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Biomedical subjects

J Xu

Publications and source records attributed to J Xu.

At least 1,171 records · Page 65Linked to original sources
PubMed1993

[Expression of human multidrug resistance gene (mdr1) cDNA in murine ES cells and in chimeric mice].

Human multidrug resistance gene (mdr1) was introduced into mouse embryonic stem cells (ES-5 line) by calcium phosphate mediated transfection, and transfected ES-5 cells were then selected by stepwise increase in colchicine concentration (30, 50, 100, and 200 ng/ml respectively). Finally, we obtained 4 clones that could be stably grown in culture medium with colchicine at 200 ng/ml and designated as ES-mdr1 clones A, B, C, and D. Southern blot analysis of DNA from ES-mdr1 A and D cells digested by Hind III and hybridized with mdr1 cDNA 5 A probe was shown in Fig. 3. Characteristic 4.8 and 2.4 kb fragments of mdr1 gene were found as expected and their amplification under increased concentration of colchicine in culture medium was also evident from the figure. Slot blot and Northern analysis of total RNA and poly A+ RNA extracted from ES-mdr1 cells were shown in Fig. 4 and 5, demonstrating that ES-mdr1 cells could express mdr1 mRNA. Indirect immunofluorescence analysis with antibodies against p170 glycoprotein indicated that p170 protein translated from mdr1 mRNA was present at the surface of ES-mdr1 cells (Plate I, Fig. 2). The biological characteristics of ES-mdr1 cells cultured in medium containing 200 ng/ml colchicine were investigated. The cells maintained their undifferentiated morphology and grew in nests (Plate I, Fig. 1), like the parental ES-5 cells. When ES-mdr1 cells were cultured in suspension in vitro, these cells were still capable of producing simple and cystic embryoid bodies. ES-mdr1 cells injected subcutaneously into 129 mice formed tumor-like outgrowths giving a great variety of cell types (Plate I, Fig. 4). These results indicated that the integration and expression of human mdr1 gene and selection against colchicine did not affect the pluripotency of ES-mdr1 cells both in vitro and in vivo. However, ES-mdr1 cells, unlike their parental ES-5 cells, could no longer be induced to differentiate by either RA or HMBA (Plate I, Figs. 3a, 3b), indicating that the human mdr1 gene transfected ES cells had changed their competence of inducible response to differentiation in vitro. The details and possible significance of such change require further studies. From the above preliminary data, we are of the opinion that ES-mdr1 cells may serve as a model to study the mode of action of p170 glycoprotein at cellular level and to screen possible means to counteract the action of mdr1 gene.(ABSTRACT TRUNCATED AT 400 WORDS)

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

Percutaneous transseptal balloon valvuloplasty for dilating mitral valve stenosis (report of 200 cases).

Two hundred cases with mitral valve stenosis were treated by percutaneous single balloon (Inoue balloon) valvuloplasty at our institute from May 1988 to July 1992. The subjects included 137 females and 63 males with a mean age of 36.5 +/- 8.8 years (15-58 years). Hemodynamic and left ventriculographic findings were evaluated immediately before and after the procedure, and the results showed that the mean left atrial pressure was reduced from 25.08 +/- 9.13 mmHg to 10.64 +/- 4.10 mmHg (P < 0.001), the pressure gradient across the mitral valve was reduced from 25.49 +/- 10.22 mmHg to 6.71 +/- 4.87 mmHg (P < 0.001), and systolic pulmonary pressure was reduced from 52.78 +/- 21.42 mmHg to 38.56 +/- 16.47 mmHg (P < 0.001). At the same time, cardiac output and mitral orifice area were increased from 3.84 +/- 0.11 L/min to 4.66 +/- 0.28 L/min (P < 0.001) and from 1.08 +/- 0.28 cm2 to 2.20 +/- 0.47 cm2 (P < 0.001) respectively. Follow-up of 6-48 months (median 24 months) in 50 nonselective patients showed a symptomatic improvement rate of 100%. Percutaneous transseptal balloon mitral valvuloplasty (PBMV) proved to be a highly effective and safe nonsurgical method that can yield very good results in relieving symptomatic rheumatic mitral stenosis, with minimal morbidity and no mortality in this group. PBMV works by splitting the adhered mitral commissures toward the mitral annulus.

Adolescent↗
PubMed1993

Preliminary report on cardiovascular responses to urapidil during intubation and extubation.

Urapidil (Ebrantil), a new antihypertensive agent with central and peripheral sites of action, has proven effective in the management of both chronic and acute hypertension. This study investigates its effects on cardiovascular responses during intubation and extubation under general anesthesia. Thirty normotensive patients (ASA I-II) were randomized into control (I, without urapidil, n = 10); lower dose (II, 0.4 mg/kg, n = 10); and higher dose (III, 0.6 mg/kg, n = 10) groups. A significant fall of blood pressure was observed in all patients within 1 min after urapidil administration (P < 0.05), and the magnitude of the decrease was related to blood pressure before treatment. However, no transient drop of blood pressure to hypotensive values was observed. The results suggest that urapidil could be used under general anesthesia in patients to control fluctuating blood pressure during intubation and extubation. The increased heart rate (P < 0.05) seen for several minutes after urapidil administration may have been due to the patients' hypovolemic state.

Adolescent↗
PubMed1993

[Effect of increase and decrease of measurement voltage on skin impedance].

The skin impedance has been used as an index to plot out the meridian courses. In most of this kind of methods during measurement voltage was necessary to deliver to the subject's skin. It is unknown whether increasing the measuring voltage can change non-low skin impedance points (non-LSIP) into low skin impedance points (LSIP). In order to clarify the problem, we made an investigation on the effect of increasing and decreasing the measuring voltage on skin impedance. Subjects under observation were 12 healthy volunteers. On the medial side of forearm two levels were selected for measurement. Four or twenty non-LISP were observed on each level. The measuring system worked on the basis of bioelectrode method. The measurement and data processing were controlled by microcomputer. During measurement impedance of LSIP decreased correspondingly with the increase of voltage and vice versa, but the value of impedance was not exceeded 100k omega in spite of increasing or decreasing the voltage. That is, low impedance is the inherent characteristics of LSIP. On the contrary, the impedance of non-LSIP remained in higher than 600k omega in most of cases during increasing voltage from 10 to 50v. As the voltage increased to 65v, the impedance in a part of non-LSIP decreased to such a low level as LSIP. However, their impedance increased rapidly to high level again once the measuring voltage decreased. The above results reveal that the response of non-LSIPs and LSIPs were different from each other in nature. Increasing the voltage could not change a non-LSIP into LSIP.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Evidences for the appearance of peripheral activator during the advance of PSM].

Investigation on mechanism underlying the formation of the propagated sensation along meridians (PSM) is one of the important problems in meridian research. In order to interpret the problem more satisfactorily, we had advanced a hypothesis in 1987, that is, 'integration of periphery' and CNS under the domination of substantial process proceeding along the meridians". According to this hypothesis, "periphery" and "central mechanism" are operated as a whole. However, it also emphasized that the peripheral substantial process is the determinant factor in the formation of PSM. And then, is there really a peripheral substantial process, or, in other word, a peripheral activator during the advance of PSM. The afferent discharges were directly led from the superficial branch of radial nerve. Nineteen volunteers with marked PSM were under observation. The preliminary results demonstrated that as PSM, evoked by stimulating Jianyu (LI15) or Ying Xiang Acupoint (LI20), travelled along the course of Large Intestine Meridian to the hand or index finger, the corresponding afferent impulses could be recorded from that nerve branch in a part of experiments. Through a series of control observations, it has been proved that the impulses recorded was not resulted from other responses, but really the afferent impulse discharged by the neuroreceptor apparatus distributing along the meridian, which was activated by certain stimulation. The facts demonstrated that "the peripheral activator" really appeared during the advance of PSM. It is of significance for the investigation on the mechanism underlying the formation of PSM.

Acupuncture Points↗
PubMed1993

[Observation on the functional characteristics of cortical somatosensory area during the advance of the propagated sensation along meridians].

It is still not clear what role is played by cortical somatosensory system during the advance of propagated sensation along meridians (PSM). In this paper the short-latent somatosensory evoked potential (SLSEP) was taken as an indication to observe the characteristics of functional activity in cortical somatosensory area I (SI) during the advance of PSM. The observation was preformed on 10 subjects with marked PSM, which were clear and kept stable. Sixteen subjects without SPM were taken as control. Electrical stimulation was delivered to the acupoint Jiaxi (GB43) or Hegu (LI4). The SLSEP were recorded simultaneously from 3 scalp points corresponding to the representative areas of foot, arm and face contralateral to the stimulated side. The results are shown as follows. When Jiaxi was stimulated, the amplitudes of SLSEP component C2 (P45-N55) from above three scalp points in subjects without PSC were 0.85 +/- 0.17, 0.51 +/- 0.11 and 0.31 +/- 0.07 microv respectively. The amplitude was largest in the foot representative area, but attenuated successively in arm and face areas and a stair-shaped distribution was thus formed. During stimulating the acupoint Hegu (LI4) the amplitude of SLSEP component C2 (P25-N55) from the representative area of arm in subjects without PSM was larger than that from the representative areas of foot and face, and a distribution with high-medium and low-bilateral character was shaped. However, no matter whether stimulating Jiaxi or Hegu the amplitude of SLSEP C2 in subjects with marked PSM was nearly the same from three scalp points.(ABSTRACT TRUNCATED AT 250 WORDS)

Acupuncture Points↗
PubMed1993

[Localization of the meridian track over body surface by the method of blocking the acupuncture effect with mechanical pressure].

Plotting out the meridian course with objective methods is one of the important projects in the research of meridian at present. Therefore, selecting a proper indication to plot out the meridian track over the body surface during acupuncture is significant for elucidating the essence of meridian. The purpose of this paper was to plot out the Large Intestine Meridian track by blocking the acupuncture effect with mechanical pressure, when electroretinogram (ERG) was taken as a responsive indication. The plotting out the track was carried out on 5 subjects with marked propagated sensation along meridians (PSM) and 5 without PSM. The pressure was applied on Wenliu (LI 7), Shoushanli (LI 10), Quchi (LI 11), Binao (LI 14) and Jianyu (LI 15) respectively, when Hegu (LI 4) was punctured. Under such condition the variation of ERG amplitude decreased markedly or even disappeared. But the variation rate of ERG amplitude was still distinctly increased when the pressure was applied on both sides of any above points. The difference is highly significant (P < 0.01). The results revealed that the meridian track over the body surface during acupuncture could be plotted out not only in the subjects with marked PSM, but also in those without PSM, when the proper objective indication was used. Its course basically coincided with that of the meridian described in the books of traditional Chinese medicine. Now it is safe to say the meridian track over the body surface is existed in human in common. It provides a new approach to plot out the meridian course with objective methods and opens up broad prospects for further application.

Acupuncture Points↗
PubMed1993

[The influence of pressing the meridian course on electroretinogram during acupuncture].

Observation was performed on 23 subjects with marked propagated sensation along meridians (PSM) and 30 without PSM. The electroretinogram (ERG) was recorded with surface electrode and added by an averager. The b wave of ERG evoked by flash stimulation was positive with a latent period about 60 ms and amplitude of 22 +/- 1.66 muv (n = 53). There were 2 types of ERG response during puncturing Hegu (LI 4). The amplitude of ERG b wave increased in 33 subjects and decreased in 20 subjects. However, the acupuncture effect was kept relatively stable in each subject. The spontaneous variation of ERG amplitude was about 10%. In contrast, it changed by 26.5 +/- 2.43% (n = 20) when Hegu (LI 4) was acupunctured alone. It is particularly to be noted that the amplitude of b wave almost remained unchanged, with in the range of 10.08 +/- 2.42% (n = 20), as the pressure was applied on Shousanli (LI 10) during acupuncture, no matter whether the subjects with or without PSM. However, the variation rate of b wave increased by 24.83 +/- 3.74% (n = 15) once again, if the pressure was applied on both side of Shousanli (LI 10), it was nearly equal to the value caused by acupuncture Hegu (LI 4) alone. The contrast between the two is striking. The result revealed again that there may be a certain substantial process advancing along the channel during acupuncture. It is the blockade of this process by mechanical pressure which leads to the decrease of the acupuncture effect.

Acupuncture Therapy↗
PubMed1993

[Influence of mechanical pressure applied on the stomach meridian upon the effectiveness of acupuncture of zusanli].

Traditional Chinese Medicine holds that meridians is the regulative system of the functional activity of the human body. According to the theory of meridians there is a relatively specific connection between the acupoint and viscus. Not a few researchers have paid much attention to this problem. Our previous report showed the mechanical pressure could block the borborygmi caused by puncturing Zusanli (ST 36) in the subjects with marked propagated sensation along meridians (PSM). This paper deals with experiments to compare the influence of pressing the meridian course and non-meridian point on electrogastrogram (EGG) during puncturing Zusanli in 33 subjects without PSM. The acupoint Liangqiu (ST 34) was selected as a compressed point and the points on its either side as controls. EGG was recorded with surface non-polarizable electrode from two abdominal points corresponding to the areas of corpus ventriculi and antrum pyloricum. The effect of acupuncture on EGG appeared in two kind of responses which depended on the amplitude of EGG before acupuncture. The amplitude of EGG increased if it was low before acupuncture. On the contrary, it decreased. The response was bi-directional. It is particular to be noticed that the acupuncture effect was markedly influenced by mechanical pressure. When the pressure was applied on acupoint Liangqiu the acupuncture effect markedly decreased, even disappeared. Whereas mechanical pressure was applied on the both side of Liangqiu, an influence on acupuncture effect of EGG could not be found.(ABSTRACT TRUNCATED AT 250 WORDS)

Acupuncture Points↗
PubMed1993

[Studies on the low skin impedance points and the feature of its distribution along the channels by microcomputer. II. Distribution of LSIPS along the channels].

The distribution of low skin impedance poionts (LSIPS) was observed on 60 healthy volunteers with a computer system designed to measure the skin impedance. The results demonstrated that LSIPs basically distributed along the channels. The method used was reliable and results obtained was repeatable. Some problems, which puzzled the researchers for so many years, now have been clarified and the method for measuring the skin impedance has been developed to a new level. Under the specified condition, the skin impedance can be used as an indicator to plot out the courses of channels in the research.

Adult↗
PubMed1993

[Distribution of low skin impedance points along meridians over the medial side of forearm].

The distribution of low skin impedance points (LSIP) over the medial side of forearm was plotted with a computer system designed for the measurement of skin impedance. Twelve volunteers were under observation. The exploring electrode moved forward in a even velocity from the radial axis of forearm to its ulnar axis and crossed the Lung meridian, Pericardium meridian and Heart meridian in succession. Thus, the measurement covered the whole area of the medial side of forearm. The results showed that the most of 391 LSIPs located right on or within 5 mm bilaterally to the travelling courses of Three Ying Meridians of Hand. It could be found in the area between every two meridians only in a few cases. Just so, the courses of Three Ying Meridians of Hand were clearly displayed. Under the condition of this experiment, LSIP appeared randomly, but viewing the situation as a whole, the distribution of LSIPs was still following the meridian courses. The results further demonstrated that the distribution of LSIPs along meridian courses not caused by the errors in measurement, but really a biological phenomenon, which was objectively existed.

Adult↗
PubMed1993

[Observation on the distribution of LSIPs along three yang meridians as well as ren and du meridians].

The results of our previous works demonstrated that the low skin impedance points (LSIPs) basically distributed along the meridian courses. In order to further clarify what extent LSIPs distributed along the meridians and the feature of distribution of LSIPs in different part of the body, the Three Yang Meridians of Foot as well as Ren and Du Meridians were studied in this work once again. Twenty five volunteers were under observation. As known to all, the Three Yang Meridians of Foot, which travel over several body regions, are the longest three with most complicated courses, among the Twelve Normal Meridians. Ren and Du meridians, which travel along the anterior and posterior median line of the trunk respectively, are the representative of the Eight Extra Meridians. Regardless of their particular travelling courses, the overwhelming majority of LSIPs located right on or within 5 mm bilaterally to their courses. It could be found in non-meridian area only in a few cases. The results of observation on the back is especially to be noticed. Evidently, LSIPs appeared randomly when the exploring electrode moved forward from one side of the back, crossed 5 meridians in succession, to another side. Even so, viewing the situation as a whole, LSIPs still concentrated along 5 bands, basically coincided with the course of Du Meridian and Three Yang Meridians of Foot. The results further confirmed that LSIPs really distributed along the meridian courses in the main.

Adult↗
PubMed1993

Amplification and analysis of a male-specific SRY homologous sequence of cattle.

Based on the highly conserved region of human, rabbit and mouse SRY (sex-determining region Y) sequences, primers were designed for the amplification of the unknown homologous sequence of cattle by polymerase chain reaction (PCR). A 200-bp male-specific amplifying fragment was obtained. The fragment shares high homology with the known SRY gene. By using the cloned fragment as a probe to hybridize to the Southern blot of HindIII-digested cattle genomic DNA, a 1.7-kb male-specific fragment was detected, which is considered to contain the 200-bp fragment. When the same pair of primers was used in amplification of human and goat DNA samples, the 200-bp male-specific fragment could be detected.

Animals↗
PubMed1993

Radiologic evaluation of multichannel intracochlear implant insertion depth.

Postoperative plain film x-rays are necessary in all multichannel cochlear implant patients to confirm intracochlear position, detect possible electrode kinking, and provide a reference if postoperative slippage occurs. In addition, precise documentation of multichannel intracochlear electrode insertion depths is necessary for comparison of speech recognition results among patients and may be of use for future speech processing strategies. In the present study, a method has been devised, using a modified Stenver's view, to more accurately document insertion depths of the electrode array and location of individual electrodes on 50 multichannel cochlear implant patients. Surgical estimates of insertion depth are shown to have great variability in regard to distance along the basilar membrane when compared with x-ray documentation. Additionally, there is preliminary evidence that insertion depth, as determined by x-ray studies, has a strong correlation with open-set speech discrimination.

Basilar Membrane↗
PubMed1993

[The effect of acupuncture on plasticity of spinal Clarke's nucleus synaptic terminals].

Ten unilateral spared root cats with sectioned L1-S2 dorsal root ganglia, except L6, were used to explore the effect of acupuncture on plasticity of spinal Clarke's nucleus synaptic terminals. Five of the cats were needled on the operated hind limb for two courses (ten days as a course), and the other five were kept for control. Two pairs of acupoints located in the innervated area of L6 spinal nerve were used. The number of synaptic terminals per photo in neuropil of L3 Clarke's nucleus was compared directly, because there was no significant change in the area of Clarke's nucleus and its neuropil on the operated side of both groups. No significant difference was found in the number of three types of synaptic terminals between the unoperated sides of two groups, suggesting that acupuncture may not influence the contralateral side. In the control group, the number of giant axonal terminals from dorsal root of the operated side decreased to 75% of the unoperated side; however, in the experimental group, it recovered to contralateral or normal level of the operated side and was significantly higher than that of the control group's operated side, denoting that acupuncture may promote the plasticity such as collateral sprouting and synaptic reinnervation of coarse myelinated fibers from intact dorsal root, L6 mainly. The number of other two types of terminals from spinal interneurons showed no significant difference between the operated sides of two groups, indicating that acupuncture may not enhance the plasticity of nondorsal root nerve fibers.

Animals↗
PubMed1993

Election spin resonance studies of free radical formation and oxygen consumption of lens epithelium during ultraviolet exposure.

A long life election spin resonance (ESR) signal at g = 2.0006 was observed in the normal lens epithelium and cortical fibers. During ultraviolet (UV) exposure, a new ESR signal at g = 2.0060 was found in the lens epithelium. But this specific signal was not detected in the lens cortical fibers. This suggested that lens epithelial cells were more susceptible to the free radical formation which was induced by UV light. By means of ESR spin probe oximetry, the oxygen uptake of lens epithelial cells was measured. The more the oxygen uptake, the higher the K value was. The K value of the oxygen consumption of epithelial cell linearly correlated with time of consumption (20-60 min) and increased as a function of UV exposure time (1-5 min). The oxygen consumption rate of lens epithelial cell was approximately 1.38 x 10(6) and increased to 7.1 x 10(6) O2 molecules per cell per sec. The oxygen consumption rate increased more than 5 times. These results indicates that UV light can accelerate the respiratory function of lens epithelial cells. The necessity of excess oxygen of lens epithelial cells may play a role in the cataract formation induced by UV light.

Animals↗
PubMed1993

Early diagnosis of typhoid fever using monoclonal antibody.

In our study, a reverse passive hemagglutination assay (RPHA) method was established using monoclonal antibody-IgM to detect the Salmonella typhi O9 antigen. This method has the advantages of sensitivity, specificity, rapidity, and simplicity, and helps make an early diagnosis of typhoid fever using only small amounts of blood.

Animals↗