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Biomedical subjects

C Li

Publications and source records attributed to C Li.

At least 793 records · Page 44Linked to original sources
PubMed1997

Mg2+ inhibition of ATP-activated current in rat nodose ganglion neurons: evidence that Mg2+ decreases the agonist affinity of the receptor.

The effect of Mg2+ on ATP-activated current in rat nodose ganglion neurons was investigated with the use of the whole cell patch-clamp technique. Mg2+ decreased the amplitude of ATP-activated current in a concentration-dependent manner over the concentration range of 0.25-8 mM, with a 50% inhibitory concentration value of 1.5 mM for current activated by 10 microM ATP. Mg2+ shifted the ATP concentration-response curve to the right in a parallel manner, increasing the 50% effective concentration value for ATP from 9.2 microM in the absence of added Mg2+ to 25 microM in the presence of 1 mM Mg2+. Mg2+ increased the deactivation rate of ATP-activated current without changing its activation rate. The observations are consistent with an action of Mg2+ to inhibit ATP-gated ion channel function by decreasing the affinity of the agonist binding site on these receptors.

Adenosine Triphosphate↗
PubMed1997

Adverse outcomes of planned and unplanned pregnancies among users of natural family planning: a prospective study.

OBJECTIVES: The purpose of this study was to determine prospectively whether unplanned pregnancies are associated with adverse pregnancy outcomes among users of natural family planning. METHODS: Women who became pregnant while using natural family planning were identified in five centers worldwide: there were 373 unplanned and 367 planned pregnancies in this cohort. The subjects were followed up at 16 and 32 weeks' gestation and after delivery. The risks of spontaneous abortion, low birth-weight, and preterm birth were estimated after adjustment by logistic regression. RESULTS: The women with unplanned pregnancies were more likely to be at the extremes of age, to report more medical problems before and during the index pregnancy, and to seek antenatal care later in gestation than the women with planned pregnancies. However, women with planned pregnancies reported a higher rate of spontaneous abortion in previous pregnancies (28.8%) than did women with unplanned pregnancies (12.9%). There were no significant differences in the rates of spontaneous abortion, low birthweight, or preterm birth between the two groups. CONCLUSIONS: No increased risk of adverse pregnancy outcomes was observed among women who experienced an unplanned pregnancy while using natural family planning.

Abortion, Spontaneous↗
PubMed1997

Transmucosal delivery of oxytocin to rabbits using a mucoadhesive buccal patch.

A biocompatible, mucoadhesive buccal patch was evaluated in rabbits for transmucosal delivery of peptides. Oxytocin (OT) was incorporated into custom coformulations of Carbopol 974P and silicone polymer and the resulting plasma OT concentration versus time profiles determined following patch application. For comparative purposes, the mean values determined for the elimination half-life (t1/2), volume of distribution (Vd), and the total body clearance (CL) following intravenous injection of OT were 2.9 +/- 0.2 min, 85.3 +/- 6.7 ml, and 20.4 +/- 2.03 ml/min, respectively. Following application of oxytocin-loaded mucoadhesive patches, plasma OT concentrations remained 20- to 28-fold greater from 0.5 to 3.0 hr than control animals administered placebo patches. The steady-state plasma OT concentration (Css) following application of the buccal patches was 80.6 +/- 15.9 pg/ml. The lag-time associated with attainment of the Css was 0.45 +/- 0.18 hr. Steady-state flux (Jss) of oxytocin in vivo was 139 +/- 36.8 ng/hr/cm2. Based on the amount of OT remaining in the patches following removal, the average dose of OT released in vivo was 0.27 +/- 0.024 mg with a bioavailability of 0.1%. No significant alterations in mucosal histology were observed when underlying mucosa to which OT patches had been applied were compared to either control (no patch) mucosa or mucosa underneath placebo patches. The mucoadhesive buccal patches were easy to apply and remove, nonirritating to tissue, and able to continuously deliver a nonapeptide over 3 hr. Based on these preliminary studies, the mucoadhesive buccal patches evaluated may represent an improved transmucosal drug delivery system for peptides and conventional drug substances.

Adhesiveness↗
PubMed1997

[A study on histogenesis of gastrointestinal stromal tumors].

OBJECTIVE: The purpose of this study was to consider the histogenesis of gastrointestinal stromal tumors (GIST). METHOD: 36 cases of GIST were studied by light microscopy, histochemical and immunohistochemical techniques. RESULTS: In 15 cases of small intestine spindle cell tumors, various sized eosinophilic globules were observed between the tumor cells and were designated as skeinoid fibers, which stained blue with Masson's trichrome and strongly PAS-positive. The positive rate by immunohistochemical methods for S-100 protein and desmin were 44.44% and 8.33% respectively. The immunoexpression of tumor cells was unrelated to their differentiation. CONCLUSION: Complex immunophenotypes of GIST suggest primitive mesenchymal origin, and small intestine stromal tumors (SIST) are mostly neurogenic which may have been derived from neurilemmal cells or autonomous nerve tissue of the small intestine.

Adult↗
PubMed1997

[The serum insulin level in severe hepatitis patients].

Serum insulin (SI) levels were determined in 36 severe hepatitis patients by RIA. The average level of SI in chronic severe hepatitis (CSH) patients was 43.18 +/- 27.12 mu.L-1, and subacute severe hepatitis (SSH) patients 28.91 +/- 12.77 mu.L-1. Both were increased significantly as compared with normal controls (P < 0.01), and the level of SI in patients died from SSH and CSH was increased significantly than those alive (P < 0.05). The level of SI at the fastiguium stage of the disease was significantly higher as compared with that of the convalescence stage (P < 0.05). The results suggest that SI may aid to evaluate the severity of the illness and to estimate the outcome of the patients.

Adult↗
PubMed1997

[Early revascularization by percutaneous transluminal coronary angioplasty in acute myocardial infarction].

Twelve patients with acute myocardial infarction (AMI) underwent percutaneous transluminal coronary angioplasty (PTCA). The reperfusion blood flow of the infarct-related arteries (IRA) in eleven patients was TIMI Grade 3 with residual stenosis of 15.5 +/- 8.8%. Vascular endothelial dissection complicated by angioplasty was observed in one case and the patient died after emergency coronary artery bypass graft. It is suggested that early primary PTCA in AMI may create stable and effective revascularization which will favor reducing infarct size, improving myocardial pump function, and lowering restenosis and mortality rate.

Aged↗
PubMed1997

[Effect of jishentang on renal lesions in diabetic rats].

OBJECTIVE: To observe the ameliorative effect of Jishentang (JST) on renal lesions in experimental diabetic rats. METHODS: The diabetic rats were randomly divided into three groups: group with out treatment, group with enalapril treatment (the dose of enalapril was 1 mg/kg.d) and group with JST treatment (the dose of JST was 22.4 g/kg.d). The treatment lasted for 8 weeks. RESULTS: (1) JST treatment attenuated the renal hypertrophy and ratio of kidney and body weight (P < 0.01). (2) JST treatment reduced the levels of SCr and BUN and the levels of Alb, beta 2-m and the activity of NAG in urine in diabetic rats significantly (P < 0.01). The levels of TG and TCh decreased and the levels of HDL-C increased in the serum of the JST treated diabetic rats (P < 0.01). (3) The glomerular basement membrane thickening and volume density of PAS positive staining in mesangial area were significantly decreased in JST treated diabetic rats. CONCLUSIONS: JST exerted obvious ameliorative effect on renal function and structure in diabetic rats.

Animals↗
PubMed1997

[24 hours ambulatory blood pressure in impaired glucose tolerance patients].

We investigated the change of 24 hours ambulatory blood pressure (ABPM) in impaired glucose tolerance (IGT) patients. 40 IGT patients were divided into two group: normotension and hypertension groups. Each group was matched with normal glucose tolerance (NGT) and non-insulin-dependent diabetes mellitus (NIDDM) group. All the patients were subjected to ABPM and biochemical index examination. The profile of ABPM in IGT patients with or without hypertension was investigated. The change of the 24 hours blood pressure in both normotensive and hypertensive IGT patients was similar with NGT, but there was a tendency that night blood pressure was increased and nocturnal blood pressure was decreased in IGT. The change of ABPM in those with abnormal circadian rhythm was elevated night blood pressure.

Adult↗
PubMed1997

[Gene expression of thyrotropin receptor, thyroid peroxidase and thyroglobulin in autoimmune thyroid disease].

To investigate the expression of thyrotropin (TSH) receptor gene in autoimmune thyroid disease and the relationship with expression of thyroid peroxidase (TPO) and thyroglobulin (TG) genes, we examined TSH receptor, TPO and TG gene expression levels in 10 human thyroid tissues by Northern blot analysis, including 7 Graves disease (GD), 2 Hashimoto disease (HT), and 1 normal thyroid tissue. The expression levels of TSH-R gene and TG/TPO gene were different between GD group and HT group. In GD group, TSH-R gene expression was closely correlated to the expression of TPO gene (r = 0.882; P < 0.01) and TG gene (r = 0.723; P < 0.05). The gene expression levels in GD were higher than those in HT and control. In HT group, TPO, TG gene expression levels were relatively lower while TSH-R gene expression levels were still in normal range. The difference in gene expression is possibly related to the types of autoimmune antibodies and various dripping rates.

Adult↗
PubMed1997

Molecular subtyping of the HIV-1 V3 loop sequences detected in HIV-1-positive patients in southern Taiwan.

Polymerase chain reaction and nucleotide sequence analysis were performed to amplify and determine the V3 loop sequences of human immunodeficiency virus type 1 (HIV-1) from ten seropositive patients at National Cheng Kung University Hospital, Tainan. The nucleotide sequences and the deduced amino acid (a. a.) sequences of these V3 regions were compared with those of known HIV-1 prototypes. The V3 loop a. a. sequences detected in eight individuals belong to subtype B which predominates in North America and Europe, whereas two individuals were infected with HIV-1 subtype E which is mainly found in the heterosexual populations of Thailand. Sequence analysis of these variant HIV-1 strains revealed a number of interesting features and a phylogenetic tree was also constructed according to the V3 loop nucleotide sequences of these variant strains and HIV-1 isolates from other parts of the world. Furthermore, our results suggest that the north vs south geographical separation in terms of HIV-1 epidemiology in Taiwan is insignificant.

Amino Acid Sequence↗
PubMed1997

[Experimental study on bone formation in a denser coral used for repairing cortical defects in dogs].

The present study was designed to investigate a coral skeleton, Favites, which was originated from the reef builders in Hainan island, as a bone substitute. The coral Favites, like porites, is composed of anagonite (CaCO3), but contains less volume of porosity, higher strength and denser construction than Porites. After implanted into cortical bone defects in mandibles and femurs of dogs, skeleton fragment of coral Favites demonstrated good biocompatibility and biodegradability. A resorption of the implant and a simultaneous apposition of new bone was observed. Coral Favites was totally replaced by newly formed bone after a period of time from 6-8 months. Compared to Porites, Favites has a lower rate of resorption and therefore the defects of host bone are repaired completely without any lost of bone volume. The results showed that coral Favites may be used as a bone substitute for the segmental defects of mandibles.

Animals↗
PubMed1997

[Detection of types I, III and IV collagen in human cementum, periodontal ligament and alveolar bone].

The aim of the present study was to investigate distribution and composition of collagen Types I, III and IV in human cementum, periodontal ligament and alveolar bone with immunohistochemical localization and image analysis technique. The results showed that collagen Type I was 78.06% in periodontal ligament, 73.09% in cementum and 30.50% in alveolar bone; Type III was 11.73% in periodontal ligament and was also observed in apical cementum and bone tissue of alveolar socket; Type IV was restricted to the basement membrane of the blood vessles; Sharpey's fibers was stained by Type I and its periphery was demonstrated stronger staining by Type I and Type III as a sheath. These results provided necessary informations on healthy periodontal tissues that will be required for future studies on the effects of pathological and regenerative processes.

Alveolar Process↗
PubMed1997

[The effect of anisodaminum and dexamethasone on microcirculation, TNF, LPO and pathology in MODS].

In order to evaluate the effect of anisodaminum and dexamethasone to the microcurculation, TNF, LPO and pathology in MODS, we first established MODS model using cecem ligature and perfuration of rabbit then divided it into four groups: anisodaminum, dexamethasone, combined anisodaminum and dexamethasone and control. After used the corresponding drugs we observed the change of microcirculation, TNF, LPO and organ pathology. The result showed that microcirculation improved, the serum level of TNF and LPO decreased, and the pathomorphological changes lessensed. It is suggested that the combined use of anisodaminum and dexamethasone may be a new way for treating MODS.

Animals↗
PubMed1997

[Determination of trace silver in surface water samples by flame atomic absorption with continuous flow on-line absorption preconcentration].

In a continuous flow on-line preconcentration system, trace silver was adsorbed onto activated carbon particles packed in micro colum at pH 1, eluted with 0.3 ml of 10 g/L Na2S2O3 solution and determined by flame atomic absorption spectrometry. For surface water samples, 25 ml sufficed precise determination of silver at level of microgram/L. The relative standard deviation of 10 parallel sample determinations was 6.9%. The proposed method was successfully applied to water samples with recoveries ranging from 93.2% to 104.6% and a throughout of 7-8 sampling/h.

Silver↗
PubMed1997

[Adsorption of permanganate onto activated carbon particles].

In this paper, the adsorption behavior of permanganate onto activated carbon particles was studied as a function of pH, flow rate and the concentration of permanganate. It was found that permanganate was not adsorbed but reduced by activated carbon particles. The percent of reduction of permanganate was strongly pH-dependent. The reducing product of permanganate was mainly Mn2+ which was adsorbed onto the activated carbon particles by surface complexation.

Adsorption↗
PubMed1997

[Ara-c induced apoptosis in human myeloid leukemia cell line HL-60].

OBJECTIVE: To elucidate the pattern of chemotherapy drugs induced apoptosis and its role in chemotherapy of acute leukemia. METHODS: Apoptosis induced by Ara-c in human myeloid leukemia cell line HL-60 was investigated by applying light microscopy, electron microscopy combined with DNA electrophoresis and flow cytometry analysis techniques. RESULTS: Apoptosis persisted throughout 36 hours following addition of Ara-c with a gradual augmentation. Efficiency of apoptosis was enhanced in a dose-dependent pattern, HL-60 treated with six other chemotherapy drugs and perpherial white blood cells from a AML case undergoing DA protocol chemotherapy exhibited typical DNA ladder pattern. Further investigation indicated that chemotherapy drugs induced apoptosis came into being possibly by downregulation the oncogenes expression of c-myc and bcl-2. CONCLUSION: Chemotherapy induced apoptosis is a primary mechanism in chemotherapy.

Antimetabolites, Antineoplastic↗