size distribution of icebergs in Greenland fjords, an underestimation of iceberg area (specifically for small icebergs), and an overestimation of iceberg life span.

4.
Avian Pathol ; 49(1): 56-61, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31509002

RESUMO

In this study, the relative contribution of vertical transmission, within-farm transmission and between-farm transmission of Mycoplasma synoviae in layer pullet flocks was quantified using logistic regression analysis. Data from 311 Dutch pullet flocks, of which 172 (55%) were positive for M. synoviae, were included in the study. Also the M. synoviae status of the parent stock of these flocks was included. The M. synoviae status was determined with the M. synoviae rapid plate agglutination test. Data analysis showed that vertical transmission was the most important transmission route for M. synoviae in layers as is demonstrated by an odds ratio of 5.8 (P = 0.000). A positive association with M. synoviae infections was found for layer pullet flocks on a multi-house farm where at least one other flock was M. synoviae-positive compared to single-house farms (odds ratio 3.1, P = 0.022), while a negative association was found when no other M. synoviae-positive flocks were present (odds ratio = 0.2, P = 0.003). No association was found between M. synoviae status of pullet flocks and poultry farm density. Odds ratios were 0.54 (P = 0.288) and 0.34 (P = 0.073), respectively, for medium and highest poultry farm density compared to lowest poultry farm density. This is the first time that the relative contribution of horizontal and vertical transmission of M. synoviae has been quantified. These results can be extrapolated to M. synoviae control in general, and emphasize the importance of M. synoviae control in parent stock and practical channelling.


Assuntos
Galinhas , Transmissão Vertical de Doenças Infecciosas/veterinária , Infecções por Mycoplasma/veterinária , Mycoplasma synoviae/isolamento & purificação , Doenças das Aves Domésticas/transmissão , Testes de Aglutinação/veterinária , Animais , Feminino , Abrigo para Animais , Modelos Logísticos , Infecções por Mycoplasma/epidemiologia , Infecções por Mycoplasma/transmissão , Países Baixos/epidemiologia , Razão de Chances , Densidade Demográfica , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/microbiologia , Prevalência , Fatores de Risco
5.
Science ; 361(6399): 273-277, 2018 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-29880724

RESUMO

The largest uncertainty in the ice sheet models used to predict future sea level rise originates from our limited understanding of processes at the ice/bed interface. Near glacier termini, where basal sliding controls ice flow, most predictive ice sheet models use a parameterization of sliding that has been theoretically derived for glacier flow over a hard bed. We find that this sliding relation does not apply to the 140 Greenland glaciers that we analyzed. There is no relationship between basal sliding and frictional stress at the glacier bed, contrary to theoretical predictions. There is a strong relationship between sliding speed and net pressure at the glacier bed. This latter finding is in agreement with earlier observations of mountain glaciers that have been largely overlooked by the glaciological community.

6.
Ned Tijdschr Geneeskd ; 161: D1971, 2017.
Artigo em Holandês | MEDLINE | ID: mdl-29125084

RESUMO

When talking about 'advance care planning' (ACP), people regularly state that they do not want to go to the hospital any more. There are several reasons why this wish may be unclear in acute situations: preferred treatment is not always available or discussed, there may be different reasons for the 'no more hospital' statement and the emergency department is often insufficiently prepared for carrying out limited evaluations or treatments. To provide appropriate care, we recommend to (a) discuss the limitations of ACP, (b) evaluate preferences in the current context, (c) improve communication between primary and secondary care and to consider alternative options, (d) regularly evaluate current policies and (e) invest in local initiatives to prevent admission or long-term admission or to enable people to stay home. Treatment preferences, supported by earlier ACP discussions, always develop through the relationship between physicians and patients in specific situations.


Assuntos
Planejamento Antecipado de Cuidados , Comunicação , Hospitalização , Hospitais , Humanos , Assistência Terminal
7.
Avian Pathol ; 46(6): 615-622, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28580863

RESUMO

A quantitative Polymerase Chain Reaction (qPCR) for the seven chicken Eimeria spp. was modified and validated for direct use on fresh droppings. The analytical specificity of the qPCR on droppings was 100%. Its analytical sensitivity (non-sporulated oocysts/g droppings) was 41 for E. acervulina, ≤2900 for E. brunetti, 710 for E. praecox, 1500 for E. necatrix, 190 for E. tenella, 640 for E. maxima, and 1100 for E. mitis. Field validation of the qPCR was done using droppings with non-sporulated oocysts from 19 broiler flocks. To reduce the number of qPCR tests five grams of each pooled sample (consisting of ten fresh droppings) per time point were blended into one mixed sample. Comparison of the oocysts per gram (OPG)-counting method with the qPCR using pooled samples (n = 1180) yielded a Pearson's correlation coefficient of 0.78 (95% CI: 0.76-0.80) and a Pearson's correlation coefficient of 0.76 (95% CI: 0.70-0.81) using mixed samples (n = 236). Comparison of the average of the OPG-counts of the five pooled samples with the mixed sample per time point (n = 236) showed a Pearson's correlation coefficient (R) of 0.94 (95% CI: 0.92-0.95) for the OPG-counting method and 0.87 (95% CI: 0.84-0.90) for the qPCR. This indicates that mixed samples are practically equivalent to the mean of five pooled samples. The good correlation between the OPG-counting method and the qPCR was further confirmed by the visual agreement between the total oocyst/g shedding patterns measured with both techniques in the 19 broiler flocks using the mixed samples.


Assuntos
Galinhas/parasitologia , Coccidiose/veterinária , Eimeria/isolamento & purificação , Reação em Cadeia da Polimerase/veterinária , Doenças das Aves Domésticas/parasitologia , Animais , Coccidiose/diagnóstico , Coccidiose/parasitologia , Eimeria/genética , Fezes/parasitologia , Reação em Cadeia da Polimerase Multiplex/veterinária , Oocistos , Doenças das Aves Domésticas/diagnóstico , Sensibilidade e Especificidade , Organismos Livres de Patógenos Específicos
8.
Avian Pathol ; 46(1): 95-105, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27557362

RESUMO

Intestinal disease has a major impact on the broiler industry due to economic and welfare reasons. Intestinal disease might occur due to a large number of reasons varying from well-defined pathogens to non-specific enteritis and complex syndromes. However, knowledge about the nature of intestinal disease and presence of enteric viruses in the Dutch broiler industry is largely absent. Therefore, a large-scale field study, in which 98 broiler flocks from 86 farms were sampled weekly, was started to assess the prevalence of histopathological lesions in the jejunum, a number of enterotropic viruses by real-time quantitative reverse transcriptase PCR (RT-qPCR) and coccidia by lesion scoring. Histopathological lesions indicative of intestinal disease were found in all flocks examined. The pathogens investigated were chicken astrovirus (99% of flocks positive), avian nephritis virus 3 (100%), rotavirus A (95%), rotavirus D (52%), reovirus (100%), Eimeria acervulina (94%), E. maxima (49%) and E. tenella (40%). The enteric viruses were more prevalent in the first weeks of the growing period, while coccidiosis was more frequently found at 4 and 5 weeks of age. The abundant presence of the enteric viruses and enteric disorders stresses the need to elucidate the role of these viruses in intestinal disease. Furthermore, the high prevalence of coccidiosis despite the use of anticoccidials shows that the current coccidial management programmes might be insufficient in controlling this disease.


Assuntos
Galinhas , Coccidiose/veterinária , Gastroenteropatias/veterinária , Doenças das Aves Domésticas/epidemiologia , Infecções por Vírus de RNA/veterinária , Animais , Galinhas/parasitologia , Galinhas/virologia , Coccidiose/epidemiologia , Coccidiose/parasitologia , Coccidiose/patologia , Eimeria/isolamento & purificação , Gastroenteropatias/epidemiologia , Gastroenteropatias/parasitologia , Gastroenteropatias/virologia , Intestinos/parasitologia , Intestinos/patologia , Intestinos/virologia , Países Baixos/epidemiologia , Doenças das Aves Domésticas/parasitologia , Doenças das Aves Domésticas/patologia , Doenças das Aves Domésticas/virologia , Prevalência , Infecções por Vírus de RNA/epidemiologia , Infecções por Vírus de RNA/patologia , Infecções por Vírus de RNA/virologia , Vírus de RNA/isolamento & purificação
9.
Avian Pathol ; 44(5): 358-65, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26040652

RESUMO

To gain more insight into the within flock transmission of Histomonas meleagridis, the shedding of parasites was quantified by a newly developed real-time quantitative (q)PCR and the basic reproduction number (R0) and the mean number of secondary infections per infectious bird per day in a susceptible population (ß) of H. meleagridis in the absence of heterakis were assessed. Forty turkeys were divided into two groups of 10 and 30 birds at 14 days of age. Birds of the first group were inoculated with 200,000 histomonads each, the second group served as a susceptible contact group. Cloacal swabs were taken at -1, 1, 4, 7, 9, 11, 14, 18 and 21 days post inoculation (p.i.) to assess the shedding of the parasite by the qPCR (detection limit 330 histomonads/ml droppings). The experiment ended at 28 days p.i. Mortality was 100% in the inoculated birds and started at day 12 p.i., while in the contacts, it was 83% and started at 16 days p.i. Shedding started 1 day after the inoculation in both groups. The mean shedding levels (and 95% CI) expressed as parasite equivalents per gram cloacal content on a log10 scale in the inoculated, contact birds that died and contact birds alive were 2.0 (1.6-2.4), 1.6 (1.4-1.9) and 1.2 (0.5-2.0), respectively. Birds that died shed histomonas more often and were infectious for 13.4 days; in contrast, those that recovered were infectious for 5.7 days. R0 was estimated to be 8.4 and ß 0.70. Simulations made with the parameters obtained were in agreement with the experimental results, confirming their validity.


Assuntos
Doenças das Aves Domésticas/parasitologia , Infecções Protozoárias em Animais/parasitologia , Reação em Cadeia da Polimerase em Tempo Real/métodos , Trichomonadida/isolamento & purificação , Animais , Transmissão de Doença Infecciosa , Feminino , Estimativa de Kaplan-Meier , Masculino , Modelos Animais , Doenças das Aves Domésticas/transmissão , Infecções Protozoárias em Animais/transmissão , Sensibilidade e Especificidade , Trichomonadida/genética , Perus
10.
Nature ; 490(7418): 85-8, 2012 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-23038470

RESUMO

Methane is an important greenhouse gas that is emitted from multiple natural and anthropogenic sources. Atmospheric methane concentrations have varied on a number of timescales in the past, but what has caused these variations is not always well understood. The different sources and sinks of methane have specific isotopic signatures, and the isotopic composition of methane can therefore help to identify the environmental drivers of variations in atmospheric methane concentrations. Here we present high-resolution carbon isotope data (δ(13)C content) for methane from two ice cores from Greenland for the past two millennia. We find that the δ(13)C content underwent pronounced centennial-scale variations between 100 BC and AD 1600. With the help of two-box model calculations, we show that the centennial-scale variations in isotope ratios can be attributed to changes in pyrogenic and biogenic sources. We find correlations between these source changes and both natural climate variability--such as the Medieval Climate Anomaly and the Little Ice Age--and changes in human population and land use, such as the decline of the Roman empire and the Han dynasty, and the population expansion during the medieval period.


Assuntos
Incêndios/história , Atividades Humanas/história , Metano/história , Metano/metabolismo , Atmosfera/química , Biomassa , Isótopos de Carbono , Mudança Climática/história , Groenlândia , História do Século XV , História do Século XVI , História do Século XVII , História do Século XVIII , História do Século XIX , História do Século XX , História Antiga , História Medieval , Sacro Império Romano , Gelo/análise , Metano/análise , Dinâmica Populacional , Mundo Romano/história
11.
Science ; 327(5965): 522, 2010 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-20110484
12.
J Invest Dermatol ; 117(1): 3-15, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11442744

RESUMO

Numerous strains of mice with defined mutations display pronounced abnormalities of hair follicle cycling, even in the absence of overt alterations of the skin and hair phenotype; however, in order to recognize even subtle, hair cycle-related abnormalities, it is critically important to be able to determine accurately and classify the major stages of the normal murine hair cycle. In this comprehensive guide, we present pragmatic basic and auxiliary criteria for recognizing key stages of hair follicle growth (anagen), regression (catagen) and quiescence (telogen) in C57BL/6NCrlBR mice, which are largely based on previous work from other authors. For each stage, a schematic drawing and representative micrographs are provided in order to illustrate these criteria. The basic criteria can be employed for all mouse strains and require only routine histochemical techniques. The auxiliary criteria depend on the immunohistochemical analysis of three markers (interleukin-1 receptor type I, transforming growth factor-beta receptor type II, and neural cell-adhesion molecule), which allow a refined analysis of anatomical hair follicle compartments during all hair cycle stages. In contrast to prior staging systems, we suggest dividing anagen III into three distinct substages, based on morphologic differences, onset and progression of melanogenesis, and the position of the dermal papilla in the subcutis. The computer-generated schematic representations of each stage are presented with the aim of standardizing reports on follicular gene and protein expression patterns. This guide should become a useful tool when screening new mouse mutants or mice treated with pharmaceuticals for discrete morphologic abnormalities of hair follicle cycling in a highly reproducible, easily applicable, and quantifiable manner.


Assuntos
Dermatologia/normas , Folículo Piloso/anatomia & histologia , Folículo Piloso/crescimento & desenvolvimento , Animais , Guias como Assunto , Camundongos
13.
J Invest Dermatol ; 113(4): 523-32, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10504436

RESUMO

Numerous spontaneous and experimentally induced mouse mutations develop a hair phenotype, which is often associated with more or less discrete abnormalities in hair follicle development. In order to recognize these, it is critically important to be able to determine and to classify accurately the major stages of normal murine hair follicle morphogenesis. As an aid, we propose a pragmatic and comprehensive guide, modified after previous suggestions by Hardy, and provide a list of easily recognizable classification criteria, illustrated by representative micrographs. Basic and more advanced criteria are distinguished, the former being applicable to all mouse strains and requiring only simple histologic stains (hematoxylin and eosin, Giemsa, periodic acid Schiff, alkaline phosphatase activity), the latter serving as auxiliary criteria, which require a pigmented mouse strain (like C57BL/6J) or immunohistochemistry (interleukin-1 receptor type I, transforming growth factor-beta receptor type II). In addition, we present simplified, computer-generated schematic drawings for the standardized recording and reporting of gene and antigen expression patterns during hair follicle development. This classification aid serves as a basic introduction into the field of hair follicle morphogenesis, aims at standardizing the presentation of related hair research data, and should become a useful tool when screening new mouse mutants for discrete abnormalities of hair follicle morphogenesis (compared with the respective wild type) in a highly reproducible, easily applicable, and quantifiable manner.


Assuntos
Folículo Piloso/embriologia , Animais , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Morfogênese , Fenótipo , Proteínas Serina-Treonina Quinases , Receptor do Fator de Crescimento Transformador beta Tipo II , Receptores de Interleucina-1/análise , Receptores de Fatores de Crescimento Transformadores beta/análise
14.
Tijdschr Gerontol Geriatr ; 30(4): 153-7, 1999 Aug.
Artigo em Holandês | MEDLINE | ID: mdl-10486619

RESUMO

The case histories of five patients with cognitive disorders are presented and the policy in the assessment of driving performance is discussed. In accordance to recent consensus guidelines of an international working group on dementia and driving we recommend cessation of driving in case of dementia grade two or three on the Clinical Dementia Rating Scale. We deviate from these guidelines in case of dementia grade one. We propose to advise a road test.


Assuntos
Condução de Veículo/psicologia , Transtornos Cognitivos/classificação , Demência/diagnóstico , Demência/psicologia , Avaliação Geriátrica , Idoso , Idoso de 80 Anos ou mais , Condução de Veículo/legislação & jurisprudência , Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/psicologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Países Baixos , Encaminhamento e Consulta
15.
Tijdschr Gerontol Geriatr ; 30(4): 164-7, 1999 Aug.
Artigo em Holandês | MEDLINE | ID: mdl-10486621

RESUMO

Ten patients with the Alzheimer's disease and a mild hearing loss were tested with an audiotape with speech discrimination tests. The low frequency sounds on this audiotape had a delay of respectively 1, 2, 3 and 4 milliseconds with regard to the high frequency sounds. With a delay of 3 milliseconds the patients had a significant improvement in their speech understanding compared to the normal speech discrimination test. Patients with the Alzheimer's disease have a significant loss of haircells in the basal turn of the cochlea. This loss disturbs the function of the traveling wave of sound vibration in the basilar membrane of the cochlea. The traveling wave has no inhibition on its way through this disturbed basilar membrane. When the effect of the too fast running traveling wave was compensated by presenting the above-mentioned tape, the improvement of the speech intelligibility was significant.


Assuntos
Doença de Alzheimer/complicações , Doença de Alzheimer/psicologia , Cóclea/patologia , Acústica da Fala , Percepção da Fala , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/patologia , Correção de Deficiência Auditiva , Células Ciliadas Auditivas , Perda Auditiva/complicações , Humanos , Masculino , Testes de Discriminação da Fala
16.
J Invest Dermatol ; 111(2): 279-85, 1998 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9699730

RESUMO

Hair follicle epithelium and nervous system share a common ectodermal origin, and some neurotrophins can modulate keratinocyte proliferation and apoptosis. It is therefore reasonable to ask whether growth factors that control neural development are also involved in the regulation of hair follicle morphogenesis. Focusing on neurotrophin-3 (NT-3) and its high-affinity-receptor [tyrosine kinase C (TrkC)], we show that hair placode keratinocytes express TrkC mRNA and immunoreactivity early during murine hair follicle morphogenesis. In later stages of hair follicle development, TrkC mRNA, TrkC-, and NT-3-immunoreactivity are seen in keratinocytes of the proximal hair bulb as well as in dermal papilla fibroblasts. Compared with the corresponding wild-type animals, early stages of hair follicle morphogenesis are significantly accelerated in newborn NT-3 overexpressing mice, whereas these are retarded in newborn heterozygous NT-3 knockout (+/-) mice. These observations suggest that NT-3 is an important growth modulator during morphogenesis and remodeling of neuroectodermal-mesenchymal interaction systems like the hair follicle.


Assuntos
Folículo Piloso/embriologia , Fatores de Crescimento Neural/fisiologia , Animais , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Morfogênese , Fatores de Crescimento Neural/genética , Neurotrofina 3 , Receptores Proteína Tirosina Quinases/fisiologia , Receptor trkC , Receptores de Fator de Crescimento Neural/fisiologia
17.
J Invest Dermatol ; 111(1): 7-18, 1998 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9665380

RESUMO

In this immunohistomorphometric study, we have defined basic characteristics of the hair follicle (HF) immune system during follicle morphogenesis and cycling in C57BL/6 mice, in relation to the skin immune system. Langerhans cells and gammadelta T cell receptor immunoreactive lymphocytes were the predominant intraepithelial hematopoietic cells in neonatal mouse skin. After their numeric increase in the epidermis, these cells migrated into the HF, although only when follicle morphogenesis was almost completed. In contrast to Langerhans cells, gammadelta T cell receptor immunoreactive lymphocytes entered the HF only via the epidermis. Throughout HF morphogenesis and cycling, both cell types remained strikingly restricted to the distal outer root sheath. On extremely rare occasions, CD4+ or CD8+ alphabetaTC were detected within the HF epithelium or the sebaceous gland. Major histocompatibility complex class II+, MAC-1+ cells of macrophage phenotype and numerous mast cells appeared very early on during HF development in the perifollicular dermis, and the percentage of degranulated mast cells significantly increased during the initiation of synchronized HF cycling (first catagen). During both depilation- and cyclosporine A-induced HF cycling, the numbers of intrafollicular Langerhans cells, gammadelta T cell receptor immunoreactive lymphocytes, and perifollicular dermal macrophages fluctuated significantly. Yet, no numeric increase of perifollicular macrophages was detectable during HF regression, questioning their proposed role in catagen induction. In summary, the HF immune system is generated fairly late during follicle development, shows striking differences to the extrafollicular skin immune system, and undergoes substantial hair cycle-associated remodeling. In addition, synchronized HF cycling is accompanied by profound alterations of the skin immune system.


Assuntos
Folículo Piloso/imunologia , Sistema Imunitário/fisiologia , Cadeias alfa de Integrinas , Animais , Animais Recém-Nascidos/imunologia , Antígenos CD/análise , Caderinas/análise , Células Dendríticas/fisiologia , Antígenos de Histocompatibilidade Classe II/análise , Células de Langerhans/fisiologia , Contagem de Linfócitos , Macrófagos/fisiologia , Mastócitos/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Receptores de Antígenos de Linfócitos T gama-delta/análise
18.
J Invest Dermatol ; 111(1): 25-30, 1998 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9665382

RESUMO

Hair bulb keratinocytes generate one of the few "immune privileged" tissue compartments of the mammalian organism by suppressing classical MHC class I (MHC Ia) antigens. Expression of non-classical MHC class I (MHC Ib) antigens in the follicle has been found, but only in its distal epithelium. Here, we have defined when during murine hair follicle morphogenesis these peculiar MHC Ia and Ib expression patterns are established, how they change during the murine hair cycle, and how different MHC I modulatory agents alter follicular MHC Ia and Ib expression in vivo. During neonatal hair follicle morphogenesis in C57BL/6 mice, distal follicle keratinocytes began to express MHC Ia (H2b) only late in development. The MHC Ib antigens, Qa-1 and Qa-2, did not become visible until the initiation of follicle cycling, with Qa-1 expression being more widespread than that of Qa-2. H2b, Qa-1, and TAP-1 immunoreactivity on previously negative keratinocytes of the proximal anagen hair bulb was upregulated by intradermal injection of the proinflammatory cytokine interferon-gamma, but not by tumor necrosis factor-alpha or interleukin-1beta. Injection of the reportedly MHC class I downregulating agents interleukin-10, insulin-like growth factor-1, transforming growth factor-beta, alpha-melanocyte stimulating hormone, or dexamethasone, however, all failed to downregulate constitutive or interferon-gamma-induced follicular MHC Ia expression. This shows that the hair follicle is a previously unrecognized site of Qa-1 expression and that interferon-gamma is a key regulator of follicular MHC I expression in vivo. It also suggests that the developmental and immunologic controls of MHC I expression by follicle keratinocytes differ from those of other epithelial cells.


Assuntos
Folículo Piloso/imunologia , Antígenos de Histocompatibilidade Classe I/análise , Interferon gama/farmacologia , Animais , Anti-Inflamatórios/farmacologia , Antígenos H-2/análise , Folículo Piloso/efeitos dos fármacos , Folículo Piloso/fisiologia , Antígenos de Histocompatibilidade Classe II/análise , Camundongos , Camundongos Endogâmicos C57BL , Morfogênese
19.
J Invest Dermatol ; 110(6): 902-7, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9620297

RESUMO

Mutation of the hairless (hr) gene in mice causes severe abnormalities during the first hair follicle regression (catagen), resulting in complete baldness. Here, we further characterize how hairlessness develops in HRS/J hairless mouse skin (hr) by histology, histochemistry, immunohistology, and in situ hybridization. We show that, in hr skin, only two defined epithelial cell populations in the distal outer root sheath (ORS) retain their integrity, whereas the rest of the ORS disintegrates. The surviving distal ORS forms the characteristic utriculi, whereas the remnants of the bulge get isolated from other epithelial compartments, but retain the capacity to proliferate and to produce either columnar epithelial outgrowths or selected dermal cysts. Normal dermal papilla structures get lost during the development of hairlessness. Based on the patterns of keratin 17 mRNA and neural cell adhesion molecule antigen expression, and on the distribution of alkaline phosphatase activity, we propose that dermal cysts in hr skin arise from (i) the central ORS, (ii) bulge-derived cells, or (iii) the disintegrating proximal ORS under the influence of dermal papilla remnants. The hr mutation seems to disrupt the integrity of key functional tissue units in the hair follicle, possibly due to a dysregulation of normal, catagen-associated apoptosis and/or an impairment of cell adhesion, whereas the distal follicle epithelium (including its stem cell region) seems to be largely protected from this. Thus, hairless mice offer a unique model for dissecting the as yet obscure functional properties of the hr gene product in maintaining follicle integrity during normal catagen.


Assuntos
Cabelo/patologia , Camundongos Pelados/genética , Dermatopatias/etiologia , Fosfatase Alcalina/metabolismo , Animais , Feminino , Expressão Gênica/genética , Imuno-Histoquímica , Hibridização In Situ , Queratinas/genética , Antígeno Ki-67/genética , Camundongos , Camundongos Endogâmicos C57BL , Moléculas de Adesão de Célula Nervosa/genética , Fenótipo , RNA Mensageiro/análise , RNA Mensageiro/genética , Pele/química , Pele/enzimologia , Pele/patologia , Dermatopatias/genética , Dermatopatias/patologia
20.
J Histochem Cytochem ; 46(3): 361-70, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9487118

RESUMO

In back skin sections from adolescent C57BL/6 mice, regularly distributed, perifollicular inflammatory cell clusters (PICC) were found located around the distal noncycling portion of about 2% of all hair follicles examined. The PICC and the affected hair follicles were characterized during spontaneously developed or induced hair cycle stages, using antibodies against MHC Class II, F4/80, ER-MP23, NLDC 145, CD4, CD8, gammadeltaTCR, IL-1 receptor, and ICAM-1. PICC consisted predominantly of macrophages (MAC), accompanied by a few CD4+ cells, whereas gammadeltaTCR+ and CD8+ cells were absent. During anagen and catagen, some of the PICC+ hair follicles showed variable degenerative phenomena reminiscent of scarring alopecia: thickened basement membrane, ectopic MHC II expression, MAC infiltration into the follicle epithelium, and signs of keratinocyte apoptosis. Loss of distal outer root sheath keratinocytes was detected in 10% of PICC+ hair follicles (0.2% of all hair follicles). Because PICC were located in the vicinity of the bulge region, MAC-dependent damage to follicle stem cells might eventually lead to follicle degeneration. These perifollicular MAC clusters around selected hair follicles may indicate the existence of a physiological program of MAC-dependent controlled follicle degeneration by which damaged or malfunctioning follicles are removed by programmed organ deletion (POD).


Assuntos
Folículo Piloso/crescimento & desenvolvimento , Folículo Piloso/imunologia , Macrófagos/citologia , Animais , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD8-Positivos/citologia , Feminino , Genes MHC da Classe II , Histocitoquímica , Imuno-Histoquímica , Molécula 1 de Adesão Intercelular/análise , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Receptores de Interleucina-1/análise , Receptores Tipo I de Interleucina-1
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