Biomedical subjects

Y Lin

Publications and source records attributed to Y Lin.

At least 181 records · Page 10Linked to original sources

PubMed2000

Molecular characterization of a novel yeast cell-wall acid phosphatase cloned from Kluyveromyces marxianus.

A novel Kluyveromyces marxianus gene that encodes an acid phosphatase, Pho610, was cloned in Saccharomyces cerevisiae. The deduced amino acid sequence was distinct from S. cerevisiae phosphatases but similar to some fungal enzymes. A peculiar feature of the sequence is that it has hydrophobic stretches both at the N- and C-termini, which is a characteristic of the precursors of glycosylphosphatidylinositol(GPI)-anchored proteins. When the gene was expressed in S. cerevisiae, the active enzyme was recovered in the periplasmic fraction by glucanase digestion. The Pho610 polypeptide was highly glycosylated and a significant portion was covalently linked to the cell-wall glucan. The enzyme was secreted when the C-terminal region was truncated to remove the GPI signal. Therefore, Pho610 is a novel cell-wall protein having an enzyme activity.

Acid Phosphatase↗

PubMed2000

Cardiovascular responses to glutamate and angiotensin II in ventrolateral medulla of hypertension induced by chronic inhibition of nitric oxide.

It has been suggested that nitric oxide (NO) influences the actions of L-glutamate and angiotensin II in the brain. In the present study, we examined whether cardiovascular responses to L-glutamate and angiotensin II would be altered in the rostral ventrolateral medulla (RVLM) of rats treated with an NO synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME). Wistar rats were treated with either L-NAME (100 mg/kg/day, n=9) or vehicle (n=8) for 4 weeks. L-glutamate (2 nmol/50 nl) or angiotensin 11 (100 pmol) was then microinjected into unilateral RVLM of anesthetized rats. Upon completion of the experiments, angiotensin-converting enzyme (ACE) activity of the brain stem was measured. The systolic blood pressure after 4 weeks of the treatment was significantly higher in the L-NAME group (203+/-8 mmHg) than in the control group (142+/-3 mmHg, p< 0.01). The pressor response to L-glutamate microinjected into the RVLM was significantly greater in the L-NAME group (31+/-2 mmHg) than in the control group (24+/-1 mmHg, p< 0.01). Similarly, angiotensin II showed a greater pressor response in the L-NAME group. ACE activity of the brain stem did not differ between the groups. In conclusion, NO may have an inhibitory influence on the actions of L-glutamate and angiotensin II in the RVLM.

Angiotensin II↗

PubMed2000

Incidence of intravenous site reactions in neurotrauma patients receiving valproate or phenytoin.

OBJECTIVE: To determine the incidence of intravenous site reactions to phenytoin and valproate in a large population of patients with neurotrauma. DESIGN: Retrospective chart review of two double-blind, randomized clinical trials evaluating the use of antiepileptic drugs to prevent posttraumatic seizures in patients with neurotrauma: phenytoin versus placebo (n = 390), and valproate versus phenytoin with placebo (n = 385). Information collected from the charts included the number, type, and location of intravenous lines and intravenous site events. SETTING: Tertiary care trauma and university teaching hospital. MAIN RESULTS: Intravenous site reactions occurred in 18% and 25% of patients receiving valproate or phenytoin, respectively, with the majority of events (70%) occurring in the first intravenous site. Patients received the neurosurgery study drug (NSSD) by either central or peripheral lines; all intravenous site reactions occurred in peripheral administration sites. When patients who received the drug by central line during the course of therapy were excluded, the estimated incidence of site reactions was 21% and 30% for valproate and phenytoin, respectively (p = 0.056). The time to the first event was shorter with phenytoin compared with valproate (2.0 +/- 1.3 vs. 3.0 +/- 1.9 d; p = 0.009). Fewer adverse events were noted with phenytoin in the phenytoin-without-valproate study than in the phenytoin-with-valproate study, with 4.3% and 8.2% of intravenous site events recorded in patients receiving placebo or phenytoin, respectively. There was no significant difference in the number of intravenous lines per patient used during NSSD drug infusion for phenytoin versus placebo or phenytoin versus valproate. CONCLUSIONS: Both intravenous phenytoin and valproate resulted in intravenous site reactions, with the loading doses responsible for the majority of the events.

Adult↗

PubMed2000

Sleep patterns and total mortality: a 12-year follow-up study in Japan.

A population-based cohort study was conducted to assess the relationship between total mortality and self-reported sleep patterns as regards not only to sleep duration but also subjective sleep quality. A total of 5,322 inhabitants in Gifu Prefecture, Japan, completed a self-administered questionnaire on health status and lifestyles including habitual sleep patterns, and were followed-up for an average of 11.9 years. Relative risks were computed by using Cox proportional hazards models. Both longer and shorter sleep, compared to 7-8 hour-sleep, was related to significantly increased risk of total mortality in males (relative risk [RR] for > or = 10 hours = 1.94, and RR for < 7 hour = 1.90), but not in females. Females complaining of poor awakening state experienced a higher mortality risk compared to those who woke up normally (RR: 1.97). Males who usually fell asleep easily showed a marginally lower mortality risk compared to those who fell asleep normally (RR: 0.70). Female users of sleeping pills were at an elevated risk (RR: 1.89). These findings were almost unchanged after adjustment for sleep duration and other confounders. Poor self-reported quality of sleep seemed to be associated with an increased risk of mortality independently of sleep duration.

Adult↗

PubMed2000

Has the mammography quality standards act affected the mammography quality in North Carolina?

OBJECTIVE: The United States Food and Drug Administration implemented federal regulations governing mammography under the Mammography Quality Standards Act (MQSA) of 1992. During 1995, its first year in implementation, we examined the impact of the MQSA on the quality of mammography in North Carolina. MATERIALS AND METHODS: All mammography facilities were inspected during 1993-1994, and again in 1995. Both inspections evaluated mean glandular radiation dose, phantom image evaluation, darkroom fog, and developer temperature. Two mammography health specialists employed by the North Carolina Division of Radiation Protection performed all inspections and collected and codified data. RESULTS: The percentage of facilities that met quality standards increased from the first inspection to the second inspection. Phantom scores passing rate was 31.6% versus 78.2%; darkroom fog passing rate was 74.3% versus 88.5%; and temperature difference passing rate was 62.4% versus 86.9%. CONCLUSION: In 1995, the first year that the MQSA was in effect, there was a significant improvement in the quality of mammography in North Carolina. This improvement probably resulted from facilities' compliance with federal regulations.

Mammography↗

PubMed2000

Neuroprotective efficacy and therapeutic window of the high-affinity N-methyl-D-aspartate antagonist conantokin-G: in vitro (primary cerebellar neurons) and in vivo (rat model of transient focal brain ischemia) studies.

Conantokin-G (Con-G), a 17-amino-acid peptide derived from marine snails and a potent N-methyl-D-aspartate (NMDA) antagonist, was evaluated for its neuroprotective properties in vitro and in vivo. In primary cerebellar neurons, Con-G was shown to decrease excitotoxic calcium responses to NMDA and to exhibit differential neuroprotection potencies against hypoxia/hypoglycemia-, NMDA-, glutamate-, or veratridine-induced injury. Using the intraluminal filament method of middle cerebral artery occlusion as an in vivo rat model of transient focal brain ischemia, the neuroprotective dose-response effect of Con-G administration beginning 30 min postocclusion was evaluated after 2 h of ischemia and 22 h of reperfusion. In the core region of injury, an 89% reduction in brain infarction was measured with significant neurological and electroencephalographic recovery at the maximal dose tested (2 nmol), although mild sedation was noted. Lower doses of Con-G (0.001-0.5 nmol) were significantly neuroprotective without causing sedation. Postinjury time course experiments demonstrated a therapeutic window out to at least 4 to 8 h from the start of the injury, providing a 47% reduction in core injury. The neuroprotective effect of Con-G (0. 5 nmol) was also evaluated after 72 h of injury, where a 54% reduction in core brain infarction was measured. Critically, in both recovery models (i.e., 24 and 72 h), the reduction in brain infarction was associated with significant improvements in neurological and electroencephalographic recovery. These data provide evidence for the potent and highly efficacious effect of Con-G as a neuroprotective agent, with an excellent therapeutic window for the potential intervention against ischemic/excitotoxic brain injury.

Animals↗

PubMed2000

Two amino acids in the sixth transmembrane segment of the mouse gastrin-releasing peptide receptor are important for receptor activation.

The gastrin-releasing peptide receptor (GRP-R) is a G protein-coupled receptor that mediates a variety of cellular responses, including cell growth and modulation of neuronal activity by activation of heterotrimeric GTP-binding proteins in the Gq family. To understand the regulation of GRP-R signaling we have substituted alanine for each of 10 amino acid residues within the transmembrane (TM) helices of the GRP-R predicted to project into the binding pocket of the receptor and analyzed the importance of each of these residues for receptor function. Two mutations showed selective loss of either agonist (Y285A) or antagonist (F313A) affinity for the GRP-R. In addition, we identified two amino acid residues, Phe(270) and Asn(281), in the sixth TM segment, which are important for receptor-G protein interaction. In a competition-binding assay with an antagonist radioligand, bombesin showed a 20- to 100-fold decreased affinity for the N281A and F270A mutant GRP-R compared with wild-type GRP-R. The saturation-binding isotherms are best fit by a two-state model, indicating that the receptors are in either a low-affinity (K(D2)) or a high-affinity (K(D1)) state. The ratio of the two affinities (K(D2)/K(D1)) was significantly increased for both mutants compared with wild-type GRP-R, whereas the fraction of mutant receptors in the high-affinity state (R(1)) was decreased. GDP/guanosine-5'-O-(3-thio)triphosphate exchange catalyzed by the N281A mutant was lower than that observed for the wild-type GRP-R. However, for both mutants, bombesin was still able to stimulate 1,4,5-inositol triphosphate in transfected cells albeit with reduced activity. We conclude that these two TM residues are important for receptor-G protein coupling, and postulate that each mutation may affect GRP-R conformational change to the high-affinity, G protein-coupled state.

3T3 Cells↗

PubMed2000

Long-term kinetic study of beta-carotene, using accelerator mass spectrometry in an adult volunteer.

We present a sensitive tracer method, suitable for in vivo human research, that uses beta-[(14)C]carotene coupled with accelerator mass spectrometry (AMS) detection. Using this approach, the concentration-time course of a physiological (306 microgram 200 nCi) oral dose of beta-[(14)C]carotene was determined for 209 days in plasma. Analytes included beta-[(14)C]carotene, [(14)C]retinyl esters, [(14)C]retinol, and several [(14)C]retinoic acids. There was a 5.5-h lag between dosing and the appearance of (14)C in plasma. Labeled beta-carotene and [(14)C]retinyl esters rose and displayed several maxima with virtually identical kinetic profiles over the first 24-h period; elevated [(14)C]retinyl ester concentrations were sustained in the plasma compartment for >21 h postdosing. The appearance of [(14)C]retinol in plasma was also delayed 5.5 h postdosing and its concentration rose linearly for 28 h before declining. Cumulative urine and stool were collected for 17 and 10 days, respectively, and 57.4% of the dose was recovered in the stool within 48 h postdosing. The stool was the major excretion route for the absorbed dose. The turnover times (1/k(el)) for beta-carotene and retinol were 58 and 302 days, respectively. Area under the curve analysis of the plasma response curves suggested a molar vitamin A value of 0.53 for beta-carotene, with a minimum of 62% of the absorbed beta-carotene being cleaved to vitamin A.In summary, AMS is an excellent tool for defining the in vivo metabolic behavior of beta-carotene and related compounds at physiological concentrations. Further, our data suggest that retinyl esters derived from beta-carotene may undergo hepatic resecretion with VLDL in a process similar to that observed for beta-carotene.

Adult↗

PubMed2000

Distraction osteogenesis in functional reconstruction of mandible--report of 6 cases.

OBJECTIVE: To study the application of distraction osteogenesis in mandibular function reconstruction. METHODS: Three types of mandibular distractors were used in 6 patients with different mandibular defects due to tumor resection. For 2 cases with ramus defects, specially designed distractors were used to restore the normal height of the ramus. In 1 case, the trifoci distraction principle was used and a trifoci distractor was designed. In 3 cases, vertical distractors made in Germany or China were used. The patient average age was 31.5 years old (ages ranged from 8 to 54). RESULTS: In 5 cases the mandibular lengthenings were successful according to the direction and distance chosen before distraction. In 1 case, the trifoci distraction principle was applied and a proximal 23 mm mandibular defect was successfully corrected; however, the 23 mm distal mandibular defect was not corrected because the screws for fixation of the transport block were loosened. Infection and dysosteogenesis did not occur in any cases. CONCLUSION: Distraction osteogenesis can successfully be used in mandibular functional reconstruction and is more advantageous than traditional techniques. The most favorable time for distraction osteogenesis in mandibular reconstruction is at the time of tumor resection.

Adult↗

PubMed2000

Peri-implant mucosal inflammation and bone loss: clinical and radiographic evaluation of 108 dental implants after 1-year loading.

OBJECTIVE: To evaluate the clinical outcomes, and a possible correlation between peri-implant mucosal inflammation and marginal bone loss, 1 year after restoration in a group of Chinese patients with dental implants. METHODS: Observation of the clinical and radiographic parameters of 108 IMZ and Frialit-2 dental implants in 70 patients. RESULTS: One year after loading, there were no signs of mobility and peri-implant radiolucency in any of the implants. The average bone loss adjacent to implants was 0.63 mm (SD 0.78). The prevalence of peri-implant mucosal inflammation, as indicated by sulcus bleeding index (SBI) of 1.0 or more, was 32.9%. Significant positive correlation was found between mucosal inflammation and bone loss (P < 0.05). 92% of the observed sites had plaque index (PLI) scores greater than 1. CONCLUSIONS: The 1-year outcomes from this patient group indicate that IMZ and Frialit-2 implants provide satisfactory clinical results. One of the etiologic factors of alveolar bone loss around implants seems to be plaque-associated marginal inflammation. Improvement of oral hygiene, elimination of soft tissue inflammation, and proper treatment of periodontal disease of natural teeth are critical for maintaining the implants.

Adolescent↗

PubMed2000

Synergistic effects of clinically achievable concentrations of 12-O-tetradecanoylphorbol-13-acetate in combination with all-trans retinoic acid, 1alpha,25-dihydroxyvitamin D3, and sodium butyrate on differentiation in HL-60 cells.

Our recent studies demonstrated that 12-O-tetradecanoylphorbol-13-acetate (TPA) has pharmacological activity for the treatment of acute myelocytic leukemia patients. In the present study, we investigated the potential synergistic effect of all-trans retinoic acid (RA), 1alpha,25-dihydroxyvitamin D3 (VD3), and sodium butyrate (NaB) on TPA-induced differentiation in HL-60 human promyelocytic leukemia cells. The cells were treated once with these agents for 48 h or treated every 24 h for 96 h. Treatment of HL-60 cells once with TPA, RA, VD3, or NaB for 48 h resulted in concentration-dependent growth inhibition and cell differentiation. At clinically achievable concentrations, TPA (0.16 nM) increased the number of adherent cells and RA (0.1-1 microM) increased the number of nitroblue tetrazolium (NBT)-positive cells. The combinations of TPA (0.16 nM) with RA (0.1-1 microM), VD3 (1 nM), or NaB (100 microM) for 48 h synergistically increased differentiation as measured by the formation of adherent cells (P < or = 0.01). Moreover, cells treated with various combinations of low concentrations of TPA, RA, VD3, and NaB every 24 h for 96 h resulted in a further decrease in cell growth and an increase in differentiation. At clinically achievable concentrations, the strongest stimulation of differentiation was achieved in cells treated with a "cocktail" that combined TPA, RA, VD3, and NaB. The synergistic effect of combinations of TPA with RA or NaB at clinically effective concentrations on HL-60 cell differentiation suggests that the combination of these agents may improve the therapeutic efficacy of TPA for the treatment of acute promyelocytic leukemia (APL) patients. A differentiation "cocktail" that combines TPA, RA, VD3, and NaB may provide an even more effective strategy for improving the therapeutic efficacy of TPA and RA.

Anesthetics, Intravenous↗

PubMed2000

[Caloric values and ash contents of some mangrove woods].

The caloric values and ash contents of some mangrove woods in Dongzhai Harbor Mangrove Forest Reserve of Hainan Province were determined in Summer, and the changes of the caloric value of Kandelia candel woods at different latitudes were studied. The ash content of mangrove woods was low, ranging from 2.43% to 5.17%; and their gross and ash-free caloric values ranged from 17.23 kJ.g-1 to 19.21 kJ.g-1 and from 17.70 kJ.g-1 to 20.10 kJ.g-1, respectively. Sonneratia apetala wood had the lowest gross and ash-free caloric values. The caloric value of Kandelia candel wood decreased with increasing latitude in Summer.

Hot Temperature↗

PubMed2000

[Adaptation of transgenic strains of insect-resistance cotton to different ecological environments].

Seven transgenic strains of insect-resistance cotton, WH1, WH2, WH3, WH4, WH5, WH6 and BG2, and one common strain Simian-3 (CK) were selected to investigate their adaptation to insect-resistance and yield trait at 10 different sites. The results show that all transgenic strains had a strong resistance to bollworm(Helicoverpa armigera) and pink bollworm (Pectinophora gossypiella), with a high stability and no difference in 10 sites, but the yield trait was significantly influenced by environmental factors. The interaction between strains and sites was significant. In comparison with CK, WH6 and BG2 had a good insect-resistance and high fiber yield, and could be applied in practice.

Adaptation, Physiological↗

PubMed2000

[Nutrient content in litterfall and its translocation in plantation forests in south China].

The amounts of litterfall, nutrient content in it and leaves of five plantation forests in south China were determined. The order of litterfall biomass was in sequence of Acacia mangium (11.1 t.hm-2) > Pinus elliotii (7.3 t.hm-2) > Schima superba (6.5 t.hm-2) > Acacia auriculaiformis (4.8 t.hm-2) > Eucalyptus citriodora (2.6 t.hm-2). A. mangium returned soil much more nutrient to soil through litterfall than other forests did. N, P and K were largely translocated from senescing leaves for all the five forests, and especially for A. mangium. Nutrient translocated varied greatly with seasons. The translocation of other elements was not definite.

Biomass↗

PubMed2000

Comparative study of D2 receptors and dopamine content in striatum before and after electro-acupuncture treatment in rats.

OBJECTIVE: To evaluate the change in D2 receptors and their relationship with dopamine (DA) content in experimental hemi-parkinsonism rats before and after electro-acupuncture (EA) treatment. METHODS: 125I-IBZM D2 receptor cerebral autoradiographic analysis, HPLC-ECD detection of DA and its metabolites, homovanillic acid (HVA), 3, 4-dihydroxyphenylacetic acid (DOPAC) were used to study their levels in striatum in pre-EA, EA and EA control group. RESULTS: The DA, HVA and DOPAC levels in striatum of the lesioned side in the EA group were elevated compared to the pre-EA and EA control group (P < 0.05). For the EA group, the striatum/cerebellum 125I-IBZM uptake ratio of the lesioned side was 8.04 +/- 0.71, (29.34% +/- 4.83%) more than that of the contralateral side (P < 0.05), while no significant difference was observed as compared with that in the pre-EA group (8.09 +/- 0.52, 30.12% +/- 4.53%, higher than that of the intact side P > 0.05). It was lower than the EA control group (8.61 +/- 0.63, P < 0.05), and the latter was (38.63% +/- 3.71%) higher than that in its contralateral side (P < 0.05). CONCLUSION: 6-OH-DA lesions in the substantia nigra and ventral tegmental areas induce an up-regulation of striatal D2 binding sites. EA treatment could elevate the DA level of the lesioned side striatum and prevent D2 receptor up-regulation in rats with experimental hemiparkinsonism.

Animals↗

PubMed2000

[Clinical analysis of 5 cases of relapsing polychondritis].

OBJECTIVE: To describe the clinical manifestation of relapsing polychondritis(RP) and evaluate the medical therapy of RP, especially management of airway stenosis with intervening method. METHOD: Retrospective analysis of 5 cases of RP treated in our hospital since 1995 with reviewing of large series of cases in reported literatures. RESULT: RP is a rare multisystem disorder characterized by recurrent inflammation and progressive degeneration of cartilaginous structure and connective tissue. Medical treatment with corticosteroids, immunosuppressive drugs and dapsone could not interrupt the progression of the disease. Involvement of the respiratory tract is life-threatening and intervening therapy such as tracheostomy, endotracheal intubation or tracheobronchial stents is needed, one case of relieving severe dyspnea caused by extensive tracheobronchial collapse in RP with self-expanding metallic stents was presented. CONCLUSION: It is important to make the diagnosis of RP according to the clinical features and carry out medial treatment at early stage, positive airway pressure support and intervening methods to prevent the airway collapse should be considered when the laryngotracheobronchial involvement aggreviates.

Adrenal Cortex Hormones↗

PubMed2000

[The practicability of increasing exercise tolerance in mild to moderate asthmatic patients].

OBJECTIVE: By performing the cardiopulmonary exercise testing in mild to moderate asthmatic patients and healthy volunteers, to assess the practicability of increasing exercise tolerance and improving life quality in the patients, and to assess the relationship between the resting IC and the maximal workload. METHODS: 19 mild to moderate asthmatic patients participating in the cardiopulmonary exercise testing with 19 health volunteers as controls. The incremental test was used. Forced expiratory volume in one second (FEV1) and inspiratory capacity (IC) were measured before the test and FEV1 measurements were repeated after exercise. Heart rate(HR), oxygen uptake(VO2), ventilation per minute(VE), breathing frequency(BF) were continuously measured during the test. RESULTS: There were changes of FEV1 after exercise in asthmatic patients [-(15.5 +/- 13.2)%] vs [+(1.7 +/- 2.7)%], (P < 0.05). They could achieve comparable VO2max (1.8 +/- 0.5) L/min vs (1.8 +/- 0.4) L/min, VEmax (29 +/- 7) L/min vs (31 +/- 5) L/min and O2-pulse max (0.0110 +/- 0.0020) L/beat vs (0.0110 +/- 0.0020) ml/beat with controls, but the BF at maximal exercise in asthmatic patients is significantly decreased (37 +/- 5) times/min vs (41 +/- 6) times/min, (P < 0.05). IC correlate with the maximum workload (r = 0.695, P < 0.05). CONCLUSION: The mild to moderate asthmatic patients had the same cardiopulmonary exercise response as the healthy volunteers, indicating that they did not have ventilatory and circulatory limitation to exercise.

Adult↗

PubMed2000

[Bronchial hyperreactivity in patients with mitral stenosis and therapeutic effect of inhaled corticosteroids].

OBJECTIVE: To assess the role of bronchial hyperreactivity (BHR) in patients with mitral stenosis and to evaluate the effect of inhaled corticosteroids in treating these patients. METHODS: Histamine bronchial provocation testing was performed in 23 patients with mitral stenosis. Patients with BHR were randomized into beclomethasone treatment and placebo group. Patients without BHR were also treated with beclomethasone as controls. RESULTS: 15 patients showed BHR. His PD20-FEV1 were significantly higher after 6 weeks treatment (P < 0.05), and symptom scores significantly lower(P < 0.05) in beclomethasone treatment group while remained unchanged in placebo group(P > 0.05). CONCLUSIONS: BHR is commonly found in patients with symptomatic mitral stenosis. Beclomethasone can significantly decrease bronchial reactivity to histamine and improve symptoms in patients with mitral stenosis.

Administration, Inhalation↗