Spermatozoa reach the fallopian tube during ovulation by traveling through the female reproductive tract mucus. This non‐Newtonian viscoelastic medium facilitates spermatozoon movement to accomplish fertilization or, in some cases, blocks spermatozoon movement, leading to infertility. While rheological properties are known to affect spermatozoon motility with in vitro models using synthetic polymers, their precise effects in vivo are understudied. This paper reviews the rheological measurements of reproductive tract mucus during ovulation in humans and model animals, focusing on viscosity and (...) its potential effect on spermatozoa. Mucus viscosity in the female reproductive tract's different compartments is poorly understood. While information on this subject is incomplete, most mammals appear to have a viscosity decrease along their female reproductive tracts. Based on this sparse information, we hypothesize that viscosity changes in female reproductive tracts may guide spermatozoa to eggs, a novel concept that could improve our understanding of reproductive biology. (shrink)

It may be unethical to deny children with cystic fibrosis access to ethically approved clinical trials from which they might benefitDespite advances in nutritional management, aggressive antibiotic usage, and physiotherapy, cystic fibrosis remains a life limiting illness with high morbidity that imposes considerable burdens on children and families.1 Although survival to 40 years is predicted for children born in 1990s, the median age of death in 2003 was 24.2 years .The pathophysiological features of CF are produced by a defective gene (...) on chromosome 7, resulting in the defective production of a protein that regulates cellular ion transport. Defective ion transport is thought to lead to increased mucus viscosity , with poor airway clearance, recurrent bacterial infection, lung damage, and death.Gene therapy , the insertion of a normally functioning gene into deficient host cells using a suitable vector, is a potential treatment or cure for diseases produced by single gene defects—for example, CF. Gene therapy does, however, have potential or actual risks, leading many to suggest that evidence of efficacy in adults should be demonstrated before trials are conducted in children. Many serious diseases in adults such as CF have their onset in childhood. If early treatment provides greater hopes of benefit, children may be more appropriate targets for GT in CF than adults. It may be unethical to deny them access to properly constructed, ethically approved clinical trials from which they might benefit.Since research in children should be scientifically valid, in the child’s best interests, and the subject of valid consent, this article will consider these parameters in relation to trials of GT in children with CF. Because of the importance of consumer participation in the design of research we present the results of a questionnaire about GT trials delivered …. (shrink)

The issue of humoral temperament (mizāj) is mainly a subject of the field of medicine, but it has also been a subject of psychology, philosophy and moral philosophy during time. As the issue is ontologically related to the human nature, it has been dealt from many different perspectives. Within these disciplines, it has been expanded and developed during the historical process. It holds a wide range of literature as it is a rooted and ancient subject analysed within different disciplines. Stretching (...) out to the time of ancient Egypt, this theory was developed in the field of medicine by Hippocrates and by Galen in biology and it was a subject of some of the works of many Muslim scholars, first and foremost Jāḥiẓ, The issue of mizāj, first of all was explained by the theory of four composition (blood, mucus, yellow bile and black bile) Whether the amount of these liquids change within the body has always been an issue of debate according to the conditions of time and the place. Jāḥiẓ, impressed by the views of Galen, has no distinct piece of work on the issue of mizāj. However, he had put forward his views on the changes of the mizāj in some of his works but as he had unarranged writing style, he did not deal with these issues systematically. In this article, we have aimed at systematizing his views, determined in some of his own works and the studies on them, in two stages. What we mean by the change in mizāj is the point of disappearing of the ill temper and bringing good nature instead. Jāḥiẓ, considers the person as the subject of the effort to change the mizāj and evaluates this in two stages. For him, first of all, the person sinks herself into a mental effort. In this process, the person passes through the processes of remembrance, undertaking a task and suggestion. On this point, for abandoning the evilness and adopting the goodness in character, he underlines the importance of reason. Then, are these processes to change the mizāj for Jāḥiẓ are enough? Jāḥiẓ, invites the person to a second effort, accepting the person could feel hardship on the process, based on the analyses of observation and experiment. For this reason, getting a support from outside is proper for him. According to Jāḥiẓ, religion, education, being within the society and political authority are the factors affecting the change in the mizāj. Jāḥiẓ, brings forward views in an approach of taking away almost a general taboo within the society like “once a something always a something”. In an understandable and open wording, he conveys us the stance that the mizāj can change and its applicable within the daily life. In this study, the views of Jāḥiẓ, on the mizāj was evaluated in two stages, the temperament of the person was evaluated on the ground of the change of morality and was considered according to the contributions to the field of Kalam. (shrink)

M. xanthus has a complex multicellular lifestyle including swarming, predation and development. These behaviors depend on the ability of the cells to achieve directed motility across solid surfaces. M. xanthus cells have evolved two motility systems including Type‐IV pili that act as grappling hooks and a controversial engine involving mucus secretion and fixed focal adhesion sites. The necessity for cells to coordinate the motility systems and to respond rapidly to environmental cues is reflected by a complex genetic network involving (...) at least three complete sets of chemosensory systems and eukaryotic‐like signaling proteins. In this review, we discuss recent advances suggesting that motor synchronization results from spatial oscillations of motility proteins. We further propose that these dynamics are modulated by the action of multiple upstream complementary signaling systems. M. xanthus is thus an exciting emerging model system to study the intricate processes of directed cell migration. BioEssays 30:733–743, 2008. © 2008 Wiley Periodicals, Inc. (shrink)

Levonorgestrel is widely used as emergency contraception, yet much confusion surrounds its use. Consensus statements and reviews typically attribute its efficacy to prefertilization mechanisms of action, such as suppression of ovulation and interference with cervical mucus or sperm function, yet studies do not rule out a postovulatory MOA. To yield greater clarity, the authors review recent scientific studies examining the MOAs of LNG-EC. They conclude that LNG-EC exerts minimal effects on cervical mucus and sperm function and that suppression (...) of ovulation is not the dominant MOA accounting for the contraceptive efficacy of LNG-EC. Luteal deficiencies and endometrial changes reported in the literature strongly suggest a postovulatory MOA when LNG-EC is given during the critical preovulatory period. National Catholic Bioethics Quarterly 13.4 : 677–716. (shrink)

The correct positioning of organs during embryonic development requires multiple cues. The Xenopus cement gland is a mucus‐secreting epithelium that is a simple model for organogenesis, allowing detailed analysis of this complex process. The cement gland forms at a conserved anterior position, where embryonic ectoderm and endoderm touch. In all deuterostomes, this region will form the stomodeum (primitive mouth) and, in some aquatic larva, will also form a cement gland. In recent years, a model has been put forward suggesting (...) that an intermediate level of BMP signaling in the ectoderm leads to cement gland formation. We propose an alternative model whereby, during gastrulation, the cement gland (CG) is positioned by the overlap of three domains, corresponding to anterodorsal identity (AD), ventrolateral identity (VL), and ectodermal outer layer identity (EO), defining the equation (AD + VL + EO = CG). Anterodorsal identity requires a contribution by the transcription factor Otx2 while ventrolateral identity requires the BMP4 signaling pathway. These postional cues are integrated to activate cement gland differentiation. This integration appears to require intermediate steps, including expression of pitx genes, and members of the ATF/CREB and Ets transcription factor families. BioEssays 25:717–726, 2003. © 2003 Wiley Periodicals, Inc. (shrink)

In this review, we provide an overview of the dynamic changes within the microbiota and its metabolites that are implicated in establishing and maintaining gastrointestinal homeostasis during various stages of microbial colonization. The gradual conversion of the gut microbiota toward a mutualistic microbial community involves replacement of pioneer gut colonizers with bacterial taxa that are characteristic for the adult gut. An important microbial signature of homeostasis in the adult gut is the prevalence and activity of a diverse spectrum of bacterial (...) species that produce beneficial metabolites through metabolic interactions between microbial groups. Deciphering these microbial signatures and their metabolites that govern short and long‐term equilibrium, as well as imbalances in host‐microbial relationships, may provide novel diagnostic tools and/or therapeutic targets for specific disorders associated with intestinal dysbiosis and loss of homeostasis. (shrink)