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Biomedical subjects

J Tang

Publications and source records attributed to J Tang.

At least 253 records · Page 14Linked to original sources
PubMed1998

Effects of perindopril on vascular wall and left ventricular hypertrophy in rats with experimental hypertension.

The model of hypertensive rat was established by using the method of abdominal aortic constriction, 33 male SD rats were randomly divided into 4 groups: group A (sham-operated rats serving as controls), group B (hypertensive rats serving as controls), group C (hypertensive rats subjected to low-dose perindopril treatment, 0.1 mg.kg-1/d) and group D (hypertensive rats receiving high-dose perindopril treatment, 1.5 mg.kg-1/d). The drug was administered by gavage for 4 weeks. At the end of the treatment, mean arterious pressure (MAP) was measured via catheter in the carotid artery. The heart was taken and weighed to calculate the ratio of left ventricular weight to body weight (LVW/BW). The ratio of medial mean thickness to mean diameter of lumen of aorta and superior mesenteric artery was calculated by morphometry. Concentration of angiotensin II (A II) in plasma and in aortic wall were determined by radioimmunoassay (PA II, AA II). Our results showed that both high-dose and low-dose perindopril may prevent hypertrophy of left ventricle and hypertrophy of the tunica media of superior mesenteric artery. In addition, high-dose perindopril may significantly inhibit hypertrophy of aortic media. The above effects of perindopril may be explained by inhibition on tissue renin-angiotensin system of both vascular wall and heart, but is not related to circulating A II (PA II).

Angiotensin II↗
PubMed1998

Absolute volumetric coronary blood flow measurement with digital subtraction angiography.

The problems associated with visual interpretation of coronary arteriograms have been well-documented. There is a need for more physiologic means of assessing coronary artery stenosis during routine coronary arteriography. Volumetric coronary blood flow assessed as a function of time can be a valuable aid in the analysis of functional significance of arterial obstruction. A volumetric coronary blood flow measurement technique was investigated in a swine animal model using phase matched temporal subtraction images. The left anterior descending (LAD) coronary artery of swine animal models were instrumented with an ultrasound flow probe (US) and a vascular occluder producing stenosis. Contrast material injections (2-4 ml/sec for 3 sec) were made into the left coronary ostium during image acquisition. Phase-matched temporal subtraction (DSA) images were used to measure volumetric coronary blood flow in the LAD. In addition, a technique for automatic estimation of iodine calibration slope was also investigated. In 49 independent comparisons, the mean coronary blood flow (FPA) correlated extremely well with the mean US flow (FPA = 0.92US + 1.42 ml/min, r = 0.99, standard error of estimate (SEE) = 4.32 ml/min). Further more, the automatic iodine calibration technique was shown to be very accurate. In conclusion, accurate volumetric coronary blood flow measurements can be made before the onset of significant changes in coronary blood flow due to contrast injection.

Angiography, Digital Subtraction↗
PubMed1998

Optical fiber sensor for tetracycline antibiotics based on fluorescence quenching of covalently immobilized anthracene.

A new optical fiber sensor for tetracycline is fabricated with an anthracene-containing copolymer prepared from 9-anthrylmethyl methacrylate, methyl methacrylate and n-butyl acrylate (PAMB). The sensing relies on the fact that the fluorescence of the sensor membrane fabricated with PAMB can be strongly quenched by the tetracycline antibiotics extracted from the sample. The proposed sensor responds linearly in the measuring ranges 2.02 x 10(-7)-2.02 x 10(-4) mol l-1 tetracycline (TC), 2.00 x 10(-7)-2.03 x 10(-4) mol l-1 oxytetracycline (OTC) and 4.05 x 10(-7)-2.03 x 10(-4) mol l-1 doxycycline (DC) and has detection limits of 1.00 x 10(-7) mol l-1 for TC and OTC, and 2.00 x 10(-7) mol l-1 for DC. The leaching of anthracene from the sensor membrane was hindered by covalent immobilization, resulting in a drastically enhanced sensor lifetime. Moreover, the sensor can rapidly respond to the antibiotics of interest (ca. 30s) and exhibits good reproducibility, reversibility, and selectivity in the presence of some common pharmaceutical species as well as alkali and alkali-earth metal salts. The sensor was used for the direct assay of tetracycline antibiotics in commercial pharmaceutical preparations and urine. The results are comparable to those obtained by conventional spectrophotometry. The recovery for tetracycline antibiotics from urine samples is also satisfactory.

Anti-Bacterial Agents↗
PubMed1998

The effect of timing of ondansetron administration on its efficacy, cost-effectiveness, and cost-benefit as a prophylactic antiemetic in the ambulatory setting.

UNLABELLED: Although ondansetron (4 mg I.V.) is effective in the prevention and treatment of postoperative nausea and vomiting (PONV) after ambulatory surgery, the optimal timing of its administration, the cost-effectiveness, the cost-benefits, and the effect on the patient's quality of life after discharge have not been established. In this placebo-controlled, double-blind study, 164 healthy women undergoing outpatient gynecological laparoscopic procedures with a standardized anesthetic were randomized to receive placebo (Group A), ondansetron 2 mg at the start of and 2 mg after surgery (Group B), ondansetron 4 mg before induction (Group C), or ondansetron 4 mg after surgery (Group D). The effects of these regimens on the incidence, severity, and costs associated with PONV and discharge characteristics were determined, along with the patient's willingness to pay for antiemetics. Compared with ondansetron given before induction of anesthesia, the administration of ondansetron after surgery was associated with lower nausea scores, earlier intake of normal food, decreased incidence of frequent emesis (more than two episodes), and increased times until 25% of patients failed prophylactic antiemetic therapy (i.e., had an emetic episode or received rescue antiemetics for severe nausea) during the first 24 h postoperatively. This prophylactic regimen was also associated with the highest patient satisfaction and lowest cost-effectiveness ratios. Compared with the placebo group, ondansetron administered after surgery significantly reduced the incidence of PONV in the postanesthesia care unit and during the 24-h follow-up period and facilitated the recovery process by reducing the time to oral intake, ambulation, discharge readiness, resuming regular fluid intake and a normal diet. When ondansetron was given as a "split dose," its prophylactic antiemetic efficacy was not significantly different from that of the placebo group. In conclusion, the prophylactic administration of ondansetron after surgery, rather than before induction, may be associated with increased patient benefits. IMPLICATIONS: Ondansetron 4 mg I.V. administered immediately before the end of surgery was the most efficacious in preventing postoperative nausea and vomiting, facilitating both early and late recovery, and improving patient satisfaction after outpatient laparoscopy.

Adult↗
PubMed1998

The efficacy of RS-25259, a long-acting selective 5-HT3 receptor antagonist, for preventing postoperative nausea and vomiting after hysterectomy procedures.

UNLABELLED: We evaluated the safety and efficacy of RS-25259, a potent and long-acting selective 5-HT3 receptor antagonist, for the prevention of postoperative nausea and vomiting (PONV) in women undergoing hysterectomy procedures. In this randomized, double-blind, placebo controlled, dose-ranging study, 218 healthy, consenting women were assigned to one of the six treatment groups: placebo or RS-25259 0.1, 0.3, 1.0, 3.0, or 30 microg/kg. All patients underwent a standardized general anesthetic technique. The study medication was administered i.v. 20-30 min before the end of surgery. During the initial 24-h period after surgery, the incidence of vomiting, the need for rescue antiemetics, the time to the first episode of emesis, and administration of rescue antiemetic medication, as well as a nausea visual analog scale and verbal categorical scale scores were recorded. In addition, recovery times from the end of anesthesia and the incidences of perioperative side effects were noted. Only 30 microg/kg RS-25259 significantly decreased the incidence of vomiting and the requirement for rescue antiemetics. The largest dose of RS-25259 also delayed the time to the first emetic episode and reduced the number of treatment failures. However, no differences were found in the severity of postoperative nausea (versus saline), and postoperative headaches were more common after the administration of RS-25259 0.3-30 microg/kg i.v. In conclusion, RS-25259 30 microg/kg i.v. was effective in reducing the incidence of PONV after major gynecologic surgery, but the occurrence of headaches with the larger doses of RS-25259 is a concern. IMPLICATIONS: RS-25259, a long-acting 5-HT3 antagonist, was effective in reducing postoperative vomiting only at the largest dose studied (30 microg/kg). However, RS-25259 had no antinausea activity, and the larger doses were associated with an increased incidence of headaches in the postoperative period.

Adult↗
PubMed1998

New TAP2 polymorphisms in Africans.

Polymorphisms in genes encoding transporters associated with antigen processing (TAP) have been associated with heterogeneity of disease progression in HIV-1-infected homosexual men. In our recent AIDS-related studies of cohorts from Rwanda and Zambia, four new polymorphic sites in the TAP2 coding region were detected by single-strand conformation polymorphism (SSCP) and confirmed by bi-directional nucleotide sequencing and restriction enzyme digestion. The first, a substitution of Thr (GCC) for Ala (ACC) at codon position 374 in exon 5, was found in about 13% of Rwandans and Zambians (n=213). The remaining 3 new polymorphisms were seen in the 7th exon with changes of 458Thr-ACG to ACA, 466Gly-GGG to GGA, and 467Val-GTT to Ile-ATT, respectively These 3 variants occurred exclusively on the same chromosome and appeared to have arisen together from the 374Thr-bearing allele. Analyses of the relationship between the 374Thr-467Ile segment and the nearby markers in DQB1 and DRB1 suggested the existence of a unique extended haplotype related to these newly identified variants.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

[Effects of exposure to noise in oil-drilling well sites on cochlea in guinea pigs].

OBJECTIVE: To prevent from hearing damage caused by noise in the sites with drilling wells. METHODS: Intensity and spectrum of the noise produced in the sites with drilling wells were measured and analyzed. Measures, such as sound insulation, vibration damping and changing layouts of the drilling platform, were adopted, and electrocochleography (ECochG) and scanning electron microscopy were used to observe the effects of noise in the sites where drilling wells located on the hearing organs in guinea pigs after exposure. RESULTS: There was no significant difference in APN1 latency of ECochG before and after exposure to noise. There were significant difference in hearing threshold values between the groups in a room with sound isolation, in moving status and beside the diesel engine, and no significant difference in those between the groups placed one meter horizontally and vertically away from the diesel engine on the drilling platform. Damage to hairy cell under scanning electron microscope was more severe in the guinea pigs placed beside the diesel engine and at the drilling well platform, with inclination and exfoliation of static pili of outer hairy cells, especially in the second and third lines, and part exfoliation of inner hairy cell. Hairy cells of the guinea pigs in a room with sound insulation and in moving status were basically normal. Inclination of hairy cells only could be seen in the third line. CONCLUSION: Animal experiments indicated that the measures mentioned above are effective and should be applied widely for preventing from hearing damage.

Animals↗
PubMed1998

[The second phase clinical observation of anti-radiation effect by superoxide dismutase].

Multiple center randomized controlled double blind clinical trait was conducted to evaluate the anti-radiotherapy effect by SOD (produced by Hunan Biochemical Work) in 159 patients. Injection of 4000U SOD immediately after receiving radiotherapy significantly reduced the occurrence rate of skin, oral mucosal, pelvic visceral and systematic adverse reaction, only the reduction of leukopenia did not reach the statistical significant level. No adverse effect of SOD injection was observed. The results suggest that SOD is a safe and effective agent to attenuate the radiotherapy reactions.

Adolescent↗
PubMed1998

[Gamma knife treatment of meningiomas].

From October 1995 to July 1997, 52 cases of meningioma were treated with gamma knife radiosurgery. Twenty-eight cases were followed up by CT or MR. The follow-up period was from 2 to 22 months. Follow-up imaging evaluation showed tumor size shrinkage in 8 cases, central density decrease in 10 cases, no change in 8 cases and tumor volume increase in 2 cases. The actual 1-year tumor growth control rate was 92%. Radiation-induced edema was noted in 9 cases, including 7 cases of the nonbasal tumor and 2 cases of basal one. The indications and efficacy of gamma knife treatment of the meningioma were discussed. Our preliminary experience suggests that gamma knife is an effective and safe technique for carefully selected patients with meningiomas.

Adult↗
PubMed1998

Immunohistochemistry and reverse transcription-polymerase chain reaction for detecting adrenomedullin in the central nervous system.

OBJECTIVE: To demonstrate the presence of adrenomedullin in the central nervous system. METHODS: Using immunohistochemical method (ABC) and reverse transcription-polymerase chain reaction (RT-PCR) analysis, the distribution of immunoreactive (IR-) AdM and AdM mRNA was observed in the rat and the human brain. RESULTS: Immunoreactive (IR-) AdM and AdM mRNA were detectable in almost every region of the rat brain examined, including cerebral cortex, paraventricular tissues, hypothalamus, mesencephalon, medulla oblongata and cerebellum. The levels of AdM mRNA in paraventricular tissues and medulla oblongata were higher than those in the other brain regions. AdM mRNA was also detectable in the human brain. CONCLUSION: The present study shows that AdM is present in the central nervous system, suggesting that AdM might act as a neurotransmitter, neuromodulator or neurohormone in rats or humans.

Adrenomedullin↗
PubMed1998

[Laryngotracheal trauma complex (report of 14 cases)].

During 8-year period 14 patients were treated for laryngotracheal trauma complex (8 of them with blunt injury and 6 with penetrating injury). The most common signs and symptoms were respiratory distress in 85.6%(12 patients), subcutaneous emphysema in 85.6% (12 patients) hoarseness or dysphonia in 64.3%(9 patients) and hemoptysis in 64.3% (9 patients). Tracheostomy was preferred for airway control and was required in 100% of the patients. Laryngotracheal plasty in 9 patients (6 patients within 6-48 hour after injury, 3 patients in 3-8 day after injury). Long-term airway quality was measured in 11 patients (for 2-4 year follow-up): A grade in 5 patients, B in 4 patients, and C in 2 patients.

Adolescent↗
PubMed1998

Glycophorin variants and contents of sialic acid and total sulfhydryl groups on erythrocyte membranes of residents in a malaria hyperendemic area.

OBJECTIVE: To conduct a screening survey of glycophorin (GP) variants and observe the content changes of sialic acid (SA) and total sulfhydryl (SH) groups on the erythrocyte membranes among residents in a tertian malaria hyperendemic area of Guizhou Province. METHODS: GP variants were detected in the erythrocyte hemolysates of 173 local residents at two villages of Libo County by SDS-PAGE on 10% to 15% gradients gel and Western immunoblotting. Their SA and total SH group contents were estimated in erythrocyte membranes by spectrophotometric methods. 114 healthy subjects in Changsha and 49 individuals at a neighbouring village of the above area showing low morbidity of malaria served as normal and endemic controls respectively. RESULTS: Three distinct types of GP variants were found among 19 propositi in this hyperendemic area. The incidence of GP variants was 7.9% (8/101) at Yaolu Village whose population was mainly composed of Yao ethnic group; while that of Buyi ethnic group at Maolan Village was higher (15.3%; 11/72). The erythrocyte membrane contents of SA in residents at both villages exhibited a very significant tendency of decline (P < 0.01), whereas those of total SH groups increased prominently in residents of Yaolu Village only (P < 0.05). CONCLUSIONS: The frequency of GP variants in this hyperendemic area does not depend upon the severity of malarial prevalence. The evident reduction of SA contents in the residents may be related to the breaking down of the SA residues on membrane GPs by the invasion of Plasmodium vivax.

Adolescent↗
PubMed1998

[Perilunate progressive instability of the wrist: a study of wrist dynamics].

OBJECTIVE: To study the changes in dynamics of wrist motor tendons after perilunate instability of the wrist. METHODS: 14 cadaver upper extremities were used. Excursions of the principle wrist and finger motor tendons were measured during wrist flexion-extension and radiolunar deviation was determined. Data were collected in the intact wrist, then in the wrist with stage I, II and III perilunate instability. The average moment arms of the tendons during wrist motion were calculated. RESULTS: The moment arms of the wrist flexors increased and those of the finger flexors decreased after instability. Increase in the moment arms dominated changes of radial side wrist motors, while decrease in the moment arms dominated ulnar wrist motors. Moment arms of the flexor carpi radialis tendon showed a consistent increase during wrist motion. CONCLUSION: The changes in wrist dynamics play an important role in clinical manifestations of perilunate instability. The significance of kinetic information on principle of treatment of the instability is discussed.

Biomechanical Phenomena↗
PubMed1998

[Determination of azathiopurine and 6-mercaptopurine in serum by reversed-phase high performance liquid chromatography].

A method for simultaneous determination of azathiopurine(AZP) and its metabolite 6-mercaptopurine (6-MP) concentration in serum has been developed. Reversed-phase high performance liquid chromatography with gradient elution and dual wavelength detection was employed. After protein precipitation with acetonitrile, the serum sample was evaporated to dryness with a gentle N2 stream at 37 degrees C and 100 microL of the mobile phase were added to dissolve the residue. After centrifugation, 20 microL of the supernatant was injected directly into the HPLC. The detection wavelength was set at 278 nm (AZP) and 325 nm (6-MP). The internal standard was metronidazole. The minimum detectable mass concentration for both AZP and 6-MP in serum was 5 mg/L. The average recoveries were (100.6 +/- 4.2)% for AZP and (102.4 +/- 4.5)% for 6-MP.

Azathioprine↗
PubMed1998

[Clinical treatment observation of tea pigment for oral submucous fibrosis].

39 patients with oral submucous fibrosis (OSF) were divided into control and experimental groups. The control group included 22 OSF patients who were treated by oral administration of VitAD, VitBco and VitE, and the experimental group included 17 OSF patients who were treated with vitamins and tea pigment after their examinations of hemorheology. The result showed that 7 of 12 patients in the experimental group with abnormal hemorheology had average 7.9 mm improvement on the open degree (58.3%), and the open degree of other five patients (5/17) whose hemorheology was normal only increased 2 mm (20%). The therapeutic results of the experimental group (58.3%) were significantly better than that of the control group (13.6%) (P < 0.005). The results of this study indicated that tea pigment may possibly become a better therapy for the OSF patients with abnormal hemorheology.

Adult↗