Approaches of Developing Pharmacovigilance in Our Hospital / 中国药房

OBJECTIVE:To explore the working model of developing pharmacovigilance in our hospital. METHODS:179 ADR cases reported in our hospital in 2008 were analyzed and the measures to carry out pharmacovigilance were introduced. RESULTS:Due to the practice of pharmacovigilance,the incidence of serious ADRs in our hospital was lowered significantly,down to 0 case in 2008 from 8 cases during 2005～2007; the proportion of rational drug use increased and the ADR reporting rate increased. CONCLUSION:To maintain high level of rational drug use,it is imperative to develop pharmacovigilance in our hospital.

Ectopia of Epidermal Stem Cells on Wound Edge During Wound Healing Process / 中国修复重建外科杂志

Objective To investigated the distribution of epidermal stem cells in rat full-thickness wound tissues during the wound healing process and to elucidate the roles of epidermal stem cells in wound repair in vivo. Methods Eighty circular full-thickness wounds were produced on both sides of the back in 20 male Wistar rats labeled with BrdU 60 days previously (4 wounds in each rat). BrdU, β1 integrin and keratin 19 (K19) were employed to determine the epidermal stem cells with SP immunohistochemical methods, and the epithelialization was determined with routine histological methods of HE staining on the 3rd, 7th, 14th, and 21st days after operation. Results No cells with positive immunostaining for β1 integrin, K19 and BrdU were found in granulation tissue of wound in both groups during the healing process. However, a few scattered β1 integrin and K19 positive cells were found within the stratum spinosum and stratum granulosum of the epidermis on the wound edges on the 3rd day post-injury. And these positive cells gradually became more and more in number, and mostly concentrated on the border of wound edges till the wounds healed. In addition, the number of positive cells for β1 integrin and K19 in the infected wounds was less than that in non-infected wounds. These positive cells for β1 integrin and K19 staining on the wound edge were also positively stained with BrdU in the cellular nuclei. Conclusion The above results indicate that ectopia of epidermal stem cells present a major function during wound epithelialization.

Treatment of complex bone nonunion with external skeletal fixation / 中华外科杂志

<p><b>OBJECTIVES</b>To summarize the experience in the treatment of 112 cases of complex bone nonunion from 1982 to 1999 in our department and introduce the technique of external skeletal fixation.</p><p><b>METHODS</b>The two fragment ends of all cases were fixed under pressure with half-ring sulcated external skeletal fixator. Those cases complicated by bone defect or limb shortening were operated on with epiphysiotomy to restore the length of the limb in the period of compressive fixation or after the occurrence of bone union according to the condition of complicated infection and the length of the limb shortened.</p><p><b>RESULTS</b>The nonunion of the 112 cases was united eventually. The infection in 34 cases was eradicated. Bone union in cases without infection took 3 approximately 7 months (average 5.2 months) and in cases with infection took 5 approximately 11 months (average 5.5 months). The length of the limb in 11 cases with bone defect was restored in the same period of compressive external fixation and another 8 cases achieved after bone union. The length between the injured and healthy limbs was balanced.</p><p><b>CONCLUSIONS</b>When external skeletal fixation is employed to treat those troublesome cases of bone nonunion, the pins for fixation are inserted in sites far from the lesions and the non-united fragment ends are exposed only in the area without scars. Consequently, there is little interference with the blood circulation and the osteogenic potency of the fragment ends. The sclerotic bone tissue is not excised, the marrow cavity is not chased to be open and the fragment ends are only moderately modified. As a result, the stability of fixation is increased and further shortening of the limb avoided. External skeletal fixation using small pins with cross penetration results in plastic fixation and promotes bone healing. Bone lengthening with epiphysiotomy can restore the balance of the limbs.</p>

Study on the relationship between epidermal stem cells and the developing process of sweat gland in human fetal skin / 中华烧伤杂志

<p><b>OBJECTIVE</b>To explore the relationship between epidermal stem cells and the developing process of sweat gland in human fetal skin, so as to obtain a hint for future induction of epidermal stem cells to differentiate into sweat gland cells.</p><p><b>METHODS</b>Total layer of human skin from the back of fetus at gestational ages from 11 to 31 weeks, obtained from spontaneous abortion was routinely examined. The expressions of beta1 integrin and keratin 19 in sweat gland cords or buds and mature sweat gland cells were dynamically observed with SP immunohistochemical technique. The development and maturation of sweat gland were identified by the positive staining of keratin 8 with immunohistochemistry.</p><p><b>RESULTS</b>It was revealed by histologic observation that basal layer cells of the primary epidermal ridge exhibited focal aggregation and formed hillocks at 16 gestational weeks. The hillocks of cells then migrated downward as cords into the dermis during 18 - 20 gestational weeks. Then, the end part of the cell cord developed into a round lump of twining cords assuming the mature sweat gland. The expressions of beta1 integrin and keratin 19 were found not only in sweat gland cords and buds but also in the mature cells and lasted throughout the total period of sweat gland development. The expression of keratin 8 in sweat gland buds started since 14 - 16 gestational weeks and maintained thereafter.</p><p><b>CONCLUSION</b>The sweat gland started to develop during 14 - 16 gestational weeks and matured at 24 weeks. During the development process of sweat gland, epidermal stem cells were considered to be the key source.</p>

A RENEWED UNDERSTANDING OF DEDIFFERENTIATION / 解放军医学杂志

The differentiation of cell is a very important biological process. In this paper, the current understanding and advances in research on dedifferentiation are reviewed. Giving more efforts to study this subject may help us disclose the mechanisms and treatment for some diseases.

THE SIGNIFICANCE AND CHARACTERISTICS OF DISTRIBUTION OF EPIDERMAL STEM CELLS DURING WOUND HEALING PROCESS / 解放军医学杂志

To investigate the distribution of epidermal stem cells in regenerating wound tissues, and to elucidate the role of epidermal stem cells during wound repair. 80 circular full-thickness wounds were produced on both sides of the back in 20 male Wistar rats labeled 60 days previously with 5-Bromodeoxyuridine (BrdU) (4 wounds in each animal). Then these 80 wounds were randomly divided into 2 groups as follows: group A: with topical treatment of epidermal growth factor (n=40) and group B: no-treatment (n=40). BrdU, ? 1 integrin and keratin19 (K19) were employed to determine the epidermal stem cells with streptavidin-peroxidase (SP)immunohistochemical method, and the speed and quality of epithelialization were determined with routine histological methods with HE staining on the 3rd, 7th, 14th, and 21st day after the wounding. Results showed that the healing rate of wounds was 80% in group A (32/40) and 60% in group B (24/40). No cells with positive immunostaining for BrdU, ? 1 integrin, or K19 were found in the granulation tissue of all wounds in both groups during the healing process. However, a few BrdU, ? 1 integrin and K19 positive cells, bearing no anatomic relation with the epidermal stem cells in the basal layer, were found scattering in the stratum spinosum and stratum granulosum of the epidermis on the wound edges. The results suggested that epidermal stem cells appearing on the wound edges were the main source of re-epithelialization of granulating wounds.

Expression of alpha-smooth muscle actin in scar tissue and its relationship with apoptosis / 中国病理生理杂志

AIM: To examine the expression of alpha-smooth muscle actin in scar tissue, and observe the phenomenon of apoptosis and its involvement in the process of pathological scarring and the presence of myofibroblasts or absence of cell in the dermis. To investigate the potential role of reparative cell apoptosis in hyperplastic scar formation. METHODS: The samples of scar were obtained from post-burn patients undergoing plastic operation in our burn unit recently, and the samples of control came from skin donor site of the same patient correspondingly. TUNEL assays were performed to evaluate the number of apoptotic cells in scar versus normal skin. In situ hybridization and immunohistochemistry staining technique were employed to determine the expression of different dermis cells markers in scar tissue and normal skin. RESULTS: There existed evident difference in apoptotic cells in the dermis between scars tissue and normal human skin. The expression positive cells were much more in hyperplastic scars than that in normal human skin; the apoptotic cells of proliferative stage were slight more than that of mature stage. However, in proliferative stage, the number of apoptotic cells was higher for the combination of hyperplastic scar than normally healed flat scars. But in mature stage, no obviously difference was detected between hyperplastic scar and normally healed flat scar. The monoclonal anti-? smooth muscle actin (ASMA) expression was significantly stronger in proliferative stage than that of mature stage. CONCLUSIONS: With reconstitution of dermal tissue, myofibroblasts containing alpha-SM actin disappear under normal wound healing, probably as a result of apoptosis. The myofibroblast play a critical role in wound closure and in the pathologic sequelae of healing.

Effect of compressive stress on proliferation and differentiation of human epidermal stem cells cultured in vitro / 中国病理生理杂志

AIM: To investigate the mechanism of proliferation and differentiation of human epidermal stem cells cultured in vitro under the influence of compressive stress.METHODS: Epidermal stem cells were isolated by adhering to type IV collagen and were cultured with conditioned medium,then were detected by Powervision~(TM) two-step immunohistochemical method with keratin 19 and cell cycle analysis.The cultured epidermal stem cells transplanted on silica gel membranes,which were put in a new apparatus,was designed to offer cell culture and intermittent compressive stress(4 kPa,6 kPa,8 kPa,10 kPa,12 kPa) for 2 h,3 times a day simultaneously.A week later,cells on silica gel membranes were identified with keratin 19 and 10 by Powervision~(TM) two-step immunohistochemical method.RESULTS: The new apparatus offered cell culture and intermittent compressive stress simultaneously.The isolated and cultured epidermal stem cells were identified with keratin 19 positive and 84.80 percent of them were showed in G_1 period with cell cycle analysis.Cells on silica gel membranes had been subjected intermittent compressive stress above 8 kPa for a week.The number of the cells was increased,which was more than that in control group.However,some cells identified by immunohistochemical staining with keratin 10 positive were detected among the disposed epidermal stem cells.CONCLUSION: The intermittent compressive stress above 8 kPa induces and promotes epidermal stem cells to proliferate and differentiate,indicating that epidermal stem cells respond to mechanical stress,probably is one of their major biological features.

EXPERIMENTAL STUDY ON CORRELATION BETWEEN EPIDERMAL GROWTH FACTOR(EGF),MATRIX METALLOPROTEINASE(MMP-2,MMP-7) AND DEVELOPING SWEAT GLAND IN HUMAN FETAL SKIN / 解放军医学杂志

The development of sweat glands is a very complex biological process, which involves many factors. In this study, the correlation between epidermal growth factor (EGF), matrix metalloproteinases (MMP 2,MMP 7) and development of sweat glands in human embryos was explored. Furthermore, the mechanism(s) underlying the induction of epidermal stem cells into sweat gland cells was elucidated. Skin biospies of human embryos obtained from spontaneous abortions at different gestational ages from 11 to 31 weeks were used. The dynamical expression of EGF, MMP 2, MMP 7 and keratin 7(K7) in developing sweat gland cells or extracellular stroma surrounding the sweat gland cells were examined with S P immunohistochemical methods. The localization of the cellular sources of MMP 2 and MMP 7 was examined with in situ hybridization. The results showed that at 14 20 wk of gestation, a gradual increase of EGF immunoreactivity was observed not only in developing sweat gland buds but also in extracellular stroma surrounding the buds,and the expression intensity peaked at 20～22 wk of gestational age. All mRNA positive buds or cells in developing sweat glands contained corresponding immunoreactive proteins. The immunostaining for K7 appeared in early sweat gland buds at 14～16wk of gestation, and from then on, K7 was concentrated in developing sweat gland cords or cells. It is suggested that the morphogenesis of sweat gland in human fetal skin begins at 14～16wk of gestational age, and essentially completes by 24wk. There is a close relationship among EGF ,extracellular matrix remodeling and morphogenesis of sweat glands, and EGF is one of the inducers in the development and maturity of sweat gland buds or cells.

SEPARATION AND CULTURE OF EPIDERMAL STEM CELL in vitro / 解放军医学杂志

To investigate the culture method for epidermal stem cell in vitro. Rat skin was peeled from the subcutaneous tissue gently, and cut into small pieces, then incubated for 24h in 0 25%trypsin in a 4℃ shaker. The epidermis was separated from the dermis, and shaken for 10min in 0 25% trypsin at 37℃ to dissociate into single cells. Digestion was terminated by the addition of culture medium +10% serum, and the cells were gently centrifuged and resuspended in the culture medium, which constituted EMEM without calcium, supplemented with 0 05mmol/L CaCl 2 , 9% chelexed FBS, 4ng/ml EGF, 0 5?g/ml gentamicin, and 50% fibroblast conditioned medium (CM ). The CM ( EMEM without calcium, 0 05mmol/L CaCl 2 , 9% chelexed FBS, 0 5?g/ml gentamicin ) was collected from freshly isolated primary neonate fibroblast cultures after 48h, which were passed through a filter with 0 45?m pores, and stored at -20℃ for use. 1?10 6 /ml epidermal cells were incubated for 10～15min at 37℃ on dishes coated with collagen Ⅳ, then the nonadherent cells were rinsed off. The adherent cells were grown to confluency. Cultures were subcultured in a solution of TGG for 5～10min. Once free of the dish, cells were centrifuged, resuspended in fresh medium, and then cultured at 1?10 5 /ml. Cultures were observed for colony formation under a phase contrast microscope, and the structure of the rapidly adherent cells was observed under electron microscopy; the expression of ? 1 integrin and K19 was detected in the rapidly adherent cells and colony cells with SP immunohistochemical methods. The results showed that the cells selected by rapid adherence to collagen type Ⅳ formed large colonies at 7 days, and showed a im mature feature under electron microscopy, manifesting ? 1 integrin and K19 expression. It is suggested that epidermal stem cells could be cultured in vitro .