Biomedical subjects

Z Zheng

Publications and source records attributed to Z Zheng.

At least 109 records · Page 6Linked to original sources

PubMed1999

Two populations of sympathetic neurons project selectively to mesenteric artery or vein.

The objective of this study was to determine whether sympathetic neurons of the inferior mesenteric ganglion (IMG) projecting to mesenteric arteries could be distinguished by their localization, neurochemical phenotype, and electrophysiological properties from neurons projecting to mesenteric veins. In an in vitro intact vasculature-IMG preparation, neurons were labeled following intraluminal injection of Fluoro-Gold or rhodamine beads into the inferior mesenteric artery (IMA) or vein (IMV). The somata of neurons projecting to IMA were localized in the central part of the IMG, whereas those projecting to IMV were localized more peripherally. None of the labeled neurons was doubly labeled. Neuropeptide Y immunoreactivity was found in 18.9% of neurons innervating the IMA, but not in neurons innervating the IMV. Identified neurons were dissociated and characterized using whole cell patch-clamp recording. After direct soma depolarization, all of the labeled arterial and venous neurons were classified as tonic firing, compared with only 40% of unlabeled neurons; the remaining 60% of unlabeled neurons were phasic firing. The results indicate that IMG neurons projecting to mesenteric arteries are distinct from neurons projecting to mesenteric veins.

Animals↗

PubMed1999

[Analysis on the epidemic characterization and trend of AIDS in Fujian Province].

OBJECTIVE: To analysed the epidemic characterization and trend of AIDS in Fujian Province based on data obtained from HIV sero-survallance, HIV-1 subtyping and epidemiological survey. METHODS: Serum samples collected from people in high risk groups and specific subgroups were examined for antibody against human immunodeficiency virus (HIV). Epidemiological investigation was conducted toward people who were sero-positive. Clinical data on patients with AIDS were also collected. Peripheral blood mononuclear cells (PBMCs) obtained from HIV-1 infectious and patients with AIDS were used for DNA amplification between C2-V3 region by PCR. The amplified products were sequenced to identify HIV-1 subtypes. RESULTS: From January 1987 through the end of December 1997, a total number of 569,873 serum samples from high risk groups and specific subgroups including blood donors and people that travelling abroad frequently were examined for HIV antibody Seventy people with HIV-1 sero-positive were identified, accounting for 0.12/1000 of the total detected numbers. Among them, 21 patients with AIDS in which 18 cases had died. HIV/AIDS cases were mainly distributed along the coastal cities as Fuzhou, Quanzhou and Xiamen where economic development was growing rapidly. Most cases were infected abroad and spreading HIV to the country through sexual transmission. Clinical data showed that early syndromes and reversal fever of patients with AIDS were seen but survival time was short. Nucleotide sequencing showed that HIV-1 strains in the province were most subtype E. CONCLUSION: HIV epidemic in the province will mainly be spreading among people with sexually promiscuous behaviors.

Acquired Immunodeficiency Syndrome↗

PubMed1999

Dendritic cells stimulate the expansion of PML-RAR alpha specific cytotoxic T-lymphocytes: its applicability for antileukemia immunotherapy.

Dendritic cells (DC), the most potent "professional" antigen-presenting cells, hold promise for improving the immunotherapy of cancer. In this study, we investigated the ability of normal donor DC pulsed ex vivo with 12 mer PML-RAR alpha (A) peptide (SGAGEAAIETQS) to generate peptide specific autologous cytotoxic T-lymphocytes. The peptide pulsed DC-primed peripheral blood lymphocytes (PBL) displayed significantly higher cytotoxic activity compared with that of peptide non-pulsed DC-primed PBL against peptide-pulsed autologous macrophages (P<0.001). Both CD8+ and CD4+ T lymphocytes were involved in the effector cell populations. The PML-RAR alpha peptide-pulsed DC-primed T-cells were significantly superior in their production of GM-CSF and TNF-alpha, compared with peptide non-pulsed DC-primed T-cells. These intriguing preclinical studies, suggest that PML-RAR alpha pulsed-DC could be a promising immunotherapeutic modality for patients with acute promyelocytic leukemia.

CD4-Positive T-Lymphocytes↗

PubMed1999

[Comparative study of the regulation of kidney tonic and promoting blood circulation recipe on apoptosis in T cells of old rats].

OBJECTIVE: To investigate the mechanism responsible for the observed reduction in T cell function of the Kidney Deficiency Syndrome. METHODS: After 18th activation with anti-CD3 mAb, the qualitative and quantitative analysis of apoptoses in T cells were performed by using DNA gel electrophoresis, TdT-mediated dUTP nick end labelling (TUNEL) and flow cytometry. RESULTS: The percentage of apoptotic cells was 47.0% in the old and 22.2% in the young group (P < 0.01). In the Kidney tonic group, the mean percentage of apoptotic cells was 31.2%, significantly lower than that in the aged group (P < 0.05). The mean percentage of apoptotic cells in the promoting blood circulation group was 43.3% and no significant difference was seen in the percentages of apoptotoic T cells from the promoting blood circulation group compared with the old group. CONCLUSION: Activation-induced excessive apoptosis of T cells is one of the mechanisms elucidating decreased T cell function of the Kidney Deficiency Syndrome and aging, the retardation of immune senescence by Kidney tonic recipe could be accounted for by down-regulation of activation-induced apoptosis in T cells.

Aging↗

PubMed1999

[The correlation of free radicals induced by cadmium toxicess with erythrocyte injury and band3 expression].

OBJECTIVE: To study the correlation of hydrogen peroxide induced by cadmium ion with erythrocyte injury and band3 expression. METHODS: It was application immunoscanning electronmicroscopy and cytochemistry and EDX methods. RESULT: Cadmium ion not only induced a lot of hydrogen peroxide but also caused serious distortion of erythrocyte. CONCLUSION: Cadmium ion-induced free radicals lead to oxygen free radical damage of membrane and crytoskelecton of erythrocyte, affecting the stability and deformability and band3 expression in erythrocyte.

Animals↗

PubMed1999

[Application of cerium cytochemical method in observation of renal injury caused by oxygen free radical with cadmium induction].

OBJECTIVE: To study acute renal injury caused by oxygen free radical with cadmium induction. METHODS: Electron microscopy cytochemical and energy dispersive X-ray (EDX) analysis techniques were used. RESULTS: Cadmium ions could enter the epithelial cells of renal proximal convoluted tubules. Excessive production of oxygen free radical was found in the kidney tissues, which located mainly in the endothelial cells of blood vessels, mitochondria of epithelial cells of renal proximal convoluted tubules, microvilli and basement membrane. Swelling of epithelial cells and mitochondria and drop of epithelial cells could occur in renal proximal convoluted tubules. CONCLUSION: It suggests that cadmium ions can induce the formation of large amount of oxygen free radical and cause renal injury.

Acute Kidney Injury↗

PubMed1999

[Studies on the stability of sodium taurocholate in different media and in the course of sterilization].

OBJECTIVE: To investigate the stability of the main active constituent of snake gall sodium taurocholate, TCANa in 25% alcoholic solution and artificial gastric juice, and in the course of hot pressurized sterilization. METHOD: The stability of the solution was predicted by an accelerated isothermal test, and the content of TCANa was determined by TLC-colorimetry. RESULT: The half-time(t1/2) of TCANa in 25% alcoholic solution is 60.57 d at 25 degrees C, and in artificial gastric juice 11.37 d at 37 degrees C, the loss rate under the condition(115 degrees C, 30 min) of sterilization about 3%. CONCLUSION: TCANa in 25% alcoholic solution is unstable. Therefore it is suggested that in order to raise the stability of TCANa the alcoholic concentration be increased and the solution be stored at temperatures below 0 degree C.

Animals↗

PubMed1999

[A retrospective study of morphologic basis for the extraction decision in Class II, division 1 malocclusion].

OBJECTIVE: To compare the dentofacial characteristics of persons with Class II, Division 1 malocclusion treated with either an extraction or a nonextraction approach. Such comparison might help identify which parameters influence the extraction decision. METHODS: Lateral cephalograms were available on 81 cases of Class II, Division 1 malocclusion, 42 were treated with 4 premolar extractions and 39 were treated with non-extraction. The cephalometric analysis of West China University of Medical Sciences and Model Analysis were used, RESULTS: Patients in the extraction group had larger FMA, FMIA and lower anterior facial height. In the group of extraction, the upper anterior teeth tipped more anteriorly, and the tooth size-arch length discrepancy and the depth of Spee curve were greater significantly. But the saggital discrepancy and soft tissue's profiles had no significant difference between two groups. CONCLUSION: The stability of the triangle of Tweed, the tooth size-arch discrepancy and the depth of Spee curve were the keys to decide weather extraction or not.

Adolescent↗

PubMed1999

[Study on qualitative analysis method of high performance liquid chromatography by simultaneous multi-wavelength detection].

In this paper, we introduce an HPLC qualitative method, that is, multiwavelength detection qualitative analysis method. According to Beer's law, for a certain compounds the ratio of peak areas at different wavelengths is a constant. Comparing the ratio of peak areas of a component at different wavelengths with that of the standard by means of simultaneous multi-wavelength detection, we established a convenient qualitative method. This method has been applied successfully to qualitative analysis of 18 aromatic amines in the prohibited azo dyes.

Benzidines↗

PubMed1999

[A study of time-dependent blood flow distribution in ischemic myocardium and its dependence on perfusion pressure with modeling and emulation].

A mathematical model was proposed for studying the time-dependent blood flow distribution in ischemic myocardium with different developments of collateral circulation. The model includes the blood perfusion of normal myocardium and ischemic myocardium. There are three classical myocardial vascular nets in each part and each net is represented by a branch of time-dependent nonlinear resistance and compliance. Experimentally measured aortic pressure and left ventricular pressure from six male dogs were taken as input data for emulation. The results demonstrate that raising perfusion pressure with external counterpulsation can improve the blood perfusion condition in ischemic myocardium.

Animals↗

PubMed1999

[A comparative study of finger plethysmography and aortic pressure for monitoring the effect of external counterpulsation].

Invasive pressure detecting and monitoring of aortic root was conducted in 20 volunteers so as to study the effect of Enhanced External Counterpulsation (EECP) on aortic pressure and finger plethysmography. The results demonstrated that the changes of aortic diastolic pressure linearly related to the counterpusation's bladder pressure, and the aortic augmentation increased to the top of 168.56 mmHg with a D/S ratio of 2.75(amplitude ratio of diastolic waveform and systolic waveform, D/S ratio) following the bladder pressure of 0.45 Kg/cm2. With the increase of bladder pressure, the dp/dt of aortic augmentation elevated gradually, but a down-regulating trend was seen in systolic waveform. During EECP, the starting time of plethysmographic augmentation had a mean delay of 108.20 +/- 25.70 ms comparing with that of aortic augmentation. The duration between the starting time of aortic systolic waveform and that of finger plethysmogram was arround 96.69 +/- 38.70 ms. When the bladder pressure changed, no significant difference was observed among them. The D/S ratio of finger plethysmographic waveform changed in concord with that of aortic pressure with the promotion of bladder pressure. Therefore, a relationship between aortic D/S ratio (Y) and plethysmographic D/S ratio (x) was constructed by the linear regression analysis: Y = 0.376 + 0.457X. It can be concluded that EECP has significant effects on aortic D/S ratio, aortic peak augmentation and its dp/dt value. Finger plethysmography, to date, still plays important roles in monitoring and controlling EECP work safely and effectively.

Adolescent↗

PubMed1999

[The study of the control system of new generation EECP].

A new algorithm for the inflation and deflation timing of the Enhanced External Counterpulsation (EECP) have been developed, A pentium PC and 16 bit microcontroller with parallel interrupt communication were used for developing a new kind of EECP system. The 16 bit microcontroller was used to collect and pre-process the ECG and EECP signals. The pre-processing data is transmitted to PC by the parallel communication interface. According to the new algorithm, PC sent out the sequential control signals and monitor the state of EECP. It is necessary to synchronize the time of aortic valve closure and diastolic augmentation during EECP, under the condition of the patients' safety, the effect of therapy have been extremely improved.

Algorithms↗

PubMed1998

Ex vivo fibroblast transduction in rabbits results in long-term (>600 days) factor IX expression in a small percentage of animals.

Delivery of human factor IX to the circulation was analyzed in rabbits by ex vivo fibroblast transduction followed by subcutaneous implantation. Kinetic studies of human factor IX in rabbits demonstrated a half-life of approximately 16 hr and a volume distribution of 22%, where intraperitoneal and subcutaneous bioavailability was three- to sevenfold lower than by intravenous administration. Ex vivo retroviral transduction of autologous fibroblasts was performed on 15 animals. After subcutaneous injection of fibroblast-collagen mixtures, the expression of human factor IX in rabbit plasma was followed by ELISA. Of 15 rabbits injected, expression of human factor IX was detected in 2 animals, and expression was long term (>600 days). One animal had stable levels of human factor IX, at 20 ng/ml, while the second animal had lower and gradually decreasing levels of human factor IX. There were no gross differences in pathology at the injection sites, when comparing animals with human factor IX in plasma and those without. Immunological studies demonstrated antibody formation in response to injection mixture components (including human factor IX), but again there was no correlation with immune response and long-term factor IX production in animals. Tissues at the implantation sites were positive for factor IX DNA by PCR analysis, regardless of whether there was detectable plasma factor IX or not. Small numbers of PCR-positive cells were detected in the internal organs of the long term-expressing rabbits while similar tissues were negative in nonexpressing animals.

Animals↗

PubMed1998

Hematopoietic stem cell maintenance and differentiation are supported by embryonic aorta-gonad-mesonephros region-derived endothelium.

Hematopoietic stem cells are capable of extensive self-renewal and expansion, particularly during embryonic growth. Although the molecular mechanisms involved with stem cell maintenance remain mysterious, it is now clear that an intraembryonic location, the aorta-gonad-mesonephros (AGM) region, is a site of residence and, potentially, amplification of the definitive hematopoietic stem cells that eventually seed the fetal liver and adult bone marrow. Because several studies suggested that morphologically defined hematopoietic stem/progenitor cells in the AGM region appeared to be attached in clusters to the ventrally located endothelium of the dorsal aorta, we derived cell lines from this intraembryonic site using an anti-CD34 antibody to select endothelial cells. Analysis of two different AGM-derived CD34(+) cell lines revealed that one, DAS 104-8, efficiently induced fetal-liver hematopoietic stem cells to differentiate down erythroid, myeloid, and B-lymphoid pathways, but it did not mediate self-renewal of these pluripotent cells. In contrast, a second cell line, DAS 104-4, was relatively inefficient at the induction of hematopoietic differentiation. Instead, this line provoked the expansion of early hematopoietic progenitor cells of the lin-CD34(+)Sca-1(+)c-Kit+ phenotype and was proficient at maintaining fetal liver-derived hematopoietic stem cells able to competitively repopulate the bone marrow of lethally irradiated mice. These data bolster the hypothesis that the endothelium of the AGM region acts to mediate the support and differentiation of hematopoietic stem cells in vivo.

Animals↗

PubMed1998

Collagen/apatite coating on 3-dimensional carbon/carbon composite.

A three-dimensional carbon/carbon composite (3D C/C) was studied as potential bone-repairing material; its major mechanical properties were found to be closer to those of human bone than other common bone-repairing materials available. In vitro calcification tests revealed that as-received 3D C/C is almost bioinert in simulated body fluid (SBF) over an immersion period of 4 weeks. To improve the bioactivity of 3D C/C, surface modification was accomplished through two practical routes: (1) grafting with polyethylene glycol (PEG) and (2) phosphorylation and precalcification. After grafting with alpha, omega di(aminopropyl) polyethylene glycol 800 (NH2-PEG-NH2), a continuous layer of calcium phosphate was formed on the surface of 3D C/C in SBF after 4 weeks. Phosphorylated 3D C/C samples have the ability to induce apatite precipitation after precalcification in a saturated Ca(OH)2 solution for 1 week. To speed up the coating process, a calcification solution with collagen was developed in which a collagen/apatite coating layer can be formed on 3D C/C in 9 h in ambient conditions.

Apatites↗

PubMed1998

Outcomes in patients treated with gamma knife radiosurgery for brain metastases from malignant melanoma.

In order to determine the effectiveness of gamma knife (GK) radiosurgery in patients with malignant melanoma metastases, the authors conducted a prospective multicenter study. Forty-five patients with a total of 96 lesions were treated and followed to measure survival time, tumor control rate, and Karnofsky Performance Scale (KPS) score. The mean survival time was 8.7 months (median 4.2 months), and tumor control was achieved in 86% of lesions. When obtained, the median preoperative KPS of 80 was maintained at a median of 80 post-GK treatment. The authors found GK treatment for metastases of malignant melanoma to be highly effective in controlling tumor growth. Survival rates obtained after GK treatment were found to be superior to historically obtained data concerning external beam radiotherapy follow up. Radiosurgery with the GK can therefore be considered a good primary treatment option for metastatic brain disease of malignant melanoma.

Journal Article↗

PubMed1998

A highly conserved processed PTEN pseudogene is located on chromosome band 9p21.

PTEN/MMAC1/TEP1, encoding a dual-specificity phosphatase, is a tumor suppressor gene which has recently been cloned and mapped to chromosome 10q23.3. We have shown that germline mutations of PTEN are present in individuals with two hamartoma syndromes: Cowden Syndrome, associated with a predisposition to breast and thyroid cancers, and Bannayan-Zonana syndrome. Somatic mutations of PTEN have been reported in a variety of human cancer cell lines, suggesting a potential role for this gene in the pathogenesis of human malignancies. We report the identification of a highly conserved PTEN processed pseudogene, psiPTEN, which shares over 98% homology with the coding region of functional PTEN, and its localisation to chromosome 9p21. The high sequence homology of psiPTEN with the PTEN transcript may potentially lead to misinterpretation when performing mutation analyses based on cDNA templates. Caution should be exerted when using such screening approaches.

Amino Acid Sequence↗

PubMed1998

Solid-State Production of Beneficial Fungi on Apple Processing Wastes Using Glucosamine as the Indicator of Growth.

Three Trichoderma species, a Penicillium species, and a Rhizopus species were grown on apple pomace at 25 degrees C through solid-state fermentation. The effects of CaCO(3), water, and nitrogen sources on the growth of selected fungi on apple pomace were investigated. Soluble protein and glucosamine contents of fermented pomace were measured as the parameters of fungal growth. The maximum growth of all fungi was established on apple pomace supplemented with 0.05 g of CaCO(3), 2 mL of water, and 0.05 g of NH(4)NO(3) or 0.3 mL of fish protein hydrolysate per gram of pomace. The optimal water activity of the medium for fungal growth was 0.96 at 25 degrees C. This research has provided a clear indication for using glucosamine as a proper indicator of fungal growth in heterogeneous solid-state systems. It also shows potentials for bioconversion of apple processing wastes by beneficial fungi into valuable bioinoculants that are being targeted for agricultural and environmental applications.

Journal Article↗