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Biomedical subjects

H Xue

Publications and source records attributed to H Xue.

At least 145 records · Page 8Linked to original sources
PubMed1987

Induction of contraction in isolated rat aorta by cyclosporine.

Cyclosporine (CsA) is a new immunosuppressive agent that has adverse effects of nephrotoxicity and de novo appearance of hypertension. It has been hypothesized that the mechanism of the contrary effects is through an action of CsA on vascular smooth muscle. To test this hypothesis, thoracic aortas were isolated from Wistar Kyoto rats and ring segments prepared for measurement of tension. CsA (5 X 10(-6) M) induced a slow increase in tone of the isolated rings with a response at 3 hr of 0.70 +/- 0.17 N/m2 X 10(4). This contraction was significantly inhibited by the Ca2+ channel blocker verapamil (0.30 +/- 0.08 N/m2 X 10(4) after 3 hr, P less than 0.05) and by the noncompetitive alpha-antagonist phenoxybenzamine (0.06 +/- 0.07 N/m2 X 10(4) after 3 hr, P less than 0.05). The competitive alpha-antagonist phentolamine had mixed effects. CsA does not irreversibly alter vascular smooth muscle contractile ability since a 3 hr exposure to the agent had no effect on either the maximal contractile response or sensitivity to KCl. We conclude that CsA can directly induce contraction in vascular smooth muscle, perhaps by inducing a release of norepinephrine from adrenergic nerve terminals. The data are consistent with the hypothesis that CsA induces nephrotoxicity and de novo hypertension through a contractile effect on vascular smooth muscle.

Animals↗
PubMed1985

The development of mechanical strength of surgically anastomosed arteries sutured with Dexon.

The strength of surgically anastomosed arteries of the rat sutured with Dexon thread is studied. The abdominal aortas and the carotid arteries were severed, sutured and then the wounds were closed and the animal healed. After a specific period of time up to 13 months, the vessels were taken out and tested in uniaxial loading condition. The stress-strain relationship of the vessels was measured, and then the vessels were pulled to failure. It was found that the strength of the anastomosis was the lowest in about 4 months. In the first day, the force at failure was about the same as that of the control. Then the strength decreased with time, until a minimum was reached in 4-6 months. The tensile force to failure was about 25% of the control for the carotid artery and 49% of the control for the abdominal aorta. The corresponding values of the tensile stress at failure were 17 and 11%, respectively. The different percentages of forces and stresses were caused by the thickening of the vessel wall in the neighborhood of the suture line in the healing process. After 4-6 months, the strength gained again. At 13 months, the strength of the anastomosis was about the same as that of the control. The stretch ratio at failure was approximately constant through all periods.

Animals↗
PubMed1985

On the detection of messages carried in arterial pulse waves.

The hypothesis is made that a disturbance in blood flow at one place can be detected in the arterial pulse waves at a distant site. This hypothesis was motivated by the traditional Chinese medicine which uses arterial pulse waves as a principal means of diagnosis. We formulated a test by asking whether a disturbance to the blood flow in a leg can be detected by changes in the pulse waves in the radial arteries. In particular, we ask whether the radial artery can differentiate a disturbance in the right leg from that in the left leg. We put force transducers on the radial arteries, depressed them by a specific amount, and recorded the force waves in response to a 2-min occlusion of the blood flow in the right or left tibial artery. The results show that the radial artery force waves do change in response to the flow disturbance. For a given individual, the force varies with the location of the force transducer on the radial artery, the specific amount of initial depression, and the right or left leg occlusion. Generally, an occlusion in the right leg reduces the force level in both radial arteries, the more so in the right radial artery than in the left. Although the discrimination is not very strong, the phenomenon is novel, and warrants further investigation.

Adult↗
PubMed1982

Diet and vitamin nutrition of the high esophageal cancer risk population in Linxian, China.

In order to examine the nutritional status of the population of Linxian (in Henan, China) known to be at high risk for esophageal cancer (EC), we analyzed blood samples and conducted 3-day dietary surveys on 3 groups of normal adults, age 40-50, from Henan province. Two groups were from Linxian, where the EC mortality rate is about 138/100,000 (Group C, consisting of volunteers with a family history of EC, and Group NC, consisting of those who did not have a family history of EC). The third group, Group F, was from Fanxian, where the EC mortality rate is about 24/100,000. The average plasma retinol level was found to be about 0.27 micrograms/ml in all 3 groups; about 13%-20% of the individuals had a level less than 0.2 micrograms/ml. The average plasma carotene level of all 3 groups appeared to be adequate, ranging from 0.5-1.0 micrograms/ml. About 23% of the subjects in both Groups C and NC had low (less than 2 micrograms/ml) plasma ascorbate levels; in Group F, 16% had low ascorbate levels. Less than 12% of the individuals in each of the 3 groups had erythrocyte glutathione reductase activation coefficients less than 1.2, indicating a widely occurring riboflavin deficiency. Consumption of alcoholic beverages was not found to be a contributing factor to EC. The results of the present study reveal a deficiency of vitamins in the study populations, but do not indicate that the average nutritional status of the volunteers in Group C was worse than that of Groups NC and F with regard to vitamin A, ascorbate, and riboflavin.

Adult↗
PubMed1982

Fractionation and quantitation of egg antigens from Schistosoma japonicum by the single-tube kinetic-dependent enzyme-linked immunosorbent assay (k-ELISA): higher antigenic activity in urea-soluble than in aqueous-soluble fractions.

To identify sources of high potency antigens for use in serodiagnosis, aqueous-soluble egg antigens from Schistosoma japonicum were extracted with Dulbecco's phosphate-buffered saline. Residual particulates were solubilized with Tris-buffered 8 M urea, yielding a urea-soluble egg antigen fraction. The urea-soluble fraction was further fractionated with Bio Gel A50m and QAE-Sephadex. All fractions were quantitatively assayed for their specific antigenic activities against serum specimens from infected rabbits by the single-tube enzyme-linked immunosorbent assay (k-ELISA). In antigen rate-limiting conditions, the urea-soluble particulate fractions were more antigenically active than the aqueous-soluble fraction. In antigen-excess and antibody-limiting assay conditions, the ideal conditions for serologic assays, the urea-derived antigens also showed superior activities against sera from infected humans. Analysis by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) on gradient gels revealed numerous low molecular weight protein bands in the aqueous-soluble fraction, whereas the urea-soluble fractions appeared to be much simpler with the majority of their proteins concentrated in one or two high molecular weight bands (greater than or equal to 200 kdaltons). Electro-transfer blots of the SDS-PAGE onto nitrocellulose papers and subsequent visualization of antigens by enzyme-linked immunoabsorbence confirmed these findings. The above data suggest that the urea-soluble fraction of S. japonicum eggs is antigenically active and has potential use in the development of a diagnostic reagent.

Animals↗
PubMedDate not supplied

The mediating role of cPLA2 in IL-1 beta and IL-6 release in LPS-induced HeLa cells.

Studies were conducted to characterize a HeLa cell model by which the roles of the 85-kDa phospholipase A2 (cPLA2) in interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6) release could be evaluated. At first, untreated HeLa cells were compared with lipopolysaccharide (LPS)-treated HeLa cells. The latter resulted in cPLA2 overexpression and an increased trend of IL-1 beta and IL-6 release. The indicated doses of 85-kDa cPLA2 antisense oligonucleotide directed against the initiation site were then used to block cPLA2 in LPS-induced HeLa cells. The process led to a dose-dependent decrease in cPLA2 protein with no noticeable change of cPLA2 mRNA. Compared with that of LPS added only, a reduction of IL-1 beta and IL-6 levels in the supernatants of transfected cells following the repression of cPLA2 was observed. These results suggested that 85-kDa cPLA2 may mediate the signalling cascades by which IL-1 beta and IL-6 were released in LPS-induced HeLa cells.

HeLa Cells↗
PubMedDate not supplied

Altered interleukin-6 expression in fibroblasts from hypertrophic burn scars.

Hypertrophic burn scars (HBSs) are characterized by a net accumulation of collagen. The role of growth factors and various cytokines in the pathogenesis of these lesions has not been fully characterized. Interleukin-6 (IL-6) is an important immunoregulatory cytokine that can affect fibroblast function. This study showed increased expression of the IL-6 gene in fibroblasts isolated from patients with HBSs compared with control fibroblasts when the ribonuclease protection assay was used. A subsequent increase in unstimulated and stimulated IL-6 secretion was noted in HBS fibroblasts compared with normal control fibroblasts (unstimulated, 0.3627+/-0.2017 pg/cell vs 0.0662+/-0.0786 pg/cell, P = .0054; serum, 0.770+/-0.523 pg/cell vs 0.233+/-0.231 pg/cell, P = .0381; serum and interferon-gamma, 0.912+/-0.650 pg/cell and 0.244+/-0.199 pg/cell, P = .0327). These results are further evidence of the role of inflammatory cytokines in the development of HBSs.

Burns↗