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Biomedical subjects

Z Jin

Publications and source records attributed to Z Jin.

At least 145 records · Page 8Linked to original sources
PubMed1994

Velocity measurements in natural porous rocks.

In the petroleum industry, there is a general belief that there must be a correlation between porosity and permeability in oil field cores. This has been demonstrated using porosity and permeability values measured on large cores from the same oil field. Now, with MRI techniques for non-invasively measuring fluid flow velocities and porosities inside oil cores, it is possible to develop quantitative correlations between local porosity and fluid flow velocity inside single core samples. Since velocity and permeability are related, these results could eventually be extended to give empirical equations relating porosity and permeability within a particular core sample. MRI was used to obtain local values of the porosity and fluid flow velocity in Casper sandstone during water injection. The correlation between local fluid velocity and local porosity is shown graphically and indicates that the average velocity increases with porosity, with no velocity for porosity equal to zero, as expected. In addition, the average flow rate of the fluid through the cross-section, as measured by MRI, is calculated and compared to the actual flow rate through the core sample. The results indicate bypassing of fluid around the perimeter of the core, and this conclusion is supported by 1D projections of the flow velocities at different overburden pressures.

Fourier Analysis↗
PubMed1994

Improvement in left ventricular dysfunction after aortic reimplantation in 11 consecutive paediatric patients with anomalous origin of the left coronary artery from the pulmonary artery. Early results of a serial echocardiographic follow-up.

To study the potential for recovery of left ventricular function in patients with anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) after aortic reimplantation, serial two-dimensional echocardiographic examinations were performed before and up to 9 months after operation in 11 consecutive paediatric patients (group 1: six infants; group 2: five children above the age of 1 year). End-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), myocardial volume (MV), ratio of myocardial volume/end-diastolic volume (MVI), and regional wall motion of the left ventricle (LV) were studied. Pre-operatively, mean LVEDV was 339% of normal in group 1 and 289% in group 2 (P < 0.001); mean LVMV was about twice the normal value in both groups (P < 0.001); LVMVI was 0.79 +/- 0.23 in group 1 and 0.83 +/- 0.3 in group 2; LVEF was 28 +/- 10% in group 1 and 46 +/- 18% in group 2; regional wall motion was normal in two group 2 patients, the other showed uniform reduction in segmental shortening fraction. Postoperatively, mean LVEDV tended to become normal after 2 weeks in group 1 and after 3 months in group 2. In both groups mean LVEF reached the normal range after 3 months; LVMV as well as LVMVI normalized after 9 months. Three months after the operation, all infants had a nearly normal pattern of regional wall motion, while in three group 2 children a residual reduced shortening fraction could be observed in anterior or lateral segments.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta, Thoracic↗
PubMed1994

Effect of an open-door policy combined with a structured activity programme on the residual symptoms of schizophrenic in-patients. A six-month randomised controlled trial in Yanbian, Jilin.

Fifty female schizophrenic patients on the same locked ward were randomly assigned to experimental and control groups. Experimental group subjects were given as much autonomy and freedom as possible (they were permitted to leave the ward at will) and were encouraged to take part in collective activities. The control group were not permitted to leave the ward and did not take part in these activities. All patients were evaluated at enrollment and after six months-using Chinese versions of the Scale for Assessment of Negative Symptoms and the Brief Psychiatric Rating Scale-by psychiatrists who were blind to patients' treatment status. After the six-month intervention the severity of all types of both negative and positive symptoms and the mean dosage of medication in the experimental group were significantly less than in the control group.

Activities of Daily Living↗
PubMed1994

Anomalous origin of the left coronary artery from the pulmonary artery. Early results with direct aortic reimplantation.

Between January 1991 and June 1993, eleven children with anomalous origin of the left coronary artery from the pulmonary artery underwent direct aortic reimplantation of the left coronary artery at the German Heart Institute Berlin. The patients' ages ranged from 2.5 months to 10.5 years; six were infants. Three infants were intubated and their lungs ventilated before the operation, and one was resuscitated 2 days before the operation. The electrocardiograms of eight patients indicated deep Q waves. All but three of these patients had insufficient collaterals between the right and left coronary arteries. The entire group exhibited reduced left ventricular ejection fraction (minimum 15%) including mitral valve incompetence, which was moderate in six patients and severe in three. All six infants underwent emergency operations, and the remaining children, who were older, underwent elective operations involving moderate hypothermic perfusion and cold crystalloid cardioplegia. Aortic cross-clamping time ranged from 22 to 79 minutes (mean 54 minutes). A two-coronary artery system was established in all patients by direct reimplantation of the anomalous left coronary artery into the ascending aorta. Three patients who also exhibited severe mitral valve incompetence underwent modified Kay mitral valve annuloplasty. A delayed sternal closure procedure (closure performed 1 to 10 days after the operation) was used on eight patients. A 10-month-old patient was successfully treated after the operation with a centrifugal left heart assist device and a 9-year-old patient received extracorporeal membrane oxygenation because of severe heart failure. No postoperative deaths occurred. Left ventricular end-diastolic volume decreased dramatically after the operation and returned to near normal values 1 to 9 months postoperatively. At the same time, the preoperatively depressed left ventricular ejection fraction returned to normal and mitral valve incompetence decreased or vanished in eight patients. Color Doppler echocardiograms (eleven patients) and coronary angiograms (three patients) indicated that the reimplanted left coronary artery was patent in all eleven patients during the follow-up period. Reimplantation of the left coronary artery into the ascending aorta is an effective method of establishing a two-coronary artery system in children with anomalous origin of the left coronary artery from the pulmonary artery. Mitral valve annuloplasty is recommended for patients who also have severe mitral valve incompetence. Prolonged assisted circulation must be used in cases of severe postoperative heart failure.

Aorta↗
PubMed1993

Production of polyclonal antibodies against 1,1'-ethyliden bis[L-tryptophan] (EBT), a potential contaminant causing eosinophilia-myalgia syndrome (EMS).

Eosinophilia-myalgia syndrome (EMS) is thought to be caused by the intake of contaminated L-tryptophan products. 1,1'-Ethyliden bis[L-tryptophan] (EBT) is one of the contaminants in the L-tryptophan products and is thought to be a possible cause of EMS. In the present study we report that anti-EBT antibodies are generated by immunizing rabbits with the low molecular weight substance, EBT (molecular weight 434). These antibodies may be available tools for elucidating the mechanisms responsible for the outbreak and/or development of EMS.

Animals↗
PubMed1993

Increases in glomerular eicosanoid production in rats with bilateral ureteral obstruction are mediated by enhanced enzyme activities of both the cyclooxygenase and 5-lipoxygenase pathways.

Glomeruli isolated from rats with bilateral ureteral obstruction (BUO) of 24 hr duration produced significantly greater amounts of prostaglandin (PG) E2, 6-keto-PGF1 alpha, thromboxane B2, and leukotriene B4 than glomeruli isolated from sham-operated control (SOC) rats. To examine the mechanisms underlying the greater production of eicosanoids by glomeruli isolated from rats with BUO, we measured the activities of enzymes related to eicosanoid formation such as cyclooxygenase, 5-lipoxygenase, PGE2 isomerase, and PGI2 and thromboxane synthase in glomeruli isolated from SOC rats and rats with BUO. Glomeruli isolated from rats with BUO had a significantly increased activity of cyclooxygenase with de novo synthesis of this enzyme and a markedly augmented activities of PGE2 isomerase and both PGI2 and thromboxane synthases relative to glomeruli isolated from SOC rats. Similarly, the activity of membrane-bound 5-lipoxygenase, the active location of this enzyme, was significantly greater in glomeruli isolated from rats with BUO than in glomeruli isolated from SOC rats. Thus, BUO of 24 hr duration enhances the glomerular production of eicosanoids via the activation of enzymes in both the cyclooxygenase and 5-lipoxygenase pathways.

6-Ketoprostaglandin F1 alpha↗
PubMed1993

[Growth type of colorectal cancer invasion of the proper muscle in relation to DNA ploidy and distribution of PCNA].

In order to elucidate the biological characteristics of colorectal cancer invading the proper muscle, we analyzed DNA ploidy and PCNA labeling index. The growth patterns were divided into three types; those accompanied by intramucosal polypoid growth (PG+), those with non-polypoid growth (PG-), and those ranging between PG+ and PG- (PG+/-). The relationship of DNA ploidy to lymphatic vessel permeation and recurrence was also discussed. The results were as follows: 1) Growth types bore no relation to DNA ploidy and distribution of PCNA. 2) In aneuploidy cancer, it showed a high incidence of lymphatic vessel permeation. A trend of lymphatic metastasis was also observed. Aneuploidy cancer showed a poor prognosis compared with diploidy cancer.

Adult↗
PubMed1993

Analysis of heavy metals in mouse uterine secretion by X-ray microanalysis.

A method for the detection of heavy metal ions in the uterine secretion of the mouse was tested. Mice received an intravenous injection of lead, and beads of an analytical grade resin, Chelex 100, were deposited in the uterine lumen to absorb heavy metals present in the secretion. X-ray microanalysis of the flushed beads showed that lead was present in a dose-related way in the uterine secretion of mice that had received 0.05, 0.1, or 0.15 mg lead per g body weight. Thus, the technique allows quantitative analysis of lead in the uterine secretion. The amount of lead present in the secretion decreased with time after the application of lead.

Animals↗
PubMed1993

[Studies on laxative function of maren soft capsule].

The experimental results show that the Maren soft capsule can increase the amount and weight of the stool of normal mice and model mice with dry stool, promote the advanced percentage of charcoal powder in the small and large intestines of mice, enhance the movement of the smooth muscle of isolated ileum of guinea pigs under physiological conditions or low temperature, as well as strengthen the intestinal movement in rabbits.

Animals↗
PubMed1993

[Subtyping of GC globulin in human semen stain].

The group-specific component (GC) is an alpha 2 globulin with high genetic polymorphism in serum. There is also a little amount of GC in human semen. Pflug and Potsch-Schneider independently carried out GC subtyping of human semen stain with immobilized pH gradient gel isoelectric focusing (IPGIF) followed by ELISA in 1988. We report a new method there to subtype GC in human semen stains. First, the GC globulin was separated by polyacrylamide gel isoelectric focusing with pH 4.2-4.9 Pharmalyte. Then, it was immunoblotted to cellulose acetate membranes. Finally, the protein bands were shown by ELISA using horseradish peroxidase-linked secondary antibody system. All the 17 semen stains of volunteers were subtyped successfully. This method is easy to learn and convenient for applying in case work.

Enzyme-Linked Immunosorbent Assay↗
PubMed1992

Instrumented parallel bars for three-dimensional force measurement.

This paper describes the modification and instrumentation of standard parallel bars to allow for the measurement of applied forces on both horizontal bars in three dimensions. This measurement system has been used in the development and evaluation of functional electrical stimulation (FES) devices for standing and gait restoration in paralyzed patients. Real-time measurement of forces applied by the upper body of the patient to the parallel bars is of use in the evaluation of FES stimulation patterns (or automatic controllers of stimulation). Such measurements are useful in the redesign of stimulation patterns and/or stimulation controllers.

Biophysics↗
PubMed1992

Characterization of G-proteins in rat glomeruli.

G-proteins in rat glomeruli were examined using bacterial toxin-catalyzed ADP-ribosylation and specific immunoblots. ADP-ribosylation catalyzed by cholera and pertussis toxin demonstrated the existence of Gs and Gi proteins in the glomerular membranes. Immunoblots further revealed two types of Gs alpha (45 and 52 kDa), Gi alpha 1 and/or Gi alpha 2 (40-41 kDa), Gi alpha 3 (40 kDa) and G beta (35-36 kDa) but not Go alpha in the membranes of the glomeruli. The predominant subspecies of Gs alpha was a 52 kDa protein. However, detectable amounts of G-proteins did not exist in cytosolic extracts of the glomeruli. We conclude that several subspecies of Gs and Gi proteins are present in rat glomerular membranes.

Adenosine Diphosphate↗
PubMed1991

Expression of firefly luciferase gene in Xenopus laevis oocyte.

Fusion plasmid pSV-Luc20 and pSV-Luc19 were constructed by using the larger BamHI restricted fragments of plasmid pDO432 containing the firefly luciferase (luc) gene and HindIII-BamHI restricted fragment of plasmid pSVK100 containing the SV-40 promoter as insert and vector, respectively. The fusion plasmid had different ligation orientations between the encoding sequence of luc gene and the SV-40 promoter, i.e., they were sense and antisense plasmid. When they were introduced into Xenopus oocyte by micro-injection, only pSV-Luc20 could be transcribed and translated into the enzymatic protein of luciferase with high biological activity. Therefore, firefly luciferase gene and Xenopus oocyte can be used as an excellent system for monitoring the activity of various promoters.

Animals↗
PubMed1991

[Segmental distributions of sensory neurons of the "ganshu", "pishu", "liangmen", "qimen" points and the gallbladder].

One hundred guinea pigs were used. The 10% HRP 50-60 microliters solution was injected into the acupoints of "Gansu", "Pisu", "Liangmen" and "Qimen" of every animal. Moreover, the 10% HRP 80-100 solution was injected into the gallbladder of the another animals too. Under the microscope, observed the segmental distributions of sensory neurons of the four acupoints and the gallbladder. It could be found much clearly that HRP labelled cells were appearing in the spinal ganglions. The above experimental studies showed that there are mutual intersect 5-7 segments between the gallbladder and the "Gansu", "Pisu", "Liangmen" and "Qimen" four acupoints. It is probable that the mutual intersect is the neuroanatomic foundation of acupuncture and moxibustion to inhibit the formation of bilirubin gallstones.

Acupuncture Points↗
PubMed1990

Activation of CD8+ T cells by allogeneic class II-deficient B-cell lines derived from patients with bare lymphocyte syndrome.

The major histocompatibility complex (MHC) class II antigens (Ags) are known to carry the major stimulating determinants of the primary mixed lymphocyte reactions (MLR). We investigated the mechanism of generating HLA class I-directed alloreactive T-cells in primary MLR. With the use of class II-deficient EBV-transformed B-lymphoblastoid cell lines (B-LCLs) derived from patients with bare lymphocyte syndrome (BLS), we have demonstrated in the present study that class I disparity alone can trigger primary MLR in the absence of exogenous IL-2. The CD8+ T cells were primary MLR-responsive cells, and the CD4+ T cells seem to play no role in primary MLR when class II alloantigens are not involved in stimulation. Addition of autologous macrophages did not influence the primary MLR response. The primary MLR was completely blocked by anti-class I or anti-CD8 antibodies but not by anti-class II or anti-CD4 antibodies. The MLC-generated CD8+ T cells exhibited cytolytic activity as well as proliferative responses. The proliferative response of the CD8+ T cells was specifically directed against class I antigens, demonstrated by proliferative assays; and the helper-independent CD8+ T cells were generated only when the activation of CD4+ T cells did not occur. This observation suggests that functional recruitment of T-cell receptor (TCR) repertoire is under active regulation, and the suppression of CD8+ T-cell helper recruitment appears to be dictated by the CD4+ T-cell subset. Further analysis of the primed T-cell specificities showed that alloreactivity of the CD8+ T cells was mostly accounted for by the HLA-B Ags.(ABSTRACT TRUNCATED AT 250 WORDS)

B-Lymphocytes↗