Biomedical subjects

X Hu

Publications and source records attributed to X Hu.

At least 451 records · Page 25Linked to original sources

PubMed1994

[Preliminary study on expression of Leishmania donovani antigen gene in E. coli].

We constructed previously the expressing library of Leishmania donovani genomic DNA with lambda gt11 as vector. In this paper, 2 x 10(4) phages were plated on E. coli Y1090r-, and screened with a rabbit antiserum prepared by immunization with Leishmania donovani promastigotes. Bound antibodies were detected using alkaline phosphatase labeled anti-rabbit antibodies. A positive expressing clone was detected and transferred into E. coli Y1098r- to prepare lysate, a 39 kDa polypeptide in E. coli Y1089r-lysate was recognized by anti-Leishmania donovani serum. The result indicated that the 39 kDa polypeptide which was not fused with the major portion of beta-galactosidase existed disconnectedly. This finding remained to be further studied.

Animals↗

PubMed1994

[Intracellular accumulation, retention, and distribution of anthracyclines in a multidrug-resistant variant K562r].

A multidrug resistant variant (K562r) of the human K562 erythroleukemia cell line was obtained in vitro by repeated exposure of these cells to vincristine. The K562r cells were resistant to vincristine, harringtonine, mitomycin C, doxorubicin, epirubicin, and daunorubicin but retained the sensitivity to methotrexate. The resistances to vincristine and anthracyclines were reversed in the presence of verapamil. Despite being 60-or over 60-fold resistances to doxorubicin, epirubicin and daunorubicin, the net intracellular uptakes of these drugs at 2 h were reduced by only 15%, 20%, and 11%, respectively in K562r cells compared to their parental line. Verapamil did not enhance drug accumulation but inhibited drug efflux in K562r cells. Though there was no significant difference of drug content in cytoplasm between K562 and K562r cells, the drug content in the nucleus of K562r cells reduced significantly compared to that in K562 cells. The lower concentrations of anthracyclines in the nucleus of K562r cells might contribute to their acquisition of drug resistance.

Antibiotics, Antineoplastic↗

PubMed1994

Steady-state free precession imaging of the inner ear.

The authors describe a steady-state free precession technique for imaging the inner ear. Although the signal-to-noise ratio is not as great as with other three-dimensional MR techniques, the inherent high contrast of inner ear structures makes this a valuable technique for patients with sensorineural hearing loss and for those who refuse paramagnetic contrast material.

Contrast Media↗

PubMed1993

Murine cortactin is phosphorylated in response to fibroblast growth factor-1 on tyrosine residues late in the G1 phase of the BALB/c 3T3 cell cycle.

We have previously reported that BALB/c 3T3 cells require a prolonged exposure to fibroblast growth factor (FGF)-1 for the stimulation of maximal DNA synthesis, and this event correlates with the tyrosine phosphorylation of novel proteins late in G1 including a protein termed p80/p85 (Zhan, X., Hu, X., Friesel, R., and Maciag, T. (1993) J. Biol. Chem. 268, 9611-9620). We have purified, sequenced, and cloned the cDNA encoding p80/p85 and report that it is the murine homolog of the chicken cortactin gene and a member of the human hematopoietic specific-1 gene family. Immunochemical analysis of m-cortactin-tyrosine phosphorylation in response to FGF-1 demonstrates a biphasic phosphorylation pattern both as a weak immediate-early and strong mid to late G1 response protein. Because the chicken cortactin gene was originally isolated as a substrate for v-Src, FGF-1 may influence the enzymatic activity of other cell-associated tyrosine kinases which utilize p80/p85 (cortactin) as a polypeptide substrate.

3T3 Cells↗

PubMed1993

Risk factors for extended disruption of family function after severe injury to a child.

OBJECTIVE: To identify risk factors for long-lasting disruption of family function following pediatric trauma that can be measured at the time of trauma. DESIGN: Prospective, exploratory study. Personal interviews were conducted at the time of admission and 6 months and 1 year after discharge. SETTING: Level I regional pediatric trauma centre. PARTICIPANTS: One hundred and five families (86% of those eligible) with a child admitted to hospital for severe trauma with an Abbreviated Injury Scale (AIS) score of 4 or higher or with two or more injuries in different body parts and AIS scores of 2 or higher were recruited; 13 families were lost to follow-up at 6 months or 1 year, so their data were not included in the analyses. MAIN OUTCOME MEASURES: Family function status (normal or abnormal compared with function before the injury), demographic characteristics of the parents and child, injury severity, presence of maternal psychologic disorder, presence of child behaviour abnormality and functional status of the child. MAIN RESULTS: At 6 months and at 1 year 41 families (45%) and 21 families (23%) respectively reported that their family lives had not returned to normal. The relative odds for disruption of family life were about five times higher (95% confidence limits [CL] 1.4 and 19.7) and four times higher (95% CL 1.1 and 14.0) for single-parent families than for families with married parents living together at 6 months and 1 year respectively. The presence of maternal psychologic disorders at admission and increased age of the injured child were also significantly associated with extended disruption of family function. Injury severity and functional status at discharge were not good predictors of family function. CONCLUSIONS: Severe injury to a child places a heavy strain on normal family function. In particular, single parents and parents experiencing mental or emotional problems at the acute stage of the injury need help in coping with their reactions to the trauma and may benefit from individual or group counseling.

Adolescent↗

PubMed1993

Long term growth factor exposure and differential tyrosine phosphorylation are required for DNA synthesis in BALB/c 3T3 cells.

The importance of growth factor-mediated immediate-early cellular events to the cell cycle has influenced the development and identity of oncogenes and tumor suppressor genes as well as the concept that growth factors commit mammalian cells to enter a biochemical program that ultimately yields DNA synthesis. However, the mid and late events involved in the regulation of growth factor-induced signal transduction remain largely unknown. In this report we demonstrate that BALB/c 3T3 cells require continuous exposure to fibroblast growth factor (FGF)-1 for a minimum of 12 h to achieve near maximal DNA synthesis. This correlates with the continuous internalization of radiolabeled FGF-1 into the cytosol and nucleus of BALB/c 3T3 cells and the maintenance of a low level of FGF receptors on the cell surface during the entire G1 phase of the cell cycle. Further analysis demonstrates the maintenance of a continuous series of differential FGF-1-induced tyrosine phosphorylation events including the phosphorylation of phospholipase C-gamma as well as novel FGF receptor polypeptide substrates, p60, p85, p90, and p130 throughout the G1 phase of the BALB/c 3T3 cell cycle. The tyrosine phosphorylation events are biphasic during the 12-h period after the administration of FGF-1, and the second phase is characterized by hyper-tyrosine phosphorylation of p60, p85, and p130. Interestingly, NIH 3T3 cells which overexpress the FGF receptor-1 polypeptide demonstrate exaggerated tyrosine phosphorylation of p60 and p85 but not p90 and exhibit growth factor-independent cell proliferation. These results suggest that the initiation of DNA synthesis in BALB/c 3T3 cells by FGF-1 is regulated by a complex biochemical program that involves the continuous tyrosine phosphorylation of known and novel polypeptides throughout the G0 to G1 transition period of the cell cycle.

3T3 Cells↗

PubMed1993

A new T2*-weighting technique for magnetic resonance imaging.

This paper describes a method that prepares the longitudinal magnetization with T2* weighting for subsequent acquisition. The main advantage of our technique is its insensitivity to static field inhomogeneity. We have combined this approach with an ultrafast gradient-echo (Turbo-FLASH) sequence and conducted experiments on phantoms and volunteers to demonstrate its capability and utility. With such a technique a T2*-weighted image can be generated in less than a second. In the paper, the detail of the technique and experimental results are presented.

Head↗

PubMed1993

Thrombosis of the portal venous system after splenectomy for pediatric hematologic disease.

Splenic, portal, or mesenteric venous thrombosis after splenectomy for hematologic disease has not been reported in the pediatric literature. It is a rare complication associated with significant morbidity and mortality in adult reports. Between 1981 and 1991, 3 patients (13-year-old boy with hereditary elliptocytosis [HE], 13-year-old boy with thalassemia intermedia [TI], and 18-year-old girl with idiopathic thrombocytopenic purpura [ITP]) presented with abdominal pain, nausea, with or without fever, at 4, 11, and 13 days postsplenectomy, respectively. Abdominal Doppler ultrasound (US) and/or computed tomography (CT) showed: (1) an intraluminal filling defect with partial obstruction to flow in the right branch of the portal vein with the remaining vessels patent (HE); (2) splenic vein thrombosis with complete occlusion of the main portal vein and proximal superior mesenteric vein (TI); and (3) complete thrombosis of the splenic vein, proximal superior mesenteric vein and portal vein (including central radicles), with retrogastric collateralization (ITP). Subsequent imaging showed either complete resolution of vascular obstruction on no treatment (patient 1), or portal venous cavernomatous transformation with hepatofugal flow after 6 months of systemic anticoagulation (patients 2 and 3), and all 3 patients are currently asymptomatic. Postoperative sonographic evaluation of a consecutive series of pediatric splenectomies for hematologic disease (n = 16), was performed at a median of 51 days (range, 3 to 124). This demonstrated one case of asymptomatic left portal venous thrombosis with subsequent recanalization in the absence of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

Application of an event marker in the occupational epidemiologic study of acute irritant symptoms.

Field studies of occupational exposure to airborne irritants have predominantly relied on symptom surveys of study participants. As part of a new approach to the study of acute irritant symptoms, subjects exposed to sodium borate dusts recorded their symptom responses at hourly interviews as well as instantaneously on an electronic device called an event marker. Overall, the unprompted marks indicated fewer irritant events than the interviews. Marks were more frequent in the presence of more than one type of symptom and also appeared to reflect more severe symptoms. A proportion of the marked events occurred in time intervals when no symptoms were recalled during the interview. The exposure-response relations were similar regardless of whether they were based on the interview reports or the electronically marked symptoms. The event marker provided a means to examine the time of onset of the acute symptom event. It also made it possible to examine directly the timing profiles of symptom response in relation to changes in exposure levels in a field setting. Despite some inconsistencies, the finding suggests that the event marker may provide an alternative to frequent interviews of exposed workers to obtain irritant symptom responses for exposure-response modeling.

Acute Disease↗

PubMed1993

Functional magnetic resonance imaging of Broca's area during internal speech.

Conventional gradient-echo magnetic resonance imaging (MRI) at 4 Tesla was used successfully to study the activity of Broca's area during internal speech word generation in healthy right-handed volunteers. Activity was demonstrated in the internal gray matter surrounding the ascending ramus of the lateral sulcus, deep to the cortical surface representation of Broca's area, in all the subjects. These studies demonstrate the capability of functional MRI to non-invasively map language related cognitive functions. Such functional mapping has value for both the study of basic neuroscience and neurosurgical planning.

Adult↗

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

[Preliminary observations on junctional intercellular communication in the epidermis of the adult mammal skins].

1. Shown by the sagittal cryostat-microsections, the epidermis of the adult mouse and rabbit skins consisted of 3-4 layers of cells, occupying about 40 mu in thickness. When advancing a penetrating microelectrode from the surface of the epidermis vertically downward into its depth, the cell membrane potentials of these layers in series, being -4---8mv, -6---20mv, -12---20mv, -12---20mv, respectively, could be got. These potentials, in turn, could be used to mark the proper insertion of the electrode in cell of a desired layer. Beyond the depth of 40 mu usually no membrane potential was met. 2. Microinjection of carboxyfluorescein (CoF) into cell in the first (shallowest) epidermal layer, no matter how long the injection time was, produced restricted dye transfer-only to 1 or 2 neighbor cells. Transfer to 3-5 neighbor cells would be seen in 15 min. after 7 min. of CoF injection into cell in the 2nd layer, and this number would slowly increased if the injection time was further prolonged. Similar CoF injection into cell in the 3rd or 4th (Malpighi) layer resulted in dye transfer to 20-40 neighbor cells. Most testing injections in this work have been done to cells in the 3rd epidermal layer.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

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

[Experimental observation on the relation between pericardium meridian and cardiac function].

The theory of Traditional Chinese Medicine (TCM) holds that "internally, meridians connect with the visceral organs, and externally, with the joints, limbs and other superficial tissues of the body". The results of the investigations on the meridian phenomena, including propagated sensation along meridians (PSM) and others, also showed that certain lines or tracks, coincident with the course of classical meridians, really existed over the body surface. In order to probe into the relation between the pericardium meridian, acting as a organic whole, and the cardiac function, 100 cases of patients suffering from coronary heart disease, with or without PSM, were observed on the one and the same subject before and after acupuncture for comparison. Four acupoints, namely Neiguan (PC6), Ximen (PC4), Quze (PC3), Tianquan (PC2) and two other non-acupoint spots on the Pericerdium Meridian of the same person were acupunctured in different days respectively. At the same time, the spots locating on the both sides of above 4 acupoints, with a distance of 1.5-2.0 cm from them former, and Guangming (GB37) of Gall-Bladder Meridian were taken as controls. Electrocardiogram, cardiophonogram and rheocardiogram were recorded simultaneously. Taking PEP, LVET, P/L, HI, SV, CO, ST segment and T wave of ECG as indexes for analysis, the effect of acupuncture of acupoints on Pericardium Meridian and controls were compared. The results of 737 times of observation demonstrated that the 8 indexes of 4 acupoints and other two non-acupoint spots on the Pericardium Meridian all changed conspicuously after acupuncture. However, the changes of above indexes of the controls, including 8 spots beside Pericardium Meridian, were slight.(ABSTRACT TRUNCATED AT 250 WORDS)

Acupuncture Points↗