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Biomedical subjects

D Zhao

Publications and source records attributed to D Zhao.

At least 145 records · Page 8Linked to original sources
PubMed1996

Vascularized iliac periosteal transfer for the treatment of avascular necrosis of the femoral head and a new evaluation grading system.

OBJECTIVE: To introduce the surgical technique and a new evaluation grading system and to report the results of the vascular iliac periosteal grafting for avascular necrosis of the femoral head. PATIENTS AND METHODS: From 1983 to 1994, a new technique was used to treat 75 hips of 60 patients with avascular necrosis (AVN) of the femoral head using the vascular iliac periosteum with deep iliac circumflex artery and vein pedicle. 52 patients (66 hips) were followed up for 3-11 years and all patients were evaluated clinically and roentgenographically according to the new evaluation grading system for AVN by the Chinese Society for Osteonecrosis. RESULTS: Preoperatively, the average AVN score was 57 pts., and all patients had significant pain and limp. Five hips were at Ficat/Arlet stage IV, 40 were at stage III, and 21 were at stage II. Postoperatively, the average AVN score was 83 pts., 47 hips were pain free, 13 had mild pain, and 6 had moderate pain. At the latest follow-up, according to the new evaluation grading system, 26 hips were graded as excellent, 32 hips as good, 5 hips as fair, and 3 hips as poor. CONCLUSION: It is one of the better alternatives that can prevent the necrotic femoral head from progressing to collapse and promote revascularization and new bone formation by a direct mechanism, and it is suitable for the treatment of AVN of the stage I to III.

Adolescent↗
PubMed1996

The central distribution of adrenomedullin and its effects on blood pressure and heart rate in rats.

The present study was designed to make certain whether there exists adrenomedullin (ADM) in the rat central nervous system and evaluated the hemodynamic actions of intracerebroventricular administration (ICVA) of human ADM[13-52]. By immunohistochemistry (ABC method). We found that there was a discrete localization of ADM-positive immunoreactivity in the rat central system including cerebral cortex, paraventricular tissues, hypothalamus, cerebella cortex, mesencephalon and medulla oblongata. By reverse transcription-polymerase chain reaction (RT-PCR) analysis, rat ADM mRNA was found to be expressed in rat brain. These above results of immunohistochemistry and RT-PCR suggest that ADM exists in the rat brain. We also found that centrally administered ADM[13-52] in a dose of 0.4 to 3.2 nmol/kg provoked marked, prolonged and dose-dependent increases in mean arterial blood pressure (MABP) and heart rate (HR). To clarify the mechanisms of the hemodynamic changes induced by centrally administered ADM [13-52], the effect of centrally administered ADM[13-52] on renal sympathetic nerve activity (RSNA) was studied. The result showed that centrally administered ADM [13-52] (1.6 nmol/kg) provoked a marked increase in RSNA, therefore, the increases in MABP and HR induced by centrally administered ADM [13-52] might be due to the stimulation of central sympathetic mechanism. In addition, we also compared the relationship of activity and structure among the different fragments of ADM. In conclusion, ADM exists in the rat brain, and it may play an important role in the central control of cardiovascular system.

Adrenomedullin↗
PubMed1996

Changes of plasma endothelin concentrations before and after percutaneous balloon mitral valvuloplasty in patients with mitral stenosis.

Plasma concentrations of endothelin in blood from the femoral vein and the antecubital vein were measured in 35 patients with mitral stenosis and heart failure before and after percutaneous balloon mitral valvuloplasty (PBMV). The basal plasma concentrations of endothelin in blood from the antecubital vein in the patients were significantly higher than those in 32 control subjects (15.40 +/- 3.32 vs. 9.59 +/- 2.66 pg/ml, P < 0.001). Plasma endothelin concentrations in patients in New York Heart Association functional classes II and III were significantly higher than those in control subjects, respectively. The concentrations of endothelin in patients with atrial fibrillation were also significantly higher than those in patients with normal sinus rhythm. Ten to fifteen minutes after PBMV, plasma endothelin concentrations in blood from the femoral vein significantly decreased from 16.14 +/- 3.34 to 13.74 +/- 3.78 pg/ml (P < 0.01). Seventy-two hours after the procedure, the concentrations of endothelin in blood from the antecubital vein had fallen to 12.31 +/- 2.55 pg/ml (P < 0.001 vs. before PBMV and control subjects). Plasma endothelin concentrations still tended to be higher in patients with atrial fibrillation than those in normal sinus rhythm, but the difference did not reach statistical significance. There were weak but significantly correlations of plasma endothelin concentrations with the mean left atrial pressure (r = 0.424, P < 0.001), mean right atrial pressure (r = 0.323, P < 0.01), mean transmitral pressure gradient (r = 0.397, P < 0.001), heart rate (r = 0.350, P < 0.005) and mitral valve area (r = -0.454, P < 0.001) in the patients before and after PBMV.

Adolescent↗
PubMed1995

Glial potentials evoked by single afferent pulses in hippocampal CA1 area in vitro.

Single pulses were applied to the Schaffer collaterals (stratum radiatum) in the hippocampal slice in vitro, and intracellular recordings were made in putative glial cells in the CA1 cell layer. Putative glial cells showed a sustained depolarization following single pulse stimulation of stratum radiatum. The depolarization was larger with high stimulus intensity, and significantly linearly related to the size of the single population spike with a slope of 0.14 mV/mV. For slices with an average maximal single population spike of 11 mV, the average maximal glial depolarization was 2 mV. The range of maximal glial depolarization of 1-3 mV implies that the extracellular potassium concentration immediately outside of the neurons increased by 0.2-0.6 mM after a supramaximal single afferent shock.

Action Potentials↗
PubMed1995

Construction of a novel bovine papillomavirus vector without detectable transforming activity suitable for gene transfer.

Bovine papillomavirus type 1 (BPV-1)-derived vectors may be useful for gene therapy because of their episomal maintenance at intermediate to high copy number and stable, high-level expression of gene products. To increase the safety of BPV-1 for human trials, the transforming early genes E5, E6, and E7 were deleted and a new vector, B45-Neo, was established and its transforming potential, episomal maintenance, and cDNA expression determined. Deletion of E5, E6, and E7, caused a decrease of the copy number to 80 in 3T3 fibroblasts when B45-Neo was compared to the parent vector that supported more than 1,000 copies per cell. No significant difference in the copy number, which ranged between 13 and 30 per cell, was detected in other cell lines of murine or human origin. The episomal maintenance of B45 and its ability to express cDNA was retained. B45-Neo, in contrast to BMG-Neo, however, was unable to transform NIH-3T3 and C1271 cells in soft agar colony assays. Unlike BMG-Neo, B45-Neo did not cause morphological changes in 3T3 and C1271 cells characteristic for transformation. It is concluded that B45-Neo is an efficient expression vector without detectable transforming activity and may be useful and safe for human gene therapy trials.

3T3 Cells↗
PubMed1995

Vasodilator effect of human adrenomedullin(13-52) on hypertensive rats.

Human adrenomedullin (hADM) is a newly isolated peptide with hypotensive activity in normotensive rats. The objective of this study was to investigate the effect of hADM(13-52) on hypertensive animals. hADM(13-52) induced a dose-dependent decrease in the blood pressure of spontaneously hypertensive rats and renal hypertensive rats. This result suggests that hADM is a novel antihypertensive peptide. In isolated rat aortic arteries, hADM(13-52) produced nitric oxide dependent relaxation and inhibited endothelin 1 and angiotensin II release. These in vitro effects may represent the molecular mechanisms underlying the hypotensive action of hADM in vivo.

Adrenomedullin↗
PubMed1995

Effect of orthotopic transplantation of liver on systemic and splanchnic hemodynamics in conscious rat.

The long-term cardiovascular effects of orthotopic liver transplantation (OLT) were studied in conscious Lewis rats with a radioactive microsphere technique. Three months after OLT with an all-suture technique for graft revascularization (s-OLT), all hemodynamic parameters were similar to control. OLT with "cuffs" fitted to the portal vein and infrahepatic inferior vena cava (c-OLT) led to prominent hemodynamic disturbances including 1) hyperkinetic circulation with increased cardiac index (CI; 22%; P < 0.05) and decreased mean arterial pressure (15%; P < 0.05) and total peripheral resistance (TPR; 28%; P < 0.05); 2) a slight increase in portal pressure (11.8 +/- 0.9 vs. 9.3 +/- 1.7 mmHg in control) and marked portal-systemic shunting (51 +/- 11 vs. 0.05 +/- 0.04% in control; P < 0.05); 3) increased hepatic arterial blood flow (0.49 +/- 0.06 vs. 0.27 +/- 0.04 ml.min-1.g liver wt-1; P < 0.05); 4) splanchnic vasodilation with vascular resistance significantly (P < 0.05) lower in the liver, stomach, and large intestine; and 5) increased blood flow and decreased vascular resistance in the kidneys and heart. Ganglionic blockade with chlorisondamine (5 mg/kg body wt iv) indicated that the increase in CI seen in the c-OLT rats was probably sympathetically mediated, whereas the increase in renal blood flow was a reflection of the increase in CI. After ganglionic blocker administration, TPR and regional vascular resistances decreased to approximately the same extent in the control and c-OLT groups, indicating that vascular sympathetic tone was unchanged in the c-OLT rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[A study on hypotensive mechanism of adrenomedullin (13-52)].

In the present study the hypotensive mechanism of AdM (13-52) was investigated in rats, both in vitro and in vivo. It was found that the hypotensive effect of AdM (13-52) could be partially inhibited by L-NG-nitro-arginine (LNNA), an inhibitor of nitric oxide synthase. The vasodilator effect of AdM (13-52) was dependent on vascular endothelium and inhibited by LNNA in a dose-dependent manner. This LNNA induced inhibitory effect could be reversed with L-Arginine. In addition, the vasodilator effect of AdM (13-52) disappeared with methylene blue (MB), which blocked cGMP formation. Using radioimmunoassay it was shown that LNNA lowered, but AdM (13-52) elevated the vascular cGMP content, while vascular cGMP content was not altered by co-application of AdM (13-52) and LNNA. The above results suggest that the vasodilator effect of AdM (13-52) might be mediated by nitric oxide.

Adrenomedullin↗
PubMed1995

[Implementation of national tuberculosis control programme--focus on registration, case-management and treatment].

The results of three nationwide epidemiological surveys on tuberculosis showed the declination of the magnitude of tuberculosis from 1979 to 1990 was slower. The case registration rates and new case registration rates within ten years (1982-1991) were gradually increasing year by year and came to a climax in 1988. The fact indicated the improvement of case-finding and case registration. The case registration rate was going down thereafter coincided with the declination of the prevalence of tuberculosis. The proportion of registration rate to the prevalence was rather low. This is mainly attributed to the fact that the majority of detected patients were held by general medical clinics and had not been registered to the central registration of tuberculosis. Therefore, only 17.7% of detected tuberculosis cases were under proper case-management for treatment. The results of cohort analysis on smear-positive treated cases showed the rate of sputum negative conversion was gradually increasing and the case lost rate was going down. The case-management for treatment was improving year by year. The results of sociological study on tuberculosis indicated that the financial problem was the main factor inducing delay of treatment and intermission and interruption of treatment among treated patients.

China↗
PubMed1995

Regression of bile duct damage and bile duct proliferation in the non-rearterialized transplanted rat liver is associated with spontaneous graft rearterialization.

The aim of this study was to investigate the long-term consequences of non-rearterialization of the graft in rat liver transplantation. Liver transplantation with (AOLT) and without graft rearterialization (NOLT) was performed in anesthetized male Lewis rats. Quantitative morphometry and semiquantitative histopathology of the liver were performed at various times after operation. Volume fractions of tissue components were determined. The number of arteries and bile ducts per portal tract were measured in histological sections from both groups. Hepatic blood flow was measured using the radioactive microsphere technique in rats after NOLT (6 months). AOLT livers had a preserved lobular architecture at all time points and unaltered volume fractions. In addition, AOLT livers maintained approximately one artery and one bile duct per portal tract after transplantation. NOLT livers showed bile duct damage at 3 days, cellular infiltration and ductular proliferation at 1 week, increased ductular proliferation at 4 weeks, and fibrosis at 6 months. The volume fractions for nonhepatocyte parenchyma (3 days, 19.14 +/- 1.29; 1 week, 20.44 +/- 1.76; 4 weeks, 15.46 +/- 3.14), bile ducts/ductules (1 week, 4.88 +/- 1.07; 4 weeks, 7.20 +/- 2.42), and connective tissue (4 weeks, 4.02 +/- 1.66; 6 months, 14.94 +/- 0.63) were significantly increased. Hepatocyte volume fraction was significantly decreased at all time points. A total of 1.58 +/- 0.08 arteries/portal tract were found in NOLT livers after 4 weeks, rising to 2.44 +/- 0.10 arteries/portal tract after 6 months. At 6 months, hepatic arterial blood flow (0.69 mL/min/g) was significantly higher (P < .02) than control (0.25 mL/min/g).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[Preliminary study on the anti-tubercular effect of Ottelia alismoides (L.) Pers].

In clinical trials, the extract of Ottelia alismoides cured two cases of bilateral tuberculosis of cervical lymph gland within 3 months. The result of drug sensitive test showed that water extract of this herb could kill or inhibit human tubercular bacteria effectively, which suggests that Ottelia alismoides is a promising medicinal herb with anti-tubercular effect.

Antitubercular Agents↗
PubMed1995

Changes of plasma beta-endorphin levels before and after percutaneous transvenous mitral commissurotomy in patients with mitral stenosis.

To clarify the contribution of left atrial pressure to the secretion of beta-endorphin, we have investigated the relation between plasma beta-endorphin levels and hemodynamic changes in 35 patients with mitral stenosis undergoing percutaneous transvenous mitral commissurotomy (PTMC). Before PTMC, plasma beta-endorphin levels obtained from the antecubital vein (28.91 +/- 5.59 pg/ml) and from the femoral vein (28.20 +/- 5.44 pg/ml) in the patients with mitral stenosis were significantly higher than those obtained from the antecubital vein in the healthy volunteers (22.59 +/- 3.86 pg/ml, n = 34, P < 0.001 for each). The levels of beta-endorphin in the femoral vein correlated well with the mean left atrial pressure (r = 0.777, P < 0.001) and the mean right atrial pressure (r = 0.450, P < 0.01) before the procedure. The antecubital venous levels of beta-endorphin in patients in New York Heart Association functional Classes II (26.45 +/- 5.39 pg/ml, n = 20) and III (32.20 +/- 4.02 pg/ml, n = 15) were significantly higher than those in control subjects (P < 0.005 and P < 0.001, respectively). The differences between Classes II and III were significant (P < 0.001). The plasma levels of beta-endorphin in the patients complicated with atrial fibrillation were also significantly higher than those in patients with normal sinus rhythm (33.31 +/- 3.22 pg/ml, n = 13 vs 26.32 +/- 5.07 pg/ml, n = 22, P < 0.001). In ten to fifteen minutes after commissurotomy, plasma levels of beta-endorphin in the femoral vein significantly increased from 28.20 +/- 5.44 to 33.14 +/- 5.72 pg/ml (P < 0.001). In seventy-two hours after the procedure, plasma beta-endorphin levels in the antecubital vein fell to 24.37 +/- 2.59 pg/ml (P < 0.001 vs before PTMC and P < 0.05 vs control subjects). Plasma beta-endorphin levels in the patients with atrial fibrillation (26.62 +/- 2.36 pg/ml, P < 0.001 vs before PTMC and P < 0.002 vs control subjects) were still higher (P < 0.001) than those in patients with normal sinus rhythm (23.05 +/- 1.65 pg/ml, P < 0.001 vs before PTMC and P > 0.50 vs control subjects. There was a significant correlation between the levels of beta-endorphin in the antecubital vein and heart rate (r = 0.502, P < 0.001), mean transmitral pressure gradient (r = 0.543, P < 0.001) or mitral valve area (r = -0.710, P < 0.001) before and 72 hours after the procedure.

Adolescent↗
PubMed1995

Changes of plasma dynorphin levels before and after percutaneous balloon mitral commissurotomy in patients with mitral stenosis.

Plasma dynorphin A1-13 levels were measured in 33 patients with mitral stenosis before and after percutaneous balloon mitral commissurotomy (PBMC). The results show that the basal levels of plasma dynorphin in blood from the antecubital vein in the patients were significantly higher than those in 31 healthy control subjects. The increase in circulating dynorphin closely correlated with the functional cardiac status and the presence of atrial fibrillation. Ten to fifteen minutes after PBMC, plasma dynorphin levels in blood from the femoral vein increased significantly. Seventy-two hours after the procedure, the levels of plasma dynorphin in blood from the antecubital vein had decreased significantly, but they did not decrease to the normal range. Plasma dynorphin levels in blood from the femoral vein were positively correlated with the mean left atrial pressure and the mean right atrial pressure before the first balloon inflation. Plasma dynorphin levels in blood from the antecubital vein were positively correlated with the heart rate and the mean transmitral pressure gradient, and negatively with the mitral valve area before and 72 hours after PBMC.

Adolescent↗
PubMed1995

[Changes of NGF in injured spinal cord following treatment with a single large dose of methylprednisolone sodium succinate].

Nerve growth factor (NGF) was detected by ABC-ELISA in rat normal spinal cord, spinal cord with mild contusion of 25gcm, and that with mild contusion plus a single intramuscular injection of large dose of methylprednisolone sodium succinate (MPSS) (80 mg/kg). The mean preinjury NGF level in spinal cord was 10.2 +/- 2.8ng/g. Following injury, NGF level in spinal cord began to increase progressively. NGF level in spinal cord without treatment was attenuated to 30.32 +/- 0.32, 89.51 +/- 2.14, 66.02 +/- 1.51, 50.32 +/- 1.23 and 46.23 +/- 1.42ng/g at 4, 7, 14, 21 and 28 days respectively, while in cord spinal with MPSS treatment it was 121.98 +/- 4.05, 119.56 +/- 1.45, 80.39 +/- 1.50, 68.31 +/- 0.77 and 59.86 +/- 0.97 ng/g at 4, 7, 14, 21 and 28 days, respectively. This result suggests that a single large dose of MPSS enhances NGF level in injured spinal cord with a peak at day 4. The implication of this article is that the changes of NGF level in spinal cord are relevant to spinal cord self-recovery.

Animals↗