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Biomedical subjects

J Liu

Publications and source records attributed to J Liu.

At least 109 records · Page 6Linked to original sources
PubMed2005

The -174 IL-6 GG genotype is associated with a reduced risk of type 2 diabetes mellitus in a family sample from the National Heart, Lung and Blood Institute's Framingham Heart Study.

AIMS/HYPOTHESIS: We evaluated the -174 IL-6 gene polymorphism as a risk factor for type 2 diabetes mellitus in a family-based analysis. METHODS: We tested for associations between the -174 IL-6 G/C promoter polymorphism and fasting plasma glucose (FPG) and type 2 diabetes in a sample of 1,428 individuals from the largest 182 families in the National Heart, Lung and Blood Institute's Framingham Heart Study population. RESULTS: A significant association was found with FPG (p=0.01) and log (FPG) (p=0.005) using a modified family-based transmission disequilibrium test, the family-based association test (FBAT). The association between IL-6 genotype and FPG (p=0.035) and log (FPG) (p=0.03) was also found in the subset of families that were informative in FBAT using a mixed-effects regression model and strengthened after adjustment for potential confounders (p=0.008 for log [FPG]). The mean glucose level estimated from models with log (FPG) as the dependent variable for the GG genotype in the informative families was significantly lower (5.20+/-0.06 mmol/l) than for the GC (5.41+/-0.06 mmol/l) and CC (5.38+/-0.06 mmol/l) genotypes (p=0.03 for contrast between GG and GC genotypes). In the subset of informative families, the risk of type 2 diabetes associated with the GG genotype was lower relative to the GC and CC genotypes combined (potential confounder-adjusted, mixed-effects odds ratio 0.35, 95% CI 0.14-0.88, p=0.026, unaffected n=391, affected n=32). CONCLUSIONS/INTERPRETATION: These results are consistent with a protective role for the -174 IL-6 G allele against type 2 diabetes and warrant further analysis of this polymorphism.

Blood Glucose↗
PubMed2005

Oxaliplatin causes selective atrophy of a subpopulation of dorsal root ganglion neurons without inducing cell loss.

Peripheral neuropathy is induced by multiple doses of oxaliplatin and interferes with the clinical utility of the drug in patients with colorectal cancer. In this study, we sought to determine whether cell loss or selective neuronal damage was the basis for the peripheral neuropathy caused by oxaliplatin. Adult female rats were given 1.85 mg/kg oxaliplatin twice per week for 8 weeks. Nerve conduction and L5 dorsal root ganglia (DRG) were studied 1 week after the completion of all treatment. No mortality occurred during oxaliplatin treatment, but the rate of body weight gain was reduced compared to age-matched vehicle-treated controls. Oxaliplatin slowed conduction velocity and delayed conduction times in peripheral sensory nerves, without affecting central or motor nerve conduction. In L5 DRG, total numbers of neurons were unchanged by oxaliplatin, but there were significant reductions in neuronal size distribution, ganglion volume, average cell size and the relative frequency of large cells. In addition, the relative frequency of small DRG cells was increased by oxaliplatin. Oxaliplatin significantly altered the size distribution and average cell body area of the predominantly large parvalbumin-immunoreactive DRG neurons without affecting the frequency of parvalbumin staining. On the contrary, neither the staining frequency nor the size distribution of the predominantly small substance P-immunoreactive DRG neurons was changed by oxaliplatin. In conclusion, oxaliplatin causes selective atrophy of a subpopulation of DRG neurons with predominantly large parvalbumin-expressing cells without inducing neuronal loss. Because DRG cell body size and axonal conduction velocity are positively correlated, neuronal atrophy may be the morphological basis for the development of decreased sensory nerve conduction velocity that characterizes oxaliplatin-induced peripheral neuropathy.

Animals↗
PubMed2005

Serological and molecular survey of Dirofilaria immitis infection in stray cats in Gyunggi province, South Korea.

The aim of this study was to carry out a serological and molecular survey for the presence of Dirofilaria immitis infection in stray cats using an ELISA kit and PCR assay. One hundred and fifty-five stray cats (77 females and 78 males) in Gyunggi province in South Korea, were used in this study. Four (2.6%) tested with the ELISA kit showed a positive reaction, and all positive samples by the ELISA kit showed a positive reaction by PCR analysis. No significant difference was observed between the male (2.6%) and female (2.6%) cat groups by ELISA kit. The positive rates for dirofilariosis were 2.8% in the 4-6-year-old group, and 18.2% in the > 6-year-old group by ELISA kit. With regard to the age element, older cats showed a higher prevalence of D. immitis infection in this study. A statistical analysis revealed that significant difference was observed in > 6-year-old group (p < 0.01). In conclusion, D. immitis infection in stray cats was present in Gyunggi province, although its incidence was low. Therefore, heartworm treatment and/or prophylaxis for stray cats captured are required in this area.

Age Factors↗
PubMed2005

220-fs erbium-ytterbium:glass laser mode locked by a broadband low-loss silicon/germanium saturable absorber.

We demonstrate femtosecond performance of an ultrabroadband high-index-contrast saturable Bragg reflector consisting of a silicon/silicon dioxide/germanium structure that is fully compatible with CMOS processing. This device offers a reflectivity bandwidth of over 700 nm and subpicosecond recovery time of the saturable loss. It is used to achieve mode locking of an Er-Yb:glass laser centered at 1540 nm, generating 220-fs pulses, with what is to our knowledge the broadest output spectrum to date.

Journal Article↗
PubMed2005

Absence of previously reported variants in the SCNA (G88C and G209A), NR4A2 (T291D and T245G) and the DJ-1 (T497C) genes in familial Parkinson's disease from the GenePD study.

Parkinson's disease (PD) is a neurodegenerative disorder in which relatives of the probands are affected approximately 4 times as frequently as relatives of control subjects. Several genes have been implicated as genetic risk factors for PD. We investigated the presence of six reported genetic variations in the SCNA, NR4A2, and DJ-1 genes in 292 cases of familial Parkinson's disease from the GenePD study. None of the variants were found in the GenePD families. Our results suggest that other variants or genes account for the familial risk of PD within the GenePD study.

Aged↗
PubMed2005

Interactions between charged residues in the transmembrane segments of the voltage-sensing domain in the hERG channel.

Studies on voltage-gated K channels such as Shaker have shown that positive charges in the voltage-sensor (S4) can form salt bridges with negative charges in the surrounding transmembrane segments in a state-dependent manner, and different charge pairings can stabilize the channels in closed or open states. The goal of this study is to identify such charge interactions in the hERG channel. This knowledge can provide constraints on the spatial relationship among transmembrane segments in the channel's voltage-sensing domain, which are necessary for modeling its structure. We first study the effects of reversing S4's positive charges on channel activation. Reversing positive charges at the outer (K525D) and inner (K538D) ends of S4 markedly accelerates hERG activation, whereas reversing the 4 positive charges in between either has no effect or slows activation. We then use the 'mutant cycle analysis' to test whether D456 (outer end of S2) and D411 (inner end of S1) can pair with K525 and K538, respectively. Other positive charges predicted to be able, or unable, to interact with D456 or D411 are also included in the analysis. The results are consistent with predictions based on the distribution of these charged residues, and confirm that there is functional coupling between D456 and K525 and between D411 and K538.

Amino Acid Sequence↗
PubMed2005

Stoma formation for fecal diversion: a plea for the laparoscopic approach.

BACKGROUND: The aim of this study was to assess the results of laparoscopic stoma creation for fecal diversion, specifically focussing on feasibility, safety, and efficacy, as well as indications and techniques. METHODS: Within a 10-year-period, all patients requiring laparoscopic stoma creation were evaluated prospectively. Patients' profiles and indications, procedures and results of operation, conversion, morbidity, mortality and short-term complications (stoma-related, laparoscopy-associated) were analyzed. RESULTS: A total of 80 patients (39 males, 41 females) with a mean age of 55.5 years (range, 17-91) underwent laparoscopic stoma creation. Most common indications were unresectable advanced colorectal cancer (n=20), pelvic malignant cancer (e. g. ovarian, cervix and prostate cancer, n=16), and perianal Crohn's disease with complex fistulas (n=16). Only in one female patient with pelvic malignant disease was the procedure converted to laparotomy due to obesity (conversion rate, 1.3%). 79 patients underwent laparoscopic stoma creation (completion rate, 98.7%) including loop ileostomy (n=30), loop sigmoid colostomy (n=40) and end sigmoid colostomy (n=9). Postoperative complications were documented in 9 patients (overall morbidity rate, 11.4%), including 4 minor complications treated conservatively (2 cases of prolonged atonia and 1 case each of pneumonia and urinary tract infection) and 5 major complications requiring reoperation (reoperation rate, 6.3%): one parastomal abscess (drainage), one stoma retraction following rod dislocation (laparoscopic stoma recreation), small bowel obstruction in two patients (small bowel resection), one port-site hernia (fascial closure), and hemorrhage (managed by re-laparoscopy). Mean operation time was 74 min (range, 30-245 min). Mean blood loss volume was 80 ml (range, 30-400 ml). Patients were discharged from hospital after a mean of 10.3 days (range, 3-47). Within a 1-year follow-up, no further stoma complications were documented. CONCLUSIONS: The advantages of laparoscopic stoma creation are low morbidity and reoperation rates, and no procedure-related mortality; our results suggest that laparoscopic stoma creation for fecal diversion is safe, feasible and effective. Therefore, at our institution, laparoscopic stoma creation is the method of choice for fecal diversion.

Adolescent↗
PubMed2005

Minocycline prevents gentamicin-induced ototoxicity by inhibiting p38 MAP kinase phosphorylation and caspase 3 activation.

Aminoglycosides are commonly used antibiotics that often induce ototoxicity leading to permanent hair cell loss and hearing impairment. We hereby examined whether minocycline protects hair cells from gentamicin-induced hair cell damage. Two millimolar gentamicin significantly induced outer hair cell damage and the addition of minocycline to gentamicin-treated explants significantly increased hair cell survival in a dose-dependent manner. Additionally, we demonstrated that gentamicin induced p38 MAPK phosphorylation, cytochrome c release, and caspase 3 activation in these cells and these remarkable changes were blocked by minocycline treatments. Furthermore, we showed that the inhibitor of p38 MAPK or the inhibitor of caspase 3 only partially blocked gentamicin-induced hair cell damage, and the pretreatment of explants with the inhibitor of p38 MAPK and the inhibitor of caspase 3 together exerted a synergic protective effect against gentamicin-induced hair cell damage. Our results suggest that minocycline blocks gentamicin-induced hair cell loss possibly by inhibition of three mechanisms: p38 MAPK phosphorylation, cytochrome c release, and caspase 3 activation. This finding may explain why minocycline has protective activity in a variety of apoptotic models. Therapeutic intervention by using minocycline or related drugs may be a novel means for preventing inner ear injury following the use of aminoglycoside.

Animals↗
PubMed2005

Functional GABA(B) receptors are expressed at the cone photoreceptor terminals in bullfrog retina.

GABA(B) receptors at the cone terminals in bullfrog retina were characterized by immunocytochemical and whole-cell patch clamp techniques in retinal slice preparations. Somata, axons and synaptic terminals (pedicles) of cones were both GABA(B) receptor (GABA(B)R) 1 and GABA(B)R2 immunoreactive. Physiologically, barium/calcium currents of cones to voltage steps were significantly reduced in size when GABA was puffed to cone terminals in the presence of picrotoxin that is supposed to block both GABA(A) and GABA(C) receptors. Similar reduction in barium currents was obtained with puff application of baclofen to cone terminals. These results suggest the presence of functional GABA(B) receptors at the bullfrog cone terminals. Suppression of barium currents of cones by baclofen was dose-dependent. Moreover, barium currents of cones were potentiated by background illumination, as compared with those recorded in the dark. 6,7-Dinitroquinoxaline-2,3-dione, an antagonist of non-NMDA receptors that hyperpolarizes horizontal cells and reduces GABA release from these cells, and saclofen, a GABA(B) receptor antagonist, both potentiated barium currents of cones in the dark, thereby mimicking the effects of background illumination. It is suggested that changes in calcium influx into the cone synaptic terminals due to activation of GABA(B) receptors may provide a negative feedback mechanism for regulating signal transmission between cones and second-order neurons in the retina by modifying the amount of glutamate released from the cones.

Animals↗
PubMed2005

The effect of ankle ligament damage and surgical reconstructions on the mechanics of the ankle and subtalar joints revealed by three-dimensional stress MRI.

Common image-based diagnostic techniques used to detect ankle ligament injuries or the effects of those injuries (e.g., mechanical instability) include magnetic resonance imaging (MRI) and stress radiography. Each of these techniques has limitations. The interpretation of the results obtained through stress radiography, a two-dimensional technique, is highly controversial. MRI can facilitate visualization of soft tissue, but three-dimensional visualization of the full length of the ligaments or detecting partial ligament damage is difficult. This work is part of a long-term study aimed at improving the diagnostic ability of MRI by utilizing it not only to visualize the ligaments but also to detect the mechanical instability produced at the ankle and subtalar joints due to ligament damage. The goal of the present study was to evaluate the ability of a previously developed technique called 3D stress MRI (sMRI) to detect in vitro the effect of damage to the lateral collateral ligaments and the stabilizing effect produced by two common surgical reconstruction techniques. MRI data were collected from eight cadaver limbs in a MR compatible ankle-loading device in neutral, inversion, and anterior drawer. Each specimen was tested intact, after cutting the anterior talo-fibular ligament followed by the calcaneo-fibular ligament and after applying two reconstructions. Ligament injuries produced significant changes in the response of the ankle and subtalar joints to load as detected by the 3D stress MRI technique. Both surgical procedures restored mechanical stability to the joints but they differed in the amount and type of stabilization achieved. We concluded that 3D sMRI can extend the diagnostic power of MRI from the current practice of slice-by-slice visualization to the assessment of mechanical function, the compromise in this function due to injury, and the effects of surgery.

Aged↗
PubMed2005

Cocaine exposure is associated with subtle compromises of infants' and mothers' social-emotional behavior and dyadic features of their interaction in the face-to-face still-face paradigm.

Prenatal cocaine and opiate exposure are thought to subtly compromise social and emotional development. The authors observed a large sample of 236 cocaine-exposed and 459 nonexposed infants (49 were opiate exposed and 646 nonexposed) with their mothers in the face-to-face still-face paradigm. Infant and maternal behaviors were microanalytically coded. No opiate-exposure effects were detected. However, mothers of cocaine-exposed infants showed more negative engagement than other mothers. The cocaine-exposed dyads also showed higher overall levels of mismatched engagement states than other dyads, including more negative engagement when the infants were in states of neutral engagement. Infants exposed to heavier levels of cocaine showed more passive-withdrawn negative engagement and engaged in more negative affective matching with their mothers than other infants. Although effect sizes were small, cocaine exposure, especially heavy cocaine exposure, was associated with subtly negative interchanges, which may have a cumulative impact on infants' later development and their relationships with their mothers.

Adolescent↗
PubMed2005

Anti-CD25 monoclonal antibody (basiliximab) for prevention of graft-versus-host disease after haploidentical bone marrow transplantation for hematological malignancies.

Haploidentical donors are available for most patients who need allografts but do not have matched donors. However, GVHD, rejection, delayed immune reconstitution, and infections have been significant barriers. We designed a haploidentical BMT protocol focusing on prevention of GVHD and rejection. A total of 53 leukemic patients underwent haploidentical G-CSF-primed BMT without ex vivo T-cell depletion. GVHD prophylaxis consisted of antithymocyte globulin, cyclosporine, methotrexate, and mycophenolate mofetil. In all, 38 patients (the CD25 group) received additional anti-CD25 monoclonal antibody basiliximab. The results were compared to 15 patients who did not receive basiliximab. All patients achieved trilineage engraftment with full-donor chimerism. The incidence of acute II-IV GVHD was 11% in the CD25 group vs 33% in the control group (P=0.046). The overall incidence of extensive chronic GVHD was 15%. T, B, and NK cells recovered within 12 months post transplant. The disease-free survival at 2 years was 53% with a median follow-up of 31 months. In conclusion, G-CSF primed haploidentical BMT along with sequential immunosuppressive agents as described here deserves further study.

Adolescent↗
PubMed2005

Impact of implantation technique on hemodynamic results of the Pericarbon Freedom stentless valve.

BACKGROUND: The Pericarbon Freedom stentless valve has shown excellent hemodynamic results in the midterm course. However, there is no information as to whether a continuous or interrupted suture technique at the inflow site has an impact on postoperative hemodynamics. METHODS: 139 patients were enrolled in a non-randomized, prospective matched trial. An interrupted suture line technique was used in 68 patients and a continuous suture line technique was used in 71 at the inflow site. Isolated valve replacement was performed in 70.4% of the continuous and 67.6% of the interrupted suture group. Pre- and postoperative hemodynamics and one-year follow-up were obtained by echocardiography and expressed as mean and peak gradients and grade of regurgitation. RESULTS: No significant difference between continuous and interrupted suture techniques were noted with respect to mean (11.8 +/- 6.3 vs. 12.5 +/- 6.2 mm Hg, p = 0.251) and peak gradients (21.0 +/- 9.6 vs. 22.0 +/- 10.9 mm Hg, p = 0.292) as well as to the degree of regurgitation. Bypass and cross-clamping times decreased by 22.4 and 20.6 minutes, respectively, with the use of the continuous suture technique. One year follow-up showed a further, significant decrease of mean and peak gradients. CONCLUSIONS: The Pericarbon Freedom stentless valve appears to offer excellent postoperative performance. The suture line technique at the inflow site does not result in any hemodynamic differences.

Aged↗
PubMed2005

Wheat curl mite (Acari: Eriophyidae) dispersal and its relationship with kernel red streaking in maize.

Wheat curl mites, Aceria tosichella Keifer, dispersing from wheat (Triticum spp.) to nearby corn (Zea mays L.) fields play a role in the development of kernel red streaking in corn. These studies were undertaken to verify the relationship of wheat curl mite to kernel red streaking, to determine whether wheat is the main source of curl mites dispersing into corn and to determine whether planting corn in temporal or spatial isolation of wheat is a valid management strategy. These studies were conducted on farm fields using sticky traps to monitor mites, followed by sampling mature grain for kernel streaking in southwestern Ontario from 1999 to 2002. The dominant source mites were winter wheat. Mite dispersal occurred during the first 3 wk of winter wheat maturation after the wheat had reached Zadoks stage 87. Mite dispersal corresponded to prevailing winds in the area with the lowest number of mites and the lowest severity of kernel red streaking occurring 60 m from wheat fields planted to the north, south, and east of cornfields and 90 m from wheat fields planted to the west of cornfields. The severity of kernel red streaking was positively correlated with the density of wheat curl mites in corn; however, the correlation was weak and kernel red streaking was still high in many cornfields when few or no mites were present. These findings suggest that wheat curl mite migration into corn is not entirely predictive of the incidence and severity of kernel red streaking.

Acari↗
PubMed2005

Radiation safety impact for top-up operation at the NSRRC.

Radiation safety impact for the upcoming top-up operation at the National Synchrotron Radiation Research Center (NSRRC) has been investigated with emphasis on the consequence of injection efficiency. Keeping the storage ring at high stored current by frequent injections, the top-up operation will inevitably increase the radiation dose compared with that in the present decay mode, especially when the injection efficiency is low. In addition, significantly high level of radiation could stream through the ratchet wall openings during top-up injections while shutters are open. Therefore, a series of radiation safety analyses including calculations and measurements have been carried out to assess the feasibility of this mode on the prospective radiation protection. The paper summarises the evaluation and the corresponding action plans for radiation safety.

China↗
PubMed2005

Glutathione protects human airway proteins and epithelial cells from isocyanates.

BACKGROUND: Glutathione (GSH), one of the major anti-oxidants of the lung, has been linked to the human response to isocyanate exposure. However, the ability of GSH to modulate key chemical reactions, thought to be central to the development of human isocyanate allergy, has not been directly analyzed under biologic exposure conditions. OBJECTIVE: To better understand the potential role of GSH in the response to occupational isocyanate exposure, we evaluated its effects on two processes thought to be involved in the development of isocyanate allergy, isocyanate-protein conjugation and epithelial cell toxicity. METHODS: The effects of GSH on (1) isocyanate conjugation with albumin, its major target in the airway fluid and (2) isocyanate-induced toxicity to human airway epithelial cell lines, A549 and NCI-H292, were tested using two different in vitro models. For protein conjugation studies, a newly described vapour exposure system was used to model the air/liquid interface at the surface of the epithelial fluid in the airways. Epithelial cell exposures were performed in fluid phase to mimic the in vivo exposure of airway cells covered by epithelial lining fluid. RESULTS: Reduced GSH prevented hexamethylene diisocyanate (HDI) conjugation to albumin in a dose-dependent manner, while oxidized GSH (GSSG) conversely increased conjugation rates. GSH levels equivalent to those found in normal human airway fluid (100 microm) provided >90% protection against HDI-protein conjugation when albumin was exposed to HDI vapour levels 10-fold above permissible occupational limits. Physiologic levels of GSH, but not GSSG, also reduced HDI toxicity to human airway epithelial cells in a dose-dependent manner, when present extracellularly, however, drugs that modulate intra-cellular GSH levels did not significantly alter isocyanate toxicity. CONCLUSIONS: Together with previously reported genetic and toxicity studies, the data suggest that airway GSH plays an important role in protection against HDI exposure and may help prevent the development of allergic sensitization and asthma.

Air Pollutants, Occupational↗
PubMed2005

Islet-1 expression and its colocalization with luteinising hormone, thyroid-stimulating hormone and oestrogen receptor alpha in the developing pituitary gland of the sheep foetus.

Islet-1 has been reported to be involved in pituitary development in the early stages of mouse embryogenesis. Oestrogen receptor (ER) and its expression may be involved in regulating pituitary development and its hormone-secreting function. Islet-1 expression and its correlations to ER in the developing pituitary gland are unknown. We therefore determined the pituitary cell specific expression of Islet-1 and its colocalization with ER alpha (ERalpha) in sheep foetus by immunohistochemistry. The results demonstrated that Islet-1-immunoreactive (ir) cells were distributed throughout the pituitary gland from day 60 of gestation until birth. The Islet-1-ir cell number was significant higher at day 90 and 120 of gestation compared to that at day 60 and at birth. All of the ERalpha-ir cells were colocalized with Islet-1 at day 60 of gestation, although a few ERalpha-ir cells were negative for Islet-1 in the later stage of gestation. The dominant cell type expressing Islet-1 is the gonadotroph, although small proportions of thyrotrophs and lactotrophs also express Islet-1. The proportion of luteinising hormone-ir gonadotrophs possessing Islet-1 kept rising from day 60 to day 120 of gestation and persisted until birth. The proportion of thyroid-stimulating hormone-ir cells expressing Islet-1 was at a high level from day 60-120 of the gestation and significantly declined at birth. The percentage of prolactin (PRL)-ir cells expressing Islet-1 was about 20% at day 60 of gestation. Very few PRL-ir cells contained Islet-1 in later stages of gestation. These data suggest that the development and functional establishment of pituitary gonadotrophs, thyrotrophs and lactotrophs might be regulated by the expressions of Islet-1 and ERalpha and by their interactions, although any mechanisms need to be elucidated further.

Animals↗