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Biomedical subjects

A Zhou

Publications and source records attributed to A Zhou.

At least 55 records · Page 3Linked to original sources
PubMed2000

Renal protective effects of blocking the intrarenal renin-angiotensin system: angiotensin II type I receptor antagonist compared with angiotensin-converting enzyme inhibitor.

The present study compared renoprotective effects of angiotensin II type I receptor antagonist (AT1RA) with angiotensin converting enzyme inhibitor (ACEI), and their influence on the renin-angiotensin-system (RAS). Experimental nephrotic syndrome was induced in SD rats by repeated peritoneal injections of puromycin. Twenty-eight rats were randomly divided into four groups: normal control, nephrotic control, ACEI-treated, and AT1RA-treated groups. Serum, urine, and renal tissue were collected for study at the end of 12 weeks. Compared with those of the nephrotic control group, urinary protein was less and renal function was better in both treated groups. The glomerular and interstitial damage indexes of both ACEI- and AT1RA-treated rats were lower than those of nephrotic control rats, with no significant difference observed between the two treated groups. Local renal ACE activity and angiotensin II concentration were elevated in nephrotic rats (p< 0.01). However, there is no significant difference in circulating RAS, renal tissue renin, and aldosterone between the normal control and nephrotic control rats. As expected, enalapril inhibited the local renal ACE activity and significantly decreased angiotensin II (p< 0.01). Intrarenal ACE activity and angiotensin concentration returned to normal levels after treatment with irbesartan (p< 0.01). In conclusion, AT1RA and ACEI have comparable renal protective effects, and these protective effects were associated with the inhibition of intrarenal ANG II.

Angiotensin Receptor Antagonists↗
PubMed2000

[Clinical analysis of 10 cases of true histiocytic lymphoma].

OBJECTIVE: To explore the clinical and pathological characteristics of true histiocytic lymphoma. METHODS: The clinical and pathological data of 10 true histiocytic lymphoma patients admitted between 1986 and 1996 to our hospital was retrospectively reviewed. RESULTS: True histiocytic lymphoma accounted for 0.6% of non-Hodgkin's lymphoma(NHL) admitted in this period to our hospital. Enzymes associated with true histiocytic lymphoma were detected in all the 10 cases. The tumor cells were excluded from T/B lymphoid origin in 6 cases by immunohistochemistry. Eight cases received chemotherapy + irradiation +/- excision of primary lesion, 1 simply received irradiation and 1 received bone marrow transplantation. The response rate was 100%, with a 1, 3 and 5 year survival rate of 100%, 90% and 70%, respectively. The expected 10 year disease free survival rate is 40%. CONCLUSION: True histiocytic lymphoma is a rare subset of NHL. Those originated from lymph node are sensitive to chemotherapy and irradiation with a favorable prognosis.

Adolescent↗
PubMed2000

[The effects of electroporation-mediated erythropoietin (EPO) gene transfer into skeleton muscle on renal anemia].

OBJECTIVE: To investigate the effects of erythropoietin (EPO) gene transfer into skeleton muscle mediated by electroporation on renal anemia. METHODS: Renal failure models were created by adenine-excessive diet (150 mg per day). Plasmid vectors encoding EPO were transferred by electroporation after 80 days when mean blood urea nitrogen level (BUN) had increased from 3.4 mmol/L +/- 1.3 mmol/L to 18.1 mmol/L +/- 4.1 mmol/L and the hematocrit had decreased from 45.6% +/- 2.1% to 25.4% +/- 3.7%. During the process of treatment, adenine-excessive diet was given. Hb, HCT, BUN and Cre in blood were tested by automatic analyzer; EPO level in the serum was tested by EPO ELISA kit, EPO gene expression was proved by RT/PCR. The survival rate was calculated. RESULTS: Hematocrit increased to 34.4% +/- 7.5% only 7 days after the treatment and reached 91.4% of normal level (46% +/- 2%) after 5 weeks. The survival rate of test models after 9 weeks was 77.8%, which was remarkably higher than that of controls (16.7%). mRNA level of EPO gene expression was indicated by RT/PCR. CONCLUSION: Electroporation can increase the efficiency of EPO gene transfer and thus greatly improve hematocrit in mice and prolong the life-span of chronic renal anemia models. This method can provide a new way for treatment of EPO-responsive anemias.

Adenine↗
PubMed2000

[Inhibition of growth and metastasis of human giant cell carcinoma of the lung by transfection of antisense VEGF121 cDNA].

OBJECTIVE: To explore the effects of blocking the VEGF/VEGF receptor paracrine pathway on growth and metastasis of human lung carcinoma cell line PG and to evaluate its potential application in gene therapy of cancer. METHODS: The eukaryotic expression vectors bearing either sense-VEGF121 cDNA or antisense-VEGF121 cDNA was constructed and transfected into PG cells. In vitro and in vivo tests such as Northern blotting hybridization, Western blotting immunochemistry analysis, as well as xenografting in nude mice were used to analyze the effect of antisense-VEGF. RESULTS: The transfectants stably expressing antisense VEGF121 were observed to produce markedly reduced 3.3 kb VEGF mRNA and 45 KD, 41 KD, 32KD VEGF proteins. When xenografted s.c. into nude mice, growth and metastasis of the antisense-VEGF transfected cell lines were greatly inhibited when compared with control cells. CONCLUSION: Antisense VEGF gene significantly inhibited tumor growth and metastasis and may provide an experimental example for the development of antiangiogenic gene therapy.

Animals↗
PubMed2000

[The inhibition of prourokinase gene transfer on deposition of platelets on rabbit carotid artery intima].

OBJECTIVE: To observe the expression of pro-urokinase (proUK) gene in rabbit carotid artery transfected with replication-deficient adenovirus vector containing proUK gene (Ad/prouk) and the deposition of platelet on the same injured vessel. METHODS: Ad/proUK (Ad/proUK, 3 x 10(10) pfu/ml) was injected into the right carotid artery locally. Wild type adenovirus (Ad) was locally injected into the left carotid artery as self-control. The expression of proUK gene was investigated by immunohistochemistry assay. After injury of the gene-transfected vessel by electric stimulation, the deposition of (111) In-labeled platelet was quantitatively observed. The thrombosis was observed with HE-stained vessel section. RESULTS: There were lots of proUK granules in the endothelium of Ad/proUK gene-transfected vessel. The differences in (111) In-platelets deposition per gram dry weight vessel segment were significant between Ad/proUK and Ad transfected control vessels [(4.60 +/- 0.93) x 10(7)/g vs control (27.95 +/- 4.93) x 10(7)/g, P < 0.01)]. The HE-stained vessel section showed that there were only small thrombi in proUK gene-transfected vessel but massive thrombi almost blocked up the whole vessel in control vessel. CONCLUSION: The proUK gene-transfected vessel can obviously inhibit (111) In-labeled platelet deposition on injured vessel and thus thrombosis.

Adenoviridae↗
PubMed2000

[The hereditary liability of otosclerosis and the strategies for treatment and prevention].

OBJECTIVE: Otosclerosis is a disease of hereditary liability. It might be related to an autosomal dominant inheritance. The genetic penetrance is determined by multifactorial influences. This paper was designed to study the reasonable strategies for prevention and treatment of this disease. METHODS: A retrospective review derived from data of the management and follow-up of 14 cases in 6 families. According to the special pathological features of active phase of the otospongiosis, the suitable strategies for prevention and treatment of this disease were suggested. RESULTS: Diagnosis of 14 cases were confirmed by audiological, operative and/or pathological examinations. Eleven of fourteen cases underwent stapedectomy, in which 10 cases had the surgery on the ear with severer hearing loss, and one case on both sides. In all of the surgical cases, hearing levels improved significantly. Three cases have not yet received the stapedectomy, in which two cases scheduled for the surgery are currently treated by chondroitin sulfate and one case refused the surgical treatment due to financial shortage. CONCLUSION: Examination of the ear function at regular intervals (6-12 months) is recommended for the adults among the family members with high-incidence of otosclerosis. Audiological and radiological examination play an important role in early diagnosis and treatment. Attention should be paid to the medicine for management and prevention of this disease. Stapedectomy is an optimal choice for clinical otosclerosis not only due to its capacity to improve the hearing level but also to prevent the advance of hearing loss. Hearing aid is the suitable choice if stapedectomy is contraindicated.

Audiometry↗
PubMed1999

Investigation of Electrosorption of Organic Molecules onto Gold and Nickel Electrodes Using an Electrochemical Quartz Crystal Microbalance.

The adsorption behaviors of two organic molecules, benzoic acid (BA) and 2-butyne-1,4-diol (BD), on metal electrodes have been studied using an electrochemical quartz crystal microbalance (EQCM) combined with the cyclic voltammetry technique. In the range of potentials studied, BA molecules were adsorbed onto an electrodeposited gold electrode with a saturation concentration of 5.0 x 10(14) molecules/cm(2). It was found that the Frumkin isotherm model was most suitable to depict the electrosorption behavior. The isotherm parameters by nonlinear fitting, which agreed with the literature values, implied BA was chemisorbed on the gold surface. For BD on an electrodeposited nickel electrode, the equivalent molar mass of the reaction species was calculated on the basis of the voltammetry curve and mass curve, which were obtained simultaneously during the potential scan. The analysis of EQCM data for the electrosorption of BD on gold and nickel electrodes showed an irreversible characteristic; the latter effectively inhibited the hydrogen evolution reaction. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Formation of the antithrombin heterodimer in vivo and the onset of thrombosis.

Antithrombin is shown to undergo a slow spontaneous conversion to its inactive latent conformation with readily discernible amounts present in plasma on incubation at 37 degrees C for 72 hours. More rapid conversion occurs on incubation of isolated antithrombin at 41 degrees C or 50 degrees C, but the appearance on electrophoresis of free latent antithrombin is preceded by the formation, in reciprocal proportions, of a new slow band. This slow component is shown to be a heterodimer of active and latent antithrombin. It can be isolated as a single stable band either by incubation of antithrombin or by mixing equimolar proportions of active and latent antithrombin under the same conditions that give overnight crystallization of the active/latent antithrombin heterodimer. Similarly, equimolar addition of latent antithrombin to plasma results electrophoretically in a quantitative shift to the slower heterodimer mobility. Clinically, the presence of latent antithrombin is potentially deleterious, because its linkage to form the heterodimer results in inactivation of the otherwise normal molecule linked to the latent antithrombin. In the case of alpha-antithrombin, because the dimer readily dissociates, there is only a 11% additive loss of activity, but with beta-antithrombin the dimer appears more stable, with the additive loss of activity from the normal beta component being 21%, increasing to 33% on stabilization of the dimer with heparin. This linked and selective loss of activity of beta-antithrombin provides an explanation for the unexpected severity of thrombotic episodes in heterozygotes with conformationally unstable antithrombins.

Antithrombins↗
PubMed1999

Interferon action in triply deficient mice reveals the existence of alternative antiviral pathways.

Antiviral proteins encoded by the interferon (IFN)-stimulated genes provide a front-line defense against viral infections. In particular, PKR, RNase L, and Mx are considered to be the principal proteins through which IFNs mount an antiviral state. To determine whether alternative antiviral pathways exist, RNase L-/- mice and PKR-/- mice were crossed onto an Mx1(-/-) background to generate a strain of triply deficient (TD) mice. After infections with encephalomyocarditis virus, the TD mice died 3-4 days earlier than infected, wild-type mice. However, there was an IFN dose-dependent increase in survival times after encephalomyocarditis virus infections for both the TD and wild-type mice. Mice that were deficient for PKR or RNase L showed intermediate survival times between those of the TD and wild-type mice. Surprisingly, cultured embryonic fibroblasts lacking RNase L, PKR, or both proteins were still able to mount a substantial residual antiviral response against encephalomyocarditis virus or vesicular stomatitis virus after IFN-alpha treatments. These results confirm the antiviral functions of RNase L and PKR in vivo but also provide unequivocal evidence for the existence of novel, innate immune pathways against viruses.

Animals↗
PubMed1999

Decay of the GRB 990123 optical afterglow: implications for the fireball model

Broad-band (ultraviolet to near-infrared) observations of the intense gamma ray burst GRB 990123 started approximately 8.5 hours after the event and continued until 18 February 1999. When combined with other data, in particular from the Robotic Telescope and Transient Source Experiment (ROTSE) and the Hubble Space Telescope (HST), evidence emerges for a smoothly declining light curve, suggesting some color dependence that could be related to a cooling break passing the ultraviolet-optical band at about 1 day after the high-energy event. The steeper decline rate seen after 1.5 to 2 days may be evidence for a collimated jet pointing toward the observer.

Journal Article↗
PubMed1999

The neuroendocrine protein 7B2 is required for peptide hormone processing in vivo and provides a novel mechanism for pituitary Cushing's disease.

The neuroendocrine protein 7B2 has been implicated in activation of prohormone convertase 2 (PC2), an important neuroendocrine precursor processing endoprotease. To test this hypothesis, we created a null mutation in 7B2 employing a novel transposon-facilitated technique and compared the phenotypes of 7B2 and PC2 nulls. 7B2 null mice have no demonstrable PC2 activity, are deficient in processing islet hormones, and display hypoglycemia, hyperproinsulinemia, and hypoglucagonemia. In contrast to the PC2 null phenotype, these mice show markedly elevated circulating ACTH and corticosterone levels, with adrenocortical expansion. They die before 9 weeks of severe Cushing's syndrome arising from pituitary intermediate lobe ACTH hypersecretion. We conclude that 7B2 is indeed required for activation of PC2 in vivo but has additional important functions in regulating pituitary hormone secretion.

Adipose Tissue↗
PubMed1999

Effects of ELF capacitively coupled weak electric fields on metabolism of 6B1 cells.

In this study, we adopted several methods of MTT colorimetry, DAPI fluorimetry and ELISA to study the effects of extremely low frequency (ELF) capacitively coupled electric fields (EFs) on the metabolism of 6B1 cells. The result shows that 50 mV cm(-1) ELF EF (10-100 Hz) has no significant effect on proliferation, DNA synthesis and activity of succinate dehydrogenase of 6B1 cells, indicating that the effect of ELF (10-100 Hz) EF on the metabolism of 6B1 cells is not obvious. However, 50 mV cm(-1), 50 Hz EF significantly promotes the HBs-Ab (Hepatitis B surface antibody) secretion of 6B1 cells, implying that under this situation, EF has some distinctive effect on the outerface of 6B1 cell membrane.

Cell Division↗
PubMed1999

[Vascular endothelial growth factor gene therapy for peripheral artery disease: experimental study].

OBJECTIVE: To Study experimentally VEGF gene for treatment of peripheral artery disease. METHODS: The human VEGF cDNA was cloned into the eukaryotic expression vector pcD2. Using gene suture, the recombinant plasmid was transferred into the hindlimbs' adductor of Rhesus monkey, of which the distal end of the external iliac arteries were ligated and the femoral arteries were completely excised. With angiography, the biological effect of VEGF gene in experimental animals was investigated. Safety tests were analyzed by transferring of VEGF into mouse, rat, and Rhesus monkey, evaluated by biochemistry analysis, histopathological examination, PCR, and indirect ELISA. RESULTS: The transfer of VEGF gene stimulated the formation of focal microvessels, established collateral circulation, and augmented blood perfusion. The system had no adverse effect and remarkable pathological change in mouse, rat, and Rhesus monkey. CONCLUSION: The experimental studies indicated that VEGF would be effective and safe for clinical trial after approval.

Animals↗
PubMed1999

[Clinical study on treatment of chronic idiopathic thrombocytopenic purpura by Decoction of Nourishing Blood and Eliminating Purpura].

OBJECTIVE: To observe the clinical effect of treatment of chronic idiopathic thrombocytopenic purpura (CITP) by Decoction of Nourishing Blood and Eliminating Purpura (DNBEP), and study the possible mechanism. METHODS: Effect of 55 patients of CITP in treatment group treated by DNBEP and 22 patients in the control group treated by Antaisu were observed and compared. Their immunologic indexes were determined for exploring the mechanism. RESULTS: The markedly effective, improved and total effective rate of the treatment group were 32.7%, 20.0% and 87.3%, while those of the control group were 4.5%, 9.1% and 45.5% respectively, the difference between the two groups was significant (P < 0.001). The effect of the treatment group was better than the control group in platelet count restoring, hemorrhagic symptoms improving and effect initiating, P < 0.01. Immunologic test showed that the humoral and cell immune function as well as platelet function were abnormal in CITP patients. These functions were improved after treatment, and the effectiveness of the treatment group was significantly superior to that of the control group. CONCLUSIONS: DNBEP is reliable in treating CITP clinically. Its mechanism might be better due to its selective suppression of humoral immune function, bi-directional regulation of cell immune function and recovery of platelet function.

Adolescent↗
PubMed1999

[Experimental study on effect of yishen shengxue tablet in treating aplastic anemia].

OBJECTIVE: To study the mechanism of Yishen Shengxue Tablet (YSSXT) in treating aplastic anemia. METHODS: Observing the effect of YSSXT on hematopoietic, immunologic, anti-infection and body resistance of model mice of aplastic anemia. RESULTS: YSSXT had marked effect of promotion on recovering myleran injury induced reduction of colony forming unit-spleen (CFU-S), colony forming unit-culture (CFU-C), colony forming unit-erythrocyte (CFU-E), markedly promoting the peritoneal macrophage phagocytosis of normal mice, also markedly lower the mortality of Staphylococcus aureus inoculated mice, and elevate the anoxia resistant ability under normal pressure of anoxic mice, prolonging their survival time. CONCLUSION: Using YSSXT to treat aplastic anemia that the effectiveness might be realized through promoting the proliferation of hematopoietic stem cells of bone marrow, enhancing the non-specific immunity, and the anti-infection as well as body resistance.

Adjuvants, Immunologic↗
PubMed1998

Identification of genes differentially regulated by interferon alpha, beta, or gamma using oligonucleotide arrays.

The pleiotropic activities of interferons (IFNs) are mediated primarily through the transcriptional regulation of many downstream effector genes. The mRNA profiles from IFN-alpha, -beta, or -gamma treatments of the human fibrosarcoma cell line, HT1080, were determined by using oligonucleotide arrays with probe sets corresponding to more than 6,800 human genes. Among these were transcripts for known IFN-stimulated genes (ISGs), the expression of which were consistent with previous studies in which the particular ISG was characterized as responsive to either Type I (alpha, beta) or Type II (gamma) IFNs, or both. Importantly, many novel IFN-stimulated genes were identified that were diverse in their known biological functions. For instance, several novel ISGs were identified that are implicated in apoptosis (including RAP46/Bag-1, phospholipid scramblase, and hypoxia inducible factor-1alpha). Furthermore, several IFN-repressed genes also were identified. These results demonstrate the usefulness of oligonucleotide arrays in monitoring mammalian gene expression on a broad and unprecedented scale. In particular, these findings provide insights into the basic mechanisms of IFN actions and ultimately may contribute to better therapeutic uses for IFNs.

Apoptosis↗