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Biomedical subjects

L Ling

Publications and source records attributed to L Ling.

At least 37 records · Page 2Linked to original sources
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↗
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↗
PubMed1999

[The study on edge detection method of medical color image].

Considering the specificity of the medical color image, in this paper a medical color image is decomposed as three color orthogonal feature: I1, I2 and I3 in K-L transformation method, and Kirsch algorithm is used to detect the edge of the monochrome image I1 including rich information. Finally, both clarity edge and rich detail of color backdisplay image are gained, if we adopt I2 and I3 to compensate I1.

Algorithms↗
PubMed1998

Slow recovery of impaired phrenic responses to hypoxia following perinatal hyperoxia in rats.

1. Previous studies demonstrated that both ventilatory and phrenic nerve responses to acute hypoxia are greatly attenuated in adult rats (3-5 months old) previously exposed to 1 month of perinatal hyperoxia (60 % O2; perinatal treated rats). The present study tested the hypothesis that this functional impairment recovers spontaneously with advancing age in perinatal treated rats. 2. Hypoxia-induced chemoreflexes were examined by measuring integrated phrenic responses to strictly controlled isocapnic hypoxia in urethane-anaesthetized, vagotomized, paralysed and ventilated rats at different ages. 3. At 50 mmHg Pa,O2 (arterial O2 partial pressure), the hypoxia-induced increase in minute phrenic activity was significantly attenuated in both 3- to 5-month-old (166 +/- 15% of baseline) and 6-month-old (130 +/- 17%) perinatal treated rats, relative to 3- to 6-month-old, untreated control rats (279 +/- 28%; both P < 0.05). However, at 40 mmHg Pa,O2, the hypoxic minute phrenic activity response was attenuated only in 3- to 5-month-old (154 +/- 33%), but not 6-month-old (232 +/- 33%) perinatal treated rats versus control rats (293 +/- 30%). 4. The minute phrenic activity response to hypoxia was not significantly different between geriatric perinatal treated rats (14-15 months) and untreated geriatric control rats at either 50 mmHg (treated: 250 +/- 20% versus control: 274 +/- 23%) or 40 mmHg Pa,O2 (treated: 292 +/- 19% versus control: 315 +/- 36%). 5. These data suggest that partial spontaneous recovery may occur in 6-month-old perinatal treated rats and that full recovery occurs by 15 months of age.

Animals↗
PubMed1998

Chemoafferent degeneration and carotid body hypoplasia following chronic hyperoxia in newborn rats.

1. To define the role of environmental oxygen in regulating postnatal maturation of the carotid body afferent pathway, light and electron microscopic methods were used to compare chemoafferent neurone survival and carotid body development in newborn rats reared from birth in normoxia (21 % O2) or chronic hyperoxia (60 % O2). 2. Four weeks of chronic hyperoxia resulted in a significant 41 % decrease in the number of unmyelinated axons in the carotid sinus nerve, compared with age-matched normoxic controls. In contrast, the number of myelinated axons was unaffected by hyperoxic exposure. 3. Chemoafferent neurones, located in the glossopharyngeal petrosal ganglion, already exhibited degenerative changes following 1 week of hyperoxia from birth, indicating that even a relatively short hyperoxic exposure was sufficient to derange normal chemoafferent development. In contrast, no such changes were observed in the vagal nodose ganglion, demonstrating that the effect of high oxygen levels was specific to sensory neurones in the carotid body afferent pathway. Moreover, petrosal ganglion neurones were sensitive to hyperoxic exposure only during the early postnatal period. 4. Chemoafferent degeneration in chronically hyperoxic animals was accompanied by marked hypoplasia of the carotid body. In view of previous findings from our laboratory that chemoafferent neurones require trophic support from the carotid body for survival after birth, we propose that chemoafferent degeneration following chronic hyperoxia is due specifically to the loss of target tissue in the carotid body.

Afferent Pathways↗