[Emphasis on the prevention and treatment of hepatic vascular diseases]

Portal hypertension, as a common and complex hepatic vascular disease, is a key pathophysiological link in many events of acute cirrhosis decompensation and the progression of multiple organ failure. The most effective measure to reduce portal hypertension is a transjugular intrahepatic portosystemic shunt (TIPS). Maintaining liver function, reducing complications, and improving patients' quality of life and survival time are positively impacted by early TIPS insertion. Patients with cirrhosis have a risk of portal vein thrombosis (PVT) that is 1 000 times higher than that of the normal population. Hepatic sinusoidal obstruction syndrome has a severe clinical course and a high mortality risk. The primary treatment approaches for PVT and HSOS are anticoagulation and TIPS. The innovative magnetic anastomosis vascular technique significantly shortens the anhepatic time and restores normal liver function in patients following liver transplantation.

[Expert consensus for diagnosis and treatment of thrombocytopenia in China]

Thrombocytopenia is the main clinical manifestation or common complication of multiple diseases, but there is still a lack of systematic understanding of pathogenesis, underlying diseases and treatment strategies of thrombocytopenia. Based on evidence-based medicine, this consensus summarizes seven aspects related to thrombocytopenia, including definition, epidemiology, pathogenesis, clinical manifestations, laboratory examination, diagnosis and treatment. This consensus provides an important reference for the diagnosis and treatment of thrombocytopenia.

Identification of sirtuin 1 as a promising therapeutic target for hypertrophic scars

BACKGROUND AND PURPOSE

Sirtuin1 (SIRT1), the founding member of mammalian class III histone deacetylases, is reported to be a drug target involved in fibrotic diseases. However, whether it is an effective drug target in hypertrophic scar treatment is still not known.

EXPERIMENTAL APPROACH

In the present study, we observed that SIRT1 localized to both the epidermis and the dermis of skin tissues by immunohistochemistry. After knock-down of SIRT1 by shRNA or up-regulating SIRT1 by resveratrol, the expression of α-SMA, Col1 and Col3 in fibroblasts were detected by western blots. A mouse excision wound healing model was used to observe the changes in collagen fibre associated with the different expression levels of SIRT1.

KEY RESULTS

SIRT1 expression was inhibited in hypertrophic scar tissue. The down-regulation of SIRT1 resulted in an increased expression of α-SMA, Col1 and Col3 in hypertrophic scar-derived fibroblasts. In contrast, the up-regulation of SIRT1 not only inhibited the expression of α-SMA, Col1 and Col3 in hypertrophic scar-derived fibroblasts but also blocked the activation of TGFβ1-induced normal skin-derived fibroblasts. In the mouse model of wound healing, the deletion of SIRT1 resulted in denser collagen fibres and a more disordered structure, whereas resveratrol treatment led to a more organized and thinner collagen fibre, which was similar to that observed during normal wound healing.

CONCLUSIONS AND IMPLICATIONS

The results revealed that SIRT1 negatively regulates TGFβ1-induced fibroblast activation and inhibits excessive scar formation and is, therefore, a promising drug target for hypertrophic scar formation.

Acute downregulation of miR-155 at wound sites leads to a reduced fibrosis through attenuating inflammatory response

Fibrosis, tightly associated with wound healing, is a significant symptomatic clinical problem. Inflammatory response was reported to be one of the reasons. MiR-155 is relatively related with the development and requirement of inflammatory cells, so we thought reduce the expression of miR-155 in wound sites could improve the quality of healing through reduce inflammatory response. To test this hypothesis, locally antagonizing miR-155 by directly injecting antagomir to wound edge was used to reduce the expression of miR-155. We found wounds treated with miR-155 antagomir had an obvious defect in immune cells requirements, pro-inflammatory factors IL-1β and TNF-α reduced while anti-inflammatory factor IL-10 increased. With treatment of miR-155 antagomir, the expression of α-smooth muscle actin (α-SMA), Col1 and Col3 at wound sites all reduced both from mRNA levels and protein expressions. Wounds injected with antagomir resulted in the structure improvement of collagen, the collagen fibers were more regularly arranged. Meanwhile the rate of healing did not change significantly. These results provide direct evidences that miR-155 play an important role in the pathogenesis of fibrosis and show that miR-155 antagomir has the potential therapy in prevention and reduction of skin fibrosis.

Construction of the tissue engineering seed cell (HaCaT-EGF) and analysis of its biological characteristics

OBJECTIVE

To construct the tissue engineering seed cell (HaCaT cell line) with stable expression of the human epidermal growth factor (EGF), and analyze the changes of its biological characteristics.

METHODS

PCDNA3.1-EGF eukaryotic expression vector was transferred into HaCaT cell, and G418 was utilized to select the HaCaT-EGF cell line. Using an inverted microscope, PCR, ELISA method to detect the changes of the cell morphology, the expression of the EGF gene and protein, and the mRNA expression levels of apoptosis related molecule Caspase-3, the cell cycle related protein cyclin D1.

RESULTS

The mRNA expression levels of the obtained HaCaT-EGF cell were more than 100 times higher than the level of ordinary HaCaT cell. The colony of the HaCaT-EGF cells was more focused and tight compared to the empty vector transfected HaCaT cells and normal HaCaT cells. The expression levels of apoptotic factor Caspase-3 and cyclin D1 in HaCaT-EGF cell were significantly higher than those in the empty vector HaCaT- pcDNA3.1 cell, and the differences were statistically significant (P<0.01), but there was no significant difference compared to the normal HaCaT cells (P>0.05).

CONCLUSIONS

HaCaT-EGF cell can continuously secrete EGF, and the biological characteristic is stable. It can be used for tissue engineering experiment and is an ideal seed cell for constructing tissue engineered skin.

Protection against TGF-β1-induced fibrosis effects of IL-10 on dermal fibroblasts and its potential therapeutics for the reduction of skin scarring

Scarring, tightly associated with fibrosis, is a significant symptomatic clinical problem. Interleukin 10 (IL-10) has been identified as a candidate scar-improving therapy based on preclinical studies. However, the molecular mechanism of IL-10 in scar improvement is still uncertain. In this study, human dermal fibroblasts stimulated with TGF-β1 were treated with IL-10 to analyze the mRNA and some of proteins' expression levels of type I collagen (Col1), type III collagen (Col3), alpha-smooth muscle actin (α-SMA), matrix metalloproteinase-1 (MMP1), MMP2, MMP8 and tissue inhibitor of metalloproteinase 1 (TIMP1), TIMP2 by real-time PCR and Western blot, to observe α-SMA-positive fibroblasts by immunocytochemistry. The contracture and improvement of fibroblast-populated collagen lattice (FPCL) and a murine model of wound healing were used to evaluate the scar-improving effects by histological staining. The results showed that IL-10 can significantly down-regulate the mRNA and protein expression levels of Col1, Col3, α-SMA, and up-regulate the mRNA expression levels of MMP1 and MMP8, and decrease α-SMA-positive fibroblasts. FPCL analysis showed that the IL-10 (20 ng/ml) can significantly inhibit the contracture, improve the architecture of FPCL. Wounds injected with IL-10 demonstrated that the appearance of scar was improved, the wound margin of scarring was narrow, and the deposition of collagens (Col1 and Col3) in regenerated tissue was relieved. These results provide direct evidences that IL-10 has the inhibitory effects on the excessive deposition of extracellular matrix components and fibroblast-to-myofibroblast transition, and show that IL-10 has the potential therapy in prevention and reduction of skin scarring.

Disturbances of mesenteric lymph flow and in vivo intestinal lymphocyte trafficking during early gut injury induced by ischemia-reperfusion in rats

We sought to define the role of mesenteric lymph in the generation of remote organ damage at the early stage of gut ischemia-reperfusion (I/R) injury. The measurement of mesenteric lymph flow was carried out by cannulation of mesenteric lymphatics. The distribution of in vivo intestinal lymphocyte trafficking was performed by 51Cr labeled lymphocyte and measurement of 51Cr-lymphocytes distribution by gamma-counter. Endotoxin concentration was assayed using the limulus test kit and TNF-alpha level was detected by ELISA. After gut I/R injury, the volumes of lymph flow in mesenteric lymphatics per hour were sharply decreased by 72% and the number of intestinal lymphocytes per milliliter was decreased by 61%, which led to the intestinal lymphocyte output per hour significantly decreased by 90% (predominantly T cells), while the population of 51Cr-lymphocytes in Peyer's patches, small intestine (except Peyer's patches), mesenteric nodes, large intestine, and stomach increased by 87%, 191%, 87%, 266%, 262%, respectively. Meanwhile, endotoxin and TNF-alpha levels in mesenteric lymph were significantly increased. These findings demonstrate the marked disorders of mesenteric lymph flow and in vivo intestinal lymphocytes migration and the accompanying increase of endotoxin and TNF-alpha levels in mesenteric lymph in the early stage of gut I/R injury.

Reduced expression of microtubule-associated protein 1 light chain 3 in hypertrophic scars

Autophagy is a tightly regulated physiological process essential for cellular maintenance, differentiation, development, and homeostasis. Aberration of this process associates with the pathogeneses of several diseases in mammals. Hypertrophic scar (HS) is characterized by an abundance of collagenous tissue with hypercellularity. However, the molecular mechanism in HS formation is poorly understood. We compared the autophagic capacity in HS and its normal skin (NS) counterparts and explored the molecular mechanism of autophagy during the formation of HS. Microtubule-associated protein 1 light chain 3 (LC3) proteins in HS and NS were detected by immunohistochemistry, Western blot and quantitative real-time PCR (qPCR). The data showed that LC3 positive staining in HS was less intensive relative to NS group (p < 0.05). Three forms of LC3, with molecular weights of about 19 kDa (proLC3), 18 kDa (LC3-I) and 16 kDa (LC3-II), respectively, expressed in NS by Western blot. In contrast, only proLC3 expressed while both LC3-I and LC3-II were significantly downregulated in HS. The protein level of beclin 1 in HS was significantly lower compared with NS (p < 0.05). LC3 and beclin 1 mRNA levels in HS were significantly lower than that in NS (p < 0.05). These results suggest that the generation of LC3-I and LC3-II are interrupted in HS, and that the resultant decrease of autophagic capacity may associate with the pathogenesis of HS.

Smad interacting protein 1 as a regulator of skin fibrosis in pathological scars

Keloids and hypertrophic scars are significant symptomatic clinical problems characterized by the excessive and abnormal deposition of collagen-based extracellular matrix (ECM) components. However, the molecular basis of keloid and hypertrophic scar formation has not been fully elucidated. Here, we demonstrated that down-regulation of the transcription factor Smad interacting protein 1 (SIP1) could be relevant to keloid and hypertrophic scar formation. The results of the present study show that the level of SIP1 mRNA is significantly decreased in pathological scar tissues and in normal skin and pathological scar fibroblasts treated with transforming growth factor β1 (TGF-β1). In contrast, the expression of SIP1 mRNA is not decreased in normotrophic scar samples. The SIP1 mRNA level inversely correlates with the mRNA level of type I collagen (COL1A2) and directly correlates with the mRNA level of matrix metalloproteinase-1 (MMP1). Overexpression of SIP1 in keloid and hypertrophic scar fibroblasts represses TGF-β1-stimulated COL1A2 expression and induces MMP1 expression. Alternatively, knockdown of SIP1 in normal skin fibroblasts enhance TGF-β1-induced COL1A2 levels. These findings suggest that SIP1 could be a regulator of skin fibrosis, and depletion of SIP1 in pathological scar tissues could result in an up-regulation of collagen and down-regulation of matrix metalloproteinase, leading to an abnormal accumulation of ECM along with fibrosis and pathological scar formation.

[Reproduction of a model of heat injured keratinocyte in vitro and observation on its apoptosis rate]

OBJECTIVE

To reproduce a model of heat injured KC in vitro and explore its apoptosis rate of KC due to heat injury at different temperature.

METHODS

Human KCs were cultured in vitro, and they were incubated at 37, 41, 43, 45, 48, and 51 degrees C respectively for 10 mins in water bath. Trypan blue staining and Hoechst 33258 fluorescence staining were used respectively to determine necrosis and apoptosis of KC. Rates of apoptosis and necrosis of KC were analyzed quantitatively by flow cytometer. The proliferation activity of KC after heat injury was detected by MTT test.

RESULTS

The results of trypan blue staining, Hoechst 33258 fluorescence staining, and flow cytometer demonstrated that number of apoptotic and necrotic KC increased gradually along with a rise of water bath temperature. The rates of apoptosis and necrosis of KC were respectively (12.3 +/- 3.2)% and (14.1 +/- 1.6)% at 45 degrees C, (27.7 +/- 5.1)% and (58.0 +/- 4.2)% at 48 degrees C. Rate of KC necrosis reached up to (83.0 +/- 5.3)% at 51 degrees C. Inhibition of KC growth reached a stationary phase when the injurious temperature reached 45 degrees C as observed with MTT test.

CONCLUSIONS

Heat injury can induce apoptosis and growth inhibition of KC in vitro. Incubating KC at 45 degrees C for 10 mins is a good condition to reproduce a model of heat injured KC in vitro. This model may be used to study the biological character and apoptosis of KC after burn injury.

[Protective effect of melatonin on oxidative stress inducing hair follicle injury in scald rat]

OBJECTIVE

To investigate the protective effect of melatonin on residual hair follicle cells of scald rats at early stage.

METHODS

Eighteen male Sprague-Dawley rats were randomly divided into scald group, treatment group, sham group , with 6 rats in each group. The rats in scald group and treatment group were subjected to 30% TBSA partial thickness scald on the back, and were resuscitated with balanced solution after 1 hour, while those in sham group were immersed in water at 37 degrees C for 25 s to simulate scald, and did not receive fluid replacement. Rats in treatment group were intraperitoneally injected with 10 mg/kg melatonin solution at 1 minute, 8 hours and 12 hours after scald, while those in sham group and scald group were given equal volume of 1% alcohol sodium-isotonic saline instead. Tissue samples were harvested at 6, 12 and 24 post scald hours (PSH) for determination of MDA and GSH levels. Apoptosis of residul hair follicle was detected by TUNEL method and immunohistochemistry of caspase-3.

RESULTS

The level of MDA in scald group at each time point was much higher than that in sham group (P < 0.01) and treatment group (P < 0.05), and it peaked at 12 PSH. The changes in GSH were just opposite to that of MDA. Under fluorescence microscope, the residual hair follicle cells were blue, and the apoptotic cells appeared green. The apoptosis rate in scald group at 6, 12, 24 PSH was obviously higher than that in sham (P < 0.01) and treatment groups (P < 0.05), which was (20.2 +/- 3.4)% vs (4.3 +/- 2.3)% vs (10.9 +/- 3.2)%, (31.2 +/- 3.6)% vs (5.1 +/- 2.5)% vs (19.1 +/- 3.7)%, (22.4 +/- 2.7)% vs (4.1 +/- 2.4)% vs (13.1 +/- 3.4)%, respectively. The score of caspase-3 positive cell in scald group was higher than those in sham group (P < 0.01) and treatment group (P < 0.05).

CONCLUSIONS

There is obvious correlation between oxidative stress and apoptosis rate of hair follicle cells in rats with partial thickness scald. Early administration of melatonin may have anti-apoptosis ability for residual hair follicle cells by attenuation of oxidative stress.

[Protective effect of insulin on oxygen-radical induced hepatic injury in severely scalded rats]

OBJECTIVE

To investigate the protective effect of insulin on oxygen-radical induced hepatic injury in severely scalded rats in early stage of severe scald.

METHODS

Eighty-four male Sprague-Dawley rats were randomly divided into three groups: i. e, normal group, saline group, and insulin group, with 28 rat in each group. The rats in the latter two groups were subjected to 30% TBSA full-thickness scald on the back, and received intra-peritoneal injection of 40ml/kg isotonic saline, and subcutaneous injection of 3 IU/kg insulin, respectively. The total anti-oxygen capability (T-AOC), the expression of superoxide dismutase (SOD), reactive oxygen species (ROS) and intercellular adhesion molecule (ICAM-1) in hepatic tissue, and serum alanine transaminase (ALT) were determined in each group at 6, 12, 24, 48 post-scald hours (PSH) with corresponding methods.

RESULTS

The hepatic T-AOC and SOD content were obviously decreased, while the ROS content were markedly increased at 6 PSH in saline group compared with that in normal group (P < 0.05 or P < 0.01). The expression of ICAM-1 and serum content of ALT were significantly higher than that in normal group at 12 PSH and 48 PSH (P < 0.01). At 24 PSH, the hepatic T-AOC (386 +/- 75) U/g and SOD content (210 +/- 39 ) U/g were obviously higher in insulin group than those in saline group [(124 +/- 18), (111 +/- 9) U/g, respectively, P < 0.01), but the ROS content (154 +/- 29 ) U/g was much lower than that in saline group [(351 +/- 41) U/g, respectively, P < 0.01]. At 48 PSH, the serum content of ALT and hepatic expression of ICAM-1 in insulin group exhibited obvious difference when compared with those in saline group (P < 0.01). Meanwhile, Pathological examination showed that hepatic injury was alleviated by insulin administration after scald.

CONCLUSION

Insulin administration early after severe scald exhibits protective effect on liver function by improving anti-oxygen radical ability of rat liver.

[The protective effect of intensive insulin treatment on the myocardium in severely scalded rats]

OBJECTIVE

To study the protective effect of intensive insulin treatment on the myocardium of severely scalded rats, and to primarily explore its mechanism.

METHODS

Eighteen SD rats were divided into three groups, with 6 rats in each group. The rats in burn and intensive insulin group were inflicted with 30% TBSA full-thickness injury on the back. Isotonic saline containing 0.12 U/ml insulin solution, and 100 g/L glucose solution were infused into the rats in the intensive insulin group to keep plasma glucose at the level of 4.0 - 6.6 mmol/L (the total fluid amount was 2 ml x kg(-1) x 8h(-1)). In sham burn group,fluid was given according to physiological demand. The same amount of isotonic saline was infused into the rats in burn group. The venous blood was obtained for the detection of plasma glucose contents, and the left ventricular systolic pressure (LVSP) and left ventricular end-diastolic pressure (LVEDP) were recorded via aortic ventricle cannula before scald and at 1, 2, 3, 4, 5, 6 post-scald hours (PSH). The tissue of the left ventricle was harvested at 6 PSH for the detection of troponin T expression in myocardiocytes.

RESULTS

Plasma glucose level was increased to (7.6 +/- 1.7) mmol/L - (8.4 +/- 4.7) mmol/L in burn group during 1-6 PSH, which was significantly higher than that in intensive insulin group (4.5 +/- 0.9) mmol/L - (5.2 +/- 1.3) mmol/L, P < 0.01). Compared with the intensive insulin group, LVSP was markedly decreased in the burn group (60 +/- 11 mm Hg vs 72 +/- 8 mm Hg, P < 0.05) at 1 PSH,whereas LVEDP was increased significantly (21.3 +/- 11.3 mmHg vs 11.7 +/- 5.2 mmHg, P < 0.05). Intensive insulin treatment could significantly inhibit the loss of troponin T protein in myofilaments of myocardium.

CONCLUSION

Intensive insulin treatment possesses a protective effect on myocardia function after severe burns, and it may be related to its preventive effect on the loss of contractile protein in cardiocytes.

[Primary observation on construction of skin with human hair follicle bulge cells with tissue engineering technique]

OBJECTIVE

To investigate the feasibility of fabricating tissue engineering skin with human hair follicle bulge cells (HFBCs) to repair full-thickness skin wound.

METHODS

HFBCs and dermal papilla cells (DPCs) isolated from human fetal hair follicles by collagenase digestion were cultured, purified and passaged. PGA-collagen scaffolds as bioengineered dermis were randomly divided into A and B groups. The HFBCs and DPCs (1 : 2) were seeded in scaffolds of group A and the equal amount of DPCs was seeded in scaffolds of group B as control. Then the keratinocyte sheets were seeded onto the surfaces of the scaffolds as bioengineered epidermis. The tissue engineering skins were then transplanted to repair the full-thickness wound on the back of nude mice. The wound healing process was observed and the plant histological changes of the transplanted engineered skin was observed with light microscope on 2, 4, 6 post-operation weeks (POW).

RESULTS

The full-thickness defect of nude mice in A and B groups could be effectively repaired by bioengineered skins. On 2 POW, integral epidermal and dermal structures were observed in the wounds in A and B groups, with thin epithelial layer and basement membrane. On 4 POW, epithelial layer became thickening and rete pegs formation was observed in basement membrane in A group, but only thickening of epithelial layer was observed in B group. On 6 POW, rete pegs structure was seen to descend and hair-follicle-like structure was formed, while only thickened epithelial layer with flat basement membrane were formed in B group.

CONCLUSION

From the composite skin engineered with PGA-collagen hybrid scaffolds and keratinocytes, HFBCs and DPCs could effectively repair the full-thickness skin defect of nude mice. The hair follicle stem cells participate in the process of anatomic repair of wound, and might be able to induce the repair of skin structure and function.

[Establishment of rat model of scalding with high pressure steam]

OBJECTIVE

To establish a rat model of scalding with controllable depth and area by high pressure steam.

METHODS

High pressure steam apparatus consisting of an autoclave and a self-made scalding frame was employed in the study. The rats were inflicted with scalding with 0.12 Mpa (1 Mpa = 7500 mmHg) high pressure steam on the back through a hole of 2.6 cm in diameter for 3, 4, 5, 6, 7, 8, 9 and 10 seconds, with five wounds at each time point. The tissue samples were harvested at 24 post injury hour (PIH) for pathomorphological examination. The depth of scald was measured, and injury to the sweat gland and hair follicles injury, the hair growth in scalded area, and the wound healing condition were observed with Photoshop software.

RESULTS

There was positive correlation between the scalding depth and scalding time. The injury time for superficial and deep partial thickness burn and full thickness burn were 3, 5 and 7 seconds respectively. The wound healing time was similar even the scalding became more and more serious when injury time increased from 7 to 10 seconds.

CONCLUSION

The scalding depth and area in this model could be controlled, and the degree of scald injury could be graded accurately with easy manipulation. The result showed that it was an ideal model of skin burn wound.

[An experimental study on the change in neuropeptide substance P in the burn wound skin in scalded rats]

OBJECTIVE

To investigate the change in neuropeptide substance P (SP) in the burn wound skin in scalded rats.

METHODS

The SP distribution density in the rat skin samples from the burn wound, peri-wound area and remote area of scalded rats were determined by immunohistochemistry technique. The mRNA expression of SP was observed by in situ hybridization.

RESULTS

The distribution density of SP in the skin samples from the above three areas decreased obviously since 15 mins postburn, dropped to the lowest level during 6 - 12 postburn hou (PBH), and then recovered thereafter. Comparatively, the recovery in peri-wound area occurred earlier. In addition, there was emigration of macrophage-like large cells with positive SP immunoreactivity from local blood vessels in the dermal layer of the burn wound and peri-wound areas. The large cells were closely related to the local SP-containing nerve fibres at 12 PBHs. Intensified staining of the cells was identified at 24 PBHs with the disintegration of the cells into pieces with release of large amounts of positive SP immunoreactive granules, followed by disappearance of the cells at 48 PBHs. It was indicated by in situ hybridization that the preprotachykinin A (PPTA) mRNA encoding and synthesizing SP was expressed in various cells at 6 PBHs.

CONCLUSION

SP might be synthesized and released from cutaneous nerve ending or from local inflammatory cells after skin burn injury.

[The in vitro isolation, culture and transfection of human fetal epidermal stem cells]

OBJECTIVE

To explore the in vitro methods of isolation and culture of human fetal epidermal stem cells (HFESCs) and the feasibility of the cultured cells as the target cells for gene transfection.

METHODS

The HFESCs were isolated by means of type IV collagen rapid adhering method. The culture medium for HFESCs was prepared according to that for human fetal fibroblasts. The cultured cells were identified by immunohistochemistry staining of keratin-19 and integrin-beta1, cell cycle analysis and clone forming rate determination. Then the cultured cells were gene transfected in vitro by liposome mediating method in which eukaryon expression vector pcDNA3.1/VEGF165 containing vascular endothelial growth factor 165 (VEGF165) were transfected into cultured cells, or by virus vector mediating method in which recombinant adenovirus accompanied vector (raav) containing green fluorescent protein (GFP) (raav/GFP) were transfected into the cultured cells, respectively. The results of in vitro gene transfection of HFESCs were observed by immunohistochemisty staining and fluorescence microscope.

RESULTS

HFESCs grew well and formed large clones with higher cloning efficiency and higher ratio of G1 cells than keratinocytes. The cultured cells were strongly positive with immunohistochemistry staining of keratin-19 and integrin-beta1. After being gene-transfected by pcDNA3.1/VEGF165, the VEGF165 of HFESCs showed positive immunohistochemistry staining property, while the HFESCs transfected by raav/GFP exhibited strong fluorescence.

CONCLUSION

HFESCs could be isolated and cultured in vitro by means of rapid adherence to type IV collagen. It seemed feasible that HFESCs were gene transfected with liposome or adeno-associated virus as the vector.

[Long-term in vitro culture of the fibroblasts from the deep partial thickness burn wound in burn patients]

OBJECTIVE

To establish a long-term in vitro culture of the fibroblasts obtained from burn wounds.

METHODS

Skin samples were harvested from normal volunteers and the deep partial thickness burn wound in burn patients on the 5th, 10th, 21st, 28th and 35th postburn days (PBDs). The non-dermal tissue was removed from the samples and primed by chlorhexidine solution in concentration of 2.5 g/L. The skin sample was then digested by trypsin-EDTA in concentration of 1.25 g/L and was centrifuged before the cells were harvested and cultured. When the cells grew nearly to form sheet, multiple passage culture, freezing storage and revivification were carried out with routine methods. The cell morphology was continuously observed during the culture. And the cell doubling time was calculated.

RESULTS

The wound-origin fibroblasts exhibited higher purity and better activity. The cellular growth features and gross morphology kept stable during primary and secondary culture, and during freezing storage and after revivification. The cells kept their activity above 80% of their original after many times of revivification.

CONCLUSION

The establishment of the in vitro culture of fibroblasts from burn wounds might be useful in the exploration of the pathogenesis and therapeutic measures of scars.

Pediatric foot fractures: evaluation and treatment

Foot fractures account for 5% to 8% of all pediatric fractures and for approximately 7% of all physeal fractures. A thorough understanding of the anatomy of the child's foot is of central importance when treating these injuries. Due to the difficulties that may be encountered in obtaining an accurate physical examination of a child with a foot injury and the complexities of radiographic evaluation of the immature foot, a high index of suspicion for the presence of a fracture facilitates early and accurate diagnosis. Although the treatment results in pediatric foot trauma are generally good, potential pitfalls in the treatment of Lisfranc fractures, talar neck and body fractures, and lawn mower injuries to the foot must be anticipated and avoided if possible.

Elbow aspiration and arthrogram: an alternative method

We describe a posterior elbow-aspiration approach that is safe, easy, and effective in all settings, including trauma.

Use of P wave configuration during atrial tachycardia to predict site of origin

OBJECTIVES

This study sought to construct an algorithm to differentiate left atrial from right atrial tachycardia foci on the basis of surface electrocardiograms (ECGs).

BACKGROUND

Atrial tachycardia is an uncommon form of supraventricular tachycardia, often resistant to drug therapy.

METHODS

A total of 31 consecutive patients with atrial tachycardia due to either abnormal automaticity or triggered rhythm underwent detailed atrial endocardial mapping and successful radiofrequency catheter ablation of a single atrial focus. P wave configuration was analyzed from 12-lead ECGs during tachycardia during either spontaneous or pharmacologically induced atrioventricular block. P waves inscribed above the isoelectric line (TP interval) were classified as positive, below as negative, above and below (or conversely, below and above) as biphasic and flat P waves as isoelectric (0). In 17 patients the tachycardia was located in the right atrium: crista terminalis (n = 4); right atrial appendage (n = 4); lateral wall (n = 4); posteroinferior right atrium (n = 3); tricuspid annulus (n = 1); and near the coronary sinus (n = 1). In 14 patients, atrial tachycardia was located in the left atrium: at the entrance of the right (n = 6) or left (n = 4) superior pulmonary veins; left inferior pulmonary vein (n = 1); inferior left atrium (n = 1); base of left atrial appendage (n = 1); and high lateral left atrium (n = 1).

RESULTS

There were no differences in P wave vectors between sites at the right atrial lateral wall versus the right atrial appendage or between sites at the entrance of right versus left superior pulmonary veins. However, analysis of P wave configuration showed that leads aVL and V1 were most helpful in distinguishing right atrial from left atrial foci. The sensitivity and specificity of using a positive or biphasic P wave in lead aVL to predict a right atrial focus was 88% and 79%, respectively. The sensitivity and specificity of a positive P wave in lead V1 in predicting a left atrial focus was 93% and 88%, respectively.

CONCLUSIONS

1) Analyses of surface P wave configuration proved to be reasonably good in differentiating right atrial from left atrial tachycardia foci. 2) Leads II, III and aVF were helpful in providing clues for differentiating superior from inferior foci.

Elimination of sodium-24 and potassium-42 interferences in activation analysis of biological samples

We have developed a simple novel column technique for the removal of sodium-24 and potassium-42 based on a heterogeneous isotopic exchange reaction between an organic eluting solution (acetone-hydrochloric acid) and fine crystals of sodium chloride or potassium chloride or their analogs. The technique is fast, efficient, and highly selective; it has been successfully applied to irradiated human tissues prior to gamma-ray spectrometry with lithium-drifted germanium detectors.