联合应用NGF 和胰岛素对糖尿病大鼠烫伤创面表皮干细胞的影响

目的:通过局部联合应用神经生长因子和胰岛素对糖尿病大鼠深II度烫伤创面表皮干细胞标记物β1整合素和角蛋白19(K19)表达的影响,探讨神经生长因子和胰岛素联合应用于糖尿病烫伤创面治疗后对创面愈合的影响。方法:雄性wistar大鼠腹腔注射链脲佐菌素(STZ)建立糖尿病模型60只,1月后在大鼠背部造成深II度烫伤。将大鼠随机分为糖尿病对照组(B)、胰岛素治疗组(C)、神经生长因子治疗组(D)、神经生长因子联合胰岛素治疗组(E),每组15只。另取15只正常雄性wistar大鼠作为正常对照组(A)。观察伤后3、7、11、15、21 d各组创面愈合情况,检测创面β1整合素和角蛋白19(K19)的表达并计算创面愈合率。结果:E组创面愈合率自第7天起较A、B、C、D组增加,为[(25.33±2.32)%,(P<0.05)];A、C、D组创面愈合率较B组增加分别为[(22.51±1.78)%,(16.68±1.95)%,(18.29±1.70)%,(P<0.05)]。E组整合素β1和角蛋白19(K19)表达自伤后第7至21天各时相点显著增加,(P<0.05)。结论:糖尿病大鼠深II度烫伤创面局部联合应用神经生长因子和胰岛素可促进表皮干细胞的增殖与分化从而加速创面的愈合。     

Dedifferentiation derived cells exhibit phenotypic and functional characteristics of epidermal stem cells

Differentiated epidermal cells can dedifferentiate into stem cells or stem cell‐like cells in vivo. In this study, we report the isolation and characterization of dedifferentiation‐derived cells. Epidermal sheets eliminated of basal stem cells were transplanted onto the skin wounds in 47 nude athymic (BALB/c‐nu/nu) mice. After 5 days, cells negative for CK10 but positive for CK19 and β₁‐integrin emerged at the wound‐neighbouring side of the epidermal sheets. Furthermore, the percentages of CK19 and β₁‐integrin⁺ cells detected by flow cytometric analysis were increased after grafting (P < 0.01) and CK10⁺ cells in grafted sheets decreased (P < 0.01). Then we isolated these cells on the basis of rapid adhesion to type IV collagen and found that there were 4.56% adhering cells (dedifferentiation‐derived cells) in the grafting group within 10 min. The in vitro phenotypic assays showed that the expressions of CK19, β₁‐integrin, Oct4 and Nanog in dedifferentiation‐derived cells were remarkably higher than those in the control group (differentiated epidermal cells) (P < 0.01). In addition, the results of the functional investigation of dedifferentiation‐derived cells demonstrated: (1) the numbers of colonies consisting of 5–10 cells and greater than 10 cells were increased 5.9‐fold and 6.7‐fold, respectively, as compared with that in the control (P < 0.01); (2) more cells were in S phase and G2/M phase of the cell cycle (proliferation index values were 21.02% in control group, 45.08% in group of dedifferentiation); (3) the total days of culture (28 days versus 130 days), the passage number of cells (3 passages versus 20 passages) and assumptive total cell output (1 × 10⁵ cells versus 1 × 10¹² cells) were all significantly increased and (4) dedifferentiation‐derived cells, as well as epidermal stem cells, were capable of regenerating a skin equivalent, but differentiated epidermal cells could not. These results suggested that the characteristics of dedifferentiation‐derived cells cultured in vitro were similar to epidermal stem cells. This study may also offer a new approach to yield epidermal stem cells for wound repair and regeneration.     

Full-thickness tissue engineered skin constructed with autogenic bone marrow mesenchymal stem cells

To explore the feasibility of repairing clinical cutaneous deficiency, autogenic bone marrow mesenchymal stem cells (BMSCs) were isolated and differentiated into epidermal cells and fibroblasts in vitro supplemented with different inducing factors and biomaterials to construct functional tissueengineered skin. The results showed that after 72 h induction, BMSCs displayed morphologic changes such as typical epidermal cell arrangement, from spindle shape to round or oval; tonofibrils, melanosomes and keratohyaline granules were observed under a transmission electronic microscope. The differentiated cells expressed epidermal stem cell surface marker CK19 (59.66% ± 4.2%) and epidermal cells differentiation marker CK10. In addition, the induced epidermal cells acquired the anti-radiation capacity featured by lowered apoptosis following exposure to UVB. On the other hand, the collagen microfibrils deposition was noticed under a transmission electronic microscope after differentiating into dermis fibroblasts; RT-PCR identified collagen type I mRNA expression in differentiated cells; radioimmunoassay detected the secretion of interleukin-6 (IL-6) and interleukin-8 (IL-8) (up to 115.06 pg/mL and 0.84 ng/mL, respectively). Further in vivo implanting BMSCs with scaffold material shortened skin wound repair significantly. In one word, autogenic BMSCs have the potential to differentiate into epidermal cells and fibroblasts in vitro, and show clinical feasibility acting as epidermis-like and dermis-like seed cells in skin engineering.     

The proliferative and multipotent epidermal progenitor cells for human skin reconstruction in vitro and in vivo

ObjectivesThe skin exhibits tremendous regenerative potential, as different types of progenitor and stem cells regulate skin homeostasis and damage. However, in vitro primary keratinocytes present with several drawbacks, such as high donor variability, short lifespan, and limited donor tissue availability. Therefore, more stable primary keratinocytes are needed to generate multiple uniform in vitro and in vivo skin models.ResultsWe identified epidermal progenitor cells from primary keratinocytes using Integrin beta 1 (ITGB1) an epidermal stem cell marker markedly decreased after senescence in vitro. Epidermal progenitor cells exhibited unlimited proliferation and the potential for multipotent differentiation capacity. Moreover, they could completely differentiate to form an organotypic skin model including conversed mesenchymal cells in the dermis and could mimic the morphologic and biochemical processes of human epidermis. We also discovered that proliferation and the multipotent differentiation capacity of these cells relied on ITGB1 expression. Eventually, we examined the in vitro and in vivo wound healing capacity of these epidermal progenitor cells.ConclusionsOverall, the findings suggest that these stable and reproducible cells can differentiate into multiple lineages, including human skin models. They are a potentially powerful tool for studying skin regeneration, skin diseases, and are an alternative for in vivo experiments.

Our stable and reproducible epidermal progenitor cells from human epidermis have proliferation and multipotent differentiation potentials, regeneration capacity and could generate in vivo mimic 3D skin model not only for regeneration therapy but also for alternative animal experiments.     

Deletion of delta-opioid receptor in mice alters skin differentiation and delays wound healing

In addition to their well-known antinociceptive action, opioids can modulate non-neuronal functions, such as immune activity and physiology of different cell types. Several findings suggest that the delta-opioid receptor (DOR) and its endogenous ligands (enkephalins) are important players in cell differentiation and proliferation. Here we show the expression of DOR in mouse skin and human skin cultured fibroblasts and keratinocytes using RT-PCR. In DOR knock-out (KO) mice, a phenotype of thinner epidermis and higher expression of cell differentiation marker cytokeratin 10 (CK 10) were observed compared with wild type (WT). Using a burn wound model, significant wound healing delay (about 2 days) and severe epidermal hypertrophy were shown at the wound margin of DOR KO mice. This wound healing delay was further investigated by immunohistochemistry using markers for proliferation, differentiation, re-epithelialization, and dermal repair (CK 6, CK 10, and collagen IV). The levels of all these markers were increased in wounds of KO mice compared with WT. During the wound healing, the epidermal thickness in KO mice augments faster and exceeds that of the WT by day 3. These results suggest an essential role of DOR in skin differentiation, proliferation, and migration, factors that are important for wound healing.     

Immunohistochemical analyses point to epidermal origin of human Merkel cells

Merkel cells, the neurosecretory cells of skin, are essential for light-touch responses and may probably fulfill additional functions. Whether these cells derive from an epidermal or a neural lineage has been a matter of dispute for a long time. In mice, recent studies have clearly demonstrated an epidermal origin of Merkel cells. Given the differences in Merkel cell distribution between human and murine skin, it is, however, unclear whether the same holds true for human Merkel cells. We therefore attempted to gain insight into the human Merkel cell lineage by co-immunodetection of the Merkel cell marker protein cytokeratin 20 (CK20) with various proteins known to be expressed either in epidermal or in neural stem cells of the skin. Neither Sox10 nor Pax3, both established markers of the neural crest lineage, exhibited any cell co-labeling with CK20. By contrast, β1 integrin, known to be enriched in epidermal stem cells, was found in nearly 70 % of interfollicular epidermal and 25 % of follicular Merkel cells. Moreover, LRIG1, also enriched in epidermal stem cells, displayed significant co-immunolabeling with CK20 as well (approximately 20 % in the interfollicular epidermis and 7 % in the hair follicle, respectively). Further epidermal markers were detected in sporadic Merkel cells. Cells co-expressing CK20 with epidermal markers may represent a transitory state between stem cells and differentiated cells. β1 integrin is probably also synthesized by a large subset of mature Merkel cells. Summarizing, our data suggest that human Merkel cells may originate from epidermal rather than neural progenitors.     

Full-thickness tissue engineered skin constructed with autogenic bone marrow mesenchymal stem cells

To explore the feasibility of repairing clinical cutaneous deficiency, autogenic bone marrow mesenchymal stem cells (BMSCs) were isolated and differentiated into epidermal cells and fibroblasts in vitro supplemented with different inducing factors and biomaterials to construct functional tissueengineered skin. The results showed that after 72 h induction, BMSCs displayed morphologic changes such as typical epidermal cell arrangement, from spindle shape to round or oval; tonofibrils, melanosomes and keratohyaline granules were observed under a transmission electronic microscope. The differentiated cells expressed epidermal stem cell surface marker CK19 (59.66% ± 4.2%) and epidermal cells differentiation marker CK10. In addition, the induced epidermal cells acquired the anti-radiation capacity featured by lowered apoptosis following exposure to UVB. On the other hand, the collagen microfibrils deposition was noticed under a transmission electronic microscope after differentiating into dermis fibroblasts; RT-PCR identified collagen type I mRNA expression in differentiated cells; radioimmunoassay detected the secretion of interleukin-6 (IL-6) and interleukin-8 (IL-8) (up to 115.06 pg/mL and 0.84 ng/mL, respectively). Further in vivo implanting BMSCs with scaffold material shortened skin wound repair significantly. In one word, autogenic BMSCs have the potential to differentiate into epidermal cells and fibroblasts in vitro, and show clinical feasibility acting as epidermis-like and dermis-like seed cells in skin engineering. Supported by the Major Technology Program of Beijing Municipal Science & Technology Commission (Grant No. H060920050130) and the Major State Basic Research Development Program of China (Grant No. 2005CB522702)     

Burn injury suppresses human dermal dendritic cell and Langerhans cell function

Human skin contains epidermal Langerhans cells (LCs) and dermal dendritic cells (DCs) that are key players in induction of adaptive immunity upon infection. After major burn injury, suppressed adaptive immunity has been observed in patients. Here we demonstrate that burn injury affects adaptive immunity by altering both epidermal LC and dermal DC functions. We developed a human ex vivo burn injury model to study the function of DCs in thermally injured skin. No differences were observed in the capacity of both LCs and dermal DCs to migrate out of burned skin compared to unburned skin. Similarly, expression levels of co-stimulatory molecules were unaltered. Notably, we observed a strong reduction of T cell activation induced by antigen presenting cell (APC) subsets that migrated from burned skin through soluble burn factors. Further analyses demonstrated that both epidermal LCs and dermal DCs have a decreased T cell stimulatory capacity after burn injury. Restoring the T cell stimulatory capacity of DC subsets might improve tissue regeneration in patients with burn wounds.     

Epidermal stem cells are retained in vivo throughout skin aging

In healthy individuals, skin integrity is maintained by epidermal stem cells which self-renew and generate daughter cells that undergo terminal differentiation. It is currently unknown whether epidermal stem cells influence or are affected by skin aging. We therefore compared young and aged skin stem cell abundance, organization, and proliferation. We discovered that despite age-associated differences in epidermal proliferation, dermal thickness, follicle patterning, and immune cell abundance, epidermal stem cells were maintained at normal levels throughout life. These findings, coupled with observed dermal gene expression changes, suggest that epidermal stem cells themselves are intrinsically aging resistant and that local environmental or systemic factors modulate skin aging.     

Keratin-6 driven ODC expression to hair follicle keratinocytes enhances stemness and tumorigenesis by negatively regulating Notch

Over-expression of ornithine decarboxylase (ODC) is known to be involved in the epidermal carcinogenesis. However, the mechanism by which it enhances skin carcinogenesis remains undefined. Recently, role of stem cells localized in various epidermal compartments has been shown in the pathogenesis of skin cancer. To direct ODC expression in distinct epidermal compartments, we have developed keratin 6 (K6)-ODC/SKH-1 and keratin 14 (K14)-ODC/SKH-1 mice and employed them to investigate the role of ODC directed to these epidermal compartments on UVB-induced carcinogenesis. K6-driven ODC over-expression directed to outer root sheath (ORS) of hair follicle was more effective in augmenting tumorigenesis as compared to mice where K14-driven ODC expression was directed to inter-follicular epidermal keratinocytes. Chronically UVB-irradiated K6-ODC/SKH-1 developed 15 ± 2.5 tumors/mouse whereas K14-ODC/SKH-1 developed only 6.8 ± 1.5 tumors/mouse. K6-ODC/SKH-1 showed augmented UVB-induced proliferation and much higher pro-inflammatory responses than K14-ODC/SKH-1 mice. Tumors induced in K6-ODC/SKH-1 were rapidly growing, invasive and ulcerative squamous cell carcinoma (SCC) showing decreased expression of epidermal polarity marker E-cadherin and enhanced mesenchymal marker, fibronectin. Interestingly, the number of CD34/CK15/p63 positive stem-like cells was significantly higher in chronically UVB-irradiated K6-ODC/SKH-1 as compared to K14-ODC/SKH-1 mice. Reduced Notch1 expression was correlated with the expansion of stem cell compartment in these animals. However, other signaling pathways such as DNA damage response or mTOR signaling pathways were not significantly different in tumors induced in these two murine models suggesting the specificity of Notch pathway in this regard. These data provide a novel role of ODC in augmenting tumorigenesis via negatively regulated Notch-mediated expansion of stem cell compartment.     

Telocytes in liver regeneration: possible roles

Telocytes (TCs) are a novel type of interstitial cells which are potentially involved in tissue regeneration and repair ( www.telocytes.com ). Previously, we documented the presence of TCs in liver. However, the possible roles of TCs in liver regeneration remain unknown. In this study, a murine model of partial hepatectomy (PH) was used to induce liver regeneration. The number of TCs detected by double labelling immunofluorescence methods (CD34/PDGFR‐α, CD34/PDGFR‐ß and CD34/Vimentin) was significantly increased when a high level of hepatic cell proliferation rate (almost doubled) as shown by 5‐ethynyl‐2′‐deoxyuridine (EdU) immunostaining and Western Blot of Proliferating cell nuclear antigen (PCNA) was found at 48 and 72 hrs post‐PH. Meanwhile, the number of CK‐19 positive‐hepatic stem cells peaked at 72 hrs post‐PH, co‐ordinating with the same time‐point, when the number of TCs was most significantly increased. Taken together, the results indicate a close relationship between TCs and the cells essentially involved in liver regeneration: hepatocytes and stem cells. It remains to be determined how TCs affect hepatocytes proliferation and/or hepatic stem cell differentiation in liver regeneration. Besides intercellular junctions, we may speculate a paracrine effect via ectovesicles.     

Role of caveolin-1 in epidermal stem cells during burn wound healing in rats

Local transplantation of stem cells has therapeutic effects on skin damage but cannot provide satisfactory wound healing. Studies on the mechanisms underlying the therapeutic effects of stem cells on skin wound healing will be needed. Hence, in the present study, we explored the role of Caveolin-1 in epidermal stem cells (EpiSCs) in the modulation of wound healing. We first isolated EpiSCs from mouse skin tissues and established stable EpiSCs with overexpression of Caveolin-1 using a lentiviral construct. We then evaluated the epidermal growth factor (EGF)-induced cell proliferation ability using cell counting Kit-8 (CCK-8) assay and assessed EpiSC pluripotency by examining Nanog mRNA levels in EpiSCs. Furthermore, we treated mice with skin burn injury using EpiSCs with overexpression of Caveolin-1. Histological examinations were conducted to evaluate re-epithelialization, wound scores, cell proliferation and capillary density in wounds. We found that overexpression of Caveolin-1 in EpiSCs promoted EGF-induced cell proliferation ability and increased wound closure in a mouse model of skin burn injury. Histological evaluation demonstrated that overexpression of Caveolin-1 in EpiSCs promoted re-epithelialization in wounds, enhanced cellularity, and increased vasculature, as well as increased wound scores. Taken together, our results suggested that Caveolin-1 expression in the EpiSCs play a critical role in the regulation of EpiSC proliferation ability and alteration of EpiSC proliferation ability may be an effective approach in promoting EpiSC-based therapy in skin wound healing.     

In vivo dedifferentiation of human epidermal cells

Consistent with our previous study, we herein offer further evidence to demonstrate the dedifferentiation of differentiating epidermal cells into stem cells or stem cells -like in vivo. The epidermal sheets eliminated of basal cells were labeled with 6-diamidino-2-phenylindole (DAPI), and then were transplanted onto the full-thickness skin wounds nude mice. Immunohistochemical examination of the survival sheets showed that some cells were positive for both DAPI and either cytokeratins (CK19, CK14) or beta1 integrin in spinous and granular layers at day 7 after transplantation. Furthermore, there was a significant increase in the percentages of both alpha6briCDdim and alpha6briCD71bri populations in survival epidermal sheet grafts 7 d after transplantation compared with those before xenotransplantation (P<0.05), as determined by flow cytometry. The results collectively indicated that some of the differentiated cells in engrafted epidermal sheets dedifferentiated into stem cells or stem cells-like in vivo, which offer us new evidence and insights into the dedifferentiation.     

Elevated ornithine decarboxylase activity promotes skin tumorigenesis by stimulating the recruitment of bulge stem cells but not via toxic polyamine catabolic metabolites

Elevated expression of ornithine decarboxylase (ODC), the regulatory enzyme in polyamine biosynthesis, targeted to the epidermis is sufficient to promote skin tumor development following a single subthreshold dose of dimethylbenz(a)anthracene (DMBA). Since skin tumor promotion involves recruitment of hair follicle bulge stem cells harboring genetic lesions, we assessed the effect of increased epidermal ODC on recruitment of bulge stem cells in ODC-ER transgenic mice in which ODC activity is induced de novo in adult skin with 4-hydroxytamoxifen (4OHT). Bromodeoxyuridine-pulse labeling and use of K15.CrePR1;R26R;ODC-ER triple transgenic mice demonstrated that induction of ODC activity is sufficient to recruit bulge stem cells in quiescent skin. Because increased ODC activity not only stimulates proliferation but also increases reactive oxygen species (ROS) generation via subsequent induction of polyamine catabolic oxidases, we used an inhibitor of polyamine catabolic oxidase activity, MDL72527, to investigate whether ROS generation by polyamine catabolic oxidases contributes to skin tumorigenesis in DMBA-initiated ODC-ER transgenic skin. Newborn ODC-ER transgenic mice and their normal littermates were initiated with a single topical dose of DMBA. To assess tumor development originating from dormant bulge stem cells that possess DMBA-initiated mutations, epidermal ODC activity was induced in ODC-ER mice with 4OHT 5 weeks after DMBA initiation followed by MDL72527 treatment. MDL72527 treatment resulted in a shorter tumor latency time, increased tumor burden, increased conversion to carcinomas, and lower tumor levels of p53. Thus, elevated epidermal ODC activity promotes tumorigenesis by stimulating the recruitment of bulge stem cells but not via ROS generation by polyamine catabolic oxidases.     

Wnt/β-catenin signaling is critical for dedifferentiation of aged epidermal cells in vivo and in vitro

Aged epidermal cells have the capacity to dedifferentiate into stem cell-like cells. However, the signals that regulate the dedifferentiation of aged epidermal cells remain unclear. Here, we provide evidence that Wnt/β-catenin is critical for aged epidermal cell dedifferentiation in vivo and in vitro. Some aged epidermal cells in human ultrathin epidermal sheets lacking basal stem cells transplanted onto wounds dedifferentiated into stem cell-like cells that were positive for CK19 and β1 integrin but negative for CK10. In addition, Wnt/β-catenin pathway was activated during this process. There was increased expression of Wnt-1, Wnt-4, Wnt-7a, β-catenin, cyclin D1, and c-myc. Secreted frizzled-related protein 1, a Wnt/β-catenin pathway inhibitor, blocked dedifferentiation in vivo. Then, the activator, a highly specific glycogen synthase kinase (GSK)-3β inhibitor, of Wnt/β-catenin pathway was added to the culture medium of aged epidermal cells. Surprisingly, we found that the activator induced higher expression of CK19, β1 integrin, Oct4, and Nanog proteins. The induced aged epidermal cells exhibited high colony-forming efficiency, long-term proliferative potential and could regenerate a skin equivalent (as do epidermal stem cells). These results suggested that activation of Wnt/β-catenin pathway induced the dedifferentiation of aged epidermal cells, which suggest a new approach to generate epidermal stem cell-like cells.     

Tube-Like Structures with Co-Expression of D2-40 and CD34: Newly Formed Vasculatures?

Background: A great number of in vitro and in vivo studies have suggested that many pathways or factors can stimulate angiogenesis and lymphangiogenesis, which facilitate tumor progression and metastasis. However, the morphological and immunohistochemical profile of newly formed vasculatures has not been elucidated, making it difficult to differentiate them from the pre-existing ones, and to identify their unique molecular profiles for diagnosis and therapeutic interventions.Experimental findings: As cytokeratin (CK)-19 is a well-recognized stem cell marker and CK-19-positive cells are frequently detected in the peripheral blood of patients with metastatic cancer, our recent studies have assessed the involvement of CK-19 in the formation of new vasculatures in primary colorectal cancer (CRC) tissues. Our studies showed that a subset of lymph node-positive cases harbored some isolated normal epithelial structures with distinct CK-19 immunostaining within an otherwise CK-19-negative background. These structures are exclusively located within or adjacent to lymphoid follicles and are often surrounded by tube-like structures expressing lymphatic endothelial marker D2-40. Similar structures are more frequently seen at the junctions between pre-invasive and invasive CRC with the following features: (1). they consist of a single layer of endothelial cells that express both D2-40 and CD34, (2). their endothelial walls are often incomplete with disseminated cells protruding into the adjacent stroma, and (3). they are exclusively associated with disseminated CK-19-positive cellsHypothesis: Based on these findings, we propose that these tube-like structures represent newly formed vasculatures, which are derived by the convergence of aberrant lymphocyte infiltration and tumor stem cells. Because of their close physical proximity, tumor stem cells within the epithelial and stromal components contribute equally and coordinately to the morphogenesis of new vasculatures, which constitutes the basis for the unique morphologic and immunohistochemical features of newly formed vasculatures. Our hypothesis appears to be applicable to all epithelium-derived cancers.     

Mouse epidermal cell renewal after topical treatment with different concentrations of the epidermal peptide pyroGlu-Glu-Asp-Ser-GlyOH

Earlier work has shown that epidermal cells contain a peptide, pyroGlu-Glu-Asp-Ser-GlyOH, that induces a moderate but long-lasting inhibition of epidermal cell proliferation when given at low (picomol) doses ip in vivo and in vitro. In the present study, the epidermal pentapeptide was applied topically to the back skin of hairless mice at different concentrations and in a water-miscible cream. A single topical application of either high (0.25% wt/wt) or low (0.004% or 0.02% wt/ wt) doses of the pentapeptide was followed by oscillations in epidermal DNA synthesis and G₂-M cell flux (mitotic rate). In general, epidermal cell proliferation was inhibited during the first 10-day period after treatment with the two lower doses, while the highest concentration of pentapeptide (0.25%) stimulated epidermal cell proliferation. In spite of the effects on epidermal cell proliferation the size of the epidermal cell population in the treated area (number of nucleated cells and epidermal thickness) showed no corresponding alterations. The results could imply that the epidermal pentapeptide modifies epidermal cell proliferation and terminal differentiation in such a way that the two are balance with each other.     

Evaluation of cytokeratin 19 as a prognostic tumoral and metastatic marker with focus on improved detection methods

In the last few years, there has been a growing interest in Cytokeratin 19 (CK19) studies in the cancer research field. CK19 belongs to the Type I CKs, serves as a useful research tool in prognosis, diagnosis, and management of the tumors. In this paper, we dissect the metastatic potential of CK19, its relation with cancer stem cells and retinal epithelial cells behavior, its application as a tumor marker and its role among 30 cancers such as thyroid, thoracic, lung, pancreatic, cervical, colorectal, and so forth. CK19 expressed in several cancer types because of its metastatic potential. This paper also presents modified detection methods of CK19 in disseminated tumor cells.     

Development and evaluation of transdermal formulations containing metronidazole and norfloxacin for the treatment of burn wound.

In an attempt for better treatment of partial thickness burn wounds topical ointments containing metronidazole and norfloxacin in different bases were prepared and in vitro release was conducted in phosphate buffer pH 6. It was found that, diffusion of the metronidazole and norfloxacin from the lanolin petrolatum base with 0.25% w/w dimethyl sulfoxide was maximum through hairless rat abdominal skin. Antimicrobial activity of different prepared formulations was found to be more effective both against aerobic and anaerobic bacteria than marketed formulation (1% silver sulfadiazine cream USP). Formulations were significantly effective as compared to that of marketed formulation in wound contraction of the partial thickness burn wound. Histopathological reports supported effectiveness of formulations. It was found that 1% metronidazole and 1% norfloxacin ointments are suitable for treating the partial thickness burn wound.     

The human hair follicle contains two distinct K19 positive compartments in the outer root sheath: a unifying hypothesis for stem cell reservoir?

Up to now, the localization of stem cells in human anagen hair follicle relied on three complementary approaches; namely, detection of slow cycling cells, detection of high colony forming cells, and differential immunohistochemical staining. These techniques, however, gave conflicting results since stem cells were localized either as long label retaining cells in the so-called bulge area or as high colony forming cells in the lower third of the follicle. In the present study we investigated the expression of cytokeratin 19, a marker for putative stem cell-containing epithelial compartments, in order to characterize stem cell distribution in the human hair follicle throughout the hair cycle. We found that anagen human hair follicles contain two distinct reservoirs for stem cells located in the upper and lower thirds of the follicle. These two reservoirs fuse during the catagentelogen transition phase and individualize again in the newly forming anagen hair follicle.