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L Xiang

Publications and source records attributed to L Xiang.

35 records · Page 2Linked to original sources
PubMed1999

[Study on the determination of trace caesium in bittern by extraction separation graphite furnace atomic absorption spectrometry].

The atomizatiom behavior of Cs in bittern and the mechanism were studied by graphite furnace atomic absorption spectrometry. Interferences of inorganic acid from the bittern on absorption signal of Cs were examined. It is shown that there are gaseous interferences and molecular absorption interferences and ionization interferences with regard to the interference of chlorides on absorption signal of Cs. The effects of 3 crown ethers, 5 big-anion reagents and chlorides on extractability Cs have been compared. A extraction separation GFAAS method for determining Cs in bittern has been established by pyrolytic graphite tube, KNO3-NH4NO3 matrix modifier and 18-C-6, bromothymol blue, chloroform extraction separation. The method exhibits high sensitivity and selectivity, it has been used for the determination of trace Cs in bittern. The characteristic mass is 1.4 x 10(-10) g/0.004 4 A. The adding recovery is 89%-105% and the relative standard deviation is 4.13% (n = 13).

English Abstract↗
PubMed1998

Analysis of complement receptor type 1 (CR1) expression on erythrocytes and of CR1 allelic markers in Caucasian and African American populations.

CR1 expression on erythrocytes (E) is regulated by an element that is tightly linked in Caucasians to the site of an RFLP of the CR1 gene. Genomic HindIII fragments of 7.4 and 6.9 kb identify alleles that are expressed in high (H allele) or low (L allele) amounts, respectively. When age-fractionated E of donors heterozygous for both the H and L alleles and for CR1 allotypes of differing molecular weights were analyzed in Western blots, the product of the L allele appeared to have an increased rate of loss during cell aging. A coding sequence polymorphism of CR1 predicted to cause a Pro-->Arg substitution in its proximal extramembranous region was tightly linked in Caucasians to the site of the HindIII RFLP. However, neither this polymorphism nor the HindIII RFLP correlated with CR1 expression among African Americans. Relative instability of CR1 encoded by the L allele thus may derive from another coding sequence polymorphism, or may require both the Pro-->Arg substitution and epistatic effects of another polymorphic gene.

Alleles↗
PubMed1998

[The changes of pancreatic function after cardiopulmonary bypass].

OBJECTIVE: To evaluate the changes of endocrine and exocrine pancreatic function in patients who underwent heart valve replacement under cardiopulmonary bypass (CPB) in order to optimally conside clinical management perioperatively. METHOD: Sixteen patients with heart valve disease were selected. Serum glucose, lactate, insulin, C peptide, amylase and lipase were measured. RESULT: Hyperglycemia and hyperlactacemia were noted after CPB and peaked at 19:00 on the operative day. Their changes were correctly correlated. Serum glucose and lactate returned to the baseline level on the third postoperative day. The average level of serum insulin were normal, but higher on the third postoperative day. However, the level of serum C peptide was higher than the baseline. It doubled the baseline level at 19:00 on the operative day. The average level of serum amylase and lipase was normal, except the higher level of serum lipase on the fourth postoperative day. In our group, 12 patients had normal serum amylase level perioperatively, and 4 increased serum amylase level (25%), among them 2 patients accompanied with hyperlipasimia (16%). There were 8 patients with hyperlipasimia (50%). CONCLUSION: The endocrine and exocrine pancreatic functions were influenced by CPB and did produce pathophysiologic changes.

Adult↗
PubMed1998

[An analysis on therapeutic effects of excimer laser photorefractive keratectomy for high myopia].

OBJECTIVE: To evaluate the therapeutic effects of 193-nm excimer laser photorefractive keratectomy for the correction of high myopia. METHODS: A Keracor 116 excimer laser and a tapered transition zone technique were used to treat high myopia. It was divided into two groups: the first group -6.00 - 9.75 D, 233 eyes; the second group -10.00 - 14.00 D, 55 eyes. The effect of the tapered transition zone on refraction stability was investigated in a 12-month follow-up study. RESULTS: At one year, of these eyes, 79.4% eyes attained visual acuity of 0.5 or better, 31.6% improved to 1.0 or better, 93.8% of the eyes improved or their best corrected visual acuity did not change, whereas 6.2% lost at least one line. Corneal haze was observed to be severe in one month, and diminished considerably at 6 and 12 months. At one year, no haze could be seen in 87.4%. 52.0% were within +/- 1.00 D and 80.9% in +/- 2.00 D. During one year, 14.9% were complicated with glaucoma because of using steroid drops. CONCLUSION: These data show that excimer PRK for treatment of high myopia is an effective and safe refractive surgery. For severe myopia, it is an effective surgery, but predictability is not satisfactory, and long term follow-up is necessary.

Adolescent↗
PubMed1996

Fas ligand mutation in a patient with systemic lupus erythematosus and lymphoproliferative disease.

The pathogenesis of systemic lupus erythematosus (SLE) is multifactorial and multigenetic. The apoptosis genes, fas and fas ligand (fasL), are candidate contributory genes in human SLE, as mutations of these genes result in autoimmunity in several murine models of this disease. In humans, fas mutations result in a familial autoimmune lymphoproliferative syndrome, but defects in FasL have not yet been identified. In this study, DNA from 75 patients with SLE was screened by single-stranded conformational polymorphism analysis for potential mutations of the extracellular domain of FasL. A heterozygous single-stranded conformational polymorphism for FasL, was identified in one SLE patient, who exhibited lymphadenopathy. Molecular cloning and sequencing indicated that the genomic DNA of this patient contained an 84-bp deletion within exon 4 of the fasL gene, resulting in a predicted 28 amino acid in-frame deletion. Analysis of PBMC from this patient revealed decreased FasL activity, decreased activation-induced cell death, and increased T cell proliferation after activation. This is the first report of defective FasL-mediated apoptosis related to a mutation of the human Fasl, gene in a patient with SLE and suggests that fasL mutations are an uncommon cause of the disease.

Amino Acid Sequence↗
PubMed1996

Effects of modifications of residues in position 3 of dynorphin A(1-11)-NH2 on kappa receptor selectivity and potency.

Tyrosine1 and phenylalanine4 in dynorphin A (Dyn A) have been reported to be important residues for opioid agonist activity and for potency at kappa receptors. The glycine residues in the 2 and 3 positions of dynorphin A may affect the relative orientation of the aromatic rings in positions 1 and 4, but their flexibility precludes careful analysis. To examine these effects on dynorphin A, we previously have synthesized the linear analogues [D-Ala3]Dyn A(1-11)-NH2 (2) and [Ala3]Dyn A(1-11)-NH2 (3) and reported their biological activities. Analogues 2 and 3 displayed affinities for the central kappa opioid receptor (IC50 = 0.76 and 1.1 nM, respectively) similar to that of Dyn A(1-11)-NH2 (1) (IC50 = 0.58 nM) and greatly enhanced selectivities for kappa vs mu and kappa vs delta receptors (IC50 ratios of 350 and 1300 for 2, and 190 and 660 for 3, respectively). These results suggest that the structure and lipophilicity of the amino acid present in position 3 of Dyn A(1-11)-NH2 as well as the conformational changes they induce in the message sequence of dynorphin have important effects on potency and selectivity for kappa opioid receptors. To further investigate structure-activity relationships involving the residue at the 3 position of Dyn A(1-11)-NH2, a series of Dyn A analogues with aromatic, charged, and aliphatic side chain substitutions at the 3 position was designed, synthesized, and evaluated for their affinities for kappa, mu, and delta opioid receptors. It was found that analogues with lipophilic amino acids at the 3 position of Dyn A(1-11)-NH2 generally displayed higher affinity but similar selectivities for the kappa receptor than analogues with charged residues at the same position. It is suggested that the structural, configurational, and steric/lipophilic effects of amino acids at position 3 of Dyn A(1-11)-NH2 may play an important role in potency and selectivity for the kappa receptor.

Amino Acid Sequence↗
PubMed1996

Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study.

A pilot phase I study was conducted with a cyclic heptapeptide analog of alpha-melanocyte stimulating hormone (alpha-MSH). The lactam-bridged molecule, called Melanotan-II (MT-II), has the structure Ac-Nle4-Asp5-His6-D-Phe7-Arg8-Trp9-Lys10 alpha-MSH4-10-NH2 (MT-II) and has superpotent melanotropic activity in vitro. A single-blind, alternating day (saline or MT-II), placebo-controlled trial was conducted in 3 normal male volunteers at the starting dose of 0.01 mg/kg of MT-II. Subcutaneous injections of MT-II or saline were given daily (Monday-Friday) for 2 consecutive weeks. Two subjects were escalated by 0.005 mg/kg increments to 0.03 mg/kg and one to 0.025 mg/kg. The 0.03 mg/kg dose produced Grade II somnolence and fatigue in one of two subjects (WHO standards). Mild nausea, not requiring antiemetic treatment, was reported at most MT-II dose levels. A stretching and yawning complex appeared to correlate with the onset of spontaneous, penile erections which were intermittently experienced for 1-5 hours after MT-II dosing, depending on the MT-II dose. Two subjects had increased pigmentation in the face, upper body and buttock, as measured by quantitative reflectance and by visual perception 1 week after MT-II dosing ended. These results demonstrate that MT-II has tanning activity in humans given only 5 low doses every other day by subcutaneous injection. The recommended single MT-II dose for future Phase I studies is 0.025 mg/kg/day.

Adult↗
PubMed1996

[A study on cryotherapy of experimental posterior penetrating eye injury].

OBJECTIVE: The study was designed to investigate the effects of cryotherapy on intraocular tissues in ocular penetrating injury, and an experimental study was made on rabbits. METHODS: The penetrating injury models in both eyes of 23 (46 eyes) pigmental rabbits were performed. Cryotherapy was applied after the operation in the left eye but not in the right eye (the control) of each animal. All the pupils of the eyes were dilated and examined by ophthalmoscope and B-scan at different time after the operation. Enucleations were performed at 2 weeks, 6 weeks and 3 months and the enucleated eyeballs were examined pathologically by light and electron microscopy. The synchronous fundus and pathological changes were evaluated and analyzed statistically (Pearson Chi-square test). RESULTS: The intraocular reaction and proliferation in cryotreated group was much more severe than those in the control one (P = 0.027), especially in the vitreous (P = 0.016). The incidence of tractional retinal detachment in cryotreated group was higher than that in the control. CONCLUSION: It is suggested that the prophylactic cryotherapy in the posterior penetrating ocular injury of rabbits increase intraocular proliferation.

Animals↗
PubMed1996

[TCD observation on cerebral blood flow dynamics inference of cerebral palsy with scalp therapy].

Through TCD test, observation on the blood flow dynamics change before and after treatment with 31 cases of the child cerebral atrophy was made. It is found that scalp therapy is able to speed up the blood flow of part artery, especially increase the even blood flow speed of MCA, ACA obviously (P < 0.05), which preliminary shows the mechanism of scalp therapy for child cerebral atrophy mean while. It is found that scalp therapy also has the function to restrain epilepsy.

Acupuncture Therapy↗
PubMed1996

[Preliminary study of colloid osmotic pressure for cardiopulmonary bypass].

The ideal colloid osmotic pressure is beneficial to decrease the fluid accumulated in the pulmonary and other tissue during cardiopulmonary bypass. Schupbach reported the proper colloidosmotic pressure for cardiopulmonary bypass was 2.1 kPa (16 mmHg). Colloid osmotic pressures of blood and priming fluid during cardiopulmonary bypass were measured in 28 patients with heart disease by using colloid osmotic pressure detection apparatus. The value of colloid osmotic pressure suitable for the designed standard was apparently different among the Gelofusine group and other groups. P value was 0.005. Priming fluid for cardiopulmonary bypass needs to satisfy the quality and the quantity of colloid osmotic pressure. Using Albumin isn't economical. Whole blood and plazma are not suitable for increasing colloid osmotic pressure. Hydroxyethyl starch or Gelofusine is best choice in priming to get designed standard of colloid osmotic pressure. The ratio of hydroxyethyl starch or Gelofusine in priming fluid should beyond 1/2.

Adolescent↗
PubMed1994

Effects of the seed sludge on the performance of UASB reactors for treatment of toxic wastewater.

A comparative study of different sludges (anaerobic sewage sludge and anaerobic sewage sludge cultivated for 30 days) as the seed of UASB reactors for treatment of synthetic resin production wastewater was carried out on a laboratory scale. Significant differences in reactor performance were observed. With anaerobic sewage sludge seed, the reactor obtained a 71% COD removal efficiency and produced 2.94 dm3 biogas per dm3 wastewater under an organic loading rate of 4.5 kg COD m-3 day-1. The sludge in the reactor was diffuse and possessed poor settling ability, which led to effluent SS as high as 1200 mg dm-3. However, with anaerobic sewage sludge cultivated with synthetic substrate for 30 days as a seed, the same reactor gave 78% COD removal efficiency and produced 3.5 dm-3 biogas per dm3 wastewater at the same loading rate. Moreover, the sludge in the reactor was completely granulated and possessed good settling ability, which resulted in effluent SS as low as 200 mg dm-3. The granular sludge produced less biomass per gram COD removed than the diffused sludge. Anaerobic sewage sludge cultivated for a short time could form the nuclei of granules for the reactor, allowing granulation to proceed smoothly. Therefore, sludge nuclei are a prerequisite of sludge granulation in UASB reactors for treatment of toxic wastewater.

Anaerobiosis↗
PubMed1993

Brain potentials in a phonological matching task using Chinese characters.

In readers of English, involved in a rhyme judgement task, mismatch trials are associated with an enhanced N450 component of the Event Related Potentials (ERPs). It has been suggested that N450 is related to orthographic or phonological priming. In this paper ERPs were recorded during a phonological matching task, using pairs of logographically dissimilar Chinese characters. A pair was considered to match if they sounded alike with identical phoneme sequences. The subjects (native Chinese speakers) were instructed to ignore vowel-inflections, which in Chinese have lexical status. Since sublexical assembly of phonology is not used in reading Chinese characters, and the members of each pair were logographically dissimilar, match and mismatch trials did not suffer in the amount of orthographic or sublexical phonological priming. An enhanced negative component (latency near 400 msec), was observed in ERPs elicited by the second character in non-matching pairs. The negativity could be similar to N450. If this were so, then N450 could not be associated with orthographic priming, nor with sublexical phonology, but would probably be associated with postlexical processing. Also, in both readers of Chinese and English, the negativity enhanced in non-match trials is larger over the right side of the scalp, suggesting a similar brain lateralization of the underlying processes.

Adolescent↗
PubMed1993

[Influences of acupuncture on gastroduodenal mucosal lesion and electrical changing induced by stress in rats].

Experiments were performed in 57 SD rats. The stress was induced by binding plus revolving (5.5 xg, 170 c/min, 10 min) or cold (0-4 degrees C, 30-60 min). Selected acupuncture points were "Zusanli" and "Weishu". Bipolar Ag-AgCl recording electrodes were respectively implanted on the serous membrane surface of the antrum, duodenum and on the abdominal skin corresponding to above areas. The results were as follows: (1) There are 63.2% individuals in the stress group which showed a large quantity of bleeding points spreading over the gastroduodenal mucosal membrane. The area density of lesion was 15.8-27.7%. Under microscope the signs emerged including mucosal blood vessel dilatation and hyperaemia, gland cell swelling, virlus broken and peeling off and lymph cell accumulating, etc. 84% individuals showed obvious inhibition of gastroduodenal electroactivities including that the amplitude of slow wave was lower, the frequency decreased even the rhythm was disordered, the number of fast wave reduced and the IDMEC III cycle was prolonged. (2) In the group of acupuncture plus stress only 16.7% individuals showed bleeding or hyperaemia, and the lesion area density was only 1.7%. Also the pathohistological changes were obviously decreased. Gastroduodenal electrical changes were hardly seen (27.2%) or the inhibitory state above were significantly reduced (54.5%) when compared with the stress group. There is strong reason to consider that acupuncture could effectively reduce the mucosal lesion and the electrical inhibition of stomach and duodenum induced by stress in rats.

Acupuncture Therapy↗