Biomedical subjects

G X Zhao

Publications and source records attributed to G X Zhao.

At least 19 recordsLinked to original sources

PubMed2000

[Effects of -30 degrees head down tilt on lung function].

OBJECTIVE: To investigate the effects of short-term simulated weightlessness on lung function in healthy males. METHOD: -30 degrees head down tilt for 45 min was used to simulate short-period weightlessness. Lung function of 12 healthy males, aged 18-21, were studied with plethysmography during seating, supine and head down tilt positions. At the same time, blood flow in pulmonary artery and function of right ventricle were measured with Doppler Echo-Cardiography. Comparative analysis was done. RESULT: As body position changed from seating or supine into head down tilt, FVC, FEV1, FEV1%, MVV, VA and IVC decreased. The change of MVV was the most prominent (P < 0.000). As the position changed, pulmonary diffusion increased dramatically (DL(CO) P<0.001, K(CO) P<0.000). CONCLUSION: HDT may lead to a decrease of pulmonary ventilation and lung capacity. The increased pulmonary diffusion might be related to uniform distribution of pulmonary blood flow and increased effective pulmonary vascular bed.

Adolescent↗

PubMed2000

[Hemodynamic changes of pulmonary circulation during HDT -30 degrees].

OBJECTIVE: To study the hemodynamic changes of pulmonary circulation during simulated weightlessness. METHOD: 12 subjects were studied using echocardiography and electrocardiography during head-down tilt (HDT) of -30 degrees lasting for 45 min. RESULT: Right ventricular ejection time increased significantly (P<0.05); peak velocity of pulmonary arterial blood flow decreased significantly (P<0.05); acceleration time of pulmonary arterial blood flow did not change significantly; significant decrease of right ventricular output occurred at the 10th minute and the 30th minute (P<0.05); pre-ejection period significantly decreased at the 30th minute and recovery. Heart rate, mean velocity of pulmonary arterial blood flow, and acceleration of pulmonary arterial blood flow did not change significantly; left ventricular cardiac output, stroke volume and blood pressure remained constant throughout the experiment. CONCLUSION: Changes of the parameters of pulmonary circulation suggested that pulmonary resistance increased, and the increase of pulmonary resistance maybe be the direct cause of the increase of pulmonary arterial pressure.

Adult↗

PubMed1999

[Star figure in medical monitoring during lower body negative pressure test].

Objective. To find a real-time, quick and audio-visual method to evaluate the subject's physiological function condition and possible development. Method. Star figure technique was adopted to analyse multiple physiological indices during lower body negative pressure test (LBNP). Based on the character and stability of the stars figure, the steadiness of the subjects physiological function can be judged. Result. Physiological function can be accurately assessed only when the model of stress response of an individual is formed. Conclusion. The changes of star figure can indicate the possible development of the physiological function stage.

Adaptation, Physiological↗

PubMed1997

Additional bioactive annonaceous acetogenins from Asimina triloba (Annonaceae).

Trilobalicin (1), a new nonadjacent bis-THF ring annonaceous acetogenin, 2,4-cis- (2) and 2,4-trans-trilobacinone (3), the ketolactones of trilobacin, an adjacent bis-THF ring acetogenin, were isolated from the stem bark of Asimina triloba (L.) Dunal (Annonaceae). Their structures were established based on chemical and spectral evidence. The relative stereochemistry of 1 was determined as trans/threo/threo/trans/erythro from C-10 to C-22 by comparisons of NMR data with those of model compounds. Compound 1 is the first example of a nonadjacent bis-THF acetogenin being isolated from the title species and represents a new type of these compounds. Bioactivities of these new structures against brine shrimp larvae and six human solid tumor cell lines were determined, and cytotoxic selectivities were shown for the lung (A-549) and breast (MCF-7) cell lines with up to a million times the potency of adriamycin.

4-Butyrolactone↗

PubMed1997

Bioactive compounds from Taiwania cryptomerioides.

Two new sesquiterpenes, 10 alpha-hydroxyamorphan-4-en-3-one (1) and 4 alpha-methylcadinane-4 alpha-methyl-1 alpha,2 alpha,10 alpha-triol (2), together with four known compounds, sesquiterpenes 10 alpha-hydroxycadinan-4-en-3-one (3) and alpha-cadinol (4), diterpene ferruginol and lignan helioxanthin, were isolated from the whole plant of Taiwania cryptomerioides under bioassay-guided fractionations. The structures of 1 and 2 were elucidated mainly by the NMR spectroscopic analyses. Bioactivities of the isolated compounds against brine shrimp, yellow fever mosquito larvae, and human tumor cells are reported; compound 4 was the most bioactive, showing selectivity for the human colon tumor cell line (HT-29).

Aedes↗

PubMed1996

(2,4-cis)-asimicinone and (2,4-trans)-asimicinone: two novel bioactive ketolactone acetogenins from Asimina triloba (Annonaceae).

Two novel bioactive ketolactone Annonaceous acetogenins, (2,4-cis)-asimicinone (1) and (2,4-trans)-asimicinone (2), have been isolated from Asimina triloba (Annonaceae) by bioactivity directed fractionation. The separation of these two epimeric compounds was achieved by HPLC methods using a Si gel normal phase column eluted with acetone in hexane gradients. The assignments of cis or trans stereochemistry of the ketolactone moieties were made on the bases of 1H-1H COSY and NOESY experiments. 1 and 2 showed selective cytotoxicities against A-549 (human lung cancer) and MCF-7 (human breast cancer) cell lines with ED50 values as low as < 10(-7) micrograms/ml with 2 being the more active isomer.

Acetylation↗

PubMed1996

The absolute configuration of adjacent bis-THF acetogenins and asiminocin, a novel highly potent asimicin isomer from Asimina triloba.

A novel acetogenin, asiminocin (1), was isolated by activity-directed fractionation from the stem bark of the paw paw tree, Asimina triloba. By spectral and chemical methods, 1 was identified as (30S)-hydroxy-4-deoxyasimicin. The absolute configuration of 1, along with those of previously reported acetogenins asimin, asiminacin, bullatin, (30S)-bullanin, and (30R) bullanin, was determined by Mosher ester methodology. Compound 1 was highly inhibitory to three human solid tumor cell lines with over a billion times the potency of adriamycin.

Animals↗

PubMed1996

Three new adjacent bis-tetrahydrofuran acetogenins with four hydroxyl groups from Asimina triloba.

Three new adjacent bis-tetrahydrofuran ring Annonaceous acetogenins with four hydroxy groups, bullatetrocin (1), 10-hydroxyasimicin (2), and 10-hydroxytrilobacin (3), were isolated by activity-directed fractionation from the stem bark of Asimina triloba. Their structures were established on the basis of chemical and spectral evidence. The absolute stereochemistry at the C-10 hydroxy position was determined by converting 2 and 3 to their ketolactone isomers, 2,4-cis/trans 10-hydroxyasimicinones and 2,4-cis/trans 10-hydroxytrilobacinones, respectively. The bioactivities of the new compounds against brine shrimp larvae and six human solid-tumor cell lines are reported, and structure-activity relationships between trihydroxylated and tetrahydroxylated acetogenins are discussed. In addition to 1-3, gigantetrocin A, 2,4-cis/trans-gigantetrocin A-ones, annonacin, and annonacin A were also isolated for the first time from this species.

Animals↗

PubMed1995

Venezenin: a new bioactive Annonaceous acetogenin from the bark of Xylopia aromatica.

Asimicin and a new cytotoxic Annonaceous acetogenin, venezenin [1], were isolated from the bark of Xylopia aromatica by bioactivity-directed fractionation using lethality to brine shrimp. Compound 1 represents an unusual type of C37 Annonaceous acetogenin, lacking either tetrahydrofuran (THF) or epoxide rings and possessing a double bond located two methylenes away from a vicinal diol in the hydrocarbon chain. The structure of 1 was elucidated by 1H- and 13C-nmr, COSY, single-relayed COSY, and by HMBC techniques, and derivatization. Annomontacin 10-one [6] and 18/21-cis-annomontacin-10-one [7], two semi-synthetic mono-THF acetogenins were prepared from 1. These acetogenins showed cytotoxicity, comparable or superior to adriamycin, against three human solid tumor cell lines. Reduction of the 10-keto of 1 to the racemic OH-10 derivative enhanced the bioactivity, as did the conversion of 1 to 6 and 7. Venezenin [1], like other Annonaceous acetogenins, showed inhibition of oxygen uptake by rat liver mitochondria and demonstrated that the THF ring may not be essential to this mode of action.

Animals↗

PubMed1995

Two new cytotoxic monotetrahydrofuran Annonaceous acetogenins, annomuricins A and B, from the leaves of Annona muricata.

The leaves of Annona muricata have yielded eight monotetrahydrofuran Annonaceous acetogenins. Two of them, annomuricins A [1] and B [2], whose chemical structures were deduced by ms, nmr, ir, and uv spectral and chemical methods, are novel and unusual. Compounds 1 and 2 each possess five hydroxyl groups; two hydroxyl groups are vicinal, with the vicinal group of 1 threo and that of 2 erythro. The absolute configurations of 1 and 2 were determined by Mosher ester methodology. Six monotetrahydrofuran acetogenins, previously described in the seeds, were found in the leaves; these are gigantetrocin A, annonacin-10-one, muricatetrocins A and B, annonacin, and goniothalamicin.

4-Butyrolactone↗

PubMed1995

Muricatocins A and B, two new bioactive monotetrahydrofuran Annonaceous acetogenins from the leaves of Annona muricata.

The leaves of Annona muricata have yielded the novel monotetrahydrofuran Annonaceous acetogenins, muricatocins A [1] and B [2]. Each compound possesses five hydroxyl groups, with two hydroxyl groups at the C-10 and C-12 positions. The absolute configurations of 1 and 2 (except for positions C-10 and C-12) were determined by Mosher ester methodology. The C-10, C-12 acetonides (1c, 2c) suggested relative stereochemistry and significantly enhanced cytotoxicity against the A-549 human lung tumor cell line. Three known monotetrahydrofuran acetogenins, annonacin A, (2,4-trans)-isoannonacin, and (2,4-cis)-isoannonacin, were also found.

4-Butyrolactone↗

PubMed1995

New bioactive monotetrahydrofuran Annonaceous acetogenins, annomuricin C and muricatocin C, from the leaves of Annona muricata.

The leaves of Annona muricata have yielded two additional monotetrahydrofuran Annonaceous acetogenins, annomuricin C [1] and muricatocin C [2]. Compounds 1 and 2 each possess five hydroxyl groups; two hydroxyl groups are at the C-10/C-11 and C-10/C-12 positions in 1 and 2, respectively. The absolute configurations of 1 and 2, except for positions C-10 and C-11 or C-12, were determined by Mosher ester methodology. The C-10/C-11 and C-10/C-12 acetonides (1c, 2c) suggested relative stereochemistry and significantly enhanced the cytotoxicities against the A-549 human lung and the MCF-7 human beast solid tumor cell lines. One known monotetrahydrofuran acetogenin, gigantetronenin, not described previously from this plant, was also found.

4-Butyrolactone↗

PubMed1995

Longicin and goniothalamicinone: novel bioactive monotetrahydrofuran acetogenins from Asimina longifolia.

Longicin [1] and (2,4-cis and trans)-goniothalamicinone [2], two new monotetrahydrofuran Annonaceous acetogenins, have been isolated from the leaves and twigs of Asimina longifolia (the long leaf paw paw) by the use of the brine shrimp lethality test for bioactivity-directed fractionation. The structures were elucidated based on spectroscopic and chemical methods. Compound 1 was converted to its ketolactone isomer, (2,4-cis and trans)-longicinone [3], to aid the stereochemical elucidation of 1. Compounds 1-3 showed selective and potent cytotoxicities to certain human tumor cell lines, with the potency of 1 against pancreatic carcinoma (PaCa-2) over one million times that of adriamycin. Nine known cytotoxic acetogenins, annonacin, xylomaticin, isoannonacin, gigantetrocins A and B, muricatetrocins A and B, gigantetrocin-A-one and goniothalamicin, were also isolated for the first time from this species.

4-Butyrolactone↗

PubMed1995

Additional bioactive acetogenins, annomutacin and (2,4-trans and cis)-10R-annonacin-A-ones, from the leaves of Annona muricata.

In a continuation of our research on bioactive components from the leaves of Annona muricata, three novel monotetrahydrofuran Annonaceous acetogenins, namely, annomutacin [1], (2,4-trans)-10R-annonacin-A-one [2], and (2,4-cis)-10R- annonacin-A-one [3], have been identified. Their structures were deduced by ms, nmr, ir, and uv spectral and chemical methods, and the absolute configurations were determined by Mosher ester methodology. A known bioactive amide, N-p-coumaroyl tyramine, was also found. Compound 1 and the mixture of compounds 2 and 3 showed selective cytotoxicities against the human A-549 lung tumor cell line.

4-Butyrolactone↗

PubMed1994

Asimin, asiminacin, and asiminecin: novel highly cytotoxic asimicin isomers from Asimina triloba.

Activity-directed fractionation of the stem bark extracts of the North American paw paw tree, Asimina triloba (Annonaceae), has yielded three further acetogenins: asimin (2), asiminacin (3), and asiminecin (4). 2-4 are structural isomers of asimicin (1), which is a potent inhibitor of mitochondrial NADH:ubiquinone oxidoreductase, and thus exhibits potent antitumor and pesticidal effects. 2-4 have the same carbon skeleton and configurations as those of 1, but they have the third hydroxyl group located at C-10, C-28, and C-29, respectively, rather than at C-4. The determinations of the hydroxyl group locations were largely based on mass spectral analyses of TMSi and TMSi-d9 derivatives. 2-4 all showed highly potent cytotoxicities (ED50 values as low as < 10(-12) micrograms/mL) with notable selectivities for the HT-29 human colon cancer cell line. The presence of a third hydroxyl at C-4, C-10, C-28, or C-29, as in 1-4, greatly enhances the bioactivity of 4-deoxyasimicin (5).

Antineoplastic Agents, Phytogenic↗

PubMed1994

[One stage reconstruction of bladder exstrophy and epispadias with abdominal wall skin flap and rectus abdominis muscle flap: report of 5 cases].

5 cases of complete bladder exstrophy were treated by one stage reconstruction with abdominal wall skin flap and rectus abdominis muscle flap. Closure of the abdominal wall and bladder defect were achieved satisfactorily in all the patients. 4 patients have been followed up for 1.5-10.5 years. 3 patients whose bladder neck had been augmented by rectus abdominis muscle flap were continent but 1 patient whose bladder neck had not been, had giggle incontinence. The renal functions were all normal in these patients.

Adult↗

PubMed1993

Biologically active acetogenins from stem bark of Asimina triloba.

In continuing our research with cytotoxic and pesticidal components from the stem bark of the North American paw paw, Asimina triloba, the novel cytotoxic monotetrahydrofuran Annonaceous acetogenins, cis- and trans-annonacin-A-one, cis- and trans-gigantetrocinone and cis-isoannonacin, in addition to the known compounds, trans-isoannonacin and squamolone, have been identified. Brine shrimp lethality testing was used to direct the fractionation. The structures were elucidated by spectral analysis and/or chemical synthesis. These acetogenins have potent cytotoxicities against the human tumour cell lines of A-549 (lung carcinoma), MCF-7 (breast carcinoma) and HT-29 (colon adenocarcinoma).

Animals↗

PubMed1993

Homotransplantation of testis. A report of 11 cases.

Testis homotransplantation has been carried out in 11 patients since 1986. Of them, 8 suffered from congenital testicular dysplasia and the other 3 from orchiatrophy as a result of orchitis. Preoperatively, manifestations were a small penis, small testes, sexual dysfunction, indistinct secondary sex characteristics and low serum testosterone (1.7-7.35 mmol/L). Three cases had cadaver transplants and 8 had living relatives' transplants. The patients were followed up for 7 months to 4 years. The secondary sex characteristics and sexual function were improved remarkably after transplantation. Serum testosterone increased up to 12.8-18.2 mmol/L. All of 5 married patients resumed sexual intercourse satisfactorily. Three others got married after transplantation and have enjoyed normal sexual functions. Spermatozoa have been found in the semen in 3 of the cases.

Adult↗