[Research advances on exosomes derived from adipose-derived mesenchymal stem cells in promoting diabetic wound healing]

Impaired healing of diabetic wounds is mainly attributed to its pathological mechanism, and refractory diabetic wounds bring heavy burdens to patients and society. Exosomes derived from stem cells possess the similar ability as stem cells in promoting tissue regeneration and more clinical advantages and are gradually playing important roles in wound healing. In recent years, researches have shown that exosomes derived from adipose-derived mesenchymal stem cells (ADSC-EXOs) can promote the healing of diabetic wounds by participating in various processes of wound healing. This article reviews the pathological mechanism leading to impaired healing of diabetic wounds, the related mechanism and the application prospect of ADSC-EXOs in promoting diabetic wound healing.

CDCA2 promotes proliferation and migration of melanoma by upregulating CCAD1

OBJECTIVE

This study aims at investigating the functional role of CDCA2 (cell division cycle associated 2) in enhancing proliferative and migratory abilities in melanoma by upregulating CCAD1, thus aggravating the progression of melanoma.

PATIENTS AND METHODS

CDCA2 levels in melanoma tissues and cell lines were determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) and Western blot. Regulatory effects of CDCA2 on proliferative and migratory abilities in melanoma cells were assessed by Cell Counting Kit-8 (CCK-8), 5-Ethynyl-2'-deoxyuridine (EdU), and wound healing assay, respectively. At last, rescue experiments were conducted to explore the involvement of CCAD1 in CDCA2-regulated progression of melanoma.

RESULTS

CDCA2 was upregulated in melanoma tissues, especially in those with metastasis. Identically, in vitro level of CDCA2 was upregulated in melanoma cell lines. The knockdown of CDCA2 in A375 and sk-mel-110 cells inhibited the proliferative and migratory abilities. The overexpression of CCAD1 could partially abolish the inhibitory effects of silenced CDCA2 on proliferative and migratory abilities in melanoma.

CONCLUSIONS

CDCA2 stimulates proliferative and migratory abilities in melanoma cells by upregulating CCAD1, thus aggravating the malignant progression of melanoma.

The role of quinazoline in ameliorating intervertebral disc degeneration by inhibiting oxidative stress and anti-inflammation via NF-κB/MAPKs signaling pathway

OBJECTIVE

Previous studies have shown that Quinazoline (QNZ) plays extremely important roles in the cellular physiological activity, but it has been rarely examined on cell behavior following intervertebral disc degeneration (IVDD). The aim of this study was to investigate whether QNZ mediates oxidative stress and inflammation contributed to IL-1β-induced nucleus pulposus (NP) cells degeneration in vitro.

PATIENTS AND METHODS

NP were isolated cells from human disc samples collected from patients and the IL-1β-induced NP cells degenerated model was constructed. The cells were randomly divided into 3 groups, namely, Control group, IL-1β group (10 µM), QNZ + IL-1β group (containing 10 nM QNZ and 10 µM IL-1β). Then, the cell viability was determined by CCK-8 assay, and the levels of collagen I, collagen II, aggrecan, p16, p53, β-galactosidase (β-gal), antioxidant enzymes, 8-hydroxy-2-deoxyguanosine (8-OHdG), NF-κB/MAPKs signaling-related proteins and inflammatory factors were examined using Western blot and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) in NP cells. Finally, the expressions of IL-1β, IL-6, and TNF-α in the cell supernatants were also determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

This study showed that IL-1β promoted the progress of IDD, with markedly increased expressions of collagen I, p16, p53, and β-gal, as well as decreased expressions of collagen II and aggrecan. However, QNZ treatment could reverse the effects of IL-1β. It was found that cell proliferation was increased, ROS level was decreased, antioxidant enzymes were upregulated, and inflammatory factors were reduced after QNZ stimulation. Moreover, NF-κB/MAPKs signaling proteins IKKβ, IκBα, p65, ERK, JNK, and p38 were significantly dephosphorylated by QNZ.

CONCLUSIONS

These results indicated that QNZ prevented NP degradation via restraining oxidative stress and inflammation through inhibition of the NF-κB/MAPKs signaling pathway. QNZ may become a novel insight into the therapy of IVDD in the future.

Arsenite induces dysfunction of regulatory T cells through acetylation control of the Foxp3 promoter

Arsenic is known to cause damage to the body's immune system by inducing epigenetic changes. However, the molecular mechanism of this damage remains elusive. Here, we report that arsenic disrupts the morphology of lymphocytes, decreases cell viability, and results in abnormal proportions of T lymphocyte subsets. Moreover, our results revealed that arsenic can reduce global acetylation of histone H4 at K16 (H4K16 ac) in lymphocytes via decreasing the level of males absent on the first but upregulates mRNA and protein levels of the forkhead/winged-helix box P3 (Foxp3) gene by increasing the acetylation of histone H4 at K16 (H4K16) at the promoter of Foxp3. Finally, arsenic-induced dysfunction of regulatory T cells (Tregs) could be ameliorated by trichostatin A. Our research indicates that arsenic-induced immunosuppressive effect in human lymphocytes may be related to the acetylation of H4K16 at the promoter of Foxp3 and that histone deacetylase inhibitors may play a role in the prevention and treatment of immune injury caused by arsenic.

Risk factors for disease progression in patients with mild to moderate coronavirus disease 2019-a multi-centre observational study

Objectives

Since December 2019, the novel coronavirus disease 2019 (COVID-19) that emerged in Wuhan city has spread rapidly around the world. The risk for poor outcome dramatically increases once a patient progresses to the severe or critical stage. The present study aims to investigate the risk factors for disease progression in individuals with mild to moderate COVID-19.

Methods

We conducted a cohort study that included 1007 individuals with mild to moderate COVID-19 from three hospitals in Wuhan. Clinical characteristics and baseline laboratory findings were collected. Patients were followed up for 28 days for observation of disease progression. The end point was the progression to a more severe disease stage.

Results

During a follow up of 28 days, 720 patients (71.50%) had recovered or were symptomatically stable, 222 patients (22.05%) had progressed to severe disease, 22 patients (2.18%) had progressed to the critically ill stage and 43 patients (4.27%) had died. Multivariate Cox proportional hazards models identified that increased age (hazard ratio (HR) 2.56, 95% CI 1.97–3.33), male sex (HR 1.79, 95% CI 1.41–2.28), presence of hypertension (HR 1.44, 95% CI 1.11–1.88), diabetes (HR 1.82, 95% CI 1.35–2.44), chronic obstructive pulmonary disease (HR 2.01, 95% CI 1.38–2.93) and coronary artery disease (HR 1.83, 95% CI 1.26–2.66) were risk factors for disease progression. History of smoking was protective against disease progression (HR 0.56, 95% CI 0.34–0.91). Elevated procalcitonin (HR 1.72, 95% CI 1.02–2.90), urea nitrogen (HR 1.72, 95% CI 1.21–2.43), α-hydroxybutyrate dehydrogenase (HR 3.02, 95% CI 1.26–7.21) and D-dimer (HR 2.01, 95% CI 1.12–3.58) at baseline were also associated with risk for disease progression.

Conclusions

This study identified a panel of risk factors for disease progression in individuals with mild to moderate COVID-19.

[New research advances and clinical treatment of scar]

Scar formation is the abnormal healing process of skin after being damaged. The mechanism of scar formation is not clear, and many studies have shown that it is affected by many factors. Based on the over deposition of collagen in scars, many researchers have carried out studies on the mechanism, pathological manifestation, and treatment method of scars. In the treatment aspect of scar, the combination of traditional and new treatment methods has been well accepted and achieved good results. To understand the new advances of scar research and combine it with clinical treatment transformation could lead to the development of more effective prophylactic and therapeutic strategies for scar treatment in the future.

[Review of 60 years' development of Department of Burns and Plastic Surgery in West China Hospital of Sichuan University]

Burn medicine of China started in 1958. Over the past 60 years, through the efforts of numerous burn discipline scholars, China's burn clinical and scientific research have reached the world's advanced level. Department of Burns and Plastics Surgery of West China Hospital of Sichuan University was founded in 1963. Department of Burns of our hospital was established earlier in China. In the past 60 years, professor Yu Baoliang, Ren Linsen, and Cen Ying had been working hard for the development of our department. Department of Burns and Plastic Surgery in West China Hospital of Sichuan University has developed from a pure therapeutic specialty group into one of the burn centers with strong technical force, first-class medical level, advanced instruments and equipment, rich scientific research achievements, and integrated medicine, teaching, and research in southwestern China, which enjoys high prestige at home and abroad.

[Advances in the research of effects of heat-shock factor 1 and heat-shock proteins on wound healing and the mechanism]

Heat-shock proteins (HSPs) are the protective proteins expressed by cells under stress. Heat-shock factors (HSFs) are the key factors to regulate HSPs. Researches about the effects of HSF1 and HSPs in cells after stress and the mechanism have become the important entry point to explore the cell response in wound healing after trauma. This article reviews the effects of HSPs and HSF1 which regulate the proteins on wound healing and the mechanism, so as to deliver message for studying effects of intervening HSF1 on expression of HSPs and wound healing and the mechanism.

[Investigation on events of bus on fire in 6 years in the mainland of China]

Objective: To retrospectively analyze the characteristics of events of bus on fire in 6 years in the mainland of China. Methods: Events of bus on fire happened between January 2009 and December 2014 were retrieved through Baidu search engine, Chinese Journals Full-text Database, and PubMed database in the search strategy with " bus" and " fire" or " arson" as keywords combined with the name of provinces, autonomous regions, and municipalities of the mainland of China. The occurrence time, region, cause of fire, casualties of each event were recorded, and the correlative analysis was conducted. Data were processed with Microsoft Excel software. Results: Totally 287 events of bus on fire were retrieved, among which 49 events happened in 2009, 36 events happened in 2010, 35 events happened in 2011, 37 events happened in 2012, and respectively 65 events happened in 2013 and 2014. The events of bus on fire most frequently happened in June and July, respectively 49 and 39 events. Among the distribution of occurrence regions of events of bus on fire, there were 78 events (27.18%) in east China, 52 events (18.12%) in northeast China, 41 events (14.29%) both in north China and south China. Among the causes of events of bus on fire, spontaneous combustion of bus ranked in the first (267 events, accounting for 93.03%), followed by arson (13 events, accounting for 4.53%). Among the 13 events of bus on fire caused by arson, 7 events happened between 16: 00 and 20: 00, and 3 events happened between 8: 00 and 10: 00. Totally 27 events of bus on fire (9.41%) were with casualties, among which 13 events (48.15%) were caused by spontaneous combustion of bus, 10 events (37.04%) were caused by arson, and 4 events (14.81%) were caused by traffic accidents. Arson caused the most severe casualties (at least 88 deaths and 287 injuries), followed by spontaneous combustion of bus (at least 35 deaths and 140 injuries) and traffic accidents (at least 9 deaths and 20 injuries). Conclusions: Events of bus on fire happened more frequently in recent years in the mainland of China, and the frequencies were much higher especially in June and July. Most events were caused by spontaneous combustion of bus, followed by arson. Most of the events of bus on fire caused by arson happened in the morning and evening rush hours of urban traffic, and althouth the occurrence rate was not high, the casualties were most severe.

[Study of the correlation between the expression of angiotensin Ⅱ and its receptors and collagen deposition in human keloid]

Objective: To study the correlation between the expression of angiotensin Ⅱ, angiotensin Ⅱ type 1 receptor (AT1R), angiotensin Ⅱ type 2 receptor (AT2R) and collagen deposition in human keloid. Methods: The keloid from 19 keloid patients and normal skin from 13 patients performed with free skin transplantation hospitalized in our unit from May 2014 to January 2015 were obtained. The expressions of angiotensin Ⅱ, AT1R, and AT2R were detected by immunohistochemical staining, and the results were semi-quantitatively analyzed by immunohistochemical scoring. The expression of collagen in keloid was detected by picrosirius-red staining, and the percentage of total collagen was calculated. Data were processed with t test. The expressions of angiotensin Ⅱ, AT1R, AT2R and the total content of collagen of 13 keloid patients were analyzed by Pearson correlation analysis. Results: (1) There was negative or probably positive expression of angiotensin Ⅱ in normal skin tissue, mainly distributed in the epidermal basal layer. The expression of angiotensin Ⅱ was strong in keloid, most distributed in spinous layer and basal layer of epidermis and most region of dermis, and was strongly positive in most cells, and most cells were fibroblasts. The expressions of AT1R and AT2R were similar to angiotensin Ⅱ in two types of tissue. The expressions of angiotensin Ⅱ, AT1R, and AT2R in keloid scored (305±34), (281±32), and (285±25) points, respectively, which were significantly higher than those in normal tissue [respectively (54±17), (89±47), and (97±32) points, with t values from 12.03 to 23.21, P values below 0.01]. (2) The total content of collagen in keloid was (88±4)%. There was a lot of thick and dense type Ⅰcollagen in keloid, with massive structure and distributed like bamboo segment and arranged in disorder. The expression of type Ⅲ collagen was increased, which was distributed scatteredly around type Ⅰcollagen. (3) There were positive correlations between the expressions of angiotensin Ⅱ, AT1R, AT2R and the total content of collagen in keloid (with r values from 0.452 to 0.720, P values below 0.05). Conclusions: The expressions of angiotensin Ⅱ, AT1R, and AT2R were abnormally increased in human keloid, which may play an important role in the collagen deposition of keloid.

[Integrated diagnosis and treatment of scar]

Scar is the common disease in the field of burn and plastic surgery, and its diagnosis and treatment should be involved in overwhelming majority hospitals. There are many substandard methods and medical hidden dangers in diagnosis and treatment of scar, due to the unevenness of doctors' clinical experience. According to the classification of integral scar and diabrotic scar, the problems related to diagnosis and treatment of scar are systemically summarized and normalized in this article for decrease in the incidence of adverse events and medical hidden dangers.

Diagnostic performance of micropthalmia transcription factor for melanoma: a systematic review and meta-analysis

BACKGROUND AND AIM

The diagnosis of melanoma is still a clinical challenge, many studies reported that micropthalmia transcription factor (MITF) plays a role in diagnosing melanoma, but with considerable inconsistent results. The present work aimed to summarize the overall performance of MITF in diagnosing melanoma.

METHODS

A systematic literature search was performed in Pubmed and Embase for studies regarding the usefulness of MITF to diagnose melanoma. Data were retrieved and pooled sensitivity, specificity, positive and negative likelihood ratios, and diagnostic odds ratio were determined. The post-test probability was performed to evaluate clinical usefulness. A summary receiver operator characteristic curve and the area under the curve were used to summarize the overall diagnostic accuracy.

RESULTS

Nine studies with 1,299 subjects (651 melanomas and 648 non-melanomas) were included for present meta-analysis. The pooled sensitivity and specificity of MITF for diagnosing melanoma were 0.84 (95% CI: 0.81-0.87) and 0.96 (95% CI: 0.95-0.98), respectively. The positive likelihood ratio was 17.73 (95% CI: 10.85-28.99), negative likelihood ratio was 0.18 (95% CI: 0.10-0.32) and diagnostic odds ratio was 221.56 (95% CI: 66.16-741.96). In a setting of 20% prevalence of melanoma, the probability of melanoma would be 92% if the MITF test was positive, and the probability of melanoma would be 1% if it was negative. The area under the summary receiver operator characteristic curve was 0.99.

CONCLUSIONS

MITF may play a valuable role in the diagnosis of melanoma with a high specificity. Nevertheless, the results of MITF should be interpreted with the combination of other test results and clinical findings.

Advances in characterization of human sirtuin isoforms: chemistries, targets and therapeutic applications

Since the discovery in 2000 that the yeast sirtuin called "Sir2" catalyzes NAD+ dependent histone deacetylation, a wave of research has focused on evaluating the biochemical and biological functions of sirtuins. Sirtuins are activated by low calorie diets in numerous organisms and are found throughout biology in species from archaea to humans. There are seven human sirtuin isoforms called SIRT1-SIRT7. The biochemical functions of SIRT1, SIRT2, SIRT3, SIRT5 and SIRT6 have been reported and NAD+ dependent deacetylase activities confirmed. In some instances the biological target substrates for each isoform have been identified, helping to connect distinct biological processes to sirtuin regulation. This knowledge has informed potential drug design strategies that target distinct sirtuin isoforms. This review presents current knowledge of biochemical activities of SIRT1-7 in humans and the biological consequences of these sirtuin activities. Regulatory principles that govern sirtuin deacetylation activity in cells are discussed as well as strategies for how sirtuins can be targeted by small molecules. Finally, this review updates research on pharmacologic sirtuin activation and allostery on sirtuins and considers new developments for detection and isolation of sirtuins in complex mixtures.

Effect of heat shock protein 47 on collagen accumulation in keloid fibroblast cells

BACKGROUND

Keloid is characterized by excessive collagen accumulation, but the mechanism of keloid formation remains unknown, and none of the treatment modalities are consistently effective. Heat shock protein (HSP) 47, known as a collagen-specific molecular chaperone, plays a critical role in collagen biosynthesis. Our previous research has demonstrated that HSP47 is highly expressed in keloid compared with normal skin tissues, which indicates that there might be a close relationship between overexpression of HSP47 and excessive collagen accumulation in keloid formation.

OBJECTIVES

To further investigate whether overexpression of HSP47 might promote excessive collagen deposition in keloid formation, we examined the alteration of intracellular and extracellular collagen expression, following inhibition of HSP47 expression in keloid fibroblast cells by the RNA interference technique.

METHODS

Three constructed psiRNA-hH1neo plasmids, carrying three pairs of related HSP47-shRNA (small hairpin RNA), respectively, were transfected into keloid fibroblast cells and compared with three control groups. After transfection, the mRNA and protein expression of HSP47 and collagen type I were detected by quantitative real-time polymerase chain reaction and Western blot; the content of extracellular secreting collagen was assessed by hydroxyproline assay; and the MTT [3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide] method was adopted to examine the proliferation of keloid fibroblast cells.

RESULTS

Both the mRNA and protein levels of HSP47 in keloid fibroblast cells decreased dramatically 48 h after post-transfection of three related HSP47-shRNA plasmids, compared with control groups. Following the downregulation of HSP47, we found that the expression of intracellular and extracellular collagen was correspondingly reduced. On the other hand, the MTT assay showed that transfection of HSP47-shRNA plasmids did not influence the growth of keloid fibroblast cells.

CONCLUSIONS

Combined with our previous histological results, we propose that overexpression of HSP47 in keloid fibroblast cells could induce excessive collagen accumulation by enhancing synthesis and secretion of collagen, which not only presents a possible mechanism of keloid formation, but also offers a therapeutic potential of RNA interference to HSP47 for the treatment of keloid and other fibroproliferative disorders.

Photohemolysis of erythrocytes by He-Ne laser irradiation: the effect of power density

The effects of He-Ne laser irradiation on erythrocyte hemolysis were studied. Erythrocytes are prone to be easily damaged with hemolysis under laser irradiation. It was found that the power density (PD) of laser irradiation, but not the total irradiation power, is the crucial parameter for the hemolysis. Under irradiation with a PD of 5.41 mW/microm(2), erythrocytes were photohemolyzed within a few seconds, while at a PD of 0.52 mW/microm(2) the average tolerance duration (TD; from the start of irradiation to hemolysis) of erythrocytes was 110 s. The TDs of erythrocytes were also individual erythrocyte-dependent, which may be due to their different ages. The average TDs of erythrocyte samples from different donors were different, reflecting individual variations.

A comparative study of 632.8 and 532 nm laser irradiation on some rheological factors in human blood in vitro

The effects of laser irradiation with 632.8 and 532 nm on rheological properties of blood were comparatively studied in vitro. Under the irradiation condition of 30 mW, laser irradiation of blood samples using a spot diameter of 5 mm with each laser, showed promising results in the modulation of hemorheological properties. When blood samples from patients with abnormally high values of erythrocyte sedimentation rate (ESR) were irradiated, the values of ESR were lowered statistically by either of the 632.8 or 532 nm lasers. The laser irradiation reduced blood viscosities at different shear rates (10-110 S(-1)) for the hyper-viscosity blood samples. Laser irradiation increased the electrophoretic mobility (EPM) of erythrocytes when the values of the sample's EPM were abnormally slow. The erythrocyte deformability was enhanced by laser irradiation when the deformability of the sample from the patients was originally poor. For verifying the improvement of laser irradiation on erythrocyte deformability, the typical erythrocyte samples with poor deformability were produced by the pre-treatment of the erythrocytes with Ca(2+). The deformability of these erythrocyte samples was also improved after laser irradiation. These results suggest that membrane-bound hemoglobin (Hbm) might be the initial site of the interaction, since Hbm is the main cause of poor deformability when erythrocytes were treated with Ca(2+). In all experiments including ESR, blood viscosity, EPM and erythrocyte deformability, the 532 nm laser demonstrated more efficient effects on modulating rheological properties than 632.8 nm laser. This wavelength effect is consistent with the absorption spectrum of hemoglobin, reflecting that hemoglobin may be one of the action targets under laser irradiation.

[The influences of crystallized compositions in the porcelain on bonding strength of titanium to porcelain]

OBJECTIVE

Sufficient porcelain-titanium bond is a vital factor determining the clinical performance of titanium-porcelain restorations. The purpose of this study was to investigate the effects of self-preparation La-porcelain composition on the porcelain-titanium bonding strength and to compare with the Vita Titankeramik.

METHODS

The present study examines 5 different recipes of porcelain by weight%: SiO2, 12%-17%; LaO2, 7%-10%; Al2O3, 9%-14%; B2O3, 23%-31%; CaO, 6%-8%; K2O, 2%-3%; SrO, 2%-4%; Na2O, 1%-3%; SnO2, 8%-10%; ZrO2, 3%-5%; TiO2, 6%-8%. Specimens were tested in push type shear with a universal testing machine. Scanning electron microscopy (SEM) and electron probe microanalyzer (EPMA) were employed to reveal the microstructures and diffusion of elements in the interfacial regions between the porcelain coating and titanium to the bond strength when fired at 800 degrees C.

RESULTS

The ratios of crystallized compositions had significant influences on the porcelain-titanium bond strength (P < 0.05). La-porcelain had the highest shear bond strength (37.76 MPa). The shear bond strength of the Vita Titankeramik to titanium was 20.18 MPa. The results of SEM revealed integrity of porcelain-titanium joints in La-porcelain and a greater amount of porosity in the interface of Vita Titankeramik to titanium. EPMA analysis demonstrated the aggregation of Si and Sn in the interfacial regions and their diffusion into the titanium.

CONCLUSION

Chemical compositions of porcelain and ratios of crystallized compositions play the important role in the titanium porcelain bond. La-porcelain had the highest shear bond strength and good porcelain-titanium joints. La-porcelain is a new-style low fusing porcelain/titanium system.

[Experimental study of Bcl-2 and Fas gene expression in fibroblast of scar]

OBJECTIVE

To explore the effect of Fas/Apo-1 and Bcl-2 gene expression on mechanism of scar formation.

METHODS

Immunohistochemical method was applied to defect the expression of Fas and Bcl-2 protein in fibroblasts from 10 cases with normal skin, 10 cases with hypertrophic scar and 10 cases with keloid.

RESULTS

The positive expression rate of Bcl-2 protein in keloid was 83.2%, significantly higher than that in hypertrophic scar (38.6%), (P < 0.01), and the positive expression rate in hypertrophic scar and keloid was higher than that in normal skin (6.78%), (P < 0.01). But the positive expression rate of Fas/Apo-1 protein was 78.4% in normal skin 80.4% in hypertrophic scar, 84.4% in keloid respectively, which showed no significant difference among them (P > 0.05).

CONCLUSION

Bcl-2 gene but Fas gene may take part in the formation of pathologic scar.

[A study on the bond interface between low-fusing dental porcelain and pure titanium]

OBJECTIVE

To evaluate the bond interface between low fusing dental porcelain and pure titanium by observing the topography and detecting the ionic diffusion in the interface area.

METHODS

The low fusing-porcelain La-porcelain produced by the authors or Vita Titankeramik porcelain was fused to the surfaces of pure titanium. The topography of the interface between pure titanium and porcelain, and the structure of experimental materials were observed with SEM. The state of ionic diffusion in the interface area was investigated with EPMA.

RESULTS

Excellent permeation and diffusion of La-porcelain were observed on the surfaces of pure titanium. The diffusion of ions of stannum and silicon was discovered in the interface area. The microstructure of La-porcelain to pure titanium bond interface was finer than that of Vita Titankeramik porcelain.

CONCLUSION

Excellent bond can be produced in the interface between La-porcelain and pure titanium. The bonding mechanism may involve mechanical bond and chemical bond. The ionic diffusion of stannum plays an important role in the bonding of porcelain to pure titanium.

[Studies on the chemical components from Sargassum fusiform]

Three compounds have been isolated from Sargassum fusiform collected from nanao island. Based on the spectral data and elemental analysis, they were identified as 2,4-dihydroxy-2,6-trimethyl-delta 1,alpha-cyclohexaneacetic-r-lactone, saringosterol and cedrol.

[The effect of heparin on the deep second-degree burn in scalded rats]

OBJECTIVE

To investigate the effects of heparin on deep second-degree burn in scalded rats.

METHODS

Thirty Sprague-Dawley rats inflicted with 20% TBSA deep second-degree scalding on the back were employed as the model and were randomly divided into two groups. i,e heparin (H) and normal saline groups (N). Heparin (100 U . kg(-1) . day(-1)) was injected subcutaneously to the rats in H group while normal saline to those in N group once a day. Wound healing rate and immunological indices were determined simultaneously.

RESULTS

(1) The wound healing time was much shorter in H group than that in N group (P < 0.005). The granulation tissue growth condition examined by LM and EM was much better in H group that than in N group. (2) The lymphocytic transforming ratio in H group was evidently increased (P < 0.005). And the phagocytic function of the macrophages increased significantly (P < 0.05). But there was no difference between the two groups in terms of hemoltytic plaque test (P > 0.05).

CONCLUSION

Injection of heparin subcutaneously could accelerate burn wound healing and strengthen the systemic cellular immune potential and the macrophage phagocytic capacity of the host, but exerted no effect on the humoral immunity.

[Therapeutic effect of liposome on II degree burn wound]

OBJECTIVE

To study the therapeutic effect of Suyuping in which liposome is the main constituent on II degree burn wound.

METHODS

From October 1998 to October 1999, 42 cases with II degree burn wound were adopted in this study. Among them, there were 30 males and 12 females, the average wound area was (23.4 +/- 9.7)%. The wounds on the left side of body were managed with sulfadiazine argentum(SD-Ag) while that on the right side with Suyuping. Healing and other situation about the burn wounds were observed and recorded at times.

RESULTS

Forty-two patients completely healed when discharged from hospital. The average wound area managed with Suyuping was (11.2 +/- 7.3)% and the area with SD-Ag was (9.4 +/- 5.8)%. The mean healing time of Suyuping group was(18.4 +/- 4.7) days while that of SD-Ag was (23.5 +/- 7.9) days, there was significant difference(P < 0.05). Suyuping group presented few wound pain, allergy, bleeding and the side effect was less.

CONCLUSION

Suyuping can accelerate wound healing and attenuate wound pain, allergy and bleeding, it is a potential and specific topical agent for treating II degree burn wound.

[The effect of heparin on wound healing of second-degree burned rats]

OBJECTIVE

To study the effect of therapeutic effect of heparin on wound healing of second-degree burned rats.

METHODS

Deep second-degree burns with 20% of total body surface were made in 20 rats, which were randomly divided into 2 groups. The experimental group was treated subcutaneously injection with 1 ml of heparin 100 U/kg and saline solution, and the control group was treated with 1 ml of saline solution, once a day until complete healing of the burned wound. The healing time were compared, the growth of granulation tissue and collagen fibers were evaluated under light microscope, and the growth of fibroblasts were observed under electronic microscope.

RESULTS

All rats survived, the healing time of experimental group (22.8 +/- 1.87 days) were much shorter than that of control group (26.2 +/- 2.82 days) (P < 0.005). Light microscope observation showed that the growth of granulation tissue and collagen fibers of experimental group were much better than that of control group, and electronic microscope also showed that the fibroblast growth was obviously better in the experimental group.

CONCLUSION

Subcutaneous injection of heparin can promote wound healing.

[Effectiveness of recombinant human growth hormone treatment for severe burn injury]

In order to investigate the effectiveness and safety of recombinant human growth hormone(rhGH) treatment for severe burn injury, we designed a randomized prospective study. The patients in rhGH group were given rhGH in a dose of 0.5 IU/(kg.d) subcutaneously between days 3-17 post-burn. Indices about protein metabolism, wound healing, hepatic and renal function and blood were measured regularly. Patients were monitored until their wound healed sufficiently so that they could be discharged for rehabilitation. The results showed: all patients survived; the rhGH group had less weight loss, increased level of serum albumin and shorter healing time of deep partial-thickness burn and donor site. The hospital stay time decreased from the control value of 45 +/- 17 days to 37 +/- 12 days for rhGH treated patients, i.e. a significant improvement. Resistant hyperglycemia was present in 2 patients in the rhGH group and disappeared after transient insulin administration. This study demonstrates that rhGH treatment for severe burn injury has obvious beneficial effects with slight side-effects.

[Preparation of tea polyphenols sustained-release microcapsule]

With ethycellulose (EC) as matrix tea polyphenols (TP) microcapsule was prepared by using emulsion solvent evaporation technique. Effect of preparation condition on size and drug entrapment efficiency of microcapsule was investigated. We also investigated the drug entrapment effect of microcapsule. The result showed that the tawny microcapsule with highly porous surface was obtained by using polyvinyl alcohol (PVA) and sodium dodccyl sulate (SDS) as dispersant. The stirring rate, polymer concentration and drug payload affected the size and drug entrapment efficiency of microcapsule. The matrix and preparation method do not damage the ingredient of TP. The microcapsule can improve the stability of TP and sustain TP released.

[Evaluation of plant protectants against pest insects]

An interference index of population control (IIPC) was constructed for investigating the complex effects of plant protectants, including the effects of repelling insect pests away from the plant, deterring the egg laying of adults and the continuation of feeding, and causing death by toxicity. At the same time, indicated by IIPC, the alcohol extracts of some common plants, such as Eucalytus rubusta, Wedelia chinensis etc. and the neem oil gave very good results to protect the plant against Plutella xylostella. The D-C-Tron NR Petroleum Spray Oil (CALTEX) also gave an excellent effect to protect citrus against red mite. All the experiments show the important role of the repellent effect on the pests.

[Effect of L-arginine supplementation on partial-thickness burned patients]

OBJECTIVE

L-arginine is a semiessential dibasic amino acid for humans and animals. This paper aims to investigate the therapeutic effect of L-arginine supplementation on partial-thickness burned patients.

METHODS

A randomized controlled clinical trial was designed to evaluate the cellular immune function (T cell count, ratio of CD4/CD8, natural killer cell activity and IL-2 level) and protein metabolism (transferrin, prealbium and nitrogen balance) of patients in the experimental group which daily given 15 g arginine and the control group which daily given 25 g glycine.

RESULTS

The natural killer cell activity and IL-2 production in the experimental group were higher than that of the control group. The suppression of transferrin and prealbium was alleviated and the nitrogen balance was improved in the experimental group.

CONCLUSION

It suggests that exogenous arginine supplementation is beneficial for recovery of cellular immunity function and protein anabolism in partial-thickness burned patients.

[Effect of arginine on deep partial-thickness burn in rats]

To investigate the therapeutic effect of arginine on burn, a randomized controlled trial in 20% TBSA deep partial-thickness burned rats was designed. The rats' wound healing, cellular immunity and nitrogen balance were evaluated at appointed postburn days. The results showed that the arginine group got better wound healing and faster recovery of cellular immunity, and achieved positive nitrogen balance. These suggest that supplement of exogenous arginine after burn may be beneficial to the victim in promoting would healing, reducing postburn immune suppression and enhancing anabolism of protein.

[Effect of gamma-interferon on the fibroblasts in hypertrophic scars]

OBJECTIVE

To study the influence and mechanism of gamma-IFN on fibroblasts in hypertrophic scars(HTS).

METHODS

The cultured fibroblastic cells were isolated from the hypertrophic scars of 10 patients. The fibroblasts were divided into two groups, one group was treated with gamma-IFN (100 U/ml, 5 days) and the other without gamma-IFN as control. The proliferative activity in both groups was investigated and compared by blood cytometer, the proportion of myofibroblast (MFB) and the ratio of apoptosis were examined and analysed between two groups by flow cytometry using alpha-smooth muscle actin (alpha-SMA) as marker.

RESULTS

The proliferative activity was downregulated with gamma-IFN. In gamma-IFN treated group, the differentiation of MFB were reduced and the decreasing ratio was 3.2% at the 2nd day and up to 10.5% at the 8th day, then it reduced gradually. The apoptosic ratio is 17.7% in gamma-IFN treated group, and is 10.9% in control group. The difference was statistically significant.

CONCLUSION

gamma-IFN could downregulate the proliferation of fibroblasts, decrease the differentiation of MFB and induce the apoptosis. It has beneficial effect in the treatment of hypertrophic scars(HTS).

[Two-stage operation in the treatment of severe cicatricial adhesion on submental-thoracic region]

In order to decrease the risk of operation, complete release of scar tissue and reduce the recurrence after operation, from February 1994 to March 1997, seventy-three cases of severe cicatricical adhesion on the submental-thoracic region were treated with release and resection of scar tissue, and delay skin graft. The grafted skin was survived completely after operation. The result from the release of scar tissue of the cervical region was good. The physiological angle of submental-thoracic angle was recovered. It was thought that two-stage operation for submental-thoracic cicatricial adhesion would decrease the risk of operation and be advantageous to the release of contracted soft tissue of anterior cervical region and reduce the recurrence of contracture. The interval between the two stages of the operation was 2 to 3 days, which did not increase the rate of infection of the wound. The shortcomings including increase of pain to patient and prolong the time in hospital.

[The preliminary study on WCMM machinable glass-ceramics]

The aim of this work was to investigate machinable glass-ceramics used as oral restoration material in K2O-MgO-Al2O3-SiO2-F glass system. By using of DTA, XRD and SEM investigation, the crystalline structure and characteristics were tested. The chemical composition of WCMM machinable glass-ceramics was defined by the following general formula: (K,Na)Mg3-3x Al2x (AlSi3) O10F2(0.5 < or = x < 0.7). The experimental results show that WCMM is an excellent oral restoration materials in the fabrication of crowns, inlayers and veneers.

[The study on apatite castable glass-ceramics in composition and physicochemical properties]

The authors reported the result of the study of the glass formation range and physicochemical characteristics of apatite (APA) castable ceramics in the CaO-MgO-Al2O3-SiO2-P2O5 system. The relationship between its component and casting properties, the mechanical property and chemical stability was mainly discussed. The result showed that homogeneous glass could be formed in the experimental scope. This glass crystallized enamel-analogous apatite phase. It has improved mechanical property of parent glass, the bending strength was up to 165 MPa and possessed a fine chemical stability. This investigation could provide a new castable ceramics material for dental restoration.

[A three-dimensional finite element stress analysis of implant-supported prosthesis and its supporting tissue in the edentulous mandible. Part 5. The influence of implant type in complete implant overdenture and its supporting tissue]

The stress distribution of implant, implant-bone interface, alveolar ridge surface and the overdenture when supported by cylindrical-type or blade-type implants under three kinds of occlusion, were investigated respectively in this study. The results showed that the extreme principle stress was greater when the denture was supported by blade-type implants than by cylindrical type one. The stress distribution of the system with application of cylindrical type implant is more acceptable.

[A three-dimensional finite element stress analysis of implant-supported prosthesis and its supporting tissue in the edentulous mandible. Part 6. The influence of superstructure in mandibular complete implant overdenture and its supporting tissue]

The effect of superstructure, including telescope, conventional-bar and modified-bar, on the stress distribution of mandibular complete implant overdenture and its supporting tissue was investigated in this study. The results demonstrated that bar could lower the extreme principle stress of the implant, but the stress distribution of implant-bone interface was better when the implants were not linked with each other. Modified-bar is not preferred because it increases the stress of implant and its interface.