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141.
Mammary development in the embryo and adult: a journey of morphogenesis and commitment 总被引:3,自引:0,他引:3
Mammary gland development occurs through distinctive stages throughout embryonic and pubertal development and reproductive life. At each stage, different signals are required to induce changes in both the epithelium and the surrounding mesenchyme/stroma. Recent studies have provided new insights into the origin, specification and fate of mammary stem and progenitor cells and into how the differentiated lineages that comprise the functional mammary gland are determined. The development of new tools and culture techniques has also enabled the factors that influence branching morphogenesis in the embryonic and pubertal gland to be identified. A surprising recent discovery has been that mammary epithelial cells commit to differentiated lineages using the same signalling pathways that regulate lineage determination in T helper cells. 相似文献
142.
García-Lerma JG Otten RA Qari SH Jackson E Cong ME Masciotra S Luo W Kim C Adams DR Monsour M Lipscomb J Johnson JA Delinsky D Schinazi RF Janssen R Folks TM Heneine W 《PLoS medicine》2008,5(2):e28
Background
In the absence of an effective vaccine, HIV continues to spread globally, emphasizing the need for novel strategies to limit its transmission. Pre-exposure prophylaxis (PrEP) with antiretroviral drugs could prove to be an effective intervention strategy if highly efficacious and cost-effective PrEP modalities are identified. We evaluated daily and intermittent PrEP regimens of increasing antiviral activity in a macaque model that closely resembles human transmission.Methods and Findings
We used a repeat-exposure macaque model with 14 weekly rectal virus challenges. Three drug treatments were given once daily, each to a different group of six rhesus macaques. Group 1 was treated subcutaneously with a human-equivalent dose of emtricitabine (FTC), group 2 received orally the human-equivalent dosing of both FTC and tenofovir-disoproxil fumarate (TDF), and group 3 received subcutaneously a similar dosing of FTC and a higher dose of tenofovir. A fourth group of six rhesus macaques (group 4) received intermittently a PrEP regimen similar to group 3 only 2 h before and 24 h after each weekly virus challenge. Results were compared to 18 control macaques that did not receive any drug treatment. The risk of infection in macaques treated in groups 1 and 2 was 3.8- and 7.8-fold lower than in untreated macaques (p = 0.02 and p = 0.008, respectively). All six macaques in group 3 were protected. Breakthrough infections had blunted acute viremias; drug resistance was seen in two of six animals. All six animals in group 4 that received intermittent PrEP were protected.Conclusions
This model suggests that single drugs for daily PrEP can be protective but a combination of antiretroviral drugs may be required to increase the level of protection. Short but potent intermittent PrEP can provide protection comparable to that of daily PrEP in this SHIV/macaque model. These findings support PrEP trials for HIV prevention in humans and identify promising PrEP modalities. 相似文献143.
The AAA+ superfamily is a large and functionally diverse superfamily of NTPases that are characterized by a conserved nucleotide-binding and catalytic module, the AAA+ module. Members are involved in an astonishing range of different cellular processes, attaining this functional diversity through additions of structural motifs and modifications to the core AAA+ module. 相似文献
144.
Sami Ahmed Al-Haidari Mohammed A. K. Mahdy Abdulsalam M. Al-Mekhlafi Walid M. S. Al Murisi Ahmed Ali Qaid Thabit Mohammed Abdullah Al-Amad Hassan Al-Shamahi Othman Saeed Bahashwan Abdulwahed Al Serouri 《PLoS neglected tropical diseases》2021,15(9)
Intestinal schistosomiasis is a neglected tropical disease, causing morbidity and mortality in tropical and subtropical countries. Despite the frequent implementation of mass drug administration with praziquantel, the reinfection with Schistosoma mansoni is still common in Yemen. In addition, there is a scarcity of information on the impact of S. mansoni on nutritional status and anemia among schoolchildren. The present study aimed to determine prevalence and risk factors of intestinal schistosomiasis and investigate its impact on nutritional status and anemia among schoolchildren in Sana’a Governorate, Yemen. It was conducted in 2018 on 445 schoolchildren aged 5–15 years. Biodata, socio-economic, demographic, behavioral and environmental data were collected using a standard questionnaire. S. mansoni was identified and quantified by microscopic examination of Kato-Katz fecal smear. Hemoglobin concentration and anthropometric measurements were estimated using standard methods. The prevalence of S. mansoni was higher in Al-Haimah Al-Dakheliah (33.9%) than Bani Mater (1.4%). Household without tap water (Adjusted Odds Ratio (AOR) = 2.9, 95% Confidence interval (CI): 1.12, 7.55, P = 0.028) was the independent risk factor of the infection. The prevalence of wasting and stunting was 25.0% (95%CI: 21.2%, 29.2%) and 45.8% (95%CI: 41.2%, 50.5%), respectively. The prevalence of underweight among schoolchildren aged 5–10 years was 27.3% (95%CI: 21.9%, 33.4%). The prevalence of anemia was 31.7% (95%CI: 27.5%, 36.2%) with 0.5%, 21.1% and 10.1% being severe, moderate and mild anemia, respectively. S. mansoni (AOR = 4.1, 95%CI: 2.16, 7.84, P < 0.001) and early adolescence (AOR = 6.8, 95%CI: 4.26, 10.82, P < 0.001) were independent predictors of stunting among schoolchildren. The early adolescent schoolchildren (AOR = 3.1, 95%CI: 1.86, 4.97, P < 0.001) and children from families with low (AOR = 2.1, 95%CI: 1.01, 4.15, P = 0.046) or moderate wealth (AOR = 2.3, 95%CI: 1.11, 4.77, P = 0.026) were significantly more wasted.Early adolescence (AOR = 1.8, 95%CI:1.14, 2.78, P = 0.011), female (AOR = 1.6, 95%CI: 1.03, 2.43, P = 0.038) and Al-Haimah Al-Dakheliah District (AOR = 3.4, 95%CI: 1.20, 9.55, P = 0.021) were independent risk factors for anemia. The study findings indicate highly focal prevalence of schistosomiasis in Sana’a Governorate with a public health significance that varies from low to high risk. Approximately half of schoolchildren were stunted, which was associated with S. mansoni infection and early adolescence. One quarter of schoolchildren were wasted with early adolescent schoolchildren and children from poor families being at high risk of wasting. Anemia was a moderate public health threat affecting the female and the early adolescent schoolchildren. The study suggests the implementation of control measures to combat schistosomiasis and integrated diseases control programmes to improve the health status of schoolchildren in Sana’a Governorate. 相似文献
145.
Growth factors and extracellular matrix proteins during wound healing promoted with frozen cultured sheets of human epidermal keratinocytes 总被引:2,自引:0,他引:2
Elisa Tamariz-Domínguez Federico Castro-Muñozledo Walid Kuri-Harcuch 《Cell and tissue research》2002,307(1):79-89
In a murine model of full-thickness wounds, healing is stimulated by the application of human frozen cultured epidermal sheets. With immunofluorescence techniques, we studied, during this process, the spatial and temporal pattern of expression of: transforming growth factor-alpha (TGF-alpha); transforming growth factor-beta (TGF-beta) isoforms 1, 2, and 3; platelet-derived growth factor (PDGF); and the extracellular matrix proteins fibronectin, collagen IV, and tenascin. The growth factors, with the exception of PDGF, were found to be located in the frozen cultured sheet of keratinocytes before and after its application to the wound, whereas collagen IV and tenascin were deposited in the connective tissue under the frozen cultures. None of these factors were detected in control wound beds. Monoclonal antibodies against collagen IV and tenascin showed that both were of murine origin. We propose that the frozen cultures of human keratinocytes promote faster reepithelialization through the release of growth factors such as TGF-alpha which directly enhance migration and proliferation of murine keratinocytes, and through the stimulation of murine subepithelial cells, by TGF-beta, to secrete basement membrane proteins such as collagen IV, laminin, and tenascin, which provide a provisional substrate that improves migration of the murine epidermal cells. 相似文献
146.
We studied the commitment of 3T3-F442A cells during stimulation with adipogenic serum or growth hormone. Confluent 3T3-F442A preadipocytes were incubated with adipogenic medium for increasing times; the number of adipose clusters, GPDH activity, and lipid accumulation were evaluated. Results show that cell commitment took place during the first 24-36 h after stimulation under adipogenic conditions. Then, cultures underwent a 2-fold increase in total cell number through selective multiplication of committed cells, followed by a dramatic decrease in colony-forming ability and 300- to 1000-fold raise in GPDH activity. Cell commitment was not modulated by insulin, but this hormone stimulated clonal expansion of committed cells and lipogenesis. Commitment was inhibited by TNF-α at concentrations as low as 5 ng/ml, and by retinoic acid. The results show that TNF-α inhibits adipose conversion at two different levels: at concentrations as low as 5 ng/ml, it blocks commitment, and at concentrations of 100 ng/ml or higher the cytokine seems to block mitotic expansion and other steps of differentiation after cell commitment. The identification of a specific time for cell commitment would allow the study of the early genes that might regulate cell reprogramming into adipocytes. 相似文献
147.
148.
Frequent simian foamy virus infection in persons occupationally exposed to nonhuman primates 总被引:4,自引:0,他引:4
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Switzer WM Bhullar V Shanmugam V Cong ME Parekh B Lerche NW Yee JL Ely JJ Boneva R Chapman LE Folks TM Heneine W 《Journal of virology》2004,78(6):2780-2789
The recognition that AIDS originated as a zoonosis heightens public health concerns associated with human infection by simian retroviruses endemic in nonhuman primates (NHPs). These retroviruses include simian immunodeficiency virus (SIV), simian T-cell lymphotropic virus (STLV), simian type D retrovirus (SRV), and simian foamy virus (SFV). Although occasional infection with SIV, SRV, or SFV in persons occupationally exposed to NHPs has been reported, the characteristics and significance of these zoonotic infections are not fully defined. Surveillance for simian retroviruses at three research centers and two zoos identified no SIV, SRV, or STLV infection in 187 participants. However, 10 of 187 persons (5.3%) tested positive for SFV antibodies by Western blot (WB) analysis. Eight of the 10 were males, and 3 of the 10 worked at zoos. SFV integrase gene (int) and gag sequences were PCR amplified from the peripheral blood lymphocytes available from 9 of the 10 persons. Phylogenetic analysis showed SFV infection originating from chimpanzees (n = 8) and baboons (n = 1). SFV seropositivity for periods of 8 to 26 years (median, 22 years) was documented for six workers for whom archived serum samples were available, demonstrating long-standing SFV infection. All 10 persons reported general good health, and secondary transmission of SFV was not observed in three wives available for WB and PCR testing. Additional phylogenetic analysis of int and gag sequences provided the first direct evidence identifying the source chimpanzees of the SFV infection in two workers. This study documents more frequent infection with SFV than with other simian retroviruses in persons working with NHPs and provides important information on the natural history and species origin of these infections. Our data highlight the importance of studies to better define the public health implications of zoonotic SFV infections. 相似文献
149.
Friel Bouzid Imen Gtif Suad Alfadhli Salma Charfeddine Walid Ghorbel Rania Abdelhdi Riadh Benmarzoug Leila Abid Nouha Bouayed Abdelmoula Ins Elloumi Saber Masmoudi Ahmed Rebai Najla Kharrat 《Bioscience reports》2022,42(7)
The coronary artery disease (CAD) is a chronic inflammatory disease involving genetic as well as environmental factors. Recent evidence suggests that the oral microbiome has a significant role in triggering atherosclerosis. The present study assessed the oral microbiome composition variation between coronary patients and healthy subjects in order to identify a potential pathogenic signature associated with CAD. We performed metagenomic profiling of salivary microbiomes by 16S ribosomal RNA (rRNA) next-generation sequencing. Oral microbiota profiling was performed for 30 individuals including 20 patients with CAD and ten healthy individuals without carotid plaques or previous stroke or myocardial infarction.We found that oral microbial communities in patients and healthy controls are represented by similar global core oral microbiome. The predominant taxa belonged to Firmicutes (genus Streptococcus, Veillonella, Granulicatella, Selenomonas), Proteobacteria (genus Neisseria, Haemophilus), Actinobacteria (genus Rothia), Bacteroidetes (genus Prevotella, Porphyromonas), and Fusobacteria (genus Fusobacterium, Leptotrichia). More than 60% relative abundance of each sample for both CAD patients and controls is represented by three major genera including Streptococcus (24.97 and 26.33%), Veillonella (21.43 and 19.91%), and Neisseria (14.23 and 15.33%).Using penalized regression analysis, the bacterial genus Eikenella was involved as the major discriminant genus for both status and Syntax score of CAD. We also reported a significant negative correlation between Syntax score and Eikenella abundance in coronary patients’ group (Spearman rho = −0.68, P=0.00094).In conclusion, the abundance of Eikenella in oral coronary patient samples compared with controls could be a prominent pathological indicator for the development of CAD. 相似文献
150.
Desert hedgehog is a mammal-specific gene expressed during testicular and ovarian development in a marsupial 总被引:1,自引:0,他引:1
William A O’Hara Walid J Azar Richard R Behringer Marilyn B Renfree Andrew J Pask 《BMC developmental biology》2011,11(1):1-12