Biomedical subjects

G Cai

Publications and source records attributed to G Cai.

At least 91 records · Page 5Linked to original sources

PubMed1996

[Inotropic effect of novel cardiotonic agent, vesnarinone--tests on anaesthetized dogs].

We studied the positive inotropic effect of the novel cardiotonic agent, vesnarinone on open chest and intact anaesthetized dogs hearts. The results indicate that vesnarinone has a dose-effect relationship on increasing the contractile force, LV dp/dt max and stroke volume, and it shortens the ejection time 21%. No effect on blood pressure and heart rate was noted. Vesnarione is more effective than amrinone in terms of positive inotropic effect.

Animals↗

PubMed1995

Purification and characterization of an endothelial cell-viability maintaining factor from fetal bovine serum.

Serum is an essential requirement for the growth and long-term survival of human endothelial cells, even in the presence of such defined elements such as polypeptide growth factors and hormones. A polypeptide from fetal bovine serum was isolated and characterized on the basis of long-term survival of human endothelial cells in serum-free culture. The endothelial cell viability maintaining factor has been purified to homogeneity by a combination of polyethylene glycol precipitation, hydroxylapatite, gel permeation and reverse-phase high performance liquid chromatography. The final purified endothelial cell viability maintaining factor has a molecular weight of 65,000 (reduced) and has been identified as bovine apolipoprotein H by amino-terminal amino acid sequence analysis and Western blot analysis. Endothelial cell viability maintaining factor improved a long-term viability of human endothelial cells at maximal concentrations of 2.5-5 micrograms protein/ml in serum-free medium.

Amino Acid Sequence↗

PubMed1995

Alpha 1-adrenoceptor responsiveness in the aging aorta.

Previous studies from this laboratory have shown that aortic alpha 1-adrenoceptor-mediated responsiveness is altered during maturation and aging. This study examines the possibility that there is a change in the alpha 1-adrenoceptor subtypes in the aorta during maturation and aging. The apparent affinity of norepinephrine, as determined by partial receptor inactivation with the alpha 1-adrenoceptor antagonist phenoxybenzamine, was found to be higher in 1-month-old rats compared to 6- and 24-month-old rats. The alpha 1B-adrenoceptor subtype-selective antagonist chlorethylclonidine was used to examine possible heterogeneity in aortic alpha 1-adrenoceptors. The inhibitory effect of chlorethylclonidine on norepinephrine-stimulated contraction was greater in young animals compared to aged animals. Chlorethylclonidine blocked norepinephrine-stimulated inositol phosphate accumulation in 1-month-old aorta but it produced only partial inhibition in the 6- and 24-month-old aortas. The relatively non-selective alpha 1-adrenoceptor antagonists phenoxybenzamine (0.1 microM) and prazosin (0.1 microM) inhibited inositol phosphate accumulation and contractile responses in all ages. The complete block of alpha 1-adrenoceptor-mediated responses by chlorethylclonidine in younger animals shows that alpha 1-adrenoceptor-mediated responses are mediated by the chlorethylclonidine-sensitive alpha 1-adrenoceptor subtypes. The partial inhibition by chlorethylclonidine of alpha 1-adrenoceptor-mediated responses in 6- and 24-month-old animals indicates an increased role of an alpha 1-adrenoceptor subtype that is relatively insensitive to chlorethylclonidine.

Adrenergic alpha-Antagonists↗

PubMed1995

High molecular weight polypeptides related to dynein heavy chains in Nicotiana tabacum pollen tubes.

Nicotiana tabacum pollen tubes contain two high molecular weight polypeptides (about 400 kDa), which are specifically expressed during pollen germination and pollen tube growth in BK medium. The high molecular weight doublet resembles the dynein heavy chains in some biochemical properties. Sedimentation profiles of pollen tube extracts show that the high molecular weight bands have sedimentation coefficients of 22 S and 12 S, respectively. ATPase assay of sedimentation fractions shows an activity ten times higher when stimulated by the presence of bovine brain microtubules in fractions containing the 22 S high molecular weight polypeptide. Both these high molecular weight polypeptides can bind microtubules in an ATP-dependent fashion. A mouse antiserum to a synthetic peptide reproducing the sequence of the most conserved ATP-binding site among dynein heavy chains recognized the two high molecular weight polypeptides. Therefore these polypeptides have sequences immunologically related to the ATP binding sites of dynein heavy chains.

Adenosine Triphosphatases↗

PubMed1995

Confocal imaging and immunogold electron microscopy of changes in distribution of myosin during pollen hydration, germination and pollen tube growth in Nicotiana tabacum L.

Using anti-myosin antibodies, standard immunocytochemical techniques in conjunction with confocal scanning laser microscopy and colloidal gold immunoelectron microscopy we compare changes in the distribution patterns of myosin during the early stages of pollen hydration, germination, tube growth, and myosin associated with isolated vegetative nucleus and the generative cell in Nicotiana tabacum L. Furthermore, on the Western blots of pollen tube proteins, the antimyosin antibodies crossreact only with one polypeptide of approximately 174 kDa. Confocal immunofluorescence microscopy reveals that in hydrated pollen, myosin is discretely associated with the cytoplasmic organelles and numerous punctate structures present in the center of the pollen. Within 30 min following transfer of pollen into the germination medium, that is, with the onset of germination, the centrally located punctate structures are displaced, and we find accumulation of myosin-associated organelles towards one of the germinal apertures from which the pollen tube would emerge. Subsequently, after 45 min of germination with the emergence of germination structure, few punctate structures are detected in the vegetative cytoplasm while intense immunostain is detected just below the plasma membrane of the emerging pollen tube tip. In the older parts of both short and long pollen tubes after 90 to 120 min of pollen germination, few fluorescent structures were found in the pollen tubes, however, numerous punctate fluorescent spots were concentrated in the tip region over a distance of 2 to 3 microns below the plasma membrane of the tube tip. This is further substantiated by colloidal gold immunoelectron microscopy wherein clusters of gold particles are associated with vesicle-like structures in the tip region of the pollen tubes.(ABSTRACT TRUNCATED AT 250 WORDS)

Blotting, Western↗

PubMed1995

[Qualitative observation and quantitative survey on the vasculature of the lateral thoracic region].

Since 1988, we had studied blood vessels on the lateral thoracic region in 21 patients using ultrasound Doppler flowmeter preoperatively, collaborating with operative observation, to measure the length, caliber and rate of existence of 3 main vascular systems. Our study attempted both to ascertain various regular patterns of vasculature, and to provide anatomical data for the choice of proper sites of pedicles of lateral thoracic flap. Our findings showed that the subscapular-thoracodorsal vascular system was the most constant among the 3 systems. Its average length was 15.43 +/- 0.504 cm, average diameter at its origin was 1.58 +/- 0.122 mm. The thoracoepigastric vein as a venous return system could be chosen first. We concluded that this method was a handy, practical and dependable way to determine the vascularity of lateral thoracic flaps.

Anthropometry↗

PubMed1995

[The lateral thoracic free flap in facio-cervical reconstruction].

We have applied the lateral thoracic free flap in 16 patients with face and/or neck defects during the past three years. 13 flaps survived completely and 3 flaps failed which was substituted with skin grafting. The lateral thoracic free flap possesses many supplying vessels and its advantages include big size, hairless skin with well matched color and texture and inconspicuous donor site that can be closed directly. The technique of hemodilution and microvascular anastomotic apparatus are introduced. The indications of the flap and the limitation of its size are discussed.

Adolescent↗

PubMed1995

[Detection of serum isoferritin level in 195 patients with cancer].

ELISA (double-determinant) was used to detect the serum isoferritin (SIF) levels in 42 patients with nasopharynx cancer (NPC), 38 with lung cancer (LC), 26 with esophageal cancer (EC) and 89 with other cancers, a total of 195 cases (151 males and 44 females). The results revealed that the positive rate of SIF in patients with cancer was 73.8% (144/195), among which, the positive rates in patients of stage I-II, stage III-IV, in patients not operated upon and in those after operation were 64.8%, 81.3%, 81.4% and 63.4%, respectively. Statistics was significantly different in SIF level between the stage I-II and III-IV groups, and between the un-operation and after operation groups (P < 0.001) by rank sum testing. The positive rates of NPC, LC and EC were 73.8%, 86.8% and 73.1%, respectively. The results have demonstrated that isoferritin is a malignant neoplasm associated antigen, and SIF level is related closely with the development of the tumor and operative treatment.

Biomarkers, Tumor↗

PubMed1995

Hairy root culture of Artemisia annua L. by Ri plasmid transformation and biosynthesis of artemisinin.

The hairy root culture system of the medical plant Artemisia annua L. was established by infection with Agrobacterium rhizogenes R1601. The transgenic state of transformed roots was confirmed by Southern blot hybridization with TL-DNA of pFw302. The expression of NPTII gene was confirmed by enzymic assay. The important secondary metabolites-artemisinin was obtained in the hairy root culture. The effects of various physical and chemical factors on the growth of the hairy roots and production of artemisinin were studied. Artemisinin could be detected in hairy roots cultures in the light. The optimum pH value of the medium was 5.4. Fast growth of the hairy roots and maximal production of artemisinin was observed in the presence of 3% sucrose. Low concentration of naphthylacetic acid (0.025 mg/L) enhanced the growth of the roots but inhibited the production of artemisinin. The growth and artemisinin production in hairy root cultures were greatly promoted by the addition of gibberellin (GA3) to the medium. Its optimum concentration was 4.8 mg/L.

Antimalarials↗

PubMed1994

Age-related changes in angiotensin II-stimulated vascular contraction and inositol phosphate accumulation in Fischer 344 rats.

This study examined the influence of age on angiotensin II (AII)-stimulated vascular contractile responses and inositol phosphate (IP) accumulation in Fischer 344 rats. In the aorta, AII-stimulated contraction and IP accumulation were markedly reduced in 6- and 24-month-old rats compared to 1-month-old rats. There was not a significant difference in the contractile response to AII between 6- and 24-month-old rats, although IP hydrolysis showed a further decrease between 6 and 24 months. In tail artery, there were no differences in contraction and phosphoinositol metabolism in response to AII in the different ages. Losartan blocked AII-stimulated vascular contraction and IP hydrolysis in both aorta and tail artery while PD123319 did not inhibit either response. These data indicate that during maturation, there is a decline in AII-stimulated aortic contraction and IP accumulation in aorta but not in tail artery and these changes are due to altered AT1 receptor function.

Aging↗

PubMed1994

Kinesin-related polypeptide is associated with vesicles from Corylus avellana pollen.

A 100-kDa polypeptide with microtubule-interacting properties was identified in a Golgi vesicle-enriched fraction from Corylus avellana pollen. The k71s23 antibody (directed to the kinesin heavy chain from bovine brain) [Tiezzi et al., 1992: Cell Motil. Cytoskeleton 21:132-137] localized the polypeptide on the external surface of membrane-bounded organelles. Some 100-kDa-containing vesicles copelleted with microtubules (polymerized from purified bovine brain tubulin) either in presence or absence of 5 mM AMPPNP, but they could be released by 10 mM ATP or 0.5 M KCl. The pollen microtubule-interacting protein, salt-extracted from membranes and partially purified by gel filtration, exhibited an ATPase activity (16.2 nmolPi/mg/min) which could be stimulated about 2-fold (32.5 nmolPi/mg/min) by addition of bovine brain microtubules. We suppose that the 100-kDa polypeptide is part of a molecular complex showing properties of the kinesin class.

Animals↗

PubMed1994

Prenatal cocaine exposure affects the development of aortic adrenergic innervation and contractile responses.

This study examines the effects of prenatal cocaine administration on the development of vascular sympathetic innervation and contractile responsiveness. Rabbits received cocaine (4 mg/kg, iv, bid) or saline during gestational days 8 to 29. Aortas were obtained on postnatal days 10, 20, 30 and 50. Vascular smooth muscle responsiveness was assessed by measuring aortic contractile responses to norepinephrine (NE) and to other vasoconstrictors. Vascular adrenergic innervation was evaluated by measuring desipramine sensitive [3H]-NE uptake into aortic ring segments and aortic NE content. [3H]-NE uptake and NE content were reduced at postnatal days 10 and 20 in the rabbits exposed prenatally to cocaine. Differences were not observed at postnatal days 30 or 50. The contractile response to NE was reduced in rabbits exposed to cocaine prenatally. Maximal response and potency were decreased at postnatal day 10 and potency was still decreased at day 20, but not at the older ages. Contractile responses to serotonin (5-HT) and angiotensin II (AII) were not affected by prenatal cocaine exposure. These results suggest that prenatal cocaine exposure delays the development of aortic adrenergic innervation and alpha adrenoceptor responsiveness.

Angiotensin II↗

PubMed1994

Confocal image analysis of spatial variations in immunocytochemically identified calmodulin during pollen hydration, germination and pollen tube tip growth in Nicotiana tabacum L.

Using monoclonal anti-calmodulin antibodies in conjunction with confocal scanning laser microscopy we have analysed the spatial variations in the distribution pattern of calmodulin (CaM) during the sequential events of pollen hydration, germination and tube growth in Nicotiana tabacum. These immunocytochemical observations have been complemented by immunochemical studies wherein the anti-calmodulin antibody raised against pea CaM recognises a polypeptide of c. 18 kDa in the pollen extracts. Digitisation of confocally acquired optical sections of immunofluorescence images reveals that in hydrated pollen a high level of CaM is consistently present in the region of the germinal apertures. Subsequently, with the onset of germination a high CaM concentration was found associated with the plasma membrane of the germination bubble and in the cytoplasm in its vicinity, while in the vegetative cytoplasm a weak diffuse and intense punctate signal was registered. CaM immunostain was also detected in association with the plasma membrane of the tube tips in both short and long pollen tubes. Furthermore, the cytosol of the tubes invariably manifested an apically focused CaM gradient. We were, however, unable to detect any vacuolar association of CaM in the older regions of the pollen tubes. Although punctate immunostain was obvious across the pollen tube numerous punctate structures were invariably present in the extreme tip. The possible implications of these findings in development of cell polarity, polarised growth, maintenance of calcium homeostasis and CaM interactions with other mechanochemical motor proteins in effecting propulsion of organelles during pollen hydration, germination and pollen tube growth are discussed.

Blotting, Western↗

PubMed1994

[Development of a monoclonal antibody (AF9) to human breast carcinoma].

A monoclonal antibody AF9 (IgG1) was raised against human breast carcinoma by fusing murine myeloma SP2/0 cells with spleen cells from BALB/c mice immunized with cell membrane extracts from primary breast carcinoma. Immunohistochemical staining using the antibody showed reactivity in 19 out of 20 breast carcinoma tissues and in some nonbreast carcinomas such as hepatic, ovarian, lung, colon, and gastric carcinoma tissues. But no staining was observed in either normal tissues or other carcinomas. By immunological treatment, the antigen recognized by AF9 was referred to be glycoprotein with lipid component, and Western blotting revealed that its molecular weight is 51, 56, 67 and 73kd.

Animals↗

PubMed1994

[Detection of isoferritin level in breast cancer tissue and serum].

ELISA (double-determinant) was used to evaluate the isoferritin level in the breast cancer tissue. The isoferritin concentration was measured in cytosol extracts of 25 breast cancer tissues (BCT), 6 cancer surrounding tissues (CST) and 8 normal breast tissues (NBT). With the results of 16,023 +/- 15,732, 2467 +/- 1360 and 1382 +/- 647 ng/mcp (milligrams of ontosol protein), respectively. The isoferritin concentrations of BCT and CST were 11.6 and 1.8 times as much as that of NBT, and the differences were statistically significant (P < 0.001 and 0.05). The serum isoferritin level was also measured in 96 healthy persons and 68 breast cancer patients (mean 58.7 +/- 35.8 and 473.3 +/- 297.3 ng/ml) with the difference as big as 8.1 times. The results have demonstrated that the level of cytosol isoferritin in BCT is an important parameter of breast tissue malignance and may be also responsible for the serum isoferritin increase. Therefore we think that serum isoferritin may be used as a marker for early diagnosis of breast cancer.

Biomarkers, Tumor↗

PubMed1992

An immunoreactive homolog of mammalian kinesin in Nicotiana tabacum pollen tubes.

A cytoskeletal apparatus is involved in the movement of vesicles, organelles, and gametes in the pollen tube. The function of microfilaments has been defined quite precisely, but the role of microtubules needs to be further clarified. On the basis of immunological and biochemical investigations, we have identified a polypeptide showing common properties with kinesin, a microtubule-based motor mainly described in nonplant tissues, in the pollen tube of Nicotiana tabacum. Like mammalian kinesin, the kinesin-immunoreactive homolog from Nicotiana tabacum pollen tubes binds to mammalian microtubules in an AMP-PNP dependent manner. The kinesin-like component is likely to be involved in the movement of vesicular material in the growing pollen tube.

Adenylyl Imidodiphosphate↗

PubMed1992

[ELISA of serum isoferritin and its clinical application].

Serum isoferritin levels were detected by ELISA in 96 normal, 11 cases of hepatocellular carcinoma (HCC), 28 breast cancer (BC), 31 lung cancer (LC), 26 breast fibroma, 11 pneumonia and 11 tuberculosis. The results reveal significant differences of serum isoferritin levels between the normals and the patients, and between the malignant cases and benign cases (P < 0.01). Serum isoferritin demonstrates higher sensitivity in detecting HCC, LC and BC and thus is of great value in the differential diagnosis of these cancers.

Adult↗

PubMed1991

[A study on characters of liver isoferritin].

The characters of liver isoferritin from Wistar rat, normal human and patient with hepatocellular carcinoma (HCC) were studied. The ratio of iron to protein of liver isoferritin from patient with HCC were 0.021, which accounts for about one-twelfth of that of liver isoferritin from normal human. The molecular weights of liver isoferritin from normal human and the patient with HCC were 20.5 kd and 21.5 kd, respectively. The electrophoresis patterns of liver isoferritin from both Wistar rat and patient with HCC showed one band, but two bands from normal human. There was cross reaction in immunity among isoferritins from normal human liver, Wistar rat liver and horse spleen by double immunodiffusion. The PAGE patterns of liver isoferritin from different sources could be clearly differentiated. The data presented may serve as a good reference for further study of the relationship between the structure and function of ferritin and may be used practically in clinical medicine.

Animals↗