Biomedical subjects

L Ling

Publications and source records attributed to L Ling.

At least 37 records · Page 2Linked to original sources

PubMed2001

Study of B Decays to Charmonium States: B-->eta(c)K and B --> chi(c0)K.

In a sample of 9.66x10(6)B&Bmacr; pairs collected with the CLEO detector we make the first observation of B decays to an eta(c) and a kaon. We measure branching fractions B(B+-->eta(c)K+) = (0.69(+0.26)(-0.21)+/-0.08+/-0.20)x10(-3) and B(B degrees -->eta(c)K degrees ) = (1.09(+0.55)(-0.42)+/-0.12+/-0.31)x10(-3), where the first error is statistical, the second is systematic, and the third is from the eta(c) branching fraction uncertainty. From these we extract the eta(c) decay constant in the factorization approximation, f(eta(c)) = 335+/-75 MeV. We also search for B decays to a chi(c0) and a kaon. No evidence for a signal is found and we set 90% C.L. upper limits: B(B+-->chi(c0)K+)<4.8x10(-4) and B(B degrees -->chi(c0)K degrees )<5.0x10(-4).

Journal Article↗

PubMed2001

Signal transduction via the growth hormone receptor.

Rapid progress has been made recently in the definition of growth hormone (GH) receptor signal transduction pathways. It is now apparent that many cytokines, including GH, share identical or similar signalling components to exert their cellular effects. This review provides a brief discourse on the signal transduction pathways, which have been demonstrated to be utilized by GH. The identification of such pathways provides a basis for understanding the pleiotropic actions of GH. The mechanisms by which the specific cellular effects of GH are achieved remain to be elucidated.

Animals↗

PubMed2001

The effects of hydraulic retention time and loading rate on brewery wastewater treatment using sequencing batch reactors.

Four laboratory-scale suspended-growth aerobic sequencing batch reactors (SBR) were used to study the effects of hydraulic retention time (HRT) and loading rate on the treatment of brewery wastewater. Factorial experiments and response surface analysis were carried out to explore the optimal operating conditions. A maximum total organic carbon (TOC) removal of 97% was estimated, at a HRT of 1.44 days with a loading rate of 3122 mg/L day. The maximum suspended solids removal, around 95%, would occur at values of HRT and loading rate of 1.32 days and 13.84 g/L day, respectively. TOC removal was more sensitive to the variations of HRT, however, the loading rate was more important than the HRT for suspended solids removal.

Beer↗

PubMed2001

Immunomodulating activity of CVT-E002, a proprietary extract from North American ginseng (Panax quinquefolium).

The activity of CVT-E002, an aqueous extract containing mainly oligosaccharides and polysaccharides from North American ginseng (Panax quinquefolium), as an immunobooster on murine spleen cells and peritoneal macrophages, was studied in-vitro. CVT-E002 stimulated the proliferation of normal mouse spleen cells, of which the major responding subpopulation was identified as B lymphocytes. CVT-E002 also activated peritoneal exudate macrophages leading to enhanced interleukin-1 (IL-1), interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-alpha) and nitric oxide (NO) production. In addition, CVT-E002 stimulated in-vivo immunoglobulin G (IgG) production in treated mice. These results identify some of the immunomodulating activities of CVT-E002 and suggest its use clinically for the modulation of immune responses.

Adjuvants, Immunologic↗

PubMed2001

[Effects of methyl mercury chloride on nuclear factor-kappa B DNA binding activities of nuclear protein extracts from developing rat cerebra and cerebella].

The effects of methyl mercury chloride (MMC) on DNA binding activities of nuclear factor kappa B(NF-kB) in developing rat cerebella and cerebra were investigated with electrophoretic mobility shift assays(EMSAs). The bindings of NF-kB in nuclei of rat cerebra and cerebella to kB probes showed two bands on gel shift in both control and experiment groups. NF-kB I and NF-kB II DNA binding activities of nuclear protein extracts from rat cerebra exposed to MMC in uterus, was lower than control groups on postnatal day 3 and 7, while that from rat cerebella was higher than control groups. The results suggested that the reactive abilities of neural cell to MMC between cerebra and cerebella were different. In binding reaction mixture, the quantities of MMC increased with the increase of NF-kB DNA binding activities of nuclear protein extracts.

Animals↗

PubMed2000

Measurements of the mass, total width, and two-photon partial width of the eta(c) meson.

Using 13.4 fb(-1) of data collected with the CLEO detector at the Cornell Electron Storage Ring, we have observed 300 events for the two-photon production of ground-state pseudoscalar charmonium in the decay eta(c)-->K(0)(S)K-/+pi(+/-). We have measured the eta(c) mass to be [2980.4+/-2.3 (stat)+/-0.6 (syst)] MeV and its full width as [27.0+/-5.8 (stat)+/-1.4 (syst)] MeV. We have determined the two-photon partial width of the eta(c) meson to be [7.6+/-0.8 (stat)+/-0.4 (syst)+/-2.3 (br)] keV, with the last uncertainty associated with the decay branching fraction.

Journal Article↗

PubMed2000

T6BP, a TRAF6-interacting protein involved in IL-1 signaling.

We report the identification of a TRAF-interacting protein, T6BP, that specifically associates with TRAF6. This interaction occurs between the coiled-coil region of T6BP and the N-terminal ring finger and zinc finger domains of TRAF6. IL-1, but not tumor necrosis factor, induces TRAF6-T6BP complex formation in a ligand-dependent manner. Formation of the TRAF6-T6BP complex depends on the presence of the IL-1 receptor-associated kinase (IRAK). After IL-1 stimulation, TRAF6 can exist in two separate complexes, TRAF6-IRAK or TRAF6-T6BP, but IRAK is not present in TRAF6-T6BP complexes. T6BP does not seem to play a direct role in activation of IkappaB kinases or Jun N-terminal kinase.

Amino Acid Sequence↗

PubMed2000

MIP-T3, a novel protein linking tumor necrosis factor receptor-associated factor 3 to the microtubule network.

In this study, we report the identification of a novel tumor necrosis factor receptor-associated factor 3 (TRAF3)-interacting protein designated MIP-T3. MIP-T3 is a 83-kDa protein with no significant homology to known mammalian proteins. MIP-T3 mRNA and TRAF3 mRNA are ubiquitously expressed, and TRAF3 is the only TRAF protein to interact with MIP-T3. The MIP-T3-TRAF3 interaction requires the coiled-coil TRAF-N domain of TRAF3. To our knowledge, this is the first case of a TRAF-binding protein that interacts with a single member of the TRAF family specifically through a TRAF-N coiled-coil domain. MIP-T3 binds to Taxol-stabilized microtubules and to tubulin in vitro, and MIP-T3 recruits TRAF3 to microtubules when both proteins are overexpressed in HeLa cells. In a 293 cell line stably expressing CD40, TRAF3 is released from the TRAF3.MIP-T3 complex and recruited to the CD40 receptor upon CD40 ligand stimulation. MIP-T3 may provide a novel mechanism in sequestering TRAF3 to the cytoskeletal network.

Amino Acid Sequence↗

PubMed2000

Regular articles: conditional disruption of hedgehog signaling pathway defines its critical role in hair development and regeneration.

Members of the vertebrate hedgehog family (Sonic, Indian, and Desert) have been shown to be essential for the development of various organ systems, including neural, somite, limb, skeletal, and for male gonad morphogenesis. Sonic hedgehog and its cognate receptor Patched are expressed in the epithelial and/or mesenchymal cell components of the hair follicle. Recent studies have demonstrated an essential role for this pathway in hair development in the skin of Sonic hedgehog null embryos. We have further explored the role of the hedgehog pathway using anti-hedgehog blocking monoclonal antibodies to treat pregnant mice at different stages of gestation and have generated viable offspring that lack body coat hair. Histologic analysis revealed the presence of ectodermal placode and primodium of dermal papilla in these mice, yet the subsequent hair shaft formation was inhibited. In contrast, the vibrissae (whisker) development appears to be unaffected upon anti-hedgehog blocking monoclonal antibody treatment. Strikingly, inhibition of body coat hair morphogenesis also was observed in mice treated postnatally with anti-hedgehog monoclonal antibody during the growing (anagen) phase of the hair cycle. The hairless phenotype was reversible upon suspension of monoclonal antibody treatment. Taken together, our results underscore a direct role of the Sonic hedgehog signaling pathway in embryonic hair follicle development as well as in subsequent hair cycles in young and adult mice. Our system of generating an inducible and reversible hairless phenotype by anti-hedgehog monoclonal antibody treatment will be valuable for studying the regulation and mechanism of hair regeneration.

Animals↗

PubMed2000

A polymorphism in the human timeless gene is not associated with diurnal preferences in normal adults.

The effect of a single nucleotide polymorphism, a glutamine to arginine amino acid substitution in the human Timeless gene (Q831R, A2634G), on diurnal preferences was studied in a random sample of normal volunteers enrolled in a population-based epidemiology study of the natural history of sleep disorders. We genotyped 528 subjects for this single nucleotide polymorphism and determined morningness-eveningness tendencies using the Horne-Ostberg questionnaire. Our results indicate that Q831R Timeless has no influence on morningness- eveningness tendencies in humans.

Adult↗

PubMed2000

Chemical and pharmacological evaluation of Hypericum perforatum extracts.

AIM: To determine the concentrations of chemical characteristic to extracts of leaves and flowers of Hypericum perforatum (St John's wort) in a number of selected samples and, following chemical characterization, to investigate the effects of these extracts on several pharmacological properties including effects of the extracts on inhibition of 5-hydroxytryptamine (5-HT) uptake and on antioxidant properties. METHODS: The samples were analyzed for the presence of characteristic chemicals by high performance liquid chromatography (HPLC) directly coupled to ultraviolet wavelength absorbance and positive or negative mode electrospray mass spectrometric detection. The effects of extracts on 5-HT uptake were determined by quantifying 3H-5-HT incorporation into rat hippocampal prisms. Estimates of effects of extracts on free radical scavenging capacity were made using a dynamic assay based on the ability of compounds to prevent the initiation of a colored reaction produced by the horseradish peroxidase catalyzed formation of hydroxyl free radicals from hydrogen peroxide using 2',2'-azinobis (3-ethylbenzthiazoline-6-sulfonic acid) as the color indicator. RESULTS: The chemical profile of a number of extracts were determined and found to differ substantially from each other. Inhibition of 5-HT uptake was found to correlate with hyperforin content and free radical scavenging capacity was found to correlate with the content of several flavonoids including quercetin and hyperoside. CONCLUSION: Standardized extracts of H perforatum varied substantially in the concentration of several characteristic chemicals. The correlation between pharmacological activity and certain characteristic chemicals found in these extracts indicates that the medicinal benefit derived from selected extracts will vary considerably depending on their chemical composition.

Animals↗

PubMed2000

[Expression of EGFR and PCNA, and DNA content in squamous cell carcinoma of larynx].

OBJECTIVE: To investigate the expression of epidermal growth factor (EGF), proliferating cell nuclear antigen (PCNA) and DNA index (DI) in laryngeal carcinoma, to analyse the correlation between these index and the biological characteristics of laryngeal carcinoma and their values of clinical prognosis. METHOD: Immunohistochemical staining was used to detect the expression of EGFR and PCNA in laryngeal cancer and normal tissue, and with MIPS-I image analysis system DNA contents of cancer cell were measured and made out DNA index. RESULT: The positive rate of EGFR in laryngeal carcinoma was 54.8%, and it was negative in all 10 normal laryngeal mucosa specimens (P < 0.01). The expression of EGFR did not correlate with histological grading and 5-years survival rate (P > 0.05), The positive expression of PCNA and DNA contents in the laryngeal carcinoma were increased with the decrease of tumorous differentiation (P < 0.05). With the increasing of PCNA positive expression and DI, the prognosis of the patients were poorer (P < 0.05). CONCLUSION: EGFR may be related to the process of carcinogenesis in laryngeal carcinoma and was used as an early biomarker identifying premalignant lesions which had the greatest risk of carcinogenesis. PCNA and DI were simultaneously detected can be used as the prediction of tumor malignancy and prognosis.

Carcinoma, Squamous Cell↗

PubMed2000

[Synthesis and DNA binding studies of Ruthenium complexes by spectra].

New Complexes Ru(bpy)2dppx2+ were synthesized. The binding of Ru(bpy)2dppx2+ to calf thymus DNA has been investigated by using electronic absorption and fluorescence spectra. The intercalation mode was proved to exist. The DNA leads to a dramatic enhancement of the photoluminescence of the drug at 599 nm (lambda ex = 471 nm) and absorption hypochromic effect and red shift. It was obvious that Ruthenium complexes may be used at a good DNA probe.

Animals↗

PubMed1999

Action of the brain stem saccade generator during horizontal gaze shifts. I. Discharge patterns of omnidirectional pause neurons.

Omnidirectional pause neurons (OPNs) pause for the duration of a saccade in all directions because they are part of the neural mechanism that controls saccade duration. In the natural situation, however, large saccades are accompanied by head movements to produce rapid gaze shifts. To determine whether OPNs are part of the mechanism that controls the whole gaze shift rather than the eye saccade alone, we monitored the activity of 44 OPNs that paused for rightward and leftward gaze shifts but otherwise discharged at relatively constant average rates. Pause duration was well correlated with the duration of either eye or gaze movement but poorly correlated with the duration of head movement. The time of pause onset was aligned tightly with the onset of either eye or gaze movement but only loosely aligned with the onset of head movement. These data suggest that the OPN pause does not encode the duration of head movement. Further, the end of the OPN pause was often better aligned with the end of the eye movement than with the end of the gaze movement for individual gaze shifts. For most gaze shifts, the eye component ended with an immediate counterrotation owing to the vestibuloocular reflex (VOR), and gaze ended at variable times thereafter. In those gaze shifts where eye counterrotation was delayed, the end of the pause also was delayed. Taken together, these data suggest that the end of the pause influences the onset of eye counterrotation, not the end of the gaze shift. We suggest that OPN neurons act to control only that portion of the gaze movement that is commanded by the eye burst generator. This command is expressed by driving the saccadic eye movement directly and also by suppressing VOR eye counterrotation. Because gaze end is less well correlated with pause end and often occurs well after counterrotation onset, we conclude that elements of the burst generator typically are not active till gaze end, and that gaze end is determined by another mechanism independent of the OPNs.

Animals↗

PubMed1999

Short- and long-term consequences of canal plugging on gaze shifts in the rhesus monkey. I. Effects on gaze stabilization.

Short- and long-term consequences of canal plugging on gaze shifts in the rhesus monkey. I. Effects on gaze stabilization. To study the contribution of the vestibular system to the coordinated eye and head movements of a gaze shift, we plugged the lumens of just the horizontal (n = 2) or all six semicircular canals (n = 1) in monkeys trained to make horizontal head-unrestrained gaze shifts to visual targets. After the initial eye saccade of a gaze shift, normal monkeys exhibit a compensatory eye counterrotation that stabilizes gaze as the head movement continues. This counterrotation, which has a gain (eye velocity/head velocity) near one has been attributed to the vestibuloocular reflex (VOR). One day after horizontal canal plugging, the gain of the passive horizontal VOR at frequencies between 0.1 and 1.0 Hz was <0.10 in the horizontal-canal-plugged animals and zero in the all-canal-plugged animal. One day after surgery, counterrotation gain was approximately 0.3 in the animals with horizontal canals plugged and absent in the animal with all canals plugged. As the time after plugging increased, so too did counterrotation gain. In all three animals, counterrotation gain recovered to between 0.56 and 0.75 within 80-100 days. The initial loss of compensatory counterrotation after plugging resulted in a gaze shift that ended long after the eye saccade and just before the end of the head movement. With recovery, the length of time between the end of the eye saccade and the end of the gaze movement decreased. This shortening of the duration of reduced gain counterrotation occurred both because head movements ended sooner and counterrotation gain returned to 1.0 more rapidly relative to the end of the eye saccade. Eye counterrotation was not due to activation of pursuit eye movements as it persisted when gaze shifts were executed to extinguished targets. Also counterrotation was not due simply to activation of neck receptors because counterrotation persisted after head movements were arrested in midflight. We suggest that the neural signal that is used to cause counterrotation in the absence of vestibular input is an internal copy of the intended head movement.

Animals↗

PubMed1999

Apparent dissociation between saccadic eye movements and the firing patterns of premotor neurons and motoneurons.

Saccadic eye movements result from high-frequency bursts of activity in ocular motoneurons. This phasic activity originates in premotor burst neurons. When the head is restrained, the number of action potentials in the bursts of burst neurons and motoneurons increases linearly with eye movement amplitude. However, when the head is unrestrained, the number of action potentials now increase as a function of the change in the direction of the line of sight during eye movements of relatively similar amplitudes. These data suggest an apparent uncoupling of premotor neuron and motoneuron activity from the resultant eye movement.

Abducens Nerve↗

PubMed1999

Academic emergency medicine's future. The SAEM Task Force on Emergency Medicine's Future. Society for Academic Emergency Medicine.

Emergency medicine (EM) will change over the next 20 years more than any other specialty. Its proximity to and interrelationships with the community, nearly all other clinicians (physicians and nonphysicians), and scientific/technologic developments guarantee this. While emergency physicians (EPs) will continue to treat both emergent and nonemergent patients, over the next decades our interventions, methods, and place in the medical care system will probably become unrecognizable from the EM we now practice and deliver. This paper, developed by the Society for Academic Emergency Medicine (SAEM) Task Force on Academic Emergency Medicine's Future, was designed to promote discussions about and actions to optimize our specialty's future. After briefly discussing the importance of futures planning, it suggests "best-case," "worst-case," and most probable future courses for academic EM over the next decades. The authors predict that EPs will practice a much more technologic and accurate form of medicine, with diagnostic, patient, reference, and consultant information rapidly available to them. They will be at the center of an extensive consultation network stemming from major medical centers and the purveyors of a sophisticated home health system, very similar to or even more advanced than what is now delivered on hospital wards. The key to planning for our specialty is for EM organizations, academic centers, and individuals to act now to optimize our possible future.

Academic Medical Centers↗

PubMed1999

Reconstruction plates to bridge mandibular defects: a clinical and experimental investigation in biomechanical aspects.

A retrospective study of 68 patients was carried out to assess the complications arising from the use of reconstruction plates in the maintainance of space and contour following mandibular segmental resection. Skin or mucosal perforation, plate fracture and loss of screw retention were the main complications. The most susceptible sites to screw loosening in the plates were situated nearest to and farthest from the resection margin on the proximal residual segments. Some of the possible causative biomechanical mechanisms of plate failure were studied using photoelastic models simulating the types of mandibular defect and plate fixation. Isochromatic fringe analysis was used to analyse stress lines in the bone surrounding screws. It was found that, during functional loading, moment and shear forces produced high concentrations of squeeze and press stress in this bone, causing bone resorption with consequent loss of screw retention.

Birefringence↗