Biomedical subjects

Z Su

Publications and source records attributed to Z Su.

At least 55 records · Page 3Linked to original sources

PubMed2000

Caffeine-induced Ca(2+) sparks in mouse ventricular myocytes.

Ca(2+) sparks are spatially localized intracellular Ca(2+) release events that were first described in 1993. Sparks have been ascribed to sarcoplasmic reticulum Ca(2+) release channel (ryanodine receptor, RyR) opening induced by Ca(2+) influx via L-type Ca(2+) channels or by spontaneous RyR openings and have been thought to reflect Ca(2+) release from a cluster of RyR. Here we describe a pharmacological approach to study sparks by exposing ventricular myocytes to caffeine with a rapid solution-switcher device. Sparks under these conditions have properties similar to naturally occurring sparks in terms of size and intracellular Ca(2+) concentration ([Ca(2+)](i)) amplitude. However, after the diffusion of caffeine, sparks first appear close to the cell surface membrane before coalescing to produce a whole cell transient. Our results support the idea that a whole cell [Ca(2+)](i) transient consists of the summation of sparks and that Ca(2+) sparks consist of the opening of a cluster of RyR and confirm that characteristics of the cluster rather than the L-type Ca(2+) channel-RyR relation determine spark properties.

Animals↗

PubMed2000

A preliminary study of single nucleotide polymorphisms of lipoprotein lipase gene in coronary atherosclerotic heart disease.

OBJECTIVE: This study inquired into the relationship between single nucleotide polymorphisms(SNPs) of lipoprotein lipase gene (LPL) and coronary atherosclerotic heart disease(CHD). METHODS: Exon 6 and fragment of intron 6 in LPL gene from 102 cases of CHD and 110 normal subjects were analysed by polymerase chain reaction amplification, temperature-modulated high-performance liquid chromatography (TmHPLC) and DNA sequencing. RESULTS: Three new SNPs (4212t/c, 4509t/c, 4576a/c) were detected in the intron 6 of LPL gene. There was significant difference in frequencies of 4212t/c, and 4576a/c between health group and CHD group(P<0.05). CONCLUSION: This study has accumulated additional data on SNPs in LPL gene and provided new data for exploring the mechanism of CHD.

Adult↗

PubMed2000

Analysis of temperature-modulated high-performance liquid chromatography as a tool for detection of single nucleotide polymorphism.

OBJECTIVE: To establish and evaluate temperature-modulated high-performance liquid chromatography(TmHPLC) as a rapid and efficient technique of detecting single nucleotide polymorphism(SNP). METHODS: Several TmHPLC parameters, such as the eluting gradient ranges and column temperatures used for analysing the amplicons have been studied. The size of DNA fragments suitable for analysis of SNP was studied. Also the sensitivity of the TmHPLC was evaluated. RESULTS: The suitable chromatographic condition of TmHPLC was found out. The elution peaks of dNTP and primers could be separated from those of polymerase chain reaction products of the genomic DNA. The heterozygotes of SNP from the sequenced DNA fragment with 178bp, 269bp and 272bp could be distinguished from the homozygotes of SNP clearly. CONCLUSION: The authors have established and evaluated the TmHPLC method, which is an efficient, sensitive and rapid method for screening out SNP in the DNA fragments of larger size.

Chromatography, High Pressure Liquid↗

PubMed2000

[Study on the relationship of alteration and expression of p16 gene to pancreatic carcinoma].

OBJECTIVE: To directly investigate the effect of genetic alteration(homozygous deletion and point mutation) and expression of p16 gene on pancreatic carcinomas. METHODS: Thirty-five cases were analyzed for genetic alteration and expression of p16 gene by polymerase chain reaction(PCR), single strand conformation polymorphism(SSCP), DNA sequencing and immunohistochemical method. RESULTS: The analysis of pancreatic carcinoma for p16 gene revealed alteration in 19 of 35 cases, among which 12 pancreatic carcinomas had 522 bp homozygous deletion at least and 7 cases had two point mutations at the same site. One of them is 126th codon GTC --> AAT (Val126Asn); the other is 127th codon GCA --> GCG (A127A). The 3D (three-dimensional) structure of P16 protein determined by computer techniques according to PDB indicated that Val126Asn influenced the space structure of P16 protein and affected the function of P16 protein. Twelve cases revealed no P16 protein and 9 cases showed low level expression of P16 protein. CONCLUSION: The alteration of p16 gene and abnormal expression of P16 protein are significantly correlated with the biological behavior and clinical staging of pancreatic carcinoma and may hence be helpful to prognostication

Adult↗

PubMed2000

[Distribution pattern and its dynamics of Taxus chinensis var. mairei population on Yunbaoshan Mountain].

Field data were sampled by the method of contiguous grid quadrate, and t-test of v/m ratio, negative binomial parameter, Green's index, Cassie's index, dispersion index, clumping index, mean crowding index and patchiness index were used to analyse the distribution pattern and its dynamics of Taxus chinensis var. mairei population. The result shows that the distribution pattern was clustering. From sapling to grown-up tree, the clustering degree was decreasing, while the big trees had a random distribution.

China↗

PubMed2000

[Structure and spatial pattern dynamics of dominant populations in a natural forest in north Guangdong Province].

Five 1000-m2 plots were set up in a forest dominated by Schima superba, Castanopsis fargesii and Pinus massoniana in Luoba Nature Reserve, Shixing County, north Guangdong Province. Field data were obtained by tally with contiguous grid quadrat method. The analysis of population structure and spatial distribution patterns of the dominant species in the forest shows that S. superba and C. fargesii had a large reserve of seedlings, with up to 1538 and 9763 seedlings per hm2, respectively, showing a pyramid shape of population structure. Both populations had a high mortality for seedlings of classes I and II in the process of development to saplings. The population structure of P. massoniana was an inverse pyramid type, with no seedlings and only 4 saplings per hm2, but 44 large trees per hm2. The spatial distribution patterns of P. massoniana and C. fargesii in coniferous broadleaved mixed community chiefly dominated by broadleaved trees were uniform, and in those chiefly dominated by P. massoniana were aggregated, but there were different causes of pattern dynamics for P. massoniana and C. fargesii. S. superba in both communities showed an aggregated distribution pattern. The aggregation intensity was different, with K values from 0.4280 to 0.9750. Regarding the distribution patterns in different development stages, S. superba was aggregated in different stages, while C. fargesii varied with uniform distribution pattern for the large trees and aggregated distribution pattern for the saplings and median trees. As for P. massoniana, its median trees showed an aggregated distribution pattern, while both the saplings and large trees were uniform. The variations in spatial distribution patterns of populations in different development stages were closely related to the biological and ecological characteristics of the species, but different block size had an impact on the outcome of spatial distribution patterns.

China↗

PubMed2000

[Changes after dynamic observation of ultrastructural cerebral infarction in renovascular hypertensive rats].

OBJECTIVE: To study the ultrastructural damages of brain tissues dynamically after middle cerebral artery obstruction (MCAO). METHODS: A middle cerebral artery obstruction (MCAO) model was reproduced in renal vascular hypertensive rats (RHR). Brain tissues in different locations were collected for eight times in row, from two hours to seven days after establishment of the animal model. RESULTS: The changes occurred in the whole brain after focal cerebral ischemia. The severity of impairment and time of emergence differed with the location sampled. The earliest in the infarcted region with necrosis was considered the major change and completely irreversible damage. The next was seen in marginal regions, mainly with microvascular collapse, formation of microthrombi, and partial necrosis of brain cells and was considered partially reversible damage. The last was in distant and contralateral hemisphere, mainly with reversible swelling of endothelial cells and astrocytes. Changes in the MCAO models reproduced by RHR models were much similar to the clinical pathological changes in cerebral infarction based on the hypertensive cerebrovascular impairment, and it was regarded as a relatively ideal model for studying focal ischemic cerebral impairment. CONCLUSION: Dynamic changes of cerebral ultrastructure in which microvascular impairment plays an important role suggest that clinical therapy cannot only be focused on infarction foci, but also on the whole brain with comprehensively effective measurements.

Animals↗

PubMed2000

[Herbological investigation on traditional Chinese medicine gegen].

In this paper, herbological investigation was carried out into a large of Ben-Cao literature that concerned the origin, clinical use and other relevant aspects of Gegen, from which we can judge that Gegen used in ancient times match to that specified in the present Chinese Pharmacopoeia.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2000

[Effects of nitric oxide on ciliary beat frequency in the human nasal mucosa].

OBJECTIVE: To investigate the effect of nitric oxide on ciliary beat frequency in human nasal mucosa. METHOD: A primary culture model of human nasal mucosa epithelial cells was established and the effect of nitric oxide on ciliary beat frequency was observed by videomicroscopy method. The data were statistically analyzed using t-test. RESULT: L-arginine significantly increased ciliary beat frequency from (400 +/- 48) beats/min to (793 +/- 68) beats/min (n = 9, P < 0.001), D-arginine had no similar effect, while NOS blocker L-NAME inhibited the effect of L-arginine. CONCLUSION: Cells cultured by our method could synthesize NOS that made L-arginine produce NO that could increase ciliary beat frequency in the human nasal mucosa.

Arginine↗

PubMed1999

Energy deficits suppress both systemic and gut immunity during infection.

Protein-energy malnutrition and gastrointestinal nematode infections widely coexist in developing countries. Evidence is provided demonstrating the profound impact of dietary energy deficiency on immune function. Energy-restricted (ER) mice infected with a gastrointestinal nematode showed impaired lymphocyte proliferation and reduced production of Th2 cytokines and lower levels of IgE, parasite-specific IgG1, and eosinophils, which led to higher worm burdens and fecundity. We conclude that mild ER, without concurrent protein malnutrition, can modulate protective immunity from (a) activation early during a primary infection to (b) the expression of acquired immunity during reinfection in both systemic and gut-associated lymphoid tissues.

Animals↗

PubMed1999

Calcium influx factor is synthesized by yeast and mammalian cells depleted of organellar calcium stores.

Depletion of endoplasmic reticulum Ca2+ stores leads to the entry of extracellular Ca2+ into the cytoplasm, a process termed capacitative or store-operated Ca2+ entry. Partially purified extracts were prepared from the human Jurkat T lymphocyte cell line and yeast in which Ca2+ stores were depleted by chemical and genetic means, respectively. After microinjection into Xenopus laevis oocytes, the extracts elicited a wave of increased cytoplasmic free Ca2+ ([Ca2+]i) that spread from the point of injection across the oocyte. Extracts from cells with replete organellar Ca2+ stores were inactive. The increases depended on extracellular Ca2+, were unaffected by the inositol 1,4,5-trisphosphate (IP3) inhibitor heparin or an anti-IP3 receptor antibody and were unchanged when the endoplasmic reticulum was segregated to the hemisphere opposite the injection site by centrifugation. Confocal microscopy revealed that [Ca2+]i increases were most pronounced at the periphery of the oocyte. The patterns of [Ca2+]i increases were replicated by computer simulations based on a diffusible messenger of about 700 Da that directly activates Ca2+ influx. In addition, ICRAC, a Ca2+ release-activated Ca2+ current monitored in Jurkat cells by whole-cell patch clamp recordings, was more rapidly activated when active extracts were included in the patch pipette than by the inclusion of a Ca2+ chelator or IP3. These data support the existence in yeast and mammalian cells depleted of Ca2+ stores of a functionally conserved diffusible calcium influx factor that directly activates Ca2+ influx.

Animals↗

PubMed1999

Quantitation of Na/Ca exchanger function in single ventricular myocytes.

A Na/Ca exchange current can be elicited in voltage clamped single ventricular myocytes by the abrupt removal of extracellular Na+ by means of a rapid switcher device. We measured this reverse Na/Ca exchange current in isolated mouse ventricular myocytes from wild-type mice, and from transgenic mice with hearts overexpressing the Na/Ca exchanger. In mouse ventricular myocytes, the current was sensitive to nickel, and was eliminated by removal of intracellular Na+. It was not influenced by 3 m m ouabain, and thus not contaminated by Na pump currents. The magnitude of the current reached a plateau within 10-15 min after obtaining a whole cell patch with the pipettes containing EGTA, to buffer [Ca2+]i and in zero extracellular K+ concentration to completely inhibit the Na pump, and allow equilibration of pipette Na+ with subsarcolemmal [Na+]. The magnitude of the current increased with increases in pipette [Na+]. Comparison of the current magnitudes in wild-type and transgenic myocytes showed a 2.5 and 2.7 fold increase in the current in transgenic myocytes at pipette [Na+] of 10 and 20 m m. The magnitude of this increase in Na/Ca exchanger currents in single transgenic myocytes compares well with the reported 2.5 fold increase in Na+-dependent 45Ca2+ uptake measured in ventricular sarcolemmal vesicles obtained from transgenic animals. With this approach, we found variation in exchanger current densities in different species, with values for mouse>rat>rabbit>dog>human. This technique should also be useful in quantifying changes in Na/Ca exchanger current density as a consequence of pathologic processes, and exposure to drugs.

Animals↗

PubMed1999

Deficiency in tumor necrosis factor alpha activity does not impair early protective Th1 responses against blood-stage malaria.

Blood-stage Plasmodium chabaudi AS infection was controlled by 4 weeks in mice with deletion of tumor necrosis factor p55 and p75 receptors (TNFR-knockout [KO]) and control wild-type (WT) mice, although female TNFR-KO mice showed slightly but significantly higher parasitemia immediately following the peak. Serum interleukin 12 (IL-12) p70 and gamma interferon (IFN-gamma) levels were similar but tumor necrosis factor alpha levels were significantly higher in TNFR-KO mice than in WT controls. Splenic IL-12 receptor beta1 and beta2 and IFN-gamma mRNA expression, as well as spleen cell production of IFN-gamma and IL-4, were comparable in both mouse types, but IL-10 production was significantly higher in cells from TNFR-KO mice than in cells from WT mice. Lipopolysaccharide-induced NO secretion by splenic macrophages in vitro was significantly reduced but systemic NO3- levels were similar in infected TNFR-KO and WT mice.

Animals↗

PubMed1999

The clinical evaluation of peripheral nerve regeneration using turns/amplitude analysis system in EMG.

OBJECTIVE: The aim of this study was to explore the value of turns/amplitude analysis system in EMG in evaluating peripheral nerve regeneration. METHODS: Twenty-eight patients were investigated using turns/amplitude analysis system and conventional method in EMG after nerve repair. The patients were grouped according to their muscle power and their parameters in EMG were recorded and compared among groups as well as between the two methods. RESULTS: Statistical differences of recovery percentage were shown among the groups except turns between M3:M4 using turns/amplitude system. However, none of the differences were present among them using conventional method. Among the parameters, amplitude/s advanced the fastest although it was the lowest at early stage and it also got the highest correlation coefficient (r = 0.848). CONCLUSION: Turns/amplitude system was a reliable and sensitive method for evaluating nerve regeneration during nerve repair, which is more precise than the conventional method, and the amplitude was closely related to muscle function recovery.

Adolescent↗

PubMed1999

[Study on the safety after cesarean section].

OBJECTIVE: In order to assess the safety after cesarean section, the complications and morbidity rate within 2 years after delivery between cesarean section and spontaneous delivery were compared. METHODS: A retrospective cohort study was used in this study. RESULTS: The prevalence of anemia, mobility restriction of uterus, chronic pelvic pain and wound ache during the 2 years postpartum in cesarean section group were 11.1%, 9.6%, 4.3% and 5.1% respectively, which were significantly higher than those in women with spontaneous delivery. CONCLUSION: In order to protect women's health, the indications for cesarean section must be mastered strictly.

Adult↗

PubMed1999

[Changes of interleukin-2 and soluble interleukin-2 receptor serum level and multiple organ dysfunction syndrome in severely traumatic patients].

OBJECTIVE: To evaluate the role in the changes of interleukin-2 (IL-2) and soluble interleukin-2R (sIL-2R) serum level in the mechanism of post-traumatic multiple organ dysfunction syndrome (MODS). METHODS: 59 severe traumatic patients were divided into MODS group (n = 24) and non-MODS group (n = 35) according to the occurrence of MODS after trauma. The changes in IL-2 and sIL-2R serum level were observed by enzyme linked immunoabsorbed assay (ELISA). Sera from 30 healthy individuals were used as normal controls. RESULTS: The serum level of sIL-2R was increased and that of IL-2 decreased in 59 traumatic patients. These changes were more marked in the MODS group than in non-MODS group (p < 0.05). CONCLUSIONS: The changes in IL-2 and sIL-2R serum level after trauma might participate in the mechanism of post-traumatic MODS.

Adolescent↗

PubMed1999

[Determination on chemical constituents of Curcuma L. produced in China].

OBJECTIVE: To provide some valuable information for the research on species systematization and quality standardization of Curcuma drugs. METHODS: Colorimetry, TLC-colorimetry and water vapour distillation were used to determine the contents of curcuminoids, curcumin and essential oils of 34 samples of Curcuma produced in China. RESULTS AND CONCLUSION: The contents of curcuminoids and curcumin are different upto an extent of over 100 times among the varieties of Curcuma, and those of essential oils to an extent of 6 times. But there is little difference in the samples of the same species from different producing areas. There is also an obvious correlativity between the contents of curcuminoids and essential oils in the varieties of curcuma.

Curcuma↗

PubMed1999

[Preliminary study on chemical changes in the decocting process of radix et rhizoma Rhei].

OBJECTIVE: To understand the chemical changes in the decocting process of Radix et Rhizoma Rhei. METHOD: Comparing the contents of many kinds of anthraquinones in the crude drug, decoction and drug sediments of Radix et Rhizoma Rhei by HPLC. RESULT: The contents of combined and free anthraquinones changed after the crude drug was decocted. CONCLUSION: These changes may be related to the hydrolysis of combined anthraquinones, the decomposition of free anthraquinones, and the inter-transition among anthraquinones.

Anthraquinones↗