"10-year-old Lola is the confident and smart daughter of a rich African ambassador. She can fly jet planes and control speedboats despite her age, and is secretly in love with Tommy (but would be devastated if he ever found out)."
She's a 10 year old, blue-eyed daughter of a wealthy African ambassador. Lola is a very well-educated, mature and intelligent girl. Despite her young age, she can pilot jet planes and speedboats among many other surprising skills. She has a huge crush on Tommy Turnbull but is very secretive about it, and Tommy doesn't even seem to realize that Lola has these feelings for him.
I especially loved how the romantic elements were woven into this incredible mystery adventure. The characters were larger than life, and the goals they set out to achieve were equally audacious. This to me was a great adventure, great mystery, and truly a great thriller. How to conquer a nation, how to indulge the fantasies and make them reality, and in the process give form to two broken lives.
I read this sublime short story collection just after I moved to England from India. Saying that these stories of displacement, yearning, loss, love spoke to me is an understatement. I was new to England, missing India which I still thought of as home and while some of the stories brought India back vividly to me, others I could absolutely identify with as they detailed the immigrant experience so beautifully. A book that will always be very close to my heart as I read it and laughed and cried and yearned alongside the characters.
This book will have you up all night. It is a humorous, steamy contemporary romance between a boss and his apprentice. Both are architects in a family business. You will fall in love with the witty dialogue and the irresistible chemistry between the hero and heroine in this multicultural romance.
Dendritic cells (DCs) are the most efficient, professional antigen-presenting cells of the immune system and are key components for the induction of primary immune responses and the maintenance of immunologic tolerance.1 DCs are heterogeneous; and in humans, one can recognize immature and mature DCs and, among the former, epidermal DCs (ie, Langerhans cells [LCs] and connective tissue DCs).
LCs are immature DCs of the epidermis and neighboring mucosae. Because of this position, they are critical in the induction of immune responses toward infections and skin tumors3 and are credited to play a role in allergic skin diseases.4 The defining marker of LCs is the presence of Birbeck granules (BGs), which are detected by electron microscopy.5 LCs are characterized by the expression of MHC-II, CD1a, E-cadherin, and langerin (CD207).6 The c-type lectin CD207 is localized not only at the cell surface, but also in the endosomal recycling compartment, in BG, and in other tubular and vesicular structures.7,8 CD1a and BG-positive cells, also defined as LCs, have been furthermore described in the arterial wall,9 besides skin and skin-draining lymph nodes.
The most commonly used marker to identify human hematopoietic stem cells is CD34, a stage-specific antigen associated with hematopoietic stem and progenitor cells. CD34 antigen density is highest on early progenitors, and the density decreases progressively as cells mature. Fully differentiated hematopoietic cells do not express CD34.11
Experiments designed to generate LCs from immature precursors in vitro have given contradictory results (Table 1). Starting from apparently similar populations of CD34+ circulating progenitors, DCs have been obtained in culture using very different mixtures and timing of administration of cytokines. In particular, LCs equipped with BG have been obtained in some instances,17,26 whereas in other instances the cells generated in vitro were said to be LCs without verification by electron microscopy,18,19 and in one report the generated cells had immunocytochemical features of LCs but were explicitly defined as devoid of BG20 ; DCs with features of LCs but lacking the expression of BG have been described also by other groups.21,22 Strunk et al,23 culturing CD34+ cells isolated from human peripheral blood, obtained 3 distinct CD1a+ populations: LCs, as evidenced by the presence of BG; CD14+ monocytes; and BG-negative cells with a dendritic morphology. They interpreted this last population as LCs that had not yet acquired BG. Although langerin is involved in the formation of BG,8 DCs expressing this marker do not necessarily display BG and langerin expression does not fully correlate with BG formation; hence, additional signals must be necessary to complete LC differentiation.21
Here we have adopted a culture protocol that had been successfully used by other authors17 to generate LCs from CD34+ progenitors (Table 1), to generate mature DCs from CD133+ hematopoietic stem cells in vitro. We aimed at: (1) verifying the possibility of differentiating DCs in general and LCs in particular from CD133+ cord blood progenitors; (2) assessing the steps during this differentiation, as a premise for manipulating these steps in future studies; and (3) verifying the influence of TGF-β on the differentiation of DCs from CD133+ precursors, given the ambiguity of existing studies on the role of this cytokine on the differentiation of LCs from CD34+ precursors.
After 7-day culture with TGF-β, part of the cells adhered to the flask and some showed thin projections all around (Figures 1F, 2D). The expression of immature cell antigens was reduced, more markedly than that of CD133, whereas CD45 persisted; MHC-II came to be expressed by a majority of cells, and CD11b by a minority of cells (Figure 4). The mitochondria appeared significantly increased in number, as shown by the intensity of MitoTracker cell staining (Figure 1E). The intensity of blue autofluorescent emission did not change appreciably (Figure 2C,I-J). At electron microscopy, large cells with cytoplasmic projections of various width and length and with oval, indented nuclei became apparent (Figure 3C) together with cells retaining immature features. Here and at later time points, the organelles of the secretory pathway (rough endoplasmic reticulum and Golgi apparatus) were relatively small with respect to the amount of cytoplasm. Occasional multilaminar inclusions were found, which appeared as round or cup-shaped, membrane-bound bodies with a tightly arranged inner array of concentric electron-dense lamellae (Figure 5A-C).
In cultures with TGF-β, all the cells adhered to the flask and the majority were large, with dendritic shape (Figures 1J, 2F). The immature cell antigens CD34 and CD133 were no more expressed, whereas MHC-II and CD11b were expressed by approximately as many cells as after 7-day culture (Figure 4). At immunocytochemistry, part of the cells were stained for CD1a (Figure 6D). The mitochondria appeared increased in number above what had been seen at 7-day culture (Figure 1D,I). The brightly blue autofluorescent structures in the cytoplasm were much more numerous than at day 7 (Figure 2E), with a much higher emission peak at 460 nm, and the spectral analysis of autofluorescence showed a new, relevant peak at approximately 580 nm (Figure 2I-J). At electron microscopy, the cells showed a variable number of long, thin cytoplasmic projections (Figure 3E); the nuclei appeared with highly irregular profile, sometimes convoluted with lobes connected by extremely thin sheets. The cytoplasm contained areas of smooth endoplasmic reticulum, many multilaminar inclusions, myelin-like figures in various amounts among cells, and occasional inclusions containing tightly packed tubules (Figure 5D-F).
In this study, we could show that CD133+ cells harvested from human cord blood can be drawn to differentiate in vitro, through well-defined steps, into cells with aspect, immunophenotype, and lymphocyte-stimulating capacity of LCs but without demonstrable BGs; the process requires 18 days. The selected cells were highly homogeneous for morphology and antigen expression; they were small, with few organelles. On culture, early differentiating cells were larger, with cytoplasmic projections of various widths and lengths, a nucleus with shallow indentations, and many mitochondria. The further stage was represented by immature dendritic cells with a deeply indented nucleus and multilaminar inclusions; the latter have features of class II compartments known to develop from multivesicular bodies.37 Other, less numerous inclusions contained multitubular arrays and resembled tubuloreticular inclusions, which may be interpreted as correlated with the secretion of cytokines.38 The mitochondria reached the zenith at this step, and a new emission peak at 580 nm appeared in the cytoplasm at autofluorescence. The last stage was represented by cells morphologically similar to those just described and also expressing costimulatory molecules (CD54, CD80, CD86), CD1a, and langerin and capable of stimulating mixed leukocyte reaction; therefore, they proved to be mature, immunostimulatory DCs; at this last stage, the number of mitochondria and the 580 nm peak were reduced with respect to the previous stage.
The addition of TGF-β, besides serum, does not seem necessary for the morphologic differentiation of cells but is required for the full acquisition of mature immunophenotypic and functional features. 781b155fdc