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Biomedical subjects

Z Song

Publications and source records attributed to Z Song.

At least 91 records · Page 5Linked to original sources
PubMed1999

Death by design: mechanism and control of apoptosis.

Active cellular suicide by apoptosis plays important roles in animal development, tissue homeostasis and a wide variety of diseases, including cancer, AIDS, stroke and many neurodegenerative disorders. A central step in the execution of apoptosis is the activation of an unusual class of cysteine proteases, termed caspases, that are widely expressed as inactive zymogens. Originally, the mechanisms for regulating the caspase-based cell death programme seemed to be different in Caenorhabditis elegans, mammals and insects. However, recent results suggest that these apparent differences in the control of cell death reflect our incomplete knowledge, rather than genuine mechanistic differences between different organisms.

Animals↗
PubMed1999

[Investigation on acute stroke patients being admitted to hospital].

One hundred and twelve patients with acute stroke were studied. The results revealed that about 42 percent of 112 patients could get to hospital within 6 hours after onset, in which included 60.4 percent of the hemorrhagic group and 28.1 percent of the infarction group. Comparatively, among 30.3 percent of 112 patients CT scan was carried out within 6 hours, which included 41.7 percent of the hemorrhagic group and 21.8 percent of the infarction group. Linear correlation analysis was studied between admission time(AT) and the assessment of neural function defect(ANFD). The results showed that there was significant negative correlation between AT and ANFD in stroke patients. After analysing the serial reasons of delaying hospitalization, the authors have found that the key factor is the ignorance of the importance of stroke in early stage.

Cerebral Hemorrhage↗
PubMed1999

Comparison of bone mass in forearm, lumbar vertebra and hip by single and/or dual energy X-ray absorptiometry.

OBJECTIVE: Bone mineral density (BMD) was measured in normal Chinese women with single X-ray absorptiometry (SXA) and dual energy X-ray absorptiometry (DEXA). These two methods were compared to evaluate the sensitivity in reflecting bone loss. METHODS: Measurements were performed in 300 women aged 20 to approximately 79 (5 for each age). The 8mm distal, 1/4 distal, ultra distal site of the nondominant forearm were measured with SXA; the AP spine (L2-4), right femoral neck (Neck), Ward's triangle (Ward) and trochantor (Troch) were measured with DEXA. Ten women had 5 repeated measurements to evaluate the reproducibility of the equipments. RESULTS: The BMD peak for Neck and Ward was found between age 20 to approximately 29, for ultra distal and L2-4 at age 30 to approximately 39, for 8mm distal, 1/4 distal and Troch at age 40 to approximately 49. After reaching the peak values, BMD at all sites decreased with increasing age. The highest rate of yearly loss of BMD was at 8mm distal. Results of measurement showed significant correlation between SXA and DEXA. Comparing with premenopausal women, the bone loss rate in postmenopausal women was faster and highest up to 11 to approximately 15 years and the highest rate was at the Ward. CONCLUSION: The present study gives the normal values of BMD at seven sites for normal Chinese women. The ages of BMD peak were different at seven sites. The yearly loss of BMD was highest at 8mm distal, it seemed to be the sensitive region for bone loss with age. The postmenopausal women had highly significantly loss bone mass than the premenopausal women. Comparing with premenopause, postmenopause BMD for Ward's triangle with DEXA seemed to be most sensitive to the effect of menopause.

Absorptiometry, Photon↗
PubMed1999

[The 1. 54 microm laser and upconversion luminescence of YELPP noncrystalline induced by 969 nm LD laser].

In this paper, the absorption of Er3+, Yb3+ penta-phosphate noncrystalline (YELPP) was measured and the basic spectral parameters were calculated. Adopting the longitudinal-pump method with a domestic diode laser (LD), we achieved CW 1.5 microm chipped laser in China for the first time. The power of 1.5 microm laser was quite stable. The target of 1.5 microm laser reached the international level of early 1990s' in this field. In addition, the up-conversion luminescence was measured under the condition that 1.5 microm laser was either oscillating or not. The relationship between 1.5 microm chipped laser and up-conversion luminescence was analyzed initially.

English Abstract↗
PubMed1999

[Study on the human serums by absorption spectra].

The absorption spectra of normal human and cancer patient serums were measured, and those of human serum after adding some cancer cells were also measured. The results showed some difference in absorbance among the three kinds of serums. Some useful results were obtained.

Humans↗
PubMed1998

The molecular chaperone alphaA-crystallin enhances lens epithelial cell growth and resistance to UVA stress.

alphaA-Crystallin (alphaA) is a member of the small heat shock protein (sHSP) family and has the ability to prevent denatured proteins from aggregating in vitro. Lens epithelial cells express relatively low levels of alphaA, but in differentiated fiber cells, alphaA is the most abundant soluble protein. The lenses of alphaA-knock-out mice develop opacities at an early age, implying a critical role for alphaA in the maintenance of fiber cell transparency. However, the function of alpha-crystallin in the lens epithelium is unknown. To investigate the physiological function of alphaA in lens epithelial cells, we used the following two systems: alphaA knock-out (alphaA(-/-)) mouse lens epithelial cells and human lens epithelial cells that overexpress alphaA. The growth rate of alphaA(-/-) mouse lens epithelial cells was reduced by 50% compared with wild type cells. Cell cycle kinetics, measured by fluorescence-activated cell sorter analysis of propidium iodide-stained cells, indicated a relative deficiency of alphaA(-/-) cells in the G2/M phases. Exposure of mouse lens epithelial cells to physiological levels of UVA resulted in an increase in the number of apoptotic cells in the cultures. Four hours after irradiation the fraction of apoptotic cells in the alphaA(-/-) cultures was increased 40-fold over wild type. In cells lacking alphaA, UVA exposure modified F-actin, but actin was protected in cells expressing alphaA. Stably transfected cell lines overexpressing human alphaA were generated by transfecting extended life span human lens epithelial cells with the mammalian expression vector construct pCI-neoalphaA. Cells overexpressing alphaA were resistant to UVA stress, as determined by clonogenic survival. alphaA remained cytoplasmic after exposure to either UVA or thermal stress indicating that, unlike other sHSPs, the protective effect of alphaA was not associated with its relocalization to the nucleus. These results indicate that alphaA has important cellular functions in the lens over and above its well characterized role in refraction.

Actins↗
PubMed1998

Sialic-acid-binding lectin from the slug Limax flavus--cloning, expression of the polypeptide, and tissue localization.

A cDNA library of Limax flavus was constructed and screened for sialic-acid-specific lectins. Complementary DNA clones were categorized into seven groups corresponding to closely related but different sequences. Group 1 clones contained an ORF encoding 199 amino acids including a sequence identical to the partial amino acid sequence obtained from the lectin protein. Within its 1074-bp 3' untranslated region, ten closely related 60-bp sequence repeats were found. Group 2 clones contained an ORF encoding a polypeptide chain of the same number of amino acid residues, with 89.1% overall identity to that of the group 1 and eight 60-bp repeat sequences in the 3' untranslated region. The remaining groups of clones contained ORF with highly similar full or partial sequences, with or without 60 bp repeats in the 3' untranslated region. The large number of closely related but different cDNA clones obtained indicated that the slug sialic-acid-specific lectin gene is a member of a multigene family. The lectin amino acid sequence showed significant similarity with the fibrinogen domain of human tenascin-C, with a human C-type serum lectin, and with pig ficolin. Immunostaining analysis of slug tissue for the lectin indicated that it is present primarily on the epidermal surface and in mucous glands. Recombinant slug lectin protein lacking the 20-amino-acid N-terminal signal sequence produced in a bacterial expression system from a group-1 clone accumulated as aggregates in inclusion bodies, suggesting that large-scale production of the active agglutinin may be possible.

Amino Acid Sequence↗
PubMed1998

Studies of multimerin in human endothelial cells.

Multimerin is a novel, massive, soluble protein that resembles von Willebrand factor in its repeating, homomultimeric structure. Both proteins are expressed by megakaryocytes and endothelial cells and are stored in the region of platelet alpha-granules resembling Weibel-Palade bodies. These findings led us to study the distribution of multimerin within human endothelial cells. Multimerin was identified in vascular endothelium in situ. In cultured endothelial cells, multimerin was identified within round to rod-shaped, dense-core granules, some of which contained intragranular, longitudinally arranged tubules and resembled Weibel-Palade bodies. However, multimerin was found primarily in different structures than the Weibel-Palade body proteins von Willebrand factor and P-selectin. After stimulation with secretagogues, multimerin was observed to redistribute from intracellular structures to the external cellular membrane, without detectable accompanied secretion of multimerin into the culture media. In early passage endothelial cell cultures, multimerin was associated with extensive, fibrillary, extracellular matrix structures, in a different distribution than fibronectin. Although multimerin and von Willebrand factor are stored together in platelets, they are mainly found within different structures in endothelial cells, indicating that there are tissue-specific differences in the sorting of these soluble, multimeric proteins.

Blood Proteins↗
PubMed1998

Effects of ginseng treatment on neutrophil chemiluminescence and immunoglobulin G subclasses in a rat model of chronic Pseudomonas aeruginosa pneumonia.

Chronic Pseudomonas aeruginosa lung infection in cystic fibrosis (CF) patients is almost impossible to eradicate with antibiotic treatment. In the present study, the effects of treatment with the Chinese herbal medicine ginseng on blood polymorphonuclear leukocyte (PMN) chemiluminescence and serum specific antibody responses were studied in a rat model of chronic P. aeruginosa pneumonia mimicking CF. An aqueous extract of ginseng was administered by subcutaneous injection at a dosage of 25 mg/kg of body weight/day for 2 weeks. Saline was used as a control. Two weeks after the start of ginseng treatment, significantly increased PMN chemiluminescence (P </= 0. 001) and a decreased level in serum of immunoglobulin G (IgG) against P. aeruginosa (P < 0.05) were found. Furthermore, a higher IgG2a level (P < 0.04) but lower IgG1 level (P < 0.04) were found in the ginseng-treated infected group than in the control group. In the ginseng-treated group the macroscopic lung pathology was milder (P = 0.0003) and the percent PMNs in the cells collected by bronchoalveolar lavage was lower (P = 0.0006) than in the control group. However, the alveolar macrophage (AM) chemiluminescence values were not significantly different in the two groups infected with P. aeruginosa. The differences between the ginseng-treated noninfected rats and the control group (without P. aeruginosa lung infection) for the PMN chemiluminescence and AM chemiluminescence were not significant. These results suggest that ginseng treatment leads to an activation of PMNs and modulation of the IgG response to P. aeruginosa, enhancing the bacterial clearance and thereby reducing the formation of immune complexes, resulting in a milder lung pathology. The changes in IgG1 and IgG2a subclasses indicate a possible shift from a Th-2-like to a Th-1-like response. These findings indicate that the therapeutic effects of ginseng may be related to activation of a Th-1 type of cellular immunity and down-regulation of humoral immunity.

Animals↗
PubMed1998

Clinical evaluation of a new generation membrane oxygenator: a prospective randomized study.

A new generation hollow-fibre membrane oxygenator (Spiral Gold) has been introduced by Baxter Healthcare (Irvine, CA, USA). The purpose of this study was to evaluate the operational performance of this device under clinical conditions and to compare it to the Univox Gold membrane oxygenator. Following institutional review board approval, and the obtainment of informed consent, 26 patients undergoing coronary artery bypass grafting were randomly assigned to either a Spiral Gold (Spiral) (n = 13) or Univox Gold (Univox) (n = 13) group. Study parameters were grouped into the following categories: haematological, haemodynamic, oxygenator performance and perioperative outcomes. All patients received identical surgical, anaesthesia and postoperative care. There were no statistically significant differences in either preoperative or operative parameters between groups. During cardiopulmonary bypass, the Spiral group had a significantly lower pressure drop (26.9 +/- 8.2 vs 46.7 +/- 16.2 mmHg, p < 0.001). The Spiral group had significantly lower plasma free haemoglobin levels during all time periods of CPB compared to the Univox group. Heat exchange coefficients were higher during the rewarming period in the Spiral patients (0.59 +/- 0.28) compared to the Univox group (0.36 +/- 0.19), p = 0.06. There were no differences in oxygen transfer between groups, but ventilation gas sweep rates and FiO2 levels were statistically lower in the Spiral group at two of the three sampling time periods. The ratio of ventilating gas sweep rate to blood flow rate was lower in the Spiral group (0.56 +/- 0.12) compared to the Univox group (0.74 +/- 0.23), p < 0.03. The Spiral Gold oxygenator had superior oxygen transfer efficiency and lower haemolysis rates than the Univox Gold oxygenator.

Adult↗
PubMed1998

Antibiotic activities and affinities for bacterial cell wall analogue of N-demethylvancomycin and its derivatives.

N-Demethylvancomycin, which has been clinically used in China, is one member of vancomycin group (glycopeptide) antibiotics. It differs from vancomycin only in that methyl group on the amino group of the N-terminal residue of vancomycin has been replaced by H. By reductive alkylation of N-demethylvancomycin, we synthesized N-alkyl and N,N'-dialkyl N-demethylvancomycins, which closely correlated with vancomycin in structure. The association constants of the complexes of N-demethylvancomycin and its analogues with di-N-Ac-L-Lys-D-Ala-D-Ala and the antibiotic activity against Staphylococcus aureus of the glycopeptides were determined. Results showed that N-demethylvancomycin has higher affinity for bacterial cell wall analogue di-N-Ac-L-Lys-D-Ala-D-Ala and more potent antibiotic activity against Staphylococcus aureus than vancomycin. Both N-alkylation and N,N'-dialkylation of N-demethylvancomycin reduced the affinity and antibiotic activity. The longer the alkyl groups, the less potent antibiotic activities and lower affinities have the glycopeptides. The antibiotic activities against Staphylococcus aureus of N-demethylvancomycin and its analogues roughly parallel their affinities for di-N-Ac-L-Lys-D-Ala-D-Ala.

Alkylation↗
PubMed1998

[Effects of subcutaneous injection with different doses of ginseng on the rat model of chronic Pseudomonas aeruginosa pneumonia].

OBJECTIVE: To observe the effect of ginseng extracts on a rat model of chronic Pseudomonas aeruginosa (PA) pneumonia. METHODS: Subcutaneous injection with four different doses of ginseng aqueous extracts to the model rats for two weeks. RESULTS: Milder macroscopic lung pathology and lower incidence of lung abscesses were found in all the four groups received different doses of ginseng treatment compared to the control group (P < 0.05). Histopathology of the lungs was negatively correlated with the ginseng doses (r = -0.95, P < 0.01). The mast cell number in the lung foci in group I, II and IV was significantly lower than that in the control group (P < 0.05). Bacterial clearance in group II and group III was enhanced significantly (P < 0.05) compared with that in the control group. The specific antibody responses were down-regulated in group II, III and IV (P < 0.01), and IgM level in group I was lower compared to the control group (P < 0.01). Serum IgM level was positively correlated with the ginseng doses (r = 0.93, P < 0.05). IgG2a titer in group I was higher than that in the control group (P < 0.05). Serum IgG2a level was positively correlated with the ginseng doses (r = 0.90, P < 0.02). Two weeks after PA lung infection, the serum level of IgG against PA, aeruginosa alginate in group I, II, and III was higher than that in the control and group IV (P < 0.05), and the anti-alginate IgA level in group I, III and IV was lower than that in the control (P < 0.05). CONCLUSIONS: The ginseng dose of 2.5 mg/kg was the best dosage in the present study, and it showed an effect of stimulating T helper type I response.

Animals↗
PubMed1998

[Study of portable synchronous ECG recorder and its long-distance communication system].

This paper presents a convenient long-distance ECG communication system. It is made up of portable ECG recorder, hospital work station and public telephone network. This paper also introduces a kind of modulation and demodulation method in sound coupling communication-pulse edge modulation and demodulation. This system has rational structure, convenient operation and strong management power. A Philips 80C552 used as CPU in the recoder which is portable, cheap and reliable.

Electrocardiography, Ambulatory↗
PubMed1998

[Function of modified YSI membrane in glucose sensor].

This study was designed to improve the stability, accuracy and interference resistance of the glucose sensor system and to fomodify the correlation between electrode current and glucose concentration. Catalase was immobilized in YSI membrane. Experiments in vitro were conducted in different concentrations of glucose or ascorbic acid or paracetomol. The results showed the background current, 0.37 +/- 0.06 nA; the drift values in 0 mM G.S. and 10 mM G.S. were (0.20 +/- 0.14)%/30 hr and (3.22 +/- 0.40)%/30 hr respectively. The mean value of drift in 10 mM G.S. was 0.103% mM-1hr-1. The correlation between electrode current and glucose concentration gave satisfaction (r = 0.986); it ranged from 0 mM G.S. to 20 mM G.S. Lower concentration of ascorbic cid could not interfere n the glucose sensor system; higher concentration of ascorbic acid and paracetomol only produced very low interference current. These suggest that the modified YSI membrane contributes greatly to a stable, accurate and reliable glucose sensor system.

Biosensing Techniques↗
PubMed1998

[Pulsatile microdialysis method with glucose sensor system].

To develop a miniature subcutaneous glucose sensor system, to simplify calibration procedure before or after glucose monitor, and to improve its temperature characteristics, a pulsatile micropump and the microdialysis technique were used. The experiments of glucose recovery in 5.5 mM and 10 mM G.S. and the temperature experiment from 20 degrees C to 40 degrees C were conducted. The results showed that glucose recovery was (97 +/- 2)%, the current values of glucose sensor varied with temperature, but the temperature parameter was only 3.4%. These indicate that the glucose sensor system is miniature and the calibration procedure is simple. Because of its modified temperature characterisic, it is useful to monitor the blood glucose of feverish diabetics.

Biosensing Techniques↗