Biomedical subjects

Chuan-Mu Chen

Publications and source records attributed to Chuan-Mu Chen.

At least 19 recordsLinked to original sources

PubMed2007

Reconstruction of juxta-articular huge defects of distal femur with vascularized fibular bone graft and Ilizarov's distraction osteogenesis.

BACKGROUND: We evaluate the effect of reconstructing huge defects (mean, 15.8 cm) of the distal femur with Ilizarov's distraction osteogenesis and free twin-barreled vascularized fibular bone graft (TVFG). METHODS: We retrospectively reviewed a consecutive series of five patients who had cases of distal femoral fractures with huge defects and infection that were treated by the Ilizarov's distraction osteogenesis. After radical debridement, two of the five cases had free TVFG and monolocal distraction osteogenesis, and another two cases had multilocal distraction osteogenesis with knee fusion because of loss of the joint congruity. The other case with floating knee injury had bilocal distraction osteogenesis and a preserved knee joint. The mean defect of distal femur was 15.8 cm (range, 14-18 cm) in length. RESULTS: The mean length of distraction osteogenesis by Ilizarov's apparatus was 8.2 cm. The mean length of TVFG was 8 cm. The average duration from application of Ilizarov's apparatus to achievement of bony union was 10.2 months (range, 8-13 months). At the end of the follow-up, ranges of motion of three knees were 0 to 45 degrees, 0 to 60 degrees, and 0 to 90 degrees. Two cases had knee arthrodesis with bony fusion because of loss of the joint congruity. There were no leg length discrepancies in all five patients. In addition, three patients had pin tract infections and one case had a 10 degree varus deformity of the femur. CONCLUSIONS: Juxta-articular huge defect (>10 cm) of distal femur remains a challenge to orthopedic surgeons. Ilizarov's technique provides the capability to maintain stability, eradicate infection, restore leg length, and to perform adjuvant reconstructive procedure easily. In this study, we found that combining Ilizarov's distraction osteogenesis with TVFG results in improved patient outcome for patients with injuries such as supracondylar or intercondylar infected fractures or nonunion of distal femur with huge bone defect.

Adolescent↗

PubMed2006

Production and characterization of human extracellular superoxide dismutase in the methylotrophic yeast Pichia pastoris.

Reactive oxygen species are associated with various diseases including cardiovascular diseases, neurological disorders, and pulmonary diseases. Extracellular superoxide dismutase (ECSOD) is an antioxidant enzyme secreted by cells to prevent overproduction of reactive oxygen species. We expressed an ECSOD gene isolated from a human aortic smooth muscle cDNA library in the methylotrophic yeast Pichia pastoris. A synthetic secretion cassette was constructed with the inducible promoter of the alcohol oxidase 1 gene (AOX1) and the yeast alpha-mating factor signal peptide. As much as 25% of the total protein was ECSOD in some transformants grown under inducing conditions. After 36 h of methanol induction, ECSOD was exported into the culture medium at a concentration of approximately 440 mg/L with an antioxidative activity of 760 +/- 20 U/mg ECSOD. Transformed yeast cells were more resistant to heat shock and H(2)O(2) oxidative stress, indicating that the human ECSOD expressed by P. pastoris had multiple biological functions. Our data suggest that the methylotrophic yeast inducible system is suitable for large-scale production of enzymatically active human ECSOD.

Aorta↗

PubMed2006

Synthetic porcine lactoferricin with a 20-residue peptide exhibits antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Candida albicans.

Lactoferricins are positively charged, highly basic peptides that are generated upon gastric pepsin cleavage of various lactoferrins. In the past decade, there has been active investigation of the key antimicrobial segments of the various shorter synthetic bovine and human lactoferricins, but not in porcine lactoferricin. These studies have demonstrated the distinct solution structures of lactoferricin in bovine and human and established the multifunctional nature of the antibacterial, antifungal, antiendotoxin, and antiviral activities of lactoferricins. However, the protective effects of porcine lactoferricins have yet to be elucidated. In the present study, a series of synthetic derivatives of porcine, bovine, and human lactoferricins with 20-residue and 9-residue peptides were prepared to investigate their antimicrobial nature. We found that the 20-residue porcine lactoferricin (LFcin P-20) displayed antimicrobial activity against Escherichia coli ATCC25922, Staphylococcus aureus ATCC25923, and Candida albicans ATCC14053. The minimal inhibitory concentrations and minimal bactericidal concentrations of LFcin P-20 ranged from 12 to 25 microM when tested in bacteria and fungi. LFcin P-20 was 4 times more effective than human lactoferricin (LFcin H-20), but slightly less effective than bovine lactoferricin (LFcin B-20).

Animals↗

PubMed2006

Promoter region methylation and reduced expression of thrombospondin-1 after oxygen-glucose deprivation in murine cerebral endothelial cells.

Angiogenesis is induced in response to ischemia. Thrombospondin-1 (TSP-1) is a potent angiostatic factor. Silencing of TSP-1 expression may contribute to the postischemic angiogenesis. Upregulation of TSP-1, in contrast, may terminate the postischemic angiogenesis. A possible mechanism that silences TSP-1 expression is the DNA methylation of its promoter region. DNA methylation has been reported following cerebral ischemia. The present study aimed to explore whether methylation of the promoter region of TSP-1 regulates its expression after oxygen-glucose deprivation (OGD) in murine cerebral endothelial cells (CECs) in vitro. Sublethal OGD increased the extent of methylation of the promoter region of TSP-1 with a concurrent decrease in TSP-1 mRNA and protein expression in CECs. After reoxygenation, demethylation of the TSP-1 promoter region led to the restoration of TSP-1 mRNA and protein expression. The extent of methylation of the promoter region of TSP-1 was inversely correlated with the extent of TSP-1 gene expression at mRNA and protein levels after OGD. Oxygen-glucose deprivation-induced reduction in the TSP-1 mRNA level was not accompanied by a change in mRNA stability. These findings raise the possibility that OGD downregulation of TSP-1 expression is at least in part due to methylation of its promoter region.

Animals↗

PubMed2006

Experience in the use of the long Gamma nail for 16 femoral shaft fracture that have occurred following initial Asian Pacific Gamma nail fixation for pertrochanteric fractures.

From January 1993 to September 2002, 931 patients suffered from intertrochanteric fracture and subrochanteric fracture received open reduction and internal fixation with APGN in our institute. Among these patients, 16 patients (1.7%) developed a femoral shaft fracture after the initial fixation with APGN. Removal of the APGN, closed reduction and fixation with long Gamma nail (LGN) was performed in all the 16 patients. The patients were followed for 12-60 months (average, 39.8 months). The union time of fracture was 12-24 weeks (average, 18.5 weeks) for femoral shaft fractures and 12-20 weeks (average, 16 weeks) for peritrochanteric fractures. Two early complications were noted, including one superficial (6%) infection and one deep (6%) infection. Two malunions (12.5%) developed with no definite functional impairment. The functional results using the Harris hip score were good to excellent. In conclusion, closed reduction and internal fixation with a LGN is very effective in the management of a femoral shaft fracture, a complication of a previous APGN that had been initially used for stabilisation of a pertrochanteric fracture.

Aged↗

PubMed2005

Treatment of nonunion of humeral shaft fracture with dynamic compression plate and cancellous bone graft.

BACKGROUND: This study was conducted to evaluate the treatment of aseptic nonunion of the humeral shaft with a dynamic compression plate (DCP) and cancellous bone graft. METHODS: One hundred and five cases of nonunion of a humeral shaft fracture between 1982 and 2001 were analyzed retrospectively. The study population comprised 66 males and 39 females with an average age of 46.2 years (range, 17-81 years). Sixty-seven fractures were defined as atrophic nonunion, and 20 as hypertrophic nonunion, whereas 18 could not be defined clearly. All the fractures were managed by open reduction and internal fixation with DCP and cancellous bone graft. The mean follow-up period was 20 months (range, 14-28 months). RESULTS: All nonunion fractures united within an average of 16 weeks (range, 10-26 weeks). Complications included 4 patients with temporary radial-nerve palsies, and 3 patients with wound infections. At the final follow-up, shoulder and elbow functions of the operated limbs were all satisfactory. CONCLUSION: Fixation by DCP with supplemental cancellous bone graft is a reliable and effective treatment for nonunion of a humeral shaft fracture.

Adolescent↗

PubMed2005

Surgical treatment of open diaphyseal fractures of both the radius and ulna.

BACKGROUND: This study was designed to determine the effects of surgical treatment of acute, open and displaced diaphyseal fractures of both the radius and ulna by early debridement, reduction and internal fixation with a dynamic compression plate (DCP). METHODS: From 1991 to 2003, data from 25 patients with acute, open and displaced diaphyseal fractures of both the radius and ulna were collected and evaluated retrospectively. Twenty-four patients were managed with early surgical debridement, open reduction and internal fixation with a DCP, and 1 fracture was reduced and fixed 3 days after the initial injury. The mean follow-up period was 74.7 months (standard deviation [SD], 38.6 months; range, 16-150 months). All patients had complete functional and radiographic assessments. RESULTS: Twenty-four patients (96%) achieved normal union in a mean of 20.2 weeks (SD, 3.8 weeks; range, 12-24 weeks). One patient with an open type I fracture had nonunion. Functional outcomes showed that 15 patients had excellent results, 8 had satisfactory results, 1 had an unsatisfactory result, and there was 1 failure. There was 1 delayed superficial wound infection. CONCLUSION: Early meticulous debridement, good open reduction and internal fixation with a small DCP proved very effective in the management of type I and II open fractures of both the radial and ulnar diaphyses.

Adult↗

PubMed2005

Treatment of complex subtrochanteric fracture with the long gamma AP locking nail: a prospective evaluation of 64 cases.

BACKGROUND: Complex subtrochanteric fractures are uncommon injuries and challenging to manage. We elucidate the role of the Long Gamma AP Locking Nail (LGAPN) in the management of such fractures in the acute stage. METHODS: Between 1992 and 2002, 64 consecutive cases with nonpathologic complex subtrochanteric fractures managed with the LGAPN were enrolled in this study. Associated injuries were present in 16 cases. The average follow-up period was 68 months. RESULTS: Mean time to union was 14 weeks. There were two complications (one wound infection and one delayed union). The time to union and functional results were not statistically different between different ages (below 50 years old, or older than 50 years) and the number of distal locking screws used (one or two). Longer time to union is noted in patients with a longer operation time and a more comminuted fracture pattern by the AO classification. CONCLUSION: Closed reduction and internal fixation with the LGAPN were proven to be safe and effective in the treatment of complex traumatic subtrochanteric fractures in all age groups, and one distal locking screw is sufficient for distal fixation.

Adult↗

PubMed2004

Effect of Helicobacter pylori infection on intragastric acidity in patients with reflux esophagitis.

BACKGROUND: The effect of Helicobacter pylori infection on intragastric acidity in patients with reflux esophagitis was investigated. METHODS: Esophageal motility and 24-h intragastric acidity were assessed in endoscopy-proven reflux esophagitis patients with ( n = 50) and without ( n = 50) H. pylori infection. RESULTS: Most of the patients had a mild degree of esophagitis. There was no difference in the age, sex, or body mass index (BMI) between patients with and without H. pylori infection. The 24-h intragastric pH monitoring showed less acidity in patients with H. pylori infection than in those without H. pylori infection (median pH, 1.6 +/- 0.3 vs 1.4 +/- 0.1, with vs without H. pylori infection; P < 0.01). No difference in the patterns of esophageal motility dysfunction was noted between these two groups of patients. CONCLUSIONS: Patients with reflux esophagitis and H. pylori infection had less intragastric acidity than those without H. pylori infection. However, the extent of acid suppression was insufficient to protect the esophagus from acid injury. In addition, the degree of esophageal motility dysfunction was similar in both groups. Therefore, H. pylori infection may play no role in the pathogenesis of reflux esophagitis.

Aged↗

PubMed2004

Transacromial Knowles pin in the treatment of Neer type 2 distal clavicle fracturesA prospective evaluation of 32 cases.

BACKGROUND: The high rate of non-union makes surgical intervention necessary for a distal clavicle fracture. This report presents the outcome of a simple surgical method using a transacrominal Knowles pin for this unstable fracture. METHODS: In this study, 32 patients with Neer type 2 distal clavicle fractures were treated using a single transacromial Knowles pin without repair of the torn ligament. All 32 patients were studied prospectively and followed up for a mean of 80 months (range, 12-132 months). The clinical outcome was evaluated with the UCLA score, and the fracture union was judged roentgenographically. RESULTS: All the patients showed excellent results with solid union. The mean union time was 6.8 weeks (range, 4-12 weeks). No major complication was noted, and only one asymptomatic acromioclavicular arthrosis developed. CONCLUSIONS: Single transacrominal Knowles pin fixation offers a simple and safe method for treating patients with displaced Neer type 2 distal clavicle fractures.

Accidental Falls↗

PubMed2004

Production of recombinant porcine lactoferrin exhibiting antibacterial activity in methylotrophic yeast, Pichia pastoris.

Lactoferrin is a metal-binding glycoprotein exhibiting multifunctional immunoregulation of antibacterial, antioxidant, anti-endotoxin and antiviral activities. Uptake of porcine lactoferrin (PLF) has been shown to enhance resistance to diarrhea and anemia in neonatal piglets. In this study, the methylotrophic yeast, Pichia pastoris, was used to express a recombinant PLF (rPLF) gene from swine mammary gland. A synthetic secretion cassette was constructed using the inducible promoter of the alcohol oxidase-1 gene (AOX1) and the yeast alpha-mating factor signal peptide. After electroporation and Zeocin selection, several clones expressed high levels of rPLF protein which constitutes more than 30% of the total protein. A time-course study showed that rPLF mRNA transcripts are stably expressed during 120 h of culture induction. rPLF was exported into the culture supernatant at approximately 87 mg/l and a large portion of rPLF was accumulated in the cell cytoplasm at approximately 760 mg/l after 72 h of methanol induction. Recombinant PLF protein was purified via a heparin column using a fast protein liquid chromatography system. The glycosylation of P. pastoris-derived rPLF was analyzed and similar patterns to milk PLF were observed. Pepsin hydrolysate of rPLF displayed high bactericidal activity against Escherichia coli ATCC 25922 under scanning electron microscopy observation and minimal inhibitory concentration and minimal bactericidal concentration tests. Our results suggested that the methylotrophic yeast-inducible system is suitable for large-scale production of active antibacterial rPLF glycoprotein.

Animals↗

PubMed2003

The androgen receptor gene is preferentially hypermethylated in follicular non-Hodgkin's lymphomas.

This investigation examined promoter DNA methylation of the androgen receptor (AR) gene in non-Hodgkin's lymphoma (NHL) representing different stages of B-cell differentiation. Steroid hormones are important endocrine messengers with a broad range of physiological functions, including regulation of B-cell lymphopoiesis. Some of these effects are mediated via specific receptors such as AR that can act as a ligand-dependent transcription factor for other genes. DNA was isolated from 76 NHL specimens representing pregerminal center, germinal center, and postgerminal center states of differentiation. Initial methylation data were obtained from oligonucleotide microarrays and was confirmed and extended using methylation-specific PCR. Methylation of the AR gene promoter was present in a nonrandom pattern. Those tumors derived from pregerminal center or postgerminal center stages showed virtually no methylation and expressed AR mRNA. Cases of germinal center origin, mainly follicular lymphomas and some diffuse large B-cell lymphomas, showed hypermethylation. Studies with NHL cell lines revealed that demethylation or reversal of histone deacetylation partially restored AR expression but reversal of both simultaneously provided a synergistic release from suppression. Promoter methylation of AR occurs in a differentiation stage-selective manner; those cases arising in the germinal center are preferentially methylated. Full re-expression of AR requires both demethylation and reacetylation, a finding that may affect treatment decisions.

Cell Line, Tumor↗

PubMed2003

Methylation target array for rapid analysis of CpG island hypermethylation in multiple tissue genomes.

Hypermethylation of multiple CpG islands is a common event in cancer. To assess the prognostic values of this epigenetic alteration, we developed Methylation Target Array (MTA), derived from the concept of tissue microarray, for simultaneous analysis of DNA hypermethylation in hundreds of tissue genomes. In MTA, linker-ligated CpG island fragments were digested with methylation-sensitive endonucleases and amplified with flanking primers. A panel of 468 MTA amplicons, which represented the whole repertoire of methylated CpG islands in 93 breast tumors, 20 normal breast tissues, and 4 breast cancer cell lines, were arrayed on nylon membrane for probe hybridization. Positive hybridization signals detected in tumor amplicons, but not in normal amplicons, were indicative of aberrant hypermethylation in tumor samples. This is attributed to aberrant sites that were protected from methylation-sensitive restriction and were amplified by PCR in tumor samples, while the same sites were restricted and could not be amplified in normal samples. Hypermethylation frequencies of the 10 genes tested in breast tumors and cancer cell lines were 60% for GPC3, 58% for RASSF1A, 32% for 3OST3B, 30% for HOXA5, 28% for uPA, 25% for WT1, 23% for BRCA1, 9% for DAPK1, and 0% for KL. Furthermore, hypermethylation of 5 to 7 loci of these genes was significantly correlated with hormone receptor status, clinical stages, and ages at diagnosis of the patients analyzed. This novel approach thus provides an additional avenue for assessing clinicopathological consequences of DNA hypermethylation in breast cancer.

Breast Neoplasms↗

PubMed2003

Double-strut free vascular fibular grafting for reconstruction of the lower extremities.

This article reports our experience on the treatment of long-bone defects with double-strut vascular fibular graft in 11 patients. The defects were 6-12 cm in length while 10-25 cm of vascular fibular grafts were harvested. Nine patients achieved solid union in 6 months, and two patients required additional procedures to achieve solid union. No major complications were observed, except for three patients. who had knee stiffness due to long-term immobilization and one patient who had experienced a stress fracture because of strenuous exercise at 10 months after grafting procedures. Bone union in this patient was achieved 3 months after reapplying an external fixator. It is suggested that a rigid external or internal fixator is mandatory in the course of treatment for facilitating early knee mobilization to prevent exacerbation of already compromised knee-joint motion. Vigorous exercise should be avoided for at least 12 months after solid union of the graft to prevent graft fracture. We concluded that the double-strut vascular fibular graft is an effective treatment for complicated long-bone defects of lower extremity.

Adult↗

PubMed2003

The combination of systemic antibiotics and antibiotics impregnated cement in primary total knee arthroplasty in patients of rheumatoid arthritis--evaluation of 60 knees.

BACKGROUND: We evaluated the effect of combination of systemic antibiotics and antibiotics-impregnated cement in prevention of deep infection in primary total knee arthroplasty (TKA) in patients of rheumatoid arthritis (RA). METHODS: Between 1993-2000, primary TKA were performed for 60 RA patients. Systemic antibiotics with cefazolin and gentamycin were applied in all the patients. Cefuroxime-impregnated cement was used for fixation of tibial and patellar components in all the patients; femoral component was fixed noncementedly in 45 patients (hybrid TKA) and cementedly in 15 patients (cemented TKA). The preoperative, intraoperative and postoperative courses were evaluated in detail. The mean follow-up period was 61 months (range: 24-108 months). The effect of cefuroxime-impregnated cement in the prevention of postoperative deep infection in primary TKA in cases of RA was evaluated. RESULTS: Except 1 (1.6%) superficial infection, no other complication was noted. There was no deep infection, either. CONCLUSIONS: Cefuroxime-impregnated cement combining with systemic antibiotics seems to be effective in the prevention of early or intermediate deep infection in primary TKA in patients of RA.

Adult↗

PubMed2002

Expressed CpG island sequence tag microarray for dual screening of DNA hypermethylation and gene silencing in cancer cells.

We present a novel concept by using expressed CpG island sequence tags (ECISTs)for dual analysis of DNA methylation and gene expression in cancer cells. ECISTs are present in the genome and are DNA fragments expected to be located in the promoter and first exon region of genes. Their GC-rich segments can be used for screening hypermethylated CpG sites in cancer cells, and their exon-containing portions can be used for measuring levels of the corresponding transcripts. A total of 1162 loci met the criteria of ECISTs from an initial screening of 7776 CpG island tags. This ECIST panel was used to analyze the breast cancer cell line MDA-MB-231, which was treated with a demethylating agent. Microarray profile analysis identified 30 methylation-silenced genes, the expression of which could be directly reactivated by demethylation. An additional group of 96 up-regulated genes was also identified but appeared to be downstream from this epigenetic cascade. Thus, this study shows that the ECIST microarray can be used to differentiate the primary and secondary causes of demethylation and provides an effective tool to elucidate the mechanisms of aberrant DNA methylation in cancer.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗

PubMed2002

Spread of hepatitis E virus among different-aged pigs: two-year survey in Taiwan.

Swine are reservoirs of hepatitis E virus (HEV). In this study, a 2-year survey of HEV in feces and sera of swine was conducted to determine if: 1) HEV has circulated among pigs for some time in Taiwan; 2) the spread of HEV among different-aged pigs; and 3) there exists HEV strains possibly imported through trading. From 1998-2000, 521 serum samples and 54 fecal specimens from pigs were examined by reverse transcription polymerase chain reaction. None of the 11 pigs in suckling stage (< 2 months) were serum HEV RNA positive. The highest viremia rate (4.5%) was in pigs of 2 months age, followed by 1.2% and 1.8% in pigs of growing (3-4 months) and finishing stages (5-6 months), and none in pigs older than 6 months. Viremia showed little variation in different years and areas. None of the 20 fecal samples from pigs in suckling stage were HEV RNA positive, whereas 9% of the 34 samples from pigs in growing or finishing stages were positive. Most swine HEV isolates in Taiwan clustered within the genotype 4, whereas the three HEV isolates cloned from pigs imported recently from the U.S. belonged to the genotype 3 HEV in the U.S. The results suggest that HEV may infect pigs at an early growing stage and spread unnoticed among pigs and possibly across countries through trading.

Age Factors↗

PubMed2002

Temporal and spatial expression of biologically active human factor VIII in the milk of transgenic mice driven by mammary-specific bovine alpha-lactalbumin regulation sequences.

Hemophilia A is one of the major inherited bleeding disorders caused by a deficiency or abnormality in coagulation factor VIII (FVIII). Hemophiliacs have been treated with whole plasma or purified FVIII concentrates. The risk of transmitting blood-borne viruses and the cost of highly purified FVIII are the major factors that restrict prophylaxis in hemophilia therapy. One of the challenges created by the biotechnology revolution is the development of methods for the economical production of highly purified proteins in large scales. Recent developments indicate that manipulating milk composition using transgenesis has focused mainly on the mammary gland as a bioreactor to produce pharmaceuticals. In the present study, a hybrid gene containing bovine alpha-lactalbumin and human FVIII cDNA was constructed for microinjection into the pronuclei of newly fertilized mouse eggs. The alphaLA-hFVIII hybrid gene was confirmed to be successfully integrated and stably germ-line transmitted in 12 (seven females/five males) lines. Western-blot analysis of milk samples obtained from eight of the transgenic founders and F1 offspring indicated that the recombinant hFVIII was secreted into the milk of the transgenic mice. The concentrations of rFVIII ranged from 7.0 to 50.2 microg/ml, over 35-200-fold higher than that in normal human plasma. Up to 13.4 U/ml of rFVIII was detected in an assay in which rFVIII restored normal clotting activity to FVIII-deficient human plasma.

Animals↗