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Biomedical subjects

J Zhu

Publications and source records attributed to J Zhu.

At least 361 records · Page 20Linked to original sources
PubMed1999

Electrical physiological evidence for highand low-affinity vagal CCK-A receptors.

We have demonstrated that under physiological conditions CCK acts through vagal high-affinity CCK-A receptors to mediate pancreatic secretion. In this study, we evaluated the vagal afferent response to endogenous CCK in rats and defined the CCK-receptor affinity states and the vagal-receptive field responsive to CCK stimulation using electrophysiological studies. Experiments were performed on anesthetized rats prepared with bile-pancreatic fistula. Plasma CCK levels were elevated by diverting bile-pancreatic juice (BPJ). The single-unit discharge of sensory neurons supplying the gastrointestinal tract was recorded from the nodose ganglia. All units studied were either silent or they had a very low resting discharge frequency. Thirty-two single units were studied extensively; seven were shown to be stimulated by diversion of BPJ (2.6 +/- 2 impulses/min at basal to 40 +/- 12 impulses/min after diversion). Acute subdiaphragmatic vagotomy or perivagal capsaicin treatment abolished the response. The CCK-A-receptor antagonist CR-1409, but not the CCK-B antagonist L-365260, blocked the vagal response to endogenous CCK stimulation. Infusion of the low-affinity CCK-receptor antagonist CCK-JMV-180 completely blocked the vagal afferent response to the diversion of BPJ in three of seven rats tested but had no effect on the response in the remaining four. In a separate study, we demonstrated that gastric, celiac, or hepatic branch vagotomy abolished the response in different subgroups of neurons. In conclusion, under physiological conditions, CCK acts on both high- and low-affinity CCK-A receptors present on distinct vagal afferent fibers. The vagal CCK-receptor field includes the regions innervated by the gastric, celiac, and hepatic vagal branches. This study provides electrophysiological evidence that vagal CCK receptors are present on the vagal gastric, celiac, and hepatic branches and may occur in high- and low-affinity states.

Afferent Pathways↗
PubMed1999

Neuroprotective effects of gelsolin during murine stroke.

Increased Ca2+ influx through activated N-methyl-D-aspartate (NMDA) receptors and voltage-dependent Ca2+ channels (VDCC) is a major determinant of cell injury following brain ischemia. The activity of these channels is modulated by dynamic changes in the actin cytoskeleton, which may occur, in part, through the actions of the actin filament-severing protein gelsolin. We show that gelsolin-null neurons have enhanced cell death and rapid, sustained elevation of Ca2+ levels following glucose/oxygen deprivation, as well as augmented cytosolic Ca2+ levels in nerve terminals following depolarization in vitro. Moreover, major increases in infarct size are seen in gelsolin-null mice after reversible middle cerebral artery occlusion, compared with controls. In addition, treatment with cytochalasin D, a fungal toxin that depolymerizes actin filaments, reduced the infarct size of both gelsolin-null and control mice to the same final volume. Hence, enhancement or mimicry of gelsolin activity may be neuroprotective during stroke.

Animals↗
PubMed1999

Cytokine-induced airway epithelial ICAM-1 upregulation: quantification by high-resolution scanning and transmission electron microscopy.

The aim of this study was to investigate the variation of intercellular adhesion molecule (ICAM)-1 which occurs between individual airway epithelial cells of distinct phenotype. 16HBE14o- (16HBE) and BEAS-2B cell lines and human airway explants were cultured with medium alone or a mixture of tumour necrosis factor (TNF)-alpha (10 ng x mL(-1)) and interferon (IFN)-gamma (40 ng x mL(-1)) before being immunogold-labelled and examined quantitatively using sensitive high-resolution electron microscopic techniques. By enzyme-linked immunosorbent assay there was a 1.6-fold increase of ICAM-1 in the BEAS-2B cells following the cytokine mix which was not apparent in the 16HBE cells. However, high-resolution scanning electron microscopy demonstrated that an upregulation had occurred; median and ranges for gold particle number per 10 microm2 cell surface were: 7.9 (0-40) for nonstimulated and 19.1 (0-60 for stimulated) (p<0.01, Mann-Whitney U-test). The value for the nonstimulated BEAS-2B cells was 24.2 (0-60), 3-times higher that the constitutive expression in the 16HBE cells (p<0.01), whereas following stimulation, it was 68.5 (20-130) (p<0.01). Values for explant epithelial outgrowths were similar to the 16HBE cells. Immunohistochemistry of the explanted mucosa showed both constitutive and upregulated expression of epithelial ICAM-1 associated with basal and indeterminate cells rather than with ciliated or goblet cells. These results using high-resolution techniques indicate that there is marked cell-to-cell variation in cellular adhesion molecule expression and that it is the basal cells and less well differentiated (indeterminate) epithelial cells which are likely to play key roles in leukocyte retention via intercellular adhesion molecule-1.

Bronchi↗
PubMed1999

Effects of diagnostic levels of color Doppler ultrasound energy on the cell cycle of newborn rats.

Our objective was to evaluate the safety of diagnostic levels of color Doppler ultrasound energy in the field of obstetrics and to provide the experimental data for its clinical application. After insonating pregnant rats with diagnostic levels of color Doppler ultrasound energy, we studied the cell cycles of the newborn rats by flow cytometry and factorial analysis. We found that the deoxyribonucleic acid content was not affected in any phase of the cell cycle in newborn rats by any of the different insonation times and frequencies.

Animals↗
PubMed1999

[A preliminary study of human Y chromosome specific short tandem repeat loci].

OBJECTIVE: To understand the allele structure and reveal genetic polymorphism of Y chromosome specific short tandem repeat (Y-specific STR) loci in Chinese Han population. METHODS: The authors used a set of five Y-specific STR loci which were tetrameric tandem repeat loci chosen from the Genome Database. EDTA-blood specimens were collected from the unrelated individuals. DNA was extracted by Chelex method and amplified by the polymerase chain reaction (PCR). The PCR products were analyzed using both the PAGE horizontal electrophoresis with discontinuous buffer system and the automated fluorescence detection approach. RESULTS: The authors observed that the alleles at the five Y-specific STR loci were composed of some complex repeat structures. They successfully prepared a set of human allele ladders for the typing of the five Y-specific STRs and demonstrated the polymorphisms at the five Y-specific STR loci in Chinese Han population. CONCLUSION: Y-specific STRs are good genetic markers for the purpose of analysis of genetic relationship between populations. This preliminary study not only reveals allele frequencies and haplotype distribution of Y-specific STR in Chinese Han population, but also indicates a reference population for detecting male migration events and for reconstructing paternal history.

Chromosome Mapping↗
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

Database search based on Bayesian alignment.

The size of protein sequence database is getting larger each day. One common challenge is to predict protein structures or functions of the sequences in databases. It is easy when a sequence shares direct similarity to a well-characterized protein. If there is no direct similarity, we have to rely on a third sequence or a model as intermediate to link two proteins together. We developed a new model based method, called Bayesian search, as a means to connect two distantly related proteins. We compared this Bayesian search model with pairwise and multiple sequence comparison methods on structural databases using structural similarity as the criteria for relationship. The results show that the Bayesian search can link more distantly related sequence pairs than other methods, collectively and consistently over large protein families. If each query made one error on average against SCOP database PDB40D-B, Bayesian search found 36.5% of related pairs, PSI-Blast found 32.6%, and Smith-Waterman method found 25%. Examples are presented to show that the alignments predicted by the Bayesian search agree well with structural alignments. Also false positives found by Bayesian search at low cutoff values are analyzed.

Algorithms↗
PubMed1999

[The effects of IL-1 on synthesis of collagen in scar-derived fibroblasts].

OBJECTIVE: To investigate modulation of cytokines on biological activities of scar-derived fibroblasts. METHODS: This study focused on the effects of interleukin-1 (IL-1) on collagen biosynthesis, nucleic acid, and cell organs of fibroblasts. RESULTS: The results showed the IL-1 could reduce not only the collagen synthesis of fibroblasts, but also quantity of nucleic acid. CONCLUSION: The authors confirm that IL-1 is a cytokine with down-regulation effect on scar formation, and suggest that IL-1 can play an important role in prevention and treatment of scar.

Adolescent↗
PubMed1999

Quality of life of patients with mild hypertension treated with captopril: a randomized double-blind placebo-controlled clinical trial.

OBJECTIVE: To determine the quality of life (QOL) of mild hypertensive patients treated with captopril as compared to placebo. METHODS: This is a randomized, double-blind, placebo-controlled clinical trial held in the out-patient clinic of Zhong Shan Hospital. Adult patients aged from 28 to 75 years with mild hypertension defined as diastolic blood pressure from 90 to 105 mm Hg were the inclusion criteria of the study. There were 278 patients who were eligible to enter the study. They were randomized to receive captopril or placebo 25 to 50 mg bid for 12 weeks. Change of QOL was compared both quantitatively and qualitatively between captopril and placebo groups. Change of blood pressure and side effects were also compared. RESULTS: With intention-to-treat analysis, significantly more improved QOL patients could be found qualitatively in patients with captopril treatment (45.3% vs 23.7%, P = 0.0002 for physical health domain; 48.9% vs 26.6%, P = 0.0002 for mental health domain; 33.8% vs 11.5%, P = 0.0001 for general function domain). Quantitatively, the change of score of mental health, general function and total QOL of captopril (3.18 +/- 5.90; 1.65 +/- 4.43; 7.84 +/- 11.03) were significantly higher than those of placebo (1.32 +/- 5.13, P = 0.00004; 0.64 +/- 3.45, P = 0.0008; 4.19 +/- 10.33, P = 0.0025 respectively), and the change of score of physical health domain (3.01 +/- 5.26 vs 2.23 +/- 4.79, P = 0.044) was of borderline statistical significant difference. Blood pressure was significantly lowered by captopril than by placebo (P = 0.000). CONCLUSION: Compared with the placebo, captopril is not only effective in lowering blood pressure, as has been established, but also effective in improving QOL in mild hypertensives.

Adult↗
PubMed1999

Rapid expression of vascular endothelial growth factor in early acute myocardial ischemia in rats.

OBJECTIVE: To study the expression of vascular endothelial growth factor (VEGF) in different parts of heart during early acute myocardial ischemia. METHODS: The expression of VEGF in control and study group in rats was performed with the Strept Avidin-Biotin-Peroxidase Complex (SABC) method. RESULTS: A rapid expression of VEGF in ischemic areas was observed 1 hour after the ligation of rat left anterior descending (LAD) coronary artery, and in peri-ischemic and non-ischemic areas 3 hours after ischemia. The grade of expression of VEGF increased with the continuation of myocardial ischemia, the positive myocytes of SABC-VEGF staining mainly localized in peri-ischemic areas 5 hours after ischemia. No expression of VEGF in control group was found. CONCLUSION: The expression of VEGF may be up-regulated in rapid and continuous manner with characteristic spatial and temporal kinetic during early acute myocardial ischemia.

Animals↗
PubMed1999

[Buddhist influences on Sun Simiao's precious prescriptions for emergency].

Living in a period when the Buddhism was quite flourishing, Sun had a close contact with the monk Dao Xuan, the founder of Nanshan Sect Buddhism. Sun's Quian jin fang adopted all schools including Buddhism, evidenced by the following 3 aspects: 1) Direct Buddhist influence, mainly on medical morality; 2) Indian medicine coming together with Buddhism, including the theory of "four - element theory", the conception of all matters are medicines, pills of all disorders, recipes, and keep - fit art. Buddhism acts as a carrier here; 3) the achievements of treatment for beriberi by monks. However, Buddhist influence was far inferior to Taoism as far as Sun's work is concerned.

Buddhism↗
PubMed1999

[Effects of all-trans retinoic acid, arsenic trioxide and daunorubicin on tissue factor expression in NB4 cells].

OBJECTIVE: To investigate the effects of all-trans retinoic acid(ATRA), arsenic trioxide(As2O3) and daunorubicin(DNR) on tissue factor(TF) expression in acute promyelocytic leukemia (APL) cell line NB4 cells. METHODS: Procoagulant activity(PCA) of NB4 cells treated with 1 mumol/L ATRA, 1 mumol/L As2O3 or 0.2 microgram/ml DNR was detected using one-stage clotting assay, TF antigen by ELISA, and TF mRNA by RT-PCR. RESULTS: Both ATRA and As2O3 could down-regulate the TF antigen, its mRNA transcription and membrane PCA of NB4 cells with a time-dependent manner, while DNR was shown to increase these parameters. Moreover, by dideoxy sequencing of DNA fragment derived from PCR, it was found that there was a exon 5 deletion transcript of TF in APL cells. Its biological significance remained unknown. CONCLUSION: TF expression and PCA of APL cells may be down-regulated by ATRA and As2O3, therefore, As2O3 might also improve DIC-related hemorrhage of APL while inducing APL cells to apoptosis. The distinct regulation of TF and PCA on APL cells by As2O3 and DNR may at least partially contribute to their effects on APL coagulopathy through the influence on coagulant factors activation.

Antibiotics, Antineoplastic↗
PubMed1999

[Homozygous deletion and methylation of p16 and p15 gene in acute leukemia].

OBJECTIVE: To investigate the frequency of p16 and p15 gene inactivation in acute leukemia and to evaluate its clinical significance. METHODS: Fifty-six patients with newly diagnosed acute leukemia was studied. PCR technique was used to detect homozygous deletion of p16 and p15 gene, restriction enzyme-PCR technique was used to detect gene methylation, and TdT-mediated dUTP-digoxygenin end-labeling (TUNEL) technique was used to detect cell apoptosis. RESULTS: p16 and/or p15 gene inactivation was detected in 33 of the 56 patients, including 23/38 (60.5%) of the ALL patients (T-ALL 12/16, B-ALL 11/22) and 10/18 (55.5%) of the ANLL patients. For All patients, methylation was the major pathway of p16 and p15 gene inactivation. Patients with p16 and/or p15 gene inactivation had a delayed apoptosis, a poor response to chemotherapy, a lower remission rate and a shortened remission duration. CONCLUSION: The inactivation of p16 and p15 gene plays a key role in the pathogenesis of acute leukemia.

Apoptosis↗
PubMed1999

[Effects of relative imbalance between endothlin-1 and nitric oxide on pathogenesis of the ascaris-induced asthma in dogs].

OBJECTIVE: To investigate the effects of relative imbalance between endothlin-1 (ET-1) and nitric oxide (NO) on pathogenesis of the ascaris-induced asthma in dogs. METHODS: Allergy induced asthma in dogs was established by inhaling ascaris antigen via an ultrasonic neblizer. At first, effects of ET-1 on respiratory system resistance (Rrs) and compliance (Crs) were studied in asthmatic dogs. Then, the roles of ET-1 and NO in regulating airway hyperresponsiveness (BHR) of asthma were investigated. Finally, effects of ET-1 on airway smooth muscle proliferating were observed. RESULTS: After intravenous injection of ET-1, there was a significant maximal increase in Rrs with (14.33 +/- 0.53) mm Hg.L-1.s-1 in normal dogs and (30.75 +/- 3.38) mm Hg.L-1.s-1 (P < 0.05) in asthmatic dogs. Also, there was a significant maximal decrease in Crs with (24.9 +/- 1.2) L/mm Hg in normal dogs and (14.8 +/- 0.9) L/mm Hg (P < 0.05) in asthmatic dogs. The dose-dependent bronchoconstriction in dogs was induced by three different doses of ET-1 (0.25, 0.5, 1.0 microgram/kg). ET-1 dose-response curve was significantly shifted upward by L-NMMA (P < 0.05). This effect was inhibited by L-arg (P < 0.05). Histological studies showed that ET-1 can stimulate airway smooth muscle proliferating and thickening after one week of ET-1 (4.0 micrograms/kg) i.v. administration. CONCLUSIONS: ET-1 might be involved in BHR that may be associated with immediate asthma response (IAR) in asthmatic dogs. ET-1 may be important for airway remodeling. The relative imbalance between ET-1 and NO may contribute to pathogenesis of asthma.

Animals↗
PubMed1999

[The isolation and drug susceptibility of penicillin resistant Streptococcus pneumoniae in Guangzhou].

OBJECTIVE: To investigate the isolation rate and drug susceptibility of PRSP in Guangzhou and in vitro antimicrobial activities of 8 antimicrobial agents against PRSP. METHODS: MICs were tested by E-test. RESULTS: Of 102 strains of Streptococcus pneumoniae, 12 strains were low-level resistant against penicillin (isolation rate 11.8%) and the antimicrobial activites of 5 drugs (augmentin, cefaclor, ceftriaxone, cefuraxime, ofloxaxin) against them were within their MICs, augmentin and ceftriaxone being the most powerful. They were resistant to azithromicin, oxacillin and penicillin. CONCLUSIONS: The isolation rate of Penicillin resistant Streptococcus pneumoniae was not high in Guangzhou, but it may increase with the extensive use of antimicrobial agents, which deserves much attention.

Anti-Bacterial Agents↗
PubMed1999

[Clinical and experimental study on zhixie buye mixture in treating infantile diarrhea complicated with dehydration].

OBJECTIVE: To observe the therapeutic effect of Zhixie Buye mixture (ZXBYM) on infantile diarrhea patient with mild and middle degree of dehydration. METHODS: The controlled observation method was adopted in the clinical and experimental study. RESULTS: There was no significant difference in the treatment of dehydration between the ZXBYM group and ORS group (P > 0.05), while it was more effective for ZXBYM to eliminate the symptoms such as vomiting and abdominal distension (P < 0.01). In addition, it was confirmed that the ion concentration of sodium, potassium, chlorine, glucose and osmotic pressure in the mixture was similar to those in ORS. Animal experiment showed that it has the effect of rat intestine peristalsis suppression and water absorption promotion in colon for ZXBYM. And there was statistical difference in antidiarrhea effect between the mixture and ORS (P < 0.01). CONCLUSION: The ZXBYM is an effective mixture in the treatment of diarrhea with dehydration. It has a good prospect of development and application.

Animals↗
PubMed1999

[Cardiac syndrome X and insulin resistance].

OBJECTIVE: To determine whether there is insulin resistance in patients with syndrome X. METHODS: By using oral glucose tolerance test (OGTT), plasma glucose and insulin levels, and insulin sensitivity index (ISI) were measured in 11 patients with syndrome X and in 10 sex and age matched normal subjects as controls. RESULTS: The syndrome X group had a higher fasting insulin level and ISI than the control group (P < 0.05). After oral glucose, plasma insulin level and ISI in patients with syndrome X were significantly higher than the control group (P < 0.01). CONCLUSION: In patients with syndrome X there are hyperinsulinemia and insulin resistance.

Adult↗