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Biomedical subjects

J J Wu

Publications and source records attributed to J J Wu.

At least 19 recordsLinked to original sources
PubMed2004

The association of lumbar spondylolisthesis with collagen IX tryptophan alleles.

Two collagen type IX gene polymorphisms that introduce a tryptophan residue into the protein's triple-helical domain have been linked to an increased risk of lumbar disc disease. To determine whether a particular subset of symptomatic lumbar disease is specifically associated with these polymorphisms, we performed a prospective case-control study of 107 patients who underwent surgery of the lumbar spine. Patients were assigned to one of five clinical categories (fracture, disc degeneration, disc herniation, spinal stenosis without spondylolisthesis and spinal stenosis with spondylolisthesis) based on history, imaging results, and findings during surgery. Of the 11 tryptophan-positive patients, eight had spinal stenosis with spondylolisthesis and three had disc herniation. The presence of the tryptophan allele was significantly associated with African-American or Asian designation for race (odds ratio 4.61, 95% CI 0.63 to 25.35) and with the diagnosis of spinal stenosis with spondylolisthesis (odds ratio 6.81, 95% CI 1.47 to 41.95). Our findings indicate that tryptophan polymorphisms predispose carriers to the development of symptomatic spinal stenosis associated with spondylolisthesis which requires surgery.

Adolescent↗
PubMed2003

Bacteria ascend to liver from the bilioenteric conduit after choledochojejunostomy in the cholestatic rat.

The high incidence of postoperative cholangitis in children with clinical restoration of bile flow after Roux-Y choledochojejunostomy (RYCJ) assumed the concept of a direct ascending cholangitis caused by pathogens in the intestine, into the intrahepatic bile duct via the porta hepatis. It is also well known that jaundiced animals (patients) are more susceptible to infections of the bile ducts following the procedure of bilioenteric anastomosis. An animal experiment was conducted to compare quantitative bacterial cultures of the choledochojejunostomy area and the liver 24 hours after Escherichia coli (ATCC 25922) or sterile normal saline was injected into the bilioenteric conduit (BEC), following RYCJ in rats with or without the proceeding bile duct ligation. A significant increase of E. coli of the same strain (ATCC 25922), that we injected into the BEC, was proved with pulse-field gel electrophoresis (PFGE) and shown in the liver of the jaundiced rats receiving E. coli (ATCC 25922), compared to that in the nonjaundiced rats with normal saline treatment. It is concluded that bacteria often ascend early to the liver from the BEC following RYCJ. This ascending cholangitis model might be produced for further studies.

Animals↗
PubMed2003

A recombinant fusion protein and DNA vaccines against foot-and-mouth disease virus type Asia 1 infection in guinea pigs.

On the basis of amino acid (aa) sequence of the tandem repeat 133-158-20-34-133-158 which consisted of aa 133-158 of VP1 and aa 20-34 of VP4 of Foot-and-mouth disease virus (FMDV) type Asia 1 a recombinant prokaryotic expression vector pAS1-P encoding a fusion protein and eukaryotic expression vectors pAS1-E and pAS1-EdeltaCpG-ODN representing DNA vaccines were constructed. Guinea pigs immunized with these vaccines showed both neutralizing antibody and T cell proliferation responses. FMDV challenge tests for the first time showed that the recombinant fusion protein and pAS1-E and pAS1-EdeltaCpG-ODN vaccines protected 86%, 60% and 43% of guinea pigs from FMDV type Asia1 challenge, respectively. The results also indicated that the immune response of animals treated with the vector pAS1-E containing an oligodeoxynucleotide (ODN), which consisted of immunostimulatory cytosine-phosphate-guanosine (CpG) motifs, was augmented by CpG ODN.

Animals↗
PubMed2002

Identification of viridans streptococcal species causing bacterial meningitis in adults in Taiwan.

In order to determine the species responsible for viridans-group streptococcal meningitis in adults in Taiwan, seven cases of culture-proven meningitis due to these organisms were studied. The cases were all identified at the Chang Gung Memorial Hospital-Kaohsiung over a period of 3 years, and they accounted for 9% (7/78) of all cases of culture-proven bacterial meningitis occurring in adults during this period. Of the seven viridans streptococci isolates recovered, Streptococcus constellatus accounted for four, Streptococcus anginosus for two, and Streptococcus oralis for one. Thus, it appears that streptococci of the milleri group are the most common species causing bacterial meningitis in adults in Taiwan. The tendency for these organisms to cause invasive central nervous system infections in adults should not be overlooked when these species are recovered from cerebrospinal fluid specimens.

Adult↗
PubMed2002

Mechanical integrity of compression-moulded ultra-high molecular weight polyethylene: effects of varying process conditions.

Ultra-high molecular weight polyethylene (UHMWPE) bearing surfaces in knee and hip prostheses are frequently manufactured by direct compression moulding of the as-polymerised powder. A study was made of the important role of the temperature-time sequence in the melt state during processing, in determining the mechanical integrity of mouldings at 37 degrees C. Structural features were determined by calorimetry (for the degree of crystallinity), infra-red spectroscopy (for the degree of oxidation), density measurement, and scanning electron microscopy. Mechanical integrity was assessed by tensile tests at a constant nominal strain-rate of 10(-3) s(-1), with post-failure microscopic examination. For the whole range of melt temperatures 145-200 degrees C and times 10-90 min, essentially the same stress-strain path was followed, reflecting invariance of the degree of crystallinity. However, there were dramatic changes in elongation-to-break, from ca 10% for some mouldings at 145 degrees C to a mean of 560% at 175 degrees C where, at the 86% confidence level, there was evidence for a peak. The rise was explained by microscopy, that revealed two distinct types of fusion defect, of reducing severity with increasing temperature. Type 1 defects were voids arising from incomplete powder compaction, and persisted up to 165 degrees C. Type 2 defects were regions of enhanced deformability at inter-particle boundaries in apparently fully compacted mouldings, evidenced microscopically by localised relative displacements at particle interfaces, during the plastic deformation at 37 degrees C. They persisted up to 200 degrees C. Type 2 defects may be attributed to the slow self-diffusion of UHMWPE in the melt, leading to incomplete homogenisation. even after compaction is complete. The level of oxidation in the mouldings was small but rose with melt temperature, explaining the fall in elongation-to-break at temperatures higher than 175 degrees C.

Biocompatible Materials↗
PubMed2002

Recent developments in cartilage research: matrix biology of the collagen II/IX/XI heterofibril network.

Research on cartilage is intensifying as efforts expand to discover disease-modifying drugs to treat or prevent osteoarthritis. Proteolytic damage to the collagen fabric of cartilage is a critical, and probably early, component of the pathogenesis of degenerative joint disease. Here we summarize recent findings on the unique heteromeric structure of cartilage collagen fibrils, including the key role of collagen IX, a covalently bonded fibril-adapter molecule. A highly specific pattern of cross-linking sites that involves all three component gene products strongly suggests that collagen IX has evolved to function as an interfibrillar network-bonding agent. This is supported from the genetic evidence that mutations in all three collagen IX genes can produce a phenotype in which cartilage matrix integrity and early-onset osteoarthritis are a feature. From the structure of the cartilage collagen heteropolymer we also predict a pivotal role for telopeptide (non-triple-helical) proteolytic cleavages in the remodelling and degradation of collagen fibrils.

Animals↗
PubMed2001

Catalytic growth and characterization of gallium nitride nanowires.

The preparation of high-purity and -quality gallium nitride nanowires is accomplished by a catalytic growth using gallium and ammonium. A series of catalysts and different reaction parameters were applied to systematically optimize and control the vapor-liquid-solid (VLS) growth of the nanowires. The resulting nanowires show predominantly wurtzite phase; they were up to several micrometers in length, typically with diameters of 10-50 nm. A minimum nanowire diameter of 6 nm has been achieved. Temperature dependence of photoluminescence spectra of the nanowires revealed that the emission mainly comes from wurtzite GaN with little contribution from the cubic phase. Moreover, the thermal quenching of photoluminescence was much reduced in the GaN nanowires. The Raman spectra showed five first-order phonon modes. The frequencies of these peaks were close to those of the bulk GaN, but the modes were significantly broadened, which is indicative of the phonon confinement effects associated with the nanoscale dimensions of the system. Additional Raman modes, not observed in the bulk GaN, were found in the nanowires. The field emission study showing notable emission current with low turn-on field suggests potential of the GaN nanowires in field emission applications. This work opens a wide route toward detailed studies of the fundamental properties and potential applications of semiconductor nanowires.

Journal Article↗
PubMed2001

Molecular properties of matrilin-3 isolated from human growth cartilage.

Matrilin-3 is a recently identified matrix protein of cartilage that shows sequence homology to matrilin-1 (cartilage matrix protein or CMP). Here we identify and characterize the molecular properties of matrilin-3 from human growth cartilage by immunochemical and mass spectrometry methods. Extracts of fetal skeletal cartilage were resolved by SDS-PAGE and candidate matrilin subunits were identified by electrospray mass spectrometry of tryptic peptides. Matrilin-3 and matrilin-1 were both present in disulfide-bonded tetrameric components. Polyclonal antisera to synthetic peptides specific to each subunit confirmed the identities by Western blotting and further demonstrated the existence of several forms of tetramer. A homotetramer (matrilin-3)4 and more than one species of heterotetramer containing matrilin-3 and matrilin-1 chains were resolved. Immunohistochemistry of tissue sections confirmed that both matrilin-1 and matrilin-3 are widely codistributed throughout human skeletal growth cartilage.

Amino Acid Sequence↗
PubMed2001

Cytokine-induced metabolic dysfunction of MIN6 beta cells is nitric oxide independent.

BACKGROUND: An important obstacle to islet transplantation is graft injury due to local production of cytokines generated by host nonspecific inflammatory responses. The detrimental effects that cytokines impart on metabolic function have been associated with nitric oxide (NO) production and apoptosis. We tested the in vitro effects of interleukin (IL)-1 beta, tumor necrosis factor (TNF)alpha, and interferon (IFN)gamma on glucose-stimulated insulin release in the MIN6 beta-cell line and correlated metabolic dysfunction with NO production and rates of apoptosis. MATERIALS AND METHODS: MIN6 cells were cultured in the presence of IL-1 beta, TNFalpha, and/or IFN gamma. Insulin release was determined by radioimmunoassay. NO production was determined by the Griess reaction. Apoptosis was determined by measuring the sub-G(1) phase of DNA content of MIN6 cells by flow cytometry. RESULTS: Cytokine-induced suppression of glucose-stimulated insulin release was enhanced in a time-dependent manner. NO production was stimulated by IL-1 beta and augmented by TNFalpha and IFN gamma. N(G)-Monomethyl-l-arginine (l-NMMA) blocked cytokine-induced NO production but only partially attenuated suppression of glucose-stimulated insulin release. Apoptosis increased in the presence of cytokines and was slightly reduced when NO production was specifically inhibited. CONCLUSIONS: Proinflammatory cytokines suppressed glucose-stimulated insulin release in MIN6 cells. The dominant mechanisms involved NO-independent pathways.

Animals↗
PubMed2001

Hemodynamic response of modified fluid gelatin compared with lactated ringer's solution for volume expansion in emergency resuscitation of hypovolemic shock patients: preliminary report of a prospective, randomized trial.

The objective of this study was to compare the cardiac and hemodynamic responses to a rapid infusion of 1000 ml of modified fluid gelatin (group A) or 1000 ml of lactated Ringer's solution (group B) in emergency room patients suffering from shock. This prospective, randomized, open, noncrossover study was performed at a medical center university hospital in a surgical resuscitation room in the emergency department. The subjects were 34 patients with either hypovolemic or neurogenic shock who were admitted to the emergency room. A resuscitation protocol according to Advanced Trauma Life Support (ATLS) with an additional central venous line or Swan-Ganz catheters for hemodynamic monitoring was used. Physical parameters and hemodynamic variables were measured at baseline and 15 minutes, 30 minutes, and 1 hour after the infusion of each fluid. In both groups the mean arterial blood pressure (MAP), systolic and diastolic pressure, central venous pressure (CVP), and pulmonary artery occlusion pressure (PAOP) increased significantly. The CVP and PAOP increased significantly more in the modified fluid gelatin resuscitation group. In patients with traumatic or neurogenic shock due to acute volume deficiency, there was significantly better hemodynamic improvement, judged by CVP and PAOP measurements using the modified fluid gelatin for volume replacement than with lactated Ringer's solution during the first hour of resuscitation.

Adolescent↗
PubMed2001

Serotyping and antimicrobial susceptibility of group B Streptococcus over an eight-year period in southern Taiwan.

The increase in penicillin resistance among pneumococci and viridans streptococci and the development of serotype-specific conjugate vaccine have increased the need for knowledge of the antimicrobial susceptibility and the capsular serotypes of group B streptococci. Over an 8-year period, 351 group B streptococcal isolates from southern Taiwan were tested for antimicrobial susceptibility and serotype determination. Eighty-seven percent of the isolates were typeable. Types III (28.5%) and V (27.1%) were the most common serotypes. The occurrence of type V isolates increased with age, while that of type III isolates decreased with age, showing a predominance in children less than 1 year of age. Of 118 isolates from cases of invasive infection, types Ia, Ib, II, III, IV, and V accounted for 12.7, 11.9, 0.8, 33, 1.7, and 26.3%, respectively. Using the agar dilution method, all isolates were found to be susceptible to penicillin, cefotaxime, and vancomycin, 99.4% to ofloxacin, 78.1% to chloramphenicol, 63.2% to azithromycin, 62.6% to erythromycin, 57.3% to clindamycin, and 2.8% to tetracycline. Chloramphenicol resistance was associated with type III isolates (59 of 100, 59%) and erythromycin and azithromycin resistance with type Ib isolates (25 of 33 176%], and 21 of 33 [64%], respectively). Thus, 72% of the isolates from invasive infections were serotype III, V, or Ia, and penicillin remains the drug of choice for treatment or prophylaxis of group B streptococcal infections in southern Taiwan, despite the high prevalence of penicillin resistance among Streptococcus pneumoniae and viridans streptococci.

Adolescent↗
PubMed2001

Staphylococcus aureus meningitis in adults: a clinical comparison of infections caused by methicillin-resistant and methicillin-sensitive strains.

BACKGROUND: This study was undertaken to compare the clinical characteristics of adult methicillin-sensitive Staphylococcus aureus (MSSA) meningitis and adult methicillin-resistant S. aureus (MRSA) meningitis. PATIENTS AND METHODS: The clinical characteristics and therapeutic outcomes of 19 adult patients with S. aureus meningitis, including eight with MSSA infections and 11 with MRSA infections, were analyzed. A comparison was made between the clinical data of the patients with MSSA infections and those with MRSA infections. RESULTS: Before the end of 1995, MSSA infection was involved in all the adult patients with S. aureus meningitis but thereafter, MRSA infection was involved in 79% of the cases. The clinical characteristics found in patients with MSSA infection included underlying medical disorders (75%), community-acquired infection (75%) and mortality rate (13%). The clinical characteristics found in patients with MRSA infection included post-neurosurgical states (91%), nosocomial infections (100%), men outnumbering women (8:3), hydrocephalus (36%) and mortality rate (56%). Comparative study between the patient groups (hematogenous and post-neurosurgical) showed that only the mode of acquisition of infection had statistical significance. CONCLUSIONS: This study showed an increase in MRSA infections in adult S. aureus meningitis in recent years. The clinical characteristics of patients with MSSA and MRSA meningitis were different. Community-acquired infection was common in hematogenous S. aureus meningitis, while nosocomial infection was common in post-neurosurgical S. aureus meningitis. Vancomycin should be considered as one of the drugs of choice for initial therapy of adult bacterial meningitis, especially in post-neurosurgical patients.

Adolescent↗
PubMed2001

The role of high-resolution ultrasonography in management of calcific tendonitis of the rotator cuff.

This article predicts the possibility of resorption of the calcific plaques in the shoulder using high-resolution ultrasonography (HRUS) and color Doppler ultrasound (CDUS), and evaluates the therapeutic effect of US-guided fine-needle multiple punctures of the calcific plaque. A total of 100 patients with calcific tendenosis were divided into 3 groups: In group 1, patients having chronic shoulder pain received conservative treatment; in group 2, patients having acute exacerbation of shoulder pain also received conservative treatment; and group 3 patients received US-guided fine-needle multiple punctures or aspiration. In CDUS, all images were classified as grade 0 (no color flow signals), grade 1 (weak spotty color flow signal), grade 2 (few rod-like color flow signals), grade 3 (many rod-like or linear color flow signals). In the follow-up study, marked improvement of patients' clinical condition with more than 50% size reduction of calcific plaque was defined as an effective treatment. There was no significant difference between group 1 and group 3 (p = 0.558) in CDUS, but there was a significant difference between group 1 and group 2 (p = 0.000), and group 2 and group 3 (p = 0.000) on the basis of classification of grade < 1 and grade > or = 1. There was also significant difference in the follow-up result of effective management between group 1 and group 3 (p = 0.000), and group 1 and group 2 (p = 0.000). In conclusion, HRUS with CDUS proved to be a good modality in evaluating the possibility of resorption of shoulder calcification and, if CDUS > or = grade 1 in calcific tendonitis, we highly recommend conservative treatment with regular follow-up. On the other hand, if CDUS < grade 1, fine-needle repeated puncture could be considered as an effective alternative treatment.

Adult↗
PubMed2001

Ranitidine bismuth citrate or omeprazole-based triple therapy for Helicobacter pylori eradication in Helicobacter pylori-infected non-ulcer dyspepsia.

AIM: To test the eradication rate of Helicobacter pylori by ranitidine bismuth citrate-based triple therapy, and evaluate the symptomatic response of Helicobacter pylori eradication therapy for non-ulcer dyspepsia. METHODS: A total of 59 consecutive Helicobacter pylori infected non-ulcer dyspepsia patients were randomly selected to receive either one of two triple therapy regimens, including metronidazole, amoxycillin plus ranitidine bismuth citrate (RAM group) or omeprazole (OAM group). To determine the success of eradication, patients underwent the 13C-urea breath test, 6 weeks and one year after treatment. The dyspeptic symptom scores were also assessed at the time of enrolment, 6 weeks and one year after treatment. RESULTS: Per-protocol and intention-to-treat eradication rates were 77.7% and 70% in RAM group and 83.8% and 68.9% in OAM group (p = non significant). At both the 6th week and at the first year after treatment, the mean symptom scores were lower than pre-treatment scores in the study population, regardless of whether treatment was successful or not. However, patients, whether eradicated successfully or not-eradicated, presented similar 6-week and 1-year scores. CONCLUSIONS: One-week RAM triple therapy, which is cheaper than the OAM regimen, is a relatively effective alternative regimen for Helicobacter pylori eradication in Taiwanese. Triple therapy for Helicobacter pylori eradication was not the whole management for the relief of dyspeptic symptoms of non-ulcer dyspepsia patients.

Adult↗
PubMed2001

Pretreatment gastric histology is helpful to predict the symptomatic response after H. pylori eradication in patients with nonulcer dyspepsia.

This study aimed to test whether pretreatment gastric pathology in H. pylori-infected nonulcer dyspepsia (HpNUD) patients is relevant to and predictive of the symptomatic response after H. pylori eradication. Anti-H. pylori triple therapy was administered to 250 HpNUD patients, enrolled as the therapy group. In addition, 60 patients were enrolled as the control group, in which omeprazole was an alternatives to the triple therapy. Pretreatment gastric histology was evaluated thoroughly by the updated Sydney system. A [13C] urea breath test was also performed to evaluate the H. pylori eradication two months and 12 months later. For each patient, the baseline, month 2, and month 12 symptom scores were assessed for the month 2 or month 12 residual symptom ratio (RSR-2m or RSR-12m), calculated from: 100% x month 2 or month 12 score/baseline score. Based on either RSR-2m or RSR-12m, patients were categorized as good response (RSR < 50%), moderate response (50-70%), and poor response (> 70%) subgroups in both therapy and control groups to define the short-term and long-term symptomatic responses. Patients with successful H. pylori eradication in the therapy group showed a higher incidence of good symptomatic response (RSR < 50%) than those from the control group (month 2: 30.3 vs 12%, P < 0.05; month 12: 34.7 vs 17.1%, P < 0.05). Univariate and multivariate analysis disclosed that patients with a higher acute inflammation score (AIS) and the lowest incidence of lymphoid follicles (LF) at pretreatment gastric histology are predisposed to having a good symptom response after H. pylori eradication (P < 0.05). For HpNUD patients who have an AIS of more than three and an absence of LF at gastric histology, more than 85% had good short-term (month 2) and long-term (month 12) symptomatic relief after H. pylori eradication. In conclusion, nearly 30% of HpNUD patients can obtain symptomatic relief following H. pylori eradication. The pretreatment gastric histology of HpNUD can be helpful to monitor the symptomatic response after H. pylori eradication.

Adult↗
PubMed2001

Ascending cholangitis provokes IL-8 and MCP-1 expression and promotes inflammatory cell infiltration in the cholestatic rat liver.

BACKGROUND/PURPOSE: Postoperative cholangitis is one of the most common complications after bile duct reconstruction. The pathogenesis and early consequences of ascending cholangitis still are unidentified. METHODS: Male Sprague-Dawley rats were divided into 5 treatment groups: control (n = 4), blood sampling and liver biopsy only; group I, [BDL/Eschericha coli; n = 6], ligation of common bile duct (BDL) for a week, followed by Roux-en-Y choledochojejunostomy (RYCJ) and injection of E coli (ATCC 25922) into Roux limb after 24 hours; group II, [BDL/NS; n = 5], same procedures as in group I, with injection of normal saline (NS) into Roux limb; group III, [SBDL/E coli; n = 6], primary RYCJ was constructed 1 week after sham ligation of common bile duct (SBDL) followed by the same treatment as group I; Group IV, [SBDL/N.S; n = 6], same procedures as in group III, but injecting NS into Roux limb. All animals were killed after 24 hours of treatment. Blood was sampled for culture and serum cytokine levels. The liver was harvested for quantitative bacterial culture, as well as for MCP-1, interleukin (IL)-8 (CINC in the rat) and transforming growth factor beta1 mRNA expression by reverse transcriptase polymerase chain reaction (RT-PCR) and for immunohistochemistry. The choledochojejunostomy was resected for culture. Serum cytokine levels were detected by ELISA kits. RESULTS: A significant increase of E coli ATCC 25922, occurred in the livers of group I rats, compared with group IV (P =.037). MCP-1 expression increased in all groups, compared with control (P =.000). The IL-8 mRNA expression was significantly higher in group I than in control (P =.021). The expression of TGF-beta1 mRNA was similar among the groups (P =.361), consistent with the immunohistochemistry results. The serum MCP-1 and IL-8 levels were higher in the 4 groups than in the control (P =.000) and were significantly higher in group I than in group IV (P =.001). CONCLUSIONS: This study found that a significant colonization of E coli of the same strain was present in the cholestatic rat liver injected into the Roux limb, which was associated with a higher expression of liver MCP-1 and IL-8 mRNA, a significant increase of serum MCP-1 and IL-8, and a more evident inflammatory cell infiltration into the porta hepatis.

Anastomosis, Roux-en-Y↗
PubMed2001

Multicenter surveillance of antimicrobial resistance of major bacterial pathogens in intensive care units in 2000 in Taiwan.

A susceptibility surveillance study of 1,274 bacterial isolates recovered from various clinical specimens from patients in intensive care units (ICUs) of five major teaching hospitals was carried out from March, 2000, to June, 2000, in Taiwan. This study demonstrated a high rate (66%) of oxacillin resistance in Staphylococcus aureus (ORSA), a high rate of nonsusceptibility to penicillin (intermediate, 50% and highly resistant, 8%), and high rates of cefotaxime nonsusceptibility for S. pneumoniae (intermediate, 29% and resistant, 4%), Enterobacter cloacae (57%), Serratia marcescens (34%), and Citrobacter freundii (60%). High rate of ceftazidime nonsusceptibility for Pseudomonas aeruginosa (22%), and high rates of imipenem nonsusceptibility for P. aeruginosa (15%) and Acinetobacter baumannii (22%) were also found. The percentage (11.9%) of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli was greater than that (11.3%) for Klebsiella pneumoniae. Rates of quinupristin-dalfopristin nonsusceptibility for S. pneumoniae (42%), Enterococcus faecium (71%), and ORSA (39%) were high, but no vancomycin-resistant enterococci were found in this study. The resistance rates of some pathogen varied by institution or type of ICUs. Surveillance for antimicrobial resistance among bacterial pathogens in hospitals, particularly in ICU settings with a preexisting higher resistance burden, is mandatory in establishing and/or modifying guidelines for empirical treatment of severe infections in ICU patients caused by these antimicrobial-resistant pathogens.

Bacteria↗