Biomedical subjects

C Li

Publications and source records attributed to C Li.

At least 919 records · Page 51Linked to original sources

PubMed1996

[Acetaminophen absorption test for determination of diabetic gastroparesis and effects of erythromycin on gastric emptying].

The purpose of this study is to know the incidence of diabetic gastroparesis in diabetics and its relationship with diabetic neuropathy and to direct rational clinical treatment. Acetaminophen absorption test was performed for determination of gastric emptying function of liquid in 43 patients with diabetes mellitus (male 23, female 20, mean age 53.5 years). The patients were divided into two groups: diabetics with and without autonomic neuropathy. The change of gastric emptying time (GET) after intravenous administration of erythromycin (100 mg/h) was observed. The results showed that GET in diabetics was significantly prolonged. The incidence of abnormal gastric emptying function of liquid was 51.16%. GET in diabetics with neuropathy was significantly longer than that in those without neuropathy (42.83 +/- 13.80 min vs 26.00 +/- 11.42 min, P < 0.01). Its incidence was significantly increased in diabetic neuropathy and related to its severity. Delayed GET in diabetics was normalized after erythromycin administration (from 47.63 +/- 6.74 min to 20.53 +/- 7.43 min, P < 0.01). The results indicate that this test can be used as an objective indicator for diabetic gastric autonomic neuropathy and gastroparesis. Erythromycin accelerates gastric emptying.

Absorption↗

PubMed1996

[Expression of myelin basic protein gene in the developing human brain].

The expression of myelin basic protein (MBP) gene in the developing human brain was studied by using Northern dot blot and in situ hybridization with 32P- and biotin-labeled rat MBP cDNA and Diglabeled human MBP cRNA probes so as to explore the relation of temporal and spatial expression of human MBP gene to myelinogenesis and myelination. The results of dot blot analysis showed that the expression of MBP mRNA was near 2.0 A590/microgram of RNA in the fetal brain at 16 weeks of conceptional age, and it increased progressively with development to have 9-fold increment (18 A590/microgram of RNA) in the adult brain. The insitu hybridization was performed with the sections of fetal spinal cord and medulla oblongata at 8-25 weeks of conceptional age, and of pons, midbrain, thalamus, cerebellum and cerebrum at 20, 22 and 25 weeks. The results indicated that the expression of MBP mRNA was found as early as 8-9 weeks and localized within the perinuclear cytoplasm of the scattered cells in the ventral horn of spinal cord and near the basis of the fourth ventricle of medulla oblongata. Whether the above-mentioned labeled cells are neurons or precursors of glial cell remains to be identified because they are larger in size and have more abundant cytoplasm than oligodendrocytes. The labeling of MBP mRNA abruptly increased and spread with the processes of oligodendrocytes to form a network in spinal cord and medulla at 20 weeks; meanwhile, labeling was obvious in pons and scattering in the other brain regions examined.

Adult↗

PubMed1996

[Expression of human brain myelin basic protein gene cDNA in Escherichia coli].

A 612bp full-length cDNA sequence coding for 21.5 kd myelin basic protein (MBP) was amplified from human brain cDNA library by polymerase chain reaction, cloned into vector pGEM-3Zf(+) with blunt-end. The 561bp cloned fragment was recovered from recombinant pGEMP after BamHI digestion, and then inserted into the BamHI site downstream of the glutathione-S-transferase gene of the expression vector pGEX-5T. The recombinant vector p5TBP was transformed into E. coli JM 109 and positive colonies were incubated in LB medium containing 1 mmol/L IPTG for six hours at 37 degrees C. A new polypeptide band with an apparent molecular weight 49 kd was detected in transformed cell lysates by SDS-PAGE. Western blotting analysis confirmed that this fusion protein reacted specifically with rabbit antibodies to human MBP. The expression level of MBP in this system was about 50 mg/L of bacterial culture estimate by immuno-dot blot, ELISA and absorbance scanning of SDS-PAGE.

Cloning, Molecular↗

PubMed1996

[The serum MBP, myelin sheath immunohistochemistry and electromicroscope of expetrimental epilepsy rats].

We detected the level of myelin basic protein (MBP) in the serum of experimental epilepsy rats using simplified MBP ELISA, and the myelin sheaths of their brain with MBP immuno-histochemistry (IHC) and transmitted electronmicroscopy (TEM) in order to explore the relation of brain myelin sheaths and MBP to the pathogenic mechanism of epileptic seizure. The results show that the serum MBP level in the experimental epilepsy group is significantly higher than that in the control groups (P < 0.05), and is similar to that in some patients with generalized myoclonic seizures reported by us previously. The IHC and TEM findings in the brain of epilepsy rats indicate that the lamelliform structure of myelin sheaths in some part of hippocampus region becomes relaxing, disorderly and homogenized. Our studies imply that epileptic seizures are associated with MBP release from the subtle damaged regions of myelin sheaths during epileptic seizures, and the change of MBP component in myelin sheath may play and important role in the pathogenesis of epilepsy.

Animals↗

PubMed1996

[Determination of copper and cadmium in water by continuous flow analysis].

A continuous flow analysis system for the preconcentration of Cu2+ and/or Cd2+ in water was developed. Trace copper or cadmium in water could be concentrated on activated carbon particles packed in micro column at pH > or = 9.0. The adsorbed analyte was eluted with 0.5 ml 2.5% nitric acid and determined by flame atomic absorption spectrometry. A sample size of 10-25 ml sufficed for the determination of copper2+ or cadmium at a level as low as microgram/L. The relative standard deviation of 6 parallel determinations was 4.3% for copper and 11% for cadmium. The proposed method was applied to the determination of copper and cadmium in natural water with a recovery of 84.4%-118%.

Cadmium↗

PubMed1996

[Assay of anti-corneal endothelial antibody after penetrating keratoplasty].

OBJECTIVE: To study the effective materials in the immune response and the humoral immunity in graft rejective reaction in the host after penetrating keratoplasty (PKP). METHODS: PK was performed on 2 groups of monkeys with a 5.5 mm button in a 5.0 mm bed. The heterogroup (human to monkey) had 4 monkeys, and homo-group (monkey to monkey) also 4. Nelken's method was modified. Two kinds of antigens, corneal endothelial and stromal antigens, had been made the first time. Enzyme linked immunosorbent assay (ELISA) was used to detect the anti-corneal endothelial antibody (ACEAb) in the serum and aqueous humor of the host. RESULTS: After PKP, the anti-corneal stromal antibody did not increase obviously, while the increase of ACEAb was distinct. CONCLUSION: Humoral immune response can occur in the host after PK, and the effective material is ACEAb.

Animals↗

PubMed1996

[The micro-anatomy and clinical significance of the apical foramen in 1,282 permanent teeth].

To study the shape and size of the apical foramen of permanent teeth and their relations, we observed 1,282 permanent teeth. The teeth were photographed by XTL-2 photstero microscope. The rule of its shape and its clinical significance were discussed. In the 1,282 teeth, the round and oralshaped accounted for 94.77% (1,215/1,282), indicating that the morphological appearance of the apical foramen is inconsisted with that of vessels or/and nerves in the tissues.

Dentition, Permanent↗

PubMed1996

[A synthetical mouth study of 105 Uygur people above 100 years of age].

Oral examination was performed in 105 Uygur people aged 100 to 135 years. Among them there were 77 males and 28 females. Results were as follows: the teeth loss rate was 100.0%, edentulous rate 54.3%, dental caries 70.5%, periodontal disease 52.4%, normal labial-buccal mucosa 65.7%, fissured tongue 74.3%, no smoking 86.7%, no drinking 94.3%, and all of them had neither history of dental extration nor restoration. This study may provide data for investigating secret of human longevity.

Aged↗

PubMed1996

[Dynamic changes in soluble interleukin-2 receptor levels after rat corneal allograft].

PURPOSE: To evaluate the diagnostic utility of serum IL-2R level test in corneal allograft rejection. METHODS: Serum soluble IL-2R was detected by radioimmunoassay in rat corneal allograft model. RESULTS: Levels of soluble IL-2R were markedly elevated prior to the clinical diagnosis of rejection. CONCLUSIONS: Marked elevations of soluble IL-2R are associated with rejection, measurement of soluble IL-2R may have a useful value in the early diagnosis of corneal allograft rejection.

Animals↗

PubMed1996

[Reasonability of extracting procedures for huiyangfanben decoction].

The reasonability of extracting procedures for traditional Chinese prescriptions was studied with Huiyangfanben Decoction as sample. The comparative results of the ingredients in extractions prepared by different procedures revealed. For the prescriptions with complicated ingredients, more attention should be paid to the ingredients and their characteristics when designing the extracting procedurs, and in extraction the drugs should be classified according to the interaction of the ingredients. More extracting solvents could be used according to the characteristics of the active ingredients.

Aconitine↗

PubMed1996

[Influence of gypenoside on serum lipoprotein and atherosclerosis in hyperlipidaemia animals].

The result of the study indicates that gypenoside (GP, i.g.) can suppress the rise of serum cholesterol (CHO) and triglyceride (TRIG) in hyperlipidaemia mice and lower the content of CHO, TRIG and LDL in hyperlipidaemia quails. The study also shows that GP has a protective effect on diffuse lipoidosis in liver and atherosclerosis in hyperlipidaemia quails, and that GP can lower the lipoprotein levels in hyperlipidaemia animals.

Animals↗

PubMed1996

[Effect of leaf picking on the output of radix Astragali seu Hedysari].

Based on an orthogonal design, the experiments have shown that proportion and time of leaf picking are the major factors to influence the thickness and output of Radix Astragali seu Hedysari. If the proportion is extended and the time is delayed, both the thickness and output of the roots will be reduced accordingly. The output will not change much if the time is set on around June 15 each year and the proportion is taken 1 out of 3.

Fabaceae↗

PubMed1996

[Chemical components of Cynomorium sonaricum Rupr].

Two stigmastenol compounds were isolated from the root of Cynomorium songaricum and identified by chemical and spectral methods as 5 alpha-stigmast-9(11)-en-3 beta-ol and 5 alpha-stigmast-9(11)-en-3 beta-ol-tetracosantrienoic acid ester.

Drugs, Chinese Herbal↗

PubMed1995

Urokinase-type plasminogen activator-induced monocyte adhesion requires a carboxyl-terminal lysine and cAMP-dependent signal transduction.

Urokinase-type plasminogen activator (u-PA) or its amino-terminal fragment (ATF) containing the u-PA receptor (u-PAR) binding domain, is known to promote monocyte adhesion. In the present study, U937 monocyte adhesion to a plastic surface was used to investigate the mechanism of its promotion by u-PA and ATF. Adhesion was found to be inhibited by cycloheximide or actinomycin D, implicating protein synthesis and gene expression in u-PA-induced monocyte adhesion. Adhesion was prevented by 2'-deoxyadenosine 3'-monophosphate, indicating that a cAMP-dependent pathway of signal transduction was involved. This concept was supported by the complementary finding that u-PA-induced adhesion was greatly promoted by forskolin, cholera toxin, or 8-bromo-cAMP, which by themselves induced little adhesion. Furthermore, similar to many other cAMP-dependent activities, cGMP diminished u-PA-induced adhesion. When u-PA or ATF was treated with immobilized carboxypeptidase B, its proadhesive effect was abolished, implicating the involvement of carboxyl-terminal lysine residues (Lys158 on u-PA and Lys135 on ATF). Moreover, when a carboxyl-terminal lysine analog was added, the proadhesive effect of carboxypeptidase B-treated u-PA or ATF was restored. In conclusion, the present study indicates that u-PA- or ATF-induced monocyte adhesion involves cAMP-dependent signal transduction, which is triggered by u-PAR binding. It is also critically dependent on the presence of a carboxyl-terminal lysine.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1995

The genetic defect in two well-studied cases of Bernard-Soulier syndrome: a point mutation in the fifth leucine-rich repeat of platelet glycoprotein Ib alpha.

Bernard-Soulier syndrome (B-Ss) is a rare congenital bleeding disorder caused by abnormal giant platelets, thrombocytopenia, and defective glycoprotein (GP) Ib-V-IX, the adhesion receptor for von Willebrand factor (vWF). This report describes the molecular defect in two related individuals with well-established B-Ss whose platelets exhibit decreased GPIb-IX and normal GPV on their surfaces. The GPIb-V-IX genes of the two patients were analyzed by Southern blotting, hetero-duplex analysis, and polymerase chain reaction (PCR) amplification/sequencing. A point mutation was found in codon 129 of the GPIb alpha gene that results in the substitution of proline for leucine in the first position of the fifth leucine-rich glycoprotein repeat of the mature gene product. The mutation (CTC: leucine, wild-type to CCC: proline, mutant) eliminates a Sac I restriction site, facilitating analysis of the mutation in the propositi (both homozygotes), unaffected family members (8 heterozygotes and 8 wild-type), and 58 normal controls (116 wild-type alleles). The status of the genomes was confirmed by the sequencing of platelet cDNA. The mutation does not affect transcription of the Ib-IX genes, as estimated by PCR and Northern blot analysis, but it does inhibit surface expression of the receptor as assessed by transient transfection of mutant and wild-type GPIb alpha genes into mouse Ib beta-IX L cells. Many of the cells (43%) transfected with the normal gene express surface GPIb alpha, whereas untransfected cells and those transfected with the mutant gene lack surface GPIb alpha entirely. Patient platelets were tested both for vWF binding in the presence of ristocetin and for surface GPIb-IX expression. In these instances, despite their inability to agglutinate with ristocetin and vWF, patient platelets exhibit about 40% of normal vWF binding and 40% of normal Ib-IX surface antigens. The results suggest that the described mutation (GPIb alpha: Leu129 -> Pro) affects the conformation of the GPIb-V-IX receptor, alters its availability on platelet surfaces, and causes the observed Bernard-Soulier phenotype.

Alleles↗

PubMed1995

Age estimation from the permanent molar in northeast China by the method of average stage of attrition.

A new method of age estimation using permanent molars, the method of average stage of attrition (ASA), is described. A total of 633 molars, including the first molar (M1) and the second molar (M2) on both jaws, was collected from 57 cadavers and 54 modern dry skulls in northeast China. The attrition condition of the molar crown was analyzed, and a new graduation standard was established. Six linear equations for age estimation were obtained by means of regression analysis. The ASA method gave an estimated age at death from only one molar, either M1 or M2, on either maxilla or mandible. The maximum error of these equations was 4.53 years. The results show that the ASA method can or does reflect the attrition condition of the whole occlusal surface more objectively than some methods using dental wear because the wear degree is estimated by averaging the wear stages of all the cusps rather than of only one or partial cusps.

Adolescent↗

PubMed1995

Comparison of the structure and expression of the human and rat neprilysin (endopeptidase 24.11)-encoding genes.

The existence of a third non-coding exon in the human neprilysin-encoding gene (h-NEP), positionally located as exon 3, has been demonstrated by reverse transcription of RNA from human kidney and lung, coupled with the polymerase chain reaction. Comparison of nucleotide sequences between h-NEP and the rat NEP (r-NEP) genes shows a high degree of sequence conservation within noncoding exons 1 and 2. In contrast, the region of the gene containing exon 3 is highly divergent. Two transcripts derived from exon 2 by alternative splicing, type-2a and type-2b, were demonstrated in human kidney and lung. In contrast, only the type-2b transcript was present in these same tissues in the rat. The type-1 transcript was detected in human kidney, lung and brain, this transcript appearing to be the major species in brain.

Alternative Splicing↗

PubMed1995

Distinct Ca2+ and Sr2+ binding properties of synaptotagmins. Definition of candidate Ca2+ sensors for the fast and slow components of neurotransmitter release.

Ca(2+)-dependent neurotransmitter release consists of at least two components: a major fast component that is insensitive to Sr2+ and a minor slow component that is potentiated by Sr2+ (Goda, Y., and Stevens, C. F. (1994) Proc. Natl. Acad. U. S. A. 91, 12942-12946). These results suggest that at least two Ca2+ sensors act in synaptic vesicle fusion with distinct Ca2+ and Sr2+ binding properties. We have now investigated the relative Ca2+ and Sr2+ binding activities of synaptotagmins to evaluate their potential roles as Ca2+ sensors for the fast and slow components. Our results demonstrate that the first C2 domains of synaptotagmins I, II, III, V, and VII have very similar Ca2+ requirements for phospholipid binding (range of EC50 = 2.6 microM to 5.0 microM), but distinct Sr2+ requirements (EC50 range = 23 microM to 133 microM); synaptotagmins I and II had the lowest Sr2+ affinity, and synaptotagmin III the highest Sr2+ affinity. Purified synaptotagmin I from bovine brain exhibited similar properties as its recombinant first C2 domain, suggesting that the first C2 domain fully accounts for its Ca(2+)-dependent phospholipid binding properties. Sr2+ was unable to trigger syntaxin binding by synaptotagmin I at all concentrations tested, whereas it was effective for synaptotagmin III. These results suggest that different C2 domains have distinct Sr2+ binding properties. They support the hypothesis that synaptotagmins localized on the same vesicle perform distinct functions, with synaptotagmins I and II serving as candidate Ca2+ sensors for the fast component in release and synaptotagmin III for the slow component.

Animals↗