Hoxa2 knockdown in Xenopus results in hyoid to mandibular homeosis.

The skeletal structures of the face and throat are derived from cranial neural crest cells (NCCs) that migrate from the embryonic neural tube into a series of branchial arches (BAs). The first arch (BA1) gives rise to the upper and lower jaw cartilages, whereas hyoid structures are generated from the second arch (BA2). The Hox paralogue group 2 (PG2) genes, Hoxa2 and Hoxb2, show distinct roles for hyoid patterning in tetrapods and fishes. In the mouse, Hoxa2 acts as a selector of hyoid identity, while its paralogue Hoxb2 is not required. On the contrary, in zebrafish Hoxa2 and Hoxb2 are functionally redundant for hyoid arch patterning. Here, we show that in Xenopus embryos morpholino-induced functional knockdown of Hoxa2 is sufficient to induce homeotic changes of the second arch cartilage. Moreover, Hoxb2 is downregulated in the BA2 of Xenopus embryos, even though initially expressed in second arch NCCs, similar to mouse and unlike in zebrafish. Finally, Xbap, a gene involved in jaw joint formation, is selectively upregulated in the BA2 of Hoxa2 knocked-down frog embryos, supporting a hyoid to mandibular change of NCC identity. Thus, in Xenopus Hoxa2 does not act redundantly with Hoxb2 for BA2 patterning, similar to mouse and unlike in fish. These data bring novel insights into the regulation of Hox PG2 genes and hyoid patterning in vertebrate evolution and suggest that Hoxa2 function is required at late stages of BA2 development.     

A multidisciplinary approach to clitoral reconstruction after female genital mutilation: the crucial role of counselling

Objectives: Female genital mutilation (FGM) is becoming more widely seen in the West, due to immigration and population movement. Health services are being confronted with the need to provide care for women with FGM. One of the more recent trends is the provision of clitoral reconstruction. It remains unclear, however, what constitutes good practice with regard to this type of surgery. Methods: Based on a keynote presentation about reconstructive clitoral surgery, we briefly discuss the possible consequences of FGM and the findings from recent publications on clitoral reconstruction. Recognising individual differences in women, we suggest a multidisciplinary counselling model to provide appropriate care for women requesting clitoral reconstruction. Results: The literature shows that FGM influences physical, mental and sexual health. Clitoral reconstructive surgery can lead to an increase in sexual satisfaction and orgasm in some, but not all, women. A multidisciplinary approach would enable a more satisfactory and individually tailored approach to care. The multidisciplinary team should consist of a midwife, a gynaecological surgeon, a psychologist-psychotherapist, a sexologist and a social worker. Comprehensive health counselling should be the common thread in this model of care. Our proposed care pathway starts with taking a thorough history, followed by medical, psychological and sexological consultations. Conclusions: Women with FGM requesting clitoral reconstruction might primarily be looking to improve their sexual life, to recover their identity and to reduce pain. Surgery may not always be the right answer. Thorough counselling that includes medical, psychological and sexual advice is therefore necessary as part of a multidisciplinary approach.     

HCV quasispecies evolution during treatment with interferon alfa-2b and ribavirin in two children coinfected with HCV and HIV-1

Two children who acquired hepatitis C virus (HCV) and human immunodeficiency virus type 1 (HIV-1) infection by mother-to-child transmission were monitored during interferon alfa-2b and ribavirin treatment. In Patient C1, CD4(+) T cell counts were within normal range and HIV-1 viral load was undetectable. HCV viral load declined slightly following treatment initiation while novel variants rapidly emerged, indicative of quasispecies diversification. In Patient C2, CD4(+) T cell counts were low and HIV-1 replication was not fully controlled by antiretroviral therapy. HCV viral load rose during treatment and a striking conservation of the variant spectrum was observed. In both cases, there was no decline in quasispecies complexity following treatment initiation and sustained virological response was not achieved. These results suggest that reduction in quasispecies complexity, which is observed in adult responders following interferon treatment, may be mechanistically unrelated with evolution of the variant profile and/or selective pressure exerted on HCV.     

Pathogenic role of P-selectin in experimental cerebral malaria: importance of the endothelial compartment

P-selectin is a leukocyte adhesion receptor expressed on the surface of activated platelets and endothelial cells. Its role in the pathogenesis of cerebral malaria was explored in a murine model of cerebral malaria. Infection of mice with Plasmodium berghei ANKA led to P-selectin up-regulation in brain vessels of cerebral malaria-susceptible mice but not of cerebral malaria-resistant mice. Treatment of susceptible mice with anti-mouse P-selectin mAb failed to prevent the development of the neurological syndrome. However, P-selectin-deficient mice infected with Plasmodium berghei ANKA had a cumulative incidence of cerebral malaria which was significantly reduced compared to wild-type animals (4.5% versus 80%, respectively), despite identical levels of parasitemia, platelet and leukocyte accumulation. To determine whether P-selectin on platelets and/or endothelium was responsible for the microvascular pathology, cerebral malaria was assessed in chimeric mice deficient in platelet or endothelial P-selectin, which were generated by bone marrow transplantation. Mice deficient only in endothelial P-selectin did not show any sign of cerebral malaria (vascular plugging, hemorrhages, or edema), while mice lacking only platelet P-selectin showed signs of cerebral malaria similar to that seen in wild-type mice. These results indicate that endothelial P-selectin plays an important role in the pathogenesis of cerebral malaria.     

Phylogenetic analysis of fowl adenoviruses.

The sequences of the L1 loop of the hexon protein from representative fowl adenovirus (FAdV) strains of the different European and American collections were determined and compared. This study highlighted the lack of consensus in the numbering of the individual serotypes between the American and the European classifications. An identification system is proposed based on restriction fragment length polymorphism of the hexonA/hexonB polymerase chain reaction product. In addition, new insights into the relationships among FAdV strains are presented and discussed on the basis of phylogenetic analysis of the L1 loops sequences. Six clusters of strains that are supported by high bootstrap values were identified. Three of them are clearly independent, forming groups A, B and C, whereas the three others are clustered in a single 'supergroup', denominated D. Interestingly, the Japanese strain TR22 that is presently classified as European type 5 (species B) could not be assigned to any of the aforementioned clusters and might therefore constitute the sole representative of a seventh cluster.     

The fate of the large striatal interneurons expressing calretinin in Huntington's disease

Huntington's disease (HD) is characterized by the atrophy of the striatum due to losses of projection neurons, while interneurons are relatively spared. However, little is known about the fate of the large interneurons that express calretinin (Cr) in HD. We addressed this issue by applying a double immunofluorescent labeling technique to postmortem striatum from HD patients and controls. We compared the distribution and density of Cr-positive (+) interneurons and their degree of choline acetyltransferase (ChAT) coexpression in normal and HD cases. Large interneurons containing only Cr, ChAT, or both occurred in the normal human striatum and a twofold decrease in the density of Cr+/ChAT+ and Cr-/ChAT+ neurons was recorded in HD striatum compared to controls. However, studies undertaken with neurokinin-1 receptor as a marker of large Cr+ and ChAT+ neurons revealed that these neurons are selectively spared in HD. Hence, the apparent decrease in the number of Cr+/ChAT+ and Cr-/ChAT+ neurons in HD is better explained by a diminution in the expression of Cr and ChAT than by the degeneration of these cells. Altogether, our data suggest that neurodegenerative processes at play in HD affect the expression of Cr and ChAT in the large striatal interneurons without causing their death.     

Patient-centered care in chronic disease management: a thematic analysis of the literature in family medicine

Objective

The objective was to provide a synthesis of the results of the research and discourse lines on main dimensions of patient-centered care in the context of chronic disease management in family medicine, building on Stewart et al.’s model.

Methods

We developed search strategies for the Medline, Embase, and Cochrane databases, from 1980 to April 2009. All articles addressing patient-centered care in the context of chronic disease management in family medicine were included. A thematic analysis was performed using mixed codification, based on Stewart's model of patient-centered care.

Results

Thirty-two articles were included. Six major themes emerged: (1) starting from the patient's situation; (2) legitimizing the illness experience; (3) acknowledging the patient's expertise; (4) offering realistic hope; (5) developing an ongoing partnership; (6) providing advocacy for the patient in the health care system.

Conclusion

The context of chronic disease management brings forward new dimensions of patient-centered care such as legitimizing the illness experience, acknowledging patient expertise, offering hope and providing advocacy.

Practice implications

Chronic disease management calls for the adaptation of the family physician's role to patients’ fluctuating needs. Literature also suggests the involvement of the family physician in care transitions as a component of patient-centered care.     

A human-mouse chimera of the alpha3alpha4alpha5(IV) collagen protomer rescues the renal phenotype in Col4a3-/- Alport mice

Collagen IV is a major structural component of basement membranes. In the glomerular basement membrane (GBM) of the kidney, the alpha3, alpha4, and alpha5(IV) collagen chains form a distinct network that is essential for the long-term stability of the glomerular filtration barrier, and is absent in most patients affected with Alport syndrome, a progressive inherited nephropathy associated with mutation in COL4A3, COL4A4, or COL4A5 genes. To investigate, in vivo, the regulation of the expression, assembly, and function of the alpha3alpha4alpha5(IV) protomer, we have generated a yeast artificial chromosome transgenic line of mice carrying the human COL4A3-COL4A4 locus. Transgenic mice expressed the human alpha3 and alpha4(IV) chains in a tissue-specific manner. In the kidney, when expressed onto a Col4a3(-/-) background, the human alpha3(IV) chain restored the expression of and co-assembled with the mouse alpha4 and alpha5(IV) chains specifically at sites where the human alpha3(IV) was expressed, demonstrating that the expression of all three chains is required for network assembly. The co-assembly of the human and mouse chains into a hybrid network in the GBM restores a functional GBM and rescues the Alport phenotype, providing further evidence that defective assembly of the alpha3-alpha4-alpha5(IV) protomer, caused by mutations in any of the three chains, is the pathogenic mechanism responsible for the disease. This line of mice, humanized for the alpha3(IV) collagen chain, will also provide a valuable model for studying the pathogenesis of Goodpasture syndrome, an autoimmune disease caused by antibodies against this chain.