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Biomedical subjects

Z Jin

Publications and source records attributed to Z Jin.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Effects of aspirin on ferritin expression and resistance to oxidative damage in endothelial cells].

OBJECTIVE: To explore the mechanism of Aspirin induced ferritin synthesis on resistance to oxidative damage in endothelial cells. METHODS: Using cultured endothelial cells, we measured the effect of aspirin with different incubative time (4 - 24 h) and different concentration (0.1 - 3 mmol/L), salicylic acid and indomethacin induced ferritin expression by ELISA kit, and observed the change of lactate dehydrogenase (LDH) release rate, malondialdehyde (MDA) and cellular viability after preincubating the cell for 8 h with aspirin on resistance to hydrogen peroxide toxicity. Statistical analysis using a one-way analysis of variance. RESULTS: Aspirin at low concentration (0.1 mmol/L) induced significant increase ferritin expression in a concentration-dependent fashion: (5.8 +/- 0.3) ng/10(6) cell (0.1 mmol/L As), (6.4 +/- 0.4) ng/10(6) cell (0.5 mmol/L As), (7.0 +/- 0.7) ng/10(6) cell (1 mmol/L As), (7.4 +/- 0.4) ng/10(6) cell (2 mmol/L As), (7.7 +/- 0.5) ng/10(6) cell (3 mmol/L As), significant for all values: P < 0.05 versus normal control. Induction of ferritin levels by aspirin (1 mmol/L) was also time dependent: (5.8 +/- 1.0) ng/10(6) cell (4 h, but P > 0.05 vs control), (6.5 +/- 1.0) ng/10(6) cell (8 h, P < 0.05 vs control) and (7.8 +/- 0.8) ng/10(6) cell (24 h). Preincubating the cells with aspirin (0.1 mmol/L) reduced LDH release rate by 50%, toxicity reduction by 40%, and significant decrease MDA production. Aspirin induced cytoprotection from H(2)O(2) damage was also in a concentration dependent fashion. The cytoprotection of aspirin was mimicked by exogenous iron-free apo-ferritin but not iron-load ferritin. Salicylic acid and indomethacin failed to increase ferritin expression. CONCLUSION: Aspirin could induce significant increase ferritin synthesis at low concentration (0.1 mmol/L). Ferritin induction by aspirin was specific in nonsteroidal anti-inflammatory drugs.

Antioxidants↗
PubMed2001

Global effects of anchorage on gene expression during mammary carcinoma cell growth reveal role of tumor necrosis factor-related apoptosis-inducing ligand in anoikis.

Anchorage-independent growth is a hallmark of tumor cells. We compared gene expression profiles of anchored and nonanchored human mammary carcinoma cells to study this phenomenon. In this study, we show that anchorage had striking effects on cell growth and morphology but altered transcript levels from a limited number of genes. Only about 1% of mRNA transcripts detected in these cells was altered by anchorage. These include genes related to amino acid and polyamine metabolism, apoptosis, ion channels, cytoskeletal and stress proteins, transcription factors, and growth factors. Some of these may be crucial for the survival of transformed cells. For example, clusterin and the tumor necrosis factor-related apoptosis inducing ligand (TRAIL) were suppressed by anchorage, which could help prevent programmed cell death of these tumor cells. In addition to suppressing TRAIL expression, anchorage also decreased the susceptibility of these tumor cells to TRAIL-induced apoptosis as determined by poly(ADP-ribose) phosphorylase cleavage, annexin-V binding (P < 0.01), and cell cycle analysis (P < 0.0001). These data may help explain mechanisms by which anchorage prevents apoptosis of cells that would otherwise experience anoikis. Thus, genes found to be altered by this analysis could serve as potential targets for anticancer therapy. These findings suggest that TRAIL may be used as a means to target circulating epithelial tumor cells before their attachment and colonization at new sites.

Anoikis↗
PubMed2001

A low-power, atmospheric pressure, pulsed plasma source for molecular emission spectrometry.

A low-power, plasma source-based, portable molecular emission detector is described in this paper. The detector employs a pulsed-plasma source operated at atmospheric pressure for molecular fragmentation and excitation. The plasma was generated with a home-built high-voltage pulsed power supply. The average operational power of the detector was less than 0.2 W. The effects of operational parameters such as plasma gas, voltage, and plasma gas flow rate were investigated. Molecular emission spectra of a variety of organic compounds were studied. The features of the emission spectra obtained with the pulsed plasma source were significantly different from those obtained with direct current (dc) discharge at a power higher than 10 W. The spectra obtained in this work showed strong CH emission at 431.2 nm; however, the typical CN emission observed with a conventional dc plasma source at 383-388 nm was very weak in most cases. The strong CN emission was only obtained for compounds containing nitrogen, such as aniline. Dimethyl sulfoxide can be detected at a limit of 200 ppb using helium plasma by observing the emission band of the CH radical. The detector was very stable and did not experience electrode fouling even with the introduction of organic vapors. Such a detector is very promising for organic vapor detection.

Journal Article↗
PubMed2001

Mapping the ion kinetic energy in a helium microwave plasma orthogonal acceleration time-of-flight mass spectrometer.

The ion kinetic energy of a helium microwave plasma is studied using an orthogonal acceleration time-of-flight mass spectrometer. The ions produced in the plasma are extracted into the mass spectrometer in an 'off-cone' mode (i.e. the helium plasma plume is off the sampler cone), and enter the repelling zone in the x-direction, which is perpendicular to the flight tube. The information of ion initial kinetic energy was obtained from both theoretical calculations and experimental results. The potential influence of two x-direction steering plates (X-steering plates) on the ion energy and signal intensity was examined. The influence of gas composition on the ion kinetic energy was also investigated. The calculated results show that ions with different m/z have different velocity and kinetic energy when they enter the ion modulation zone, and lighter ions have higher velocity and lower kinetic energy. The experimental results obtained demonstrate that the ion signals of different m/z produced with an 'off-cone' sampling helium microwave plasma show similar trends as calculated with the potential difference of the X-steering plates, revealing their narrow kinetic energy distribution in the x-direction. Under typical operating conditions, the x-direction kinetic energy of ions detected mostly range from about 14.9 eV for (7)Li(+) to 16.8 eV for (208)Pb(+).

Journal Article↗
PubMed2001

Flavonol glycosides from the stems of Trigonella foenum-graecum.

Two kaempferol glycosides [kaempferol 3-O-beta-D-glucosyl(1-->2)-beta-D-galactoside 7-O-beta-D-glucoside and kaempferol 3-O-beta-D-glucosyl(1-->2)-(6"-O-acetyl)-beta-D-galactoside 7-O-beta-D-glucoside] as well as the quercetin glycoside [quercetin 3-O-beta-D-glucosyl(1-->2)-beta-D-galactoside 7-O-beta-D-glucoside] were isolated from the stems of Trigonella foenum-graecum L. (Leguminosae) along with a known kaempferol glycoside, lilyn [kaempferol 3-O-beta-D-glucosyl(1-->2)-beta-D-galactoside]. Their structures were established by analysis of chemical and spectral evidence.

Fabaceae↗
PubMed2001

Absence of BAT-26 instability in gastric intestinal metaplasia.

BAT-26 instability, a sensitive marker for the high-frequency microsatellite instability (MSI-H) phenotype, was analyzed in samples of gastric cancer and in adjacent intestinal metaplastic mucosae. Although all MSI-H gastric cancer samples showed BAT-26 instability, as assessed using 12 dinucleotide microsatellite markers, BAT-26 instability was not found in the adjacent intestinal metaplastic mucosa in any of the samples.

Genetic Markers↗
PubMed2001

[The sonochemical-degradation mechanism of toluene in aqueous solution].

The sonochemical degradation of toluene in the airproof aqueous solution was studied, and the mechanism and course of degradation was explored. It was found that the sonication time had great effect on the removal rate of toluene, and the degradation followed a pseudo-first-order kinetic law, and 90%-95% of toluene was removed only after being irradiated for 40 min, types of dissolved gas and pH also had some effects. After aqueous solution was analyzed pH and scanned UV-wavelength and identified components with SMPE-GC-MS, results confirmed that radical-oxidation controlled the sonochemical-oxidation of toluene, and main middle-products included benzaldehyde, bibenzyl, dibutyl phthalate, et al., final products were carbon dioxide and water.

Free Radicals↗
PubMed2001

[The etiology and clinical characteristics of central diabetes insipidus, a retrospective study of 408 cases].

OBJECTIVE: To study the etiology and clinical characteristics of central diabetes insipidus (CDI). METHODS: The clinical data of 408 cases with CDI treated in Peking Union Medical College Hospital between 1956 and 2000, including 113 cases caused by tumors in sella region, were analyzed retrospectively. Follow-up for three months to 16 years was made to 35 cases of CDI without etiological diagnosis during the first visit. RESULTS: Most of the cases among children and youngsters fell ill at the age of 8-12 years, while most of the adult cases fell ill at the age of 25-35 years. Idiopathic CDI accounted for 52%. CDI caused by tumor in sella region accounted for about 33% among the child and youngster cases, among which germinoma made up about 65%. CDI caused by tumor in sella region accounted for about 22% in adult cases. Trauma-induced CDI accounted for 11% among adult cases, and about 5% among child and youngster cases. All the CDI cases caused by histiocytosis X, accounting for 3%, were children. A correct diagnosis was made within the period of two years' follow-up among 86% of the cases. For those with brain tumors, the long-term survival rate reached 80% with radiotherapy and/or operation performed without delay. CONCLUSION: GH deficiency accompanied with growth failure is a potential indicator of CDI caused by space occupying lesion in sella region. A sudden alleviation of polydipsia may indicate the dysfunction of adrenal cortex. MRI is the most valuable examination means for tumor in sella region. Regular clinical follow-up with serial brain MRI may discover the covert tumor in sella region in cases diagnosed originally as idiopathic CDI. The cases without a correct diagnosis during the first visit should be followed-up every 3 to 6 months. The prognosis of the patients with CDI without tumor is satisfactory after ADH replacement. Radiotherapy is the most effective treatment of germinoma in sella region.

Adolescent↗
PubMed2001

Early changes of arginine vasopressin and angiotensin II in patients with acute cerebral injury.

OBJECTIVE: To study the changes and clinical significance of arginine vasopressin (AVP) and angiotensin II (AT-II) in patients with acute moderate and severe cerebral injury. METHODS: The early plasma concentration was checked by radioimmunoassay in 47 cases of acute moderate and severe cerebral injury, 30 cases of non-cerebral injury and 30 healthy volunteers. RESULTS: The early plasma concentrations of AVP (50.23 ng/L +/- 15.31 ng/L) and AT-II (248.18 ng/L +/- 82.47 ng/L) in cerebral injury group were higher than those in non-cerebral injury group (AVP for 30.91 ng/L +/- 11.48 ng/L and AT-II for 120.67 ng/L +/- 42.49 ng/L, P<0.01). The early plasma concentrations of AVP and AT-II in cerebral injury group were also obviously higher than those of the volunteers (AVP for 5.16 ng/L +/- 4.23 ng/L and AT-II for 43.11 ng/L +/- 16.39 ng /L, P<0.001). At the same time, the early plasma level of AVP (58.90 ng/L +/- 18.12 ng/L) and AT-II (292.13 ng/L +/- 101.17 ng/ L) was higher in severe cerebral injured patients than moderate cerebral injured ones (AVP for 36.68 ng/L +/- 12.16 ng/L and AT-II for 201.42 ng/L +/- 66.10 ng/L, P<0.01). The early level of AVP and AT-II was negatively related to the GCS scales in acute cerebral injury. The early plasma concentrations of AVP (45.98 ng/L +/- 13.48 ng/L) and AT-II (263. 28 ng/L +/- 80.23 ng/L) were lower in epidural hematoma group than those of subdural hematoma and cerebral injury group (AVP for 64.12 ng/L +/- 15.56 ng /L and AT-II for 319.82 ng/L +/- 108.11 ng/L, P<0. 01). CONCLUSIONS: AVP and AT-II may play an important role in pathophysiologic process in the secondary cerebral injury. The more severe the cerebral injury is, the higher the early level of AVP and AT-II will be. The early plasma level of AVP and AT-II may be one of the severity indexes of cerebral injury.

Acute Disease↗
PubMed2001

Nucleotide sequences of the coat protein and readthrough protein genes of the Chinese GAV isolate of barley yellow dwarf virus.

The nucleotide sequences of the coat protein (CP) and readthrough protein (RTP) genes of the Chinese GAV isolate of Barley yellow dwarf virus (BYDV) were determined. The CP and RTP genes of GAV isolate comprised 600 and 1374 nucleotides, respectively. When the CP and RTP gene sequences of GAV isolate were compared with those of BYDV isolates MAV-PS1, P-PAV, NY-SGV and Cereal yellow dwarf virus RPV (CYDV-RPV), the highest similarity (97.2%) between the CP genes of GAV and MAV-PS1 isolates was observed, while the RTP genes of these two isolates shared a lower similarity (87.8%). The results of the alignment of the deduced amino acid sequences of RTP showed that the sequence diversity observed was located at the C terminus.

Amino Acid Sequence↗
PubMed2001

[Frequency-specific responses of human brain to peripheral transcutaneous electric nerve stimulation: a functional magnetic resonance imaging study].

The purpose of the present investigation was to determine the responses of human brain to transcutaneous electric nerve stimulation (TENS) at different frequencies by functional magnetic resonance imaging (fMRI) examinations covering the whole brain of eleven healthy volunteers. Each subject received TENS at acupoints ST36 and SP6 of the left leg at the frequencies of 2 and 100 Hz. Frequency-specific responses were found in motor-related areas, thalamus, limbic system and associated cortex to stimulation of the two frequencies, while the primary somatosensory areas were activated by both. Therefore, it appears that 2 and 100 Hz TENS act through different neuro-pathways in the central nervous system.

Acupuncture↗
PubMed2001

[A study of millimeter wave's clinical and immunological effects on oral lichen planus patients].

OBJECTIVE: The aim of this study is to observe clinical effects of the millimeter wave on oral lichen planus (OLP) and its immune mechanisms. METHODS: 30 patients with OLP were randomized into the millimeter wave group and the control group. 15 patients in the millimeter wave group were treated with millimeter wave (7.1 mm, 43 GHz, 10 mW/cm2) radiation, while the other 15 patients in the control group were just given soothing treatment. Either before or after the therapy procedure, the clinical manifestations and the T-cell sub-grouping in the peripheral circulation of each patient were double-blindly evaluated. RESULTS: The pain-soothing effect in the patients treated with millimeter wave was much more obvious than that of the control group (P < 0.01). The peripheral blood CD8+ percent of millimeter wave group decreased greatly (P < 0.05), while no obvious CD8+ change was observed in the control group (P > 0.05). The millimeter wave group's CD4+/CD8+ improvement was also much more obvious than that of the control group (P < 0.05), and its CD4+/CD8+ ratio was completely recovered to the normal level. CONCLUSION: Millimeter wave can effectively relieve OLP patients' pain, and can regulate OLP patients' cellular immune condition. Millimeter wave might provide a new treatment method for OLP.

Adult↗
PubMed2001

[Studies on regulation of glutamine synthetase activity from Streptomyces lincolnensis].

Glutamine synthetase in crude extracts from Streptomyces lincolnensis growing under different nitrogen sources were studied. The results showed that NH4+ in high concentration repressed the biosynthesis of the enzyme. To determine whether Streptomyces lincolnensis has undergone covalent modification, a comparison of the glutamine synthetase isolated from cells grown on different nitrogen sources was made. No significant difference was observed in specific activity, pH optima, divalent cation response, and ultraviolet absorption spectra. Glutamine synthetase activity was not influenced by ammonia shock or snake venom phosphodiesterase treatment. Under these conditions, the activity of glutamine synthetase from K. aerogenes was markedly changed. There was therefore no evidence for enzymatic adenylylation of glutamine synthetase from Streptomyces lincolnensis. Glutamine synthetase was subject to feedback inhibition by end products of glutamine metabolism. Cumulative feedback inhibition of the Mn(2+)-dependent glutamine synthetase activity was demonstrated. These results suggest that glutamine synthetase from Streptomyces lincolnensis is an allosteric enzyme.

Ammonia↗
PubMed2001

[Surgery of the skull base assisted by sinus endoscope].

OBJECTIVE: To explore the feasibility and clinical value of the endoscopic operations around the skull base. METHODS: A retrospective study was made of 44 cases treated by endoscopic operations. Twenty-five cases underwent intranasal endoscopic operations. RESULTS: Forty of 44 cases were cured by one-stage surgery. One case of cartridge foreign body clamped in clivus was not successfully removed; only window operation and puncture biopsy were done in another case of pituitary adenoma; high cranial pressure has not been completely reduced after operation in the third case with relapsing craniopharyngioma a companied with obstructive hydrocephalus. One case of sphenoidal malignant adenoma involving saddle based and extended laterally was partly resected. Complications were follows: cerebrospinal fluid rhinorrhea in 2 cases, diabetes insipidus in 1 case, all of them were cured by conservative treatment; nasal septum perforation in 1 case, without any treatment. CONCLUSIONS: The endoscopic skull base surgery by intranasal approach is feasibility. Intranasal approach has direct path, slight wound and no wound in face. Combined with operation microscope, sinus endoscope can make up for its limits.

Endoscopy↗
PubMed2001

Assessing the resectability of pancreatic ductal adenocarcinoma: comparision of dual-phase helical CT arterial portography with conventional angiography.

OBJECTIVE: To evaluate the respective value of dual-phase helical CT arterial portography (CTAP) and conventional angiography in preoperative predicting resectability of pancreatic ductal adenocarcinoma. SUBJECTS AND METHODS: Tumor resectability was prospectively evaluated in 54 patients with pathologically proven pancreatic ductal adenocarcinoma who later underwent surgery. Both dual-phase helical CT scanning and selective angiography were obtained in each patient preoperatively. For optimal enhancement of pancreas and major peripancreatic vessels, two catheters connected to an automatic injector via a Y-shaped tube were placed selective angiography, one in celiac trunk, the other in superior mesenteric artery. Then the patient underwent dual-phase helical CTAP of pancreas and liver. The criteria of irresectability for CTAP include: tumor diameter > or = 5 cm, extrapancreatic invasion, distant metastases and vascular involvement (occlusion, stenosis or semicircular encasement of superior mesenteric artery, hepatic artery, splenic artery, celiac axis; portal vein, superior mesenteric vein or splenic vein). The results of both modalities were correlated with findings from surgery or pathology. RESULTS: Thirty-eight of 54 patients had nonresectable disease. In prediction the irresectability, sensitivity, specificity, positive predictive value, negative predictive value and overall accuracy were 94.7%, 100%, 100%, 88.9%, 96.3% respectively for helical CTAP and 63.2%, 93.89%, 96.0%, 51.7%, 72. 2% respectively for selective angiography. In assessing vascular involvements, dual-phase helical CTAP was also superior to selective angiography. CONCLUSION: Dual-phase helical CTAP is superior to angiography in assessing resectability of pancreatic ductal adenocarcinoma. The combination of the two modalities may further improve overall creatic

Adenocarcinoma↗
PubMed2000

Development and evaluation of a glow discharge microwave-induced-plasma tandem source for time-of-flight mass spectrometry.

In this work, a new glow discharge, microwave-induced-plasma (GDMIP), tandem ion source was developed, characterized, and used in conjunction with time-of-flight mass spectrometry. This tandem source was designed to be simple and compact The GD and the MIP unit are independent and demountable, providing flexibility in tuning and operating. The microwave plasma can be formed with very low power (a few watts) and overlapped with the glow discharge. The discharge current increased with the addition of microwave discharge when the GD was operated in constant-voltage mode, and the amplitude of the current increase was found to be related to microwave power, discharge pressure, and sampling distance. With the addition of microwave discharge, significant signal enhancement was achieved under a discharge pressure of 2.0 Torr and a discharge voltage of 500 V with 2.0-mm sampling distance. Enhanced factors of analyte signals ranging from approximately 1 to nearly 10 could be obtained with MIP boosting, while no significant change in noise level was observed. This new tandem source provides improved performance in direct solid sample analysis.

Journal Article↗