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Biomedical subjects

J Guo

Publications and source records attributed to J Guo.

At least 271 records · Page 15Linked to original sources
PubMed1998

[Gene expression in vivo mediated by adenoviral vector after direct gene transfer into anastomotic rat carotid arteries].

OBJECTIVE: To observe the efficiency and time course of gene expression in vivo mediated by adenoviral vector after direct gene transfer into anastomotic rat carotid arteries. METHODS: After being soaked in high concentration of glucose solution containing Adv5-CMV (control group) or Adv5-CMV/LacZ (treatment group) for 30 minutes, soluble stents were inserted into the lumina of cut rat carotid arteries and end-to-end anastomoses were performed. On the 2nd, 7th, 14th, 28th, 60th and 90th day after surgery, the anastomotic carotid arteries of the two groups were explanted. All samples were analyzed for the presence of beta-galactosidase activity and histochemical staining. RESULTS: beta-galactosidase activity was not detected in the carotid arteries of the control group. Microscopic examination of sections from vessels of the control group revealed no X-gal staining. The treatment group revealed bluestaining in all anastomotic arteries and in all layers of the arterial wall explanted including the intima, media, and adventitia on the 7th, 14th day postoperatively. CONCLUSIONS: Adenoviral vector could make foreign effectively transfer into rat carotid arteries in vivo. Mediated by adenoviral vector after direct gene transfer into anastomotic rat carotid arteries, the high level of gene expression only persisted about one month.

Adenoviruses, Human↗
PubMed1998

Brain tissue response to Holmium:YAG laser irradiation.

OBJECTIVE: To evaluate the usefulness of pulsed infrared solid-state Holmium:Yttrium-Aluminum-Garnet (Ho:YAG) laser in neurosurgery, acute responses of brain tissue to Ho:YAG irradiation and to investigate the healing processes in rats and rabbits. METHODS: Animals were divided into groups according to different survival time and laser irradiation mode. Craniotomy was made and laser energy was delivered to the brain surface by two irradiation modes: 1) contact mode with the fiber in contact with the brain surface; and 2) non-contact mode with the fiber tip 5 mm above the brain surface. Gross observations were made and histological changes were studied. RESULTS: Acute responses were studied on rats' brain. The contact mode produced a crater lined with less than 1 mm thick thermally coagulated layer of brain tissue. The non-contact mode effectively vaporized the brain tissue even with water irrigation. Good homeostatic effect was achieved. The shock waves generated by the pulsed delivery of laser energy, however, impacted on the brain resulting in debris spreading and brain vibration. The healing processes were studied on rabbits' brain one day to six weeks after irradiation. The lesions produced by the contact mode were narrow and sharply defined. With the non-contact mode, the thickness of the coagulated layer at the bottom of the crater varied between 0.8 and 1.1 mm. CONCLUSIONS: Ho:YAG laser should be a clinically useful tool in neurosurgery because of its good ablation effect, shallow penetration and convenient optic fiber transmission system. Meanwhile, a continuously waved Ho:YAG laser is desired to reduce the shock wave impact.

Animals↗
PubMed1998

[Expression and purification of recombinant hirudin].

OBJECTIVE: To express the recombinant hirudin variant 1 (rHV1) with biological activity in prokaryotic cells and then isolate and purify the expressed products. METHODS: The hirudin variant 1 gene in plasmid vector pBV220 was expressed in E. coli strain DH5 alpha. The biological activity of rHV1 was determined with chromogenic substrate method. The expressed product was purified by ultrafiltration, DEAE-Sephadex A-50 filtration and thrombin-Sepharose 4B affinity chromatography. RESULTS: The expressed rHV1 accounted for approximately 16.9% of E. coli cell proteins with an activity of 20-30 ATU (antithrombin unit) per milliliter culture. The purified rHV1 showed a homogeneous band on SDS-PAGE. CONCLUSIONS: This is the first report in China on successful expression of hirudin variant 1 gene in E. coli and purification of the expressed rHV1.

Escherichia coli↗
PubMed1998

[The role of pro-UK gene in protecting vein graft from thrombosis].

OBJECTIVE: To study the role of Pro-UK gene in protecting vein graft from thrombosis. METHODS: 42 Wister rats underwent implantation of reversed autologous jugular vein interposition grafts in the common carotid artery. Jugular veins were exercised and distended with solution containing either Adv5-CMV(control group) or Adv5-CMV/Pro-UK(treatment group) for 30 minutes, then the jugular veins were reversed and interposed into the divided carotid arteries. Proximal and distal anastomoses were performed in an end to end fashion with interrupted 11-0 polypropylene sutures. 14 days after surgery, the vein graft of two groups were explanted to examine the presence of Pro-UK gene expression. The amount of 51 Cr-labeled platelet of the two groups was counted 24 hours postoperatively. Segment of grafts of both group was explanted 14 days after surgery for histologic analysis. RESULTS: Pro-UK activity was not detected in the vein graft of the control group. In the treatment group, the amount of Pro-UK gene express was 308 IU/g tissue. The amount of 51Cr-labeled platelet of the two groups was (123.7 +/- 19.4) x 10(6)/gdrywt. (34.4 +/- 5.3) x 10(6)/gdrywt. The amount of the control group was prominent over the treatment group(P < 0.01). On the 14th day after surgery, the thrombosis rate and occlusion rate of the vein graft in the control group were 30%, 10% respectively. In the treatment group, all vein grafts were patent and free of thrombosis. CONCLUSIONS: Mediated by adenoviral vector after direct gene transfer into vein graft, Pro-UK gene expression could protect graft from thrombosis. Therefore, this method could effectively enhance venous graft patency.

Animals↗
PubMed1998

[Retroperitoneal laparoscopic unroofing of renal cyst: use of close method].

OBJECTIVE: To study the close method of retroperitoneal laparoscopic unroofing of renal cyst. METHOD: A close method retroperitoneal laparoscopic unroofing of renal cyst was attempted in 35 cases between May 1995 and December 1996. The age of the patients ranged from 30 to 72 and the cyst size from 4.0 to 9.3 cm. RESULTS: The operative procedure took around 50 minutes. After a 1 - 18 month follow up, we observed the disappearance of all renal cysts. CONCLUSION: The laparoscopic procedure renders less trauma and discomfort to the patients and may be better indicated for symptomatic, simple renal cysts.

Adult↗
PubMed1998

[Determination and significance of catecholamines in aqueous humor, plasma and 24 hour urine of patients with acute angle-closure glaucoma].

OBJECTIVE: To study the functional state of ocular and systemic sympathetic nervous system and the effects of its related neurohumoral factor, catecholamines (CA), on intraocular pressure (IOP) in patients with acute angle-closure glaucoma (AACG). METHODS: The levels of CA in the aqueous humor, plasma and the total amount of CA in 24 hour urine of cases with AACG during attack stage were determined with fluorometry, and the results were compared to that of patients with senile cataract and normal adults. RESULTS: The CA levels within aqueous humor and plasma and in 24 hour urine of the patients with AACG during attack stage were elevated obviously as compared with that of the control subjects (P < 0.001), and positively correlated with the level of IOP. CONCLUSION: During attack stage of AACG, the ocular sympathetic nervous system is highly excited and a large amount of CA is released into the aqueous humor, in the meantime the systemic sympathetic nervous system is also excited and CA is released into the blood circulation, which may play a certain role in the regulation of IOP. Possibly, CA is an important supplemental factor within the attack stage of AACG.

Acute Disease↗
PubMed1998

[A study on the mechanism of apomorphine for treatment of myopia].

OBJECTIVES: To investigate the functions of dopamine D(1) and D(2) receptor in form deprivation myopia (FDM) and the influence of apomorphine (Apo) on inhibition of FDM in chick with radioligand binding assay (RBA). METHODS: All chicks after hatching were divided into three groups: unilateral lid suture, lid-suture and treated with Apo subconjunctival injections and normal control. After two weeks, they were refracted, then were killed, their equator dimensions of the eyeballs were measured quickly, the retinas were dissected out and pooled into three above separate groups. [(3)H]SCH 23390 and [(3)H] Spiperone were used for the saturation tests for D(1) and D(2) receptor protein respectively in the three groups. RESULTS: The numbers of both dopamine receptors in FDM increased (up-regulation). With the treatment of Apo, the numbers of both dopamine receptors decreased (down-regulation). The affinities of both receptors were of no difference. CONCLUSIONS: The dopamine receptors in chick retina are under hypersensitive state in FDM, that is related to the biological level lowering of dopamine. Apo can inhibit the development of myopia, and the D(1) and D(2) receptor numbers are decreased, showing that Apo can affect dopamine receptors in various degrees. The method of this study can provide a route to screen drugs for treatment of myopia.

Animals↗
PubMed1998

[Synthesis and structure-activity relationships of novel 14 beta-side chain taxol derivatives].

In order to develop new generation of taxol-like anticancer agents with fewer side effects, improved activity, superior pharmacological properties and broad antitumor spectrum, along with structure-activity relationship study, a series of new taxol derivatives are to be synthesized starting from sinenxan A--a biosynthetic taxane. Eight new 14 beta-side chain taxol derivatives with 4-OH and 4-Ac were synthesized in 5 and 6 steps from semisynthetic taxoid intermediate 7, respectively. These included taxol derivatives modified at C-2 position with benzoate, m-Cl benzoate, valerate and phenylacetate. All target compounds together with two other 14 beta-side chain taxol derivatives were tested in a microtubule assembly assay, and in an in vitro cytotoxicity assay (KB, A2780, HCT-8 cell line). All compounds had no effect in the microtubule assembly assay at 10 mumol.L-1. Most of them showed marginal activity in the in vitro cytotoxicity. The structure-activity relationship was different from taxol derivatives. 2-Aliphatic ester displayed similar activity to 2-aromatic ester, which indicated that the aromatic group at C-2 position was not important for cytotoxicity. Comparing among themselves, 4-OH derivatives possessed stronger activity than 4-Ac.

Antineoplastic Agents, Phytogenic↗
PubMed1998

[Synthesis and cytotoxicity of the new taxoids].

Sinenxan A is a new biosynthetic taxane. In order to search for new taxol analogues with cytotoxicity, sinenxan A was modified and studied. Ten new taxoids containing the tetrahydrofuran ring were esterified at C14 or C10 positions with taxol/taxotere side chain. Preliminary pharmacological tests showed that some of the compounds have certain cytotoxicity on KB, HCT-8 and A2780. Meanwhile, the relationship between their structures and activity was discussed.

Antineoplastic Agents, Phytogenic↗
PubMed1998

[Determination of 7 bio-active alkaloids in Stephania plants by RP-HPLC].

Seven bio-active alkaloids (stepholidine, sinoacutine, isocorydine, l-tetrahydropalmatine, crebanine, fanchinoline and tetrandrine) in Stephania plants were determined by RP-HPLC, using UV detection (282 nm) and gradient elution. The reversed phase system consisted of ODS column and methanol-water-triethylamine as mobile phase. The flow rate was 1.0 ml.min-1. Good linearity between peak heights and concentrations of the alkaloids was obtained in the concentration range. The HPLC method proved accurate, precise and sensitive. The results showed that there were some differences in the occurrence and content of the alkaloids between various species and between the same species from different habitats and collecting time. Based on the results, some species with high content of the 7 bio-active alkaloids were selected. The study provided some useful information for the utilization of medicinal plant resources in the genus Stephania.

Alkaloids↗
PubMed1998

[Studies on structure modification and structure-activity relationship of new taxoids derived from sinenxan a].

In order to develop new taxol analogues with possible antitumor properties, sinenxan A (SIA), a new biosynthetic taxoid, was chemically modified, mainly by esterification of C14-OH with taxol-like side-chain acids. Twenty-one new taxoids thus formed were tested on three kinds of cell lines. Their activities are far below those of taxol. The SAR of SIA derivatives partly agree with that of taxol and can be roughly discerned.

Antineoplastic Agents, Phytogenic↗
PubMed1998

[Exploration on statistical method for calculating intensity of the infection in residents in nationwide sampling survey of schistosomiasis].

AIM: To set up statistical methods for calculation of intensity of schistosome infection in residents in nationwide sampling survey of schistosomiasis. METHODS: Based on the epidemiological survey of schistosomiasis and according to the medical statistics for multiple stratifying and clustering random sampling, the calculation method on intensity of schistosome infection was inferred. RESULTS AND CONCLUSION: Nine formulas were worked out for the calculation of the intensity of schistosome infection in different endemic provinces with different ecotypes. These formulas are of practical value.

China↗
PubMed1998

[The relation of neonatal hyaline membrane disease and congenital human cytomegalovirus infection].

To study the relation of neonatal hyaline membrane disease (HMD) and congenital human cytomegalovirus (HCMV) infection, two pairs of primers were synthesized according to the sequence of HCMV conserved region of the immediate--early(IE) gene. The nested polymerase chain reaction (nested-PCR) was used for the detection of HCMV-DNA of the paraffin-embedded lung tissues from neonatal HMD and non-neonatal HMD. 11 of 30 neonatal HMD patients were positive, the positive rate was 36.7%. Specimens of non-neonatal HMD patients were all negative. The difference between the two groups was significant (chi 2 = 5.05, P < 0.025). There is close relationship between neonatal HMD and congenital HCMV infection.

Cytomegalovirus↗
PubMed1998

[Application of computer simulation in the study of vibrational distributions for the products from energy transfer reaction].

The method of computer simulation in the study of vibrational distributions for the products from the energy transfer reaction is discussed. Taking the Ar (3P(0.2)) + PCl --> PCl (A3II) reaction as an example, we analysed the process of the simulation and the problems that should be paid attention to. The Franck-Condon factors of PCl (A3II --> X3sigma(-1)) are reported for the first time.

English Abstract↗
PubMed1998

A role for amyloid precursor-like protein 2 in corneal epithelial wound healing.

PURPOSE: The authors previously showed that the mRNA encoding the amyloid precursor-like protein 2 (APLP2) was one of several genes with upregulated expression in healing corneal epithelium. To elucidate the physiological role of APLP2 in corneal epithelial cells, the expression, distribution, and posttranslational modification of APLP2 were investigated. METHODS: Alternative splicing was assessed by reverse transcription-polymerase chain reaction; translational expression and posttranslational modification were assessed by chondroitinase digestion and Western blotting. The differential distribution of APLP2 in corneal epithelium was examined by in situ hybridization and immunohistochemical analyses. RESULTS: In rat corneal epithelium, the majority of APLP2 mRNA generated from two alternative splicing sites was found to contain the exon encoding a Kunitz protease inhibitor domain in the first site but to lack the exon encoding a 12-amino acid insert in the second site. The absence of the 12-amino acid insert indicated that APLP2 could be modified by the addition of a chondroitin sulfate (CS) glycosaminoglycan chain. The CS proteoglycan nature of APLP2 was verified by chondroitinase digestion. After wounding, APLP2 mRNA and polypeptides were increased markedly in the basal epithelial cells that were actively migrating. Furthermore, APLP2 was observed in the denuded wound bed immediately adjacent to the leading edge of migratory cells and under the epithelial sheet after wound closure. CONCLUSIONS: The wound-induced, basal-cell-specific APLP2 expression correlates with epithelial cell migration. The spatial and temporal expression of Kunitz protease inhibitor-containing, CS-modified APLP2 in healing corneal epithelium is consistent with its hypothesized role(s) in mediating reorganization of the extracellular matrix and dynamic cell-matrix adhesion during reepithelialization.

Alternative Splicing↗
PubMed1998

Expression and distribution of adhesion molecule CD44 in healing corneal epithelia.

PURPOSE: To study isoform expression and cellular distribution of CD44, a cell surface glycoprotein thought to be an adhesion molecule in cell-cell and cell-substratum interactions, during corneal epithelial wound healing. METHODS: Reverse transcription-polymerase chain reaction was performed to determine alternatively spliced rat CD44 isoforms. In situ hybridization was carried out on frozen sections of the rat corneas obtained at different time points after epithelial debridement. 35S-Labeled sense and antisense cRNA that recognizes rat CD44 standard form was used as a probe. Immunofluorescence was used to assess expression and localization of CD44 in the rat corneas during reepithelialization. RESULTS: Corneal epithelia contained several alternatively spliced CD44 variants. Four large CD44 variants with inserts V1 through V10, V2 through V10, V3 through V10, and V4 through V10 were differentially expressed in migratory epithelia. The silver grains, indicating CD44 transcripts, started to increase in the epithelial cells surrounding the wound margin 3 hours after wounding and peaked at 18 hours in the basal epithelial cell layers, at which time the epithelia were actively migrating. As the cells began proliferation after wounding, the density of CD44 mRNA label declined but was still significantly higher than that in control specimens. The label returned to basal level as epithelial cells reverted to their normal phenotype. The location of CD44 on cell surfaces during corneal reepithelialization was consistent with the pattern of mRNA production. In the corneas at 18 hours after wounding, CD44 immunoreactivity was elevated in the entire epithelium, from the leading edge to the limbal-corneal border. As happened for the mRNA, the cell surface CD44 declined as cells differentiated to reestablish the multilayered epithelium. CONCLUSIONS: The expression of CD44 correlates with corneal reepithelialization, suggesting that CD44 may be involved in cell-cell interactions that provide adhesive strength for the much-stressed epithelial sheet and in the cell-substratum interactions that mediate cell migration during reepithelialization.

Alternative Splicing↗
PubMed1998

Parallel comparative trial of amlodipine and nitrendipine monotherapy in patients with essential hypertension.

OBJECTIVES: To compare the blood pressure effects of two dihydropyridine calcium channel blockers, amlodipine and nitrendipine, in 488 patients with essential hypertension. METHODS: The study used a randomized, single-blind design of 4 weeks' duration conducted at four medical centres in China. Patients were randomized to receive either amlodipine monotherapy (5-10 mg once daily; n = 334) or nitrendipine (10 mg twice or three times daily; n = 1 54). Blood pressure was evaluated by standard blood pressure measurements before and after treatment, and by 24 h ambulatory blood pressure monitoring in a subgroup of patients (n = 18). RESULTS: Both systolic and diastolic blood pressures were reduced from baseline after 4 weeks of amlodipine and nitrendipine monotherapy. Diastolic blood pressure was reduced by 14.4% in the amlodipine group, which was significantly better than the 13.0% reduction in the nitrendipine group (P< 0.05). In addition, blood pressure response rates were significantly better with amlodipine monotherapy than with nitrendipine monotherapy. In the subgroup of patients undergoing 24 h ambulatory blood pressure monitoring, both systolic and diastolic blood pressure were reduced from baseline in the amlodipine and nitrendipine groups. Adverse effects were generally mild, with dizziness, flushing, palpitation, headache, drowsiness and ankle oedema being the most common. Rushing and headache were more frequent in the nitrendipine group than in the amlodipine group (P< 0.05 for flushing and P<0.01 for headache). CONCLUSIONS: Amlodipine monotherapy reduced blood pressure more effectively than nitrendipine monotherapy in patients with essential hypertension and was associated with fewer adverse events.

Adult↗