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Biomedical subjects

Z Xu

Publications and source records attributed to Z Xu.

At least 595 records · Page 33Linked to original sources
PubMed1990

[Detection of a circulating SJ 70 antigen in human schistosomiasis japonica using a monoclonal antibody].

A double antibody enzyme-linked immunosorbent assay (sandwich ELISA) was used for detection of a circulating antigen from human Schistosoma japonicum infections. This assay involves the use of poly clonal rabbit anti-schistosoma japonicum soluble egg antigen (SEA) antiserum to bind circulating antigen and a monoclonal antibody (MCAb-H4) to identify and quantify this antigen. Sera from 108 S. japonicum infected patients (acute and chronic) were tested. Sera from 93 of 95 (98%) patients with chronic infection were positive for this antigen; sera from 12 of 13 patients (93%) with acute infections were also positive. Antigen was not detectable in control human sera. Sera from 35 chronic schistosomiasis patients were collected between 6 and 12 months after paraziquantel treatment. Circulating antigen was not detectable in the sera from 33 of these patients (94%) and was dramatically reduced in the other two patients.

Adolescent↗
PubMed1990

[Changes in bile components during the formation and prevention of black pigment gallstone in a guinea pig model].

Black pigment gallstones were found in 22 out of 23 guinea pigs one week after the common bile ducts were partially ligated (S group). The incidence decreased to 11/20 (P less than 0.01) if the animals were fed with a chow containing bile salt mixture, glucurolactone, ane aspirin (S+M group). Three weeks after the ligation the incidence of gallstone in S group and S+M group was 17/18, and 9/10, respectively (P greater than 0.05). Glucuronidase (beta-G) activity in the bile of S group was not higher than that of control group (C group, P greater than 0.05), and all the bile samples were sterile. The biliary concentrations of ionized calcium (ICa), unconjugated bilirubin (UCB), total calcium (TCa), total bilirubin (TBr), glycoprotein (GIy. P), and PH significantly fluctuated among guinea pig groups and were parallel to gallstone incidence. The results of this study could hardly be explained by Maki beta-G theory, but were consistent with the assumption that the precipitation-dissolution equilibrium of calcium bilirubinate is the key of pigment gallstone formation, thus the increases of the above mentioned bile components, including beta-G activity, would bias this equilibrium towards calcium bilirubinate precipitation and therefore promote gallstone formation. On the contrary, stone formation would be prevented.

Animals↗
PubMed1990

[The influence of endolymphatic sac surgery on cochlear function and structure in guinea pigs].

Experimental endolymphatic sac surgery was performed in 35 guinea pigs to evaluate the changes in cochlear function and structure caused by surgical manipulations which included incising the sac, aspirating the endolymph and probing the vestibular aqueduct. The experimental data showed that the changes in the cochlear potential, the auditory reaction threshold and the cochlear morphology in some guinea pigs were induced by these manipulations, especially aspirating the endolymph or probing the vestibular aqueduct. The possible mechanisms of the cochlear impairment may be damage caused by positive or negative pressure, the change in endolymphatic environment and the secondary inner ear hydrops. The experimental findings indicate that the cochlear function and structure can be affected by surgical manipulations, especially aspirating the endolymph or probing the vestibular aqueduct. Therefore, these manipulations should be avoided during the surgical procedure.

Animals↗
PubMed1990

[Changes in responses of parafascicular nuclei during adjuvant-induced acute arthritis and effect of acupuncture in the rat].

We have previously demonstrated that during acute arthritis in the rats induced by local intraplanter adjuvant, there are dramatic alterations in the behavioral responses to noxious stimulation. The purpose of this study was to observe the changes in responses of parafascicular nuclei (Pf) neurons during acute arthritis and effect of acupuncture (EA) in the rats. It was shown that: (1). for the whole populations of somatosensory neurons there was no statistical significant between arthritic rat and normal rat (P greater than 0.05). However, nociceptive neurons activated exclusively by noxious stimulation were less in the arthritic rat (21/60) than in the normal rat (35/46) (P less than 0.01); nociceptive-non-nociceptive neurons activated by both noxious and non-noxious stimulation were more in the arthritic rat (30/60) than in the normal rat (9/46) (P less than 0.01), and there was no statistical significant different for population of non-nociceptive neurons between two groups. (2). Nociceptive responses of Pf neurons (n = 16) could be markedly inhibited by EA at Xuanzhong (G39) and Kunlun (B60) in acute arthritic rat. In particular, the inhibitory effect was of great significance (P less than 0.01) during 0-10 and 20-35 minutes following cessation of EA. These results suggest that rats were hyperalgesic during adjuvant-induced acute arthritis and EA produces a fine analgesic effect in acute arthritic rats. The results also support the view that adjuvant-induced acute arthritic rat can be considered as a model for research of pain and analgesia.

Animals↗
PubMed1990

[Reduction of effects of stimulating SmI and electroacupuncture produced by intraperitoneal injecting atropine in the adjuvant-induced acute arthritic rat].

Using the adjuvant-induced acute arthritic rat as a pain model, we have previously shown that the SmI area is implicated in the inhibitory effect of acupuncture on the afferent nociceptive information of parafascicular nuclei (Pf). The purpose of this study was to determine whether acetylcholine (ACh) participates in this modulatory process. Experiments were conducted with adjuvant-induced acute arthritic rats and extracellular recordings from pf were obtained through microelectrodes stereotaxically. The results showed that: (1) After intraperitoneal-injecting atropine (5mg/kg), the effect of stimulating SmI on nociceptive responses of Pf neurons was decreased, while it was not decreased if saline was administered. Compared in the same neurons, the difference of nociceptive responses at 0' to 15' after cessation of stimulating SmI was statistically significant. This finding indicated that ACh was involved in descending modulation of SmI. (2) The effect of acupuncture was decreased after intraperitoneal-injecting atropine (5mg/kg), while it was not decreased if saline was administered. The difference of nociceptive response was statistically significant at 0' to 10' and 20' to 40' after cessation of EA in comparison between the background of atropine and saline. It indicated that ACh was involved in acupuncture analgesia. These results suggest that ACh may be participated in acupuncture analgesia as a neurotransmitter of the corticofugal modulation of pain.

Acupuncture Analgesia↗
PubMed1990

Effect of ouabain on the rabbit ear artery contraction to serotonin: enhanced response mediated by serotonergic rather than alpha adrenergic receptors.

The effect of ouabain on the rabbit ear artery response to serotonin was assessed in isolated vascular rings mounted in tissue baths for the measurement of isometric contractions and denervated with 6-hydroxydopamine in vitro. Ouabain, 1 and 10 microM, caused 5- and 6-fold shifts to the left of the serotonin concentration-response curve (CRC). However, 10 microM ouabain caused only a 1.6-fold shift to the left of the norepinephrine CRC. In the absence of ouabain, 0.01 microM ketanserin had little effect, whereas 0.1 microM prazosin caused a marked shift to the right of the serotonin CRC. In the presence of ouabain, prazosin exhibited little or no antagonism below 3 microM serotonin. Antagonism by ketanserin was increased by 1 and 10 microM ouabain, yielding 6.5- and 10.5-fold shifts to the right of the serotonin CRC, respectively. Benextramine pretreatment to inactivate alpha adrenoceptors nearly abolished the rabbit ear artery response to serotonin. However, in the presence of 10 microM ouabain, there was a substantial recovery of the response to serotonin, and this response was antagonized by ketanserin. These results are consistent with our hypothesis that serotonergic receptors are present in the smooth muscle cell membranes of the rabbit ear artery but are either uncoupled to the contractile mechanism or in a low efficacy state. In the presence of ouabain, these receptors either become coupled or convert to a high efficacy state and thereby contribute to the serotonin-induced contraction. Because the serotonin CRC was shifted to the left in the presence of ouabain, it is likely that most of the CRC was below the threshold concentration at which serotonin activates alpha adrenoceptors. Thus antagonism by prazosin was lost.

Animals↗
PubMed1990

[Effects of processing methods on the amounts of volatile oil of nutmeg and on isolation and characterization of the volatile oil constituents].

In this paper, the authors investigated the effects of various processing methods, i.e., scalding in hot purified talc, simmering wrapped in flour in hot purified talc and stir-frying in smoking wheat bran, on nutmeg (Semen Myristicae) in terms of the quantities of the volatile oil. The experimental results revealed that the amounts of volatile oil contained in nutmeg vary remarkably with the lengths of cooking time and the fluctuation of temperature. Detected by GC-MS-computer, 32 compounds of nutmeg were characterized, and their contents were determined by GC respectively.

Allylbenzene Derivatives↗
PubMed1990

Characterization of uterine cytosol and nuclear sex steroid receptors in aging female ICR mice.

Changes in uterine wet weight and estrogen receptor levels were studied in aging female ovariectomized ICR mice. A marked increase in uterine wet weight was observed in 18-month-old mice after injection of estradiol-17 beta (E2), from 67.6 +/- 3.1 mg (control, no injection) to 98.2 +/- 14.8 mg (1 h after injection of 1.0 microgram E2) and to 125.2 +/- 15.8 mg (4 h after injection of 1.0 microgram E2). The response to E2 in old mice was greater than that in young. This observation suggests that the uteri of old mice are still sensitive to gonadal steroids up to the post-reproductive age of 18 months. A 2.7-fold age-related increase in uterine estrogen receptor content was also noted in aging ovariectomized female mice, from 0.38 pmol/uterus in young mice to 1.01 pmol/uterus in old mice (1 h after injection of E2). Both cytoplasmic estrogen receptor content and receptor concentration (expressed as estrogen binding sites/cell) increased with advancing age. In contrast, no age-related change in the dissociation constant of estrogen receptors was detected (Kd = 1.0 +/- 0.5 x 10(-9) mol/L). The progesterone receptor content also increased with advancing age. This study demonstrates a marked increase of uterine estrogen receptor content in aging mice, suggesting that the uterus is not responsible for the increased incidence of pregnancy failure in old mice.

Aging↗
PubMed1989

Mobilization of lead by esters of meso-2,3-dimercaptosuccinic acid.

An examination was made of the relative efficacies of 2,3-dimercapto-1-propanol (BAL) and three diesters ( [CH(SH)COOR]2; DMDMS, R = CH3; DEDMS, R = C2H5; and Di-PDMS, R = CH(CH3)2] of meso-2,3-dimercaptosuccinic acid (DMSA) in mobilizing freshly injected lead from mice. These diesters, like BAL, reduced the lead levels resulting from freshly injected lead in both the soft tissues (liver, kidneys, spleen, and brain) and the bone (tibia). After treatment with the dimethyl (DMDMS), the diethyl (DEDMS), and the diisopropyl (Di-PDMS) esters the lead content of each of the organs was significantly less than that present in the untreated controls. Each of the diesters reduced lead levels in the kidneys, liver, and spleen significantly below those levels found after BAL treatment. The action of the diesters in reducing brain lead levels was comparable to that of BAL. Di-PDMS was the most effective of these compounds and was significantly superior to BAL. Each of the esters was also significantly more effective than BAL in reducing the whole body level of lead.

Animals↗
PubMed1989

The effect of transposition of pedicled omentum to spinal cord ischemia segments. An animal experiment.

This animal experiment was in succession to the research on paraplegia caused by spinal cord local ischemia in an animal model. Immediately after the operative production of local spinal cord ischemia, pedicled omentum spinal transposition onto the ischemic segments of spinal cord was performed. The animals recovered from paraplegia around two months afterwards. Spinal cord specimens showed adhesion of omentum to the spinal cord without compression. Omental vessels grew into the cord. Gross sections of specimen stained with Nissl method revealed that normal structure of nerve cells were preserved but number of nerve cell decreased.

Animals↗
PubMed1989

Paraplegia caused by local spinal cord ischemia. An animal spinal cord ischemia model.

Local spinal cord ischemia model was established in 11 adult dogs. The anterior spinal artery, posterior spinal artery and radicular artery were cauterized with bipolar cautery. Ischemia of this segment of spinal cord was thus produced followed by paraplegia. The pathological findings of this spinal cord segment were softening and necrosis. The establishment of this animal model of segmental spinal cord ischemia is beneficial to scientific research in basic medicine and clinical practice.

Animals↗
PubMed1989

A study of molecular epidemiology of adenovirus of types 3 and 7 on infant pneumonia in northern China.

This paper analysed 102 strains of adenovirus types 3(Ad3) and 7(Ad7) causing infant pneumonia from 1976 to 1988 in northern China. Two genotypes of Ad7, 7b and 7d, were identified by using restriction endonucleases, BamHI, BcLI, BgLI, SmaI, XbaI and HindIII. 3 genotypes of Ad3, 3I, 3II and 3III, were identified by using BgLII and BamHI. Of 56 Ad7 strains, 34 were 7b (76.8%) spread over last 10 years; 13 7d(23.2%) occurred from 1982, together with 7b. Of 46 Ad3 strains, 42 3I(91.3%) spread over the past 12 years. 3II and 3III scattered all over these years. Ad3I and Ad7b were the dominant genotypes. The results indicated that Ad7d tended to increase with time from 1982. It is possible that Ad7d will become dominant genotype and replace Ad7b.

Adenoviridae Infections↗
PubMed1989

Evidence for allosteric blockade of serotonergic receptors in rabbit thoracic aorta.

2-Brom-d-lysergic acid diethylamide (BOL) appeared to behave as either a reversible competitive or noncompetitive antagonist of vascular serotonergic (5-HT2) receptors depending on experimental conditions. This was explored using rabbit thoracic aorta rings mounted in tissue baths for the measurement of isometric contraction. BOL caused concentration-dependent parallel rightward shifts of the 5-HT dose-response curve in untreated aortas but, in addition, caused a marked reduction of maximal response in aortas pretreated with benextramine to inactivate alpha adrenoceptors. Ketanserin behaved as a reversible competitive antagonist in both untreated and benextramine-pretreated aortas. The respective ketanserin pA2 values were 9.08 +/- 0.09 (S.E.M.) and 9.01 +/- 0.04. Ketanserin, 1 x 10(-7) M, reversed completely the reduction of maximal response caused by 1 x 10(-9) M BOL and partially reversed those caused by 1 x 10(-8) and 1 x 10(-7) M BOL. Furthermore, the 5-HT dose-response curve in the presence of 1 x 10(-7) M ketanserin and that in the presence of 1 x 10(-7) M ketanserin plus 1 x 10(-9) M BOL were superimposed. These results are consistent with the conclusion that BOL is a noncompetitive 5-HT2 receptor antagonist. We propose that BOL acts at an allosteric site to convert the 5-HT2 receptor to a low activity state, thus, reducing the maximal response. BOL does not act at the 5-HT2 receptor itself. Ketanserin competes with 5-HT at the 5-HT2 receptor and with BOL at the allosteric site.(ABSTRACT TRUNCATED AT 250 WORDS)

Allosteric Regulation↗