Biomedical subjects
Publications and source records attributed to Y L Song.
Cherubism is a benign lesion that causes painless symmetrical enlargement of the jaws, usually with a familial tendency. We describe in two Chinese families two cases of the aggressive form of cherubism with extensive swelling on both sides of the mandible, typical microscopic findings, and apparent familial history.
Seven obligately anaerobic, Gram-positive, rod-shaped, spore-forming organisms isolated from human faecal specimens were characterized using phenotypic and molecular taxonomic methods. Strains of the unidentified bacterium used carbohydrates as fermentable substrates, producing acetic acid, isovaleric acid and phenylacetic acid (PAA) as the major products of glucose metabolism, and possessed a G +C content of approximately 29.8 mol%. Comparative 16S rRNA gene sequencing showed that the 7 strains were genetically highly related to each other (displaying >99.5% sequence similarity) and represent a previously unknown sub-line within the Clostridium Cluster XI. The closest described species to the novel bacterium is Clostridium glycolicum, although a 16S rRNA sequence divergence of 4% demonstrates that they represent different species. Genomic DNA-DNA pairing studies confirmed the separateness of the unknown species and C. glycolicum (30.6% similarity between the proposed type strain of the novel species, WAL 16138, and C. glycolicum ATCC 14880(T)). Based on morphologic, phenotypic and phylogenetic evidence, it is therefore proposed that the unknown bacterium be classified as C. bartlettii sp. nov. The type strain of C. bartlettii is WAL 16138(T) (= ATCCBAA-827(T)=CCUG48940(T)).
AIM: To study and compare Great Taper (GT) hand files using a reversed balanced force technique, nickel-titanium (NiTi)flex files with a balanced force technique and stainless steel (SS) K-type files using a step-back technique. METHODOLOGY: Forty-eight extracted mandibular premolar teeth with single root canals having curvatures between 15 and 45 degrees were prepared using a modified Bramante model and randomly divided into three groups. The teeth were cross-sectioned at 2, 6 and 10 mm from the working length. Preoperative images of canals at three levels were captured at 20x magnification using a stereomicroscope. Canals in each group were, respectively, prepared to an apical size.10 GT file with 0.2 mm tip diameter, size 30 NiTiflex file and size 30 SS K-file. The GT file was used in a reversed balanced force technique, the NiTiflex file was used in a balanced force technique, and the SS K-file was used in a step-back technique. Postoperative canals were imaged under the conditions same as those for the preoperative canals. The postoperative images were superimposed over the preoperative images using software photoshop 6.0. The ability to maintain the instrument in the central axis of the canal and the deviation from the central canal axis were determined and compared by statistical analysis, along with the assessment of the amount of dentine removed. RESULTS: At apical level, the centering ratio, the distance of transportation and the dentine removed in GT and NiTiflex groups were significantly less than those in SS group (P < 0.01), but no statistical differences were found between the two NiTi groups. At other levels, there were no substantial differences amongst the groups. CONCLUSIONS: Compared with SS K-files, GT hand files and NiTiflex files remain better centered and produce significantly less transportation in curved canals.
Two groups of unknown bacteria, which phenotypically resemble members of the Bacteroides fragilis group but phylogenetically display >5% 16S rRNA gene sequence divergence from their nearest validly described species, Bacteroides thetaiotaomicron, were characterized by phenotypic and molecular taxonomic methods. Phylogenetically and phenotypically, the unidentified bacteria displayed a relatively close association with each other. However, a 16S rRNA gene sequence divergence of approximately 4% between the two unknown bacteria, as well as distinguishable biochemical characteristics, demonstrates that these organisms are genotypically and phenotypically distinct, and each group may represent a previously unknown subline within the Bacteroides phylogenetic cluster. Subsequent DNA-DNA hybridization studies confirmed that the two novel organisms were indeed distinct from each other. The previously described species closest to both of them is B. thetaiotaomicron (approximately 94% sequence similarity), but they can be differentiated easily from B. thetaiotaomicron by virtue of not utilizing trehalose. DNA-DNA pairing studies also documented the separateness of the unknown species and B. thetaiotaomicron. Based on the phenotypic and phylogenetic findings, two new species, "Bacteroides nordii" sp. nov. and "Bacteroides salyersae" sp. nov, are proposed. The G+C content of the DNA is 41.4 mol% for Bacteroides nordii and 42.0 mol% for Bacteroides salyersae. The type strains of Bacteroides nordii and Bacteroides salyersae are WAL 11050 (ATCC BAA-998 or CCUG 48943) and WAL 10018 (ATCC BAA-997 or CCUG 48945), respectively.
The objectives of this study were to investigate the potential roles of cortisol and gonadal steroids in the phagocytic activity of peripheral blood leukocytes in two teleosts, tilapia (Oreochromis niloticus x O. aureus) and common carp (Cyprinus carpio). An in vitro microtiter plate assay, measuring incorporation of FITC-latex beads into peripheral blood leukocytes, was developed for the first time in teleosts. Peripheral blood leukocytes were cultured in AL medium with tested compounds in a microfluor black plate at 25 degrees C. FITC-latex beads were further incubated for phagocytosis and engulfed fluorescent intensity in phagocytes was detected fluorometrically. Cortisol suppressed leukocyte phagocytosis in a dose (10(-14) to 10(-4) M)- and time (0.5 to 8 h)-dependent manner in tilapia. The glucocorticoid agonist dexamethasone had a suppressive effect similar to that of cortisol, while cortisone and the mineralocorticoid aldosterone had only a weak effect in tilapia. High doses of estradiol and ethynylestradiol, but not of estrone, suppressed phagocytosis in tilapia. No suppressive effect on phagocytosis was observed with various concentrations of progesterone, testosterone, and 11-ketotestosterone. Triiodothyronine was also inactive on phagocytosis. A combination of estradiol and cortisol potentiatingly suppressed phagocytosis. Actinomycin D and cycloheximide blocked the suppressive effects of cortisol and estradiol. Cortisol had weaker suppressive effects on the phagocytosis of leukocytes in common carp than tilapia. Other steroids had no suppressive action on phagocytosis in common carp. It is concluded that the suppressive effects of cortisol and estradiol on phagocytosis in tilapia are mediated by specific glucocorticoid receptors and estrogen receptors, respectively. Cortisol would play a main and important role on the down-regulation of phagocytic activity. Sexual steroids, such as estradiol, also could interact with cortisol to further suppress immunity in tilapia. Differential responsiveness of the immune system to suppressive effects of steroids, among teleosts species, has been demonstrated.
Electroporation was used to introduce pFLAG-CMV-1-BAP, a DNA fragment that includes a bacterial alkaline phosphatase gene driven by a human cytomegalovirus (CMV) promoter, into Penaeus monodon zygotes. The transgenic tiger shrimp was achievedby using 10kV, 28 pulses, 120 g sec pulse time, 10 cycles, and a DNA concentration of 37.5 microg/mL. The hatching rate of electroporated zygotes (46%) was significantly lower than that of zygotes in the untreated group (89%). The survival rate of postlarvae in the electroporated group using a DNA concentration of 37.5 microg/mL decreased from 0.6% for postlarva 45 to 0.4% for postlarva 120. Based on dot blot analysis, the rate of gene transfer was 37% in mysis-stage, 23% postlarva 15(PL15), 19% postlarva 45(PL45), and 21% 4-month-old (about PL120). Genomic Southern blotting demonstrated that DNA from transgenic tiger shrimp contained fragments of exogenous DNA that were smaller, larger and of the same molecular size as pFLAG-CMV-1-BAP. Transferred DNA fragments were integrated into the genomes of 31% of the transgenic tiger shrimp. The exogenous DNA was mosaically distributed in a wide variety of tissues. Immunohistochemical staining revealed that the FLAG-BAP fused-protein encoded by pFLAG-CMV-1-BAP was present in the ovaries of some transgenic tiger shrimp.
TRAIL is a cytokine that induces apoptosis in a wide variety of tumor cells but rarely in normal cells. It contains an extraordinarily elongated loop because of an unique insertion of 12-16 amino acids compared with the other members of tumor necrosis factor family. Biological implication of the frame insertion has not been clarified. We have determined the crystal structure of TRAIL in a complex with the extracellular domain of death receptor DR5 at 2.2 A resolution. The structure reveals extensive contacts between the elongated loop and DR5 in an interaction mode that would not be allowed without the frame insertion. These interactions are missing in the structures of the complex determined by others recently. This observation, along with structure-inspired deletion analysis, identifies the critical role of the frame insertion as a molecular strategy conferring specificity upon the recognition of cognate receptors. The structure also suggests that a built-in flexibility of the tumor necrosis factor receptor family members is likely to play a general and important role in the binding and recognition of tumor necrosis factor family members.
p73 is structurally and functionally related to p53 and is possibly a tumor suppressor gene. Using 15 surgically resected frozen esophageal specimens containing both squamous cell carcinomas (ESCC) and neighboring normal epithelia, we studied p73 gene alterations and mRNA expression. Loss of heterozygosity of the p73 loci was found in nine of 14 informative cases (64%). A polymorphism at codon 173 (Thr) of p73 was identified (eight samples had ACC and seven had ACT), but mutation was not detected in tumor samples. Nine of the 15 ESCC samples (60%) displayed significantly elevated expression of p73 over the neighboring normal epithelium; of these nine samples, four displayed loss of imprinting (LOI) and one switched the expressed allele. Hypermethylation of exon 1 of the p73 gene was not detected, using the bisulfite modification method, in normal or tumor samples. Twelve of the 15 (80%) ESCC samples contained p53 defects, including missense mutation, non-frameshift small deletion or insertion, non-detectable transcripts and protein accumulation. The ESCC samples with p53 defects were significantly correlated with those which had elevated expression of p73 (Fisher's exact test, P < 0.05). The results suggest that increased expression of p73, including that by LOI, could be a partial compensatory mechanism for defective p53.
Lysyl oxidase is an essential catalyst for the cross-linking of extracellular collagen and elastin. Abnormalities in lysyl oxidase activity may contribute to the pathogenesis of arterial diseases characterized by abnormal matrix remodeling. This study tested the hypothesis that interferon (IFN)-gamma, a proinflammatory cytokine present in aortic aneurysm and arteriosclerotic plaque rupture, downregulates lysyl oxidase gene expression in rat aortic smooth muscle cells. Steady-state lysyl oxidase mRNA levels decreased in a concentration- and time-dependent manner to 30% of control levels after 24 hours of treatment with IFN-gamma. Cell layer lysyl oxidase activity decreased in parallel with the observed changes in steady-state mRNA. Nuclear runoff studies suggested that transcriptional regulation was responsible for at least 40% of the observed downregulation. mRNA decay studies suggested that IFN-gamma also decreased lysyl oxidase mRNA half-life from 9 to 6 hours. Downregulation of lysyl oxidase by IFN-gamma did not appear to require new protein synthesis. This study documents that IFN-gamma downregulates lysyl oxidase gene expression in rat aortic smooth muscle cells by transcriptional and posttranscriptional mechanisms. If similar regulation occurs in vivo, it is possible that IFN-gamma-mediated changes in lysyl oxidase may contribute to arterial diseases characterized by abnormal extracellular matrix.
Therapeutic angiogenesis, either by protein injection or gene therapy, holds considerable promise for the treatment of coronary and peripheral artery diseases. Given the large number of angiogenic genes available, a simple, well defined, standard system to compare the relative angiogenic efficacy of such genes would be valuable. We have employed a replication-deficient adenovirus vector (complete E1a-, partial E1b- and partial E3-) to deliver the beta-galactosidase (beta-gal, AdLacZ) reporter gene or the human VEGF121 gene (AdGV VEGF121.10) to a rat sponge implant model of angiogenesis. beta-gal staining results reveal a transfection efficiency as high as 60% 24 h after 2x1010 particle units AdLacZ injection. Our results also indicate that a single injection of 2x1010 particle units of AdGVVEGF121.10 in the sponge results in >10, 000 pg VEGF protein expression per milligram of sponge tissue 24 h later. VEGF121 protein concentrations decreased 10-fold within 3 days and 100-fold within 7 days after injection. Significant VEGF121 protein levels were still detectable 14 days after initial virus injection. The high level of gene transfection efficiency was accompanied by enhanced angiogenesis in the sponge, a tissue devoid of any vessels before implantation. Compared to control (AdNull: adenovirus vector without the VEGF gene), AdGVVEGF121.10 induced a 2- to 3-fold up-regulation of angiogenesis at 7 and 14 days post vector injection as determined by both increased capillary number and increased tissue ingrowth. The angiogenic effects of AdGVVEGF121. 10 were dose-related in this model system. These findings demonstrate a dose-related angiogenic response to adenovirus-mediated gene therapy in this model.
We identified Lactobacillus isolates from Japanese women and newborn infants by a DNA-DNA hybridization method. The predominating lactobacilli were Lactobacillus crispatus and Lactobacillus gasseri in the women's vaginas and the newborns' intestines and L. gasseri and Lactobacillus fermentum in the women's intestines. All L. crispatus strains were exclusively strong H2O2 producers.
The efficacy of a biochemical kit, API50CHL kit, for identification of intestinal and vaginal lactobacilli from humans was evaluated by comparing with the results of DNA-DNA hybridization assay. The results showed that in total only 52 of the 172 strains (30.2%) tested were identified correctly by the kit at species level. Especially all strains of some species, such as Lactobacillus gasseri and Lactobacillus crispatus, were misidentified as Lactobacillus acidophilus by the kit. However, the kit was found to be reliable for identification of Lactobacillus paracasei, Lactobacillus plantarum, Lactobacillus rhamnosus, and Lactobacillus salivarius. This suggests that the exact identification of Lactobacillus isolates from human stool and vaginal specimens by API50CHL kit is difficult without the support of modern genotypic technique.
The phenoloxidase (PO) activity of hemocyte lysate supernatant (HLS) from both tiger shrimp (Penaeus monodon) and giant freshwater prawn (Macro-branchium rosenbergii) was examined by treating HLS with various factors, such as an increase in temperatures from 25 to 70 degrees C, one of four elicitors (beta-1,3-1,6-glucan, zymosan, heat-killed Vibrio cells, and lipopolysaccharide), trypsin, one of three protease inhibitors (soybean trypsin inhibitor, p-nitrophenyl-p'-guanidinobenzoate, and benzamidine), and one of two divalent cations (Mg2+ and Ca2+). The strongest PO activity in both animals was induced at 37 degrees C, while enzyme activity varied according to the concentration of the elicitors or cations added to the HLS samples. The following optimum concentrations were recorded: lipopolysaccharides at 0.5 mg/ml, both beta-glucan and zymosan at 1 mg/ml, and Vibrio cells at 10(6) cells/ml. In addition, for giant freshwater prawn, PO activity increased when HLS was treated with trypsin and decreased when it was separately treated with three protease inhibitors. However, effects of either trypsin or protease inhibitors did not occur in tiger shrimp. Strongest PO activity occurred in HLS treated with 20 mM of either calcium ion or magnesium ion, and the addition of the two cations led to an increase in enzyme activity; a decrease was noted following the treatment with EDTA. Cytochemical analysis revealed that prophenoloxidase system exists in the granulocytes of both tiger shrimp and giant freshwater prawn.
Cytokine-mediated immune responses to Mycobacterium tuberculosis infection are important determinants of M. tuberculosis disease development and pathology. However, the distinction between changes in cytokine profile attributable to M. tuberculosis infection and those associated with active pulmonary tuberculosis is unclear. We have compared T cells and their subsets, macrophages, and cytokine messenger RNA (mRNA) profile in the bronchoalveolar lavage (BAL) of patients with active pulmonary tuberculosis with inactive tuberculosis subjects. Ten patients with microbiologically confirmed active pulmonary tuberculosis and 25 subjects with inactive tuberculosis were recruited. Bronchoscopy with BAL was undertaken in all cases and BAL cytospins were examined using the techniques of immunocytochemistry and in situ hybridization. There was a significant increase in the percentage of BAL cells that were CD8+ T cells in active tuberculosis compared with inactive tuberculosis (mean +/- SEM: 7.2 +/- 0.9 versus 2.1 +/- 0.4, p < 0.001), but not CD3+ or CD4+ T cells nor macrophages. There were significant increases in the percentage of BAL cells expressing mRNA for interferon-gamma (IFN-gamma) and interleukin-12 (IL-12) in active versus inactive pulmonary tuberculosis subjects (8.0 +/- 0.6 versus 3.7 +/- 0.4 and 28.4 +/- 2.3 versus 10.2 +/- 1.0, p < 0.001, respectively). There were no significant differences between the active and inactive groups in the number of cells expressing mRNA for IL-2, tumor necrosis factor-alpha (TNF-alpha), IL-4, and IL-5. In conclusion, active pulmonary tuberculosis is associated with increased numbers of CD8+ cells and marked increases in the expression of IL-12 and IFN-gamma mRNA in the BAL, both of which may be useful markers of disease activity.
The histopathology of bronchial asthma is associated with structural changes within the airways, including subepithelial fibrosis, as well as chronic eosinophilic inflammation. The mechanisms responsible for this tissue remodeling, and in particular the role of inflammatory cells, remain to be established. Transforming growth factor-beta (TGF-beta) is a potent profibrotic cytokine which may contribute to the thickening of the reticular lamina by the deposition of collagen fibers. To investigate the molecular mechanisms underlying these structural changes, we have investigated the expression of TGF-beta1 mRNA and immunoreactivity within the bronchial mucosa of mild to severe asthmatic individuals and normal control subjects using the techniques of in situ hybridization and immunocytochemistry. As eosinophils are prominent within the asthmatic airway and are known to synthesize pro-inflammatory cytokines, the presence of TGF-beta1 mRNA and immunoreactive protein in eosinophils was also examined. Asthmatic individuals exhibited a greater expression of TGF-beta1 mRNA and immunoreactivity in the airways submucosa than normal control subjects (P < 0.05), and these increases were directly related to the severity of the disorder. The extent of airways fibrosis, as detected histochemically, was also increased in asthmatics compared with normal control subjects (P < 0.005). In asthmatic subjects, the presence of subepithelial fibrosis was associated with the severity of the disease and correlated with the decline in forced expiratory volume in 1 s (r2 = 0.78; P < 0.05). Within the asthmatic airways, EG2-positive eosinophils represented the major source of TGF-beta1 mRNA and immunoreactivity. These results provide evidence that TGF-beta1 may play a role in the fibrotic changes occurring within asthmatic airways and that activated eosinophils are a major source of this cytokine.
Non-specific disease resistance induced by yeast cell wall extract, beta-1,3-1,6-glucan, was demonstrated in the tiger shrimp. In this study beta-1,3-1,6-glucan was administered to shrimps by immersion before culturing and orally during the culturing period. Challenge of the treated shrimps with the virulent pathogens, Vibrio vulnificus and viral agents extracted from the white spot syndrome victims, yielded promising results. The tolerance of glucan-treated shrimps was slightly enhanced to stresses including catching, transport and ammonia. The growth and survival rates of treated and untreated shrimps were not significantly different. Therefore, we suggest that beta-1,3-1,6-glucan can be used as an immuno-stimulant of cultured shrimps and may benefit shrimp farmers.
The patient's posture for nerve surgery operation was improved in order to convenient to micro surgery procedure and offer cooperation further better for operators, as well as to decrease possibility of skin injury. The results indicated that emergence of skin injury in improved posture decreased 67.25% compared with that before and complications reduced significantly.
Previous studies in atopic dermatitis (AD) have shown that acute and chronic skin lesions are associated with a TH2-type profile of cytokine expression. IL-12 and IL-13 are recently described cytokines, which possess TH1-and TH2-like actions, respectively. We have used the technique of in situ hybridization to examine the expression of IL-12 and IL-13 messenger RNA in skin biopsy specimens of acute and chronic skin lesions and uninvolved skin from patients with AD. When compared with normal control skin, the acute and chronic skin lesions and unaffected skin from patients with AD had significantly greater numbers of cells that were positive for IL-13 mRNA (p < 0.05). Acute AD skin lesions expressed a higher number of positive cells than those observed in chronic AD skin lesions (p < 0.05) or psoriasis skin lesions (p < 0.05) There was a significant increase in the numbers of IL-12 mRNA-positive cells in chronic skin lesions compared with acute lesions and uninvolved skin from patients with AD (p < 0.05). These data demonstrate that acute AD skin lesions are associated with an increased expression of IL-13 mRNA. In contrast, the relative increase in IL-12 mRNA in chronic AD skin lesions suggests a possible role for IL-12-producing cells in modulating chronic inflammation.