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Biomedical subjects

Z Cheng

Publications and source records attributed to Z Cheng.

At least 145 records · Page 8Linked to original sources
PubMed1995

Molecular cloning, sequencing, and expression in Escherichia coli of the chalcone synthase gene.

Flavonoids form a class of secondary metabolites that are abundant in all higher plants. They serve important functions in flower pigmentation. Chalcone Synthase (CHS) is a key enzyme in the biosynthesis of all classes of flavonoids; therefore, variation of the expression of CHS might change the color of flowers. We cloned CHS-A gene from Petunia hybrida, which has 99% sequence homology with those that have been cloned abroad. The sequence of the coding region is 1170bp and encodes a protein of 39kDa. CHS-A gene is also expressed high-efficiently in E. coli. All this work establishes a sound basis for future research on the impact of the CHS-A gene on flower pigmentation.

Acyltransferases↗
PubMed1995

[A research of acute hemodynamics and hormonal changes of intravenous captopril in patients with cor pulmonale and pulmonary hypertension].

In 20 patients of cor pulmonale with heart failure and respiratory failure and in 11 healthy men, after intravenous captopril injection, acute hemodynamic and hormonal change were observed. The results indicated that intravenous captopril injection rapidly reduced cardiac preload and afterload, reduced pulmonary arterial pressure, increased cardiac output, inhibited renin system activity, decreased plasma level of thyroxin and atrial natriuretic peptide. A rapid symptomatic improvement in patients with acute or severe cor pulmonale was shown and there was no significant effect on blood gas immediately.

Adult↗
PubMed1994

[Microdissection of human chromosome 1].

This work began with chromosome preparation and microdissection. Booster IRS-PCR was developed to amplify DNA dissected form human chromosome 1. The accuracy of microdissection was demonstrated by chromosomal in situ suppression (CISS)-hybridization. The amplified DNA fragments were ligated to pUC 18 vector at SmaI site and the average size of the inserts was about 450bp.

Chromosomes, Human, Pair 1↗
PubMed1994

Hypocotyl protoplast culture in Brassica napus L.

Protoplasts were isolated from the hypocotyls of two oilseed rape (Brassica napus L.) cultivars, Yunbei 2 and Ningyou 7. Light treatment during seed germination could apparently increase their cell division frequency. The purified protoplasts were cultured with three different methods. The method called "agarose island" was found superior to two others ("thin liquid layer" and "agarose solid layer"). The protoplasts cultured in the "agarose island" divided more rapidly and developed into calli more frequently. Shoot regeneration occurred soon after the transfer of protoplast-derived calli onto the differentiation medium. Individual shoots were rooted on the rooting medium. Whole plants were transplanted into pots, and grew well in the phytotron. The "agarose island" method might be suitable for genetic transformation of protoplasts because the liquid medium surrounding the "island" could be conveniently replaced without strong disturbing the microenvironment of protoplasts plated.

Biotechnology↗
PubMed1993

[Cytogenetic and molecular genetic study on a female with complex translocation of t(Y;15) and t(14;21)].

A 27-year-old female having a baby with Down's syndrome was found to have a translocation t(14;21) and an acrocentric marker chromosome 15. The short arm of the marker was darkly stained in both G- and C-banded preparations, and had the normal Ag-NOR, but showed a homogeneously stained region in the distal part of the marker. By means of QM staining, the variant was found fluorescent, and Y-body like was found in about 9% interphase nuclei, which suggested that there might exist Y chromosome material in genomic DNA of proband. Dot blot hybridization using DNA probe pY3.4 derived from the heterochromatic region on the long arm of Y chromosome demonstrated that the proband carried Y chromosome material in her genome. Further, by in situ hybridization with the same probe, it showed that the variant of the marker had specific autoradiographic silver grains. So, the karyotype of the proband indicated that the combination of conventional banding analysis with chromosome-specific probe was of great significance in studying the micro-aberration of human chromosome.

Adult↗
PubMed1993

Ubiquitin immunoreactivity in corticotrophs following glucocorticoid treatment and in pituitary adenomas.

Ubiquitin involved in nonlysosomal protein degradation was studied in 31 nontumorous pituitary glands and 133 pituitary adenomas by immunocytochemical techniques. Normal nontumorous hypophyses were immunonegative for ubiquitin. Ubiquitin immunoreactivity was present in 3% to 30% of corticotrophs containing Crooke's hyaline in 10 of 12 glucocorticoid-treated patients. Fifty-eight adenomas showed ubiquitin-immunoreactive cells. Ubiquitin immunoreactivity was found in cytokeratin immunopositive filamentous inclusions of Crooke's cell adenomas and in fibrous bodies of somatotroph adenomas. Forty-five adenomas showed a diffuse cytoplasmic immunopositivity. No correlation was revealed between ubiquitin immunoreactivity, hormone content, and bromocriptine and octreotide treatments. The results are consistent with the interpretation that ubiquitin immunoreactivity in nontumorous corticotrophs containing Crooke's hyaline and in various adenomas is secondary to glucocorticoid excess or to altered metabolic activity. Whether ubiquitin expression reflects increased ubiquitin synthesis or decreased breakdown of ubiquitinated conjugates remains to be elucidated.

Adenoma↗
PubMed1993

A study on the clinical effect and immunological mechanism in the treatment of Hashimoto's thyroiditis by moxibustion.

71 cases of Hashimoto's thyroiditis were treated by moxibustion and their immune function and thyroid function were observed. It was found that moxibustion was able to reduce the thyroid antibodies in the peripheral blood of the patients with hypothyroidism and to recover their thyroid function. It was also found that moxibustion could lower the thyroid antibody secretory levels and ADCC (antibody-dependent cell-mediated cytotoxicity) activities of the lymphocytes. In addition, the action of moxibustion in reducing the secretion of thyroid antibodies was related to its action of regulating the proportions of T lymphocyte subsets. The results indicate that the treatment of Hashimoto's thyroiditis by moxibustion is probably accomplished through its effect in regulating the relationship among the T lymphocyte subsets.

Adult↗
PubMed1993

[Molecular and clinical cytogenetic studies of a family with a 22p+ marker chromosome].

A male with gonadal dysgenesis and a 22p+ was observed. Molecular and Clinical Cytogenetic studies have been carried out on the members of the family. The results showed that there was a 22p+ marker chromosome transmitted from the maternal grandmother of the proband to 6 members of this family. Its short arm showed a homogeneously dull stained region in C-banded preparations and a narrow dark or light stained band in R-, G-banded preparations respectively. A large Ag-band or double NORs was also observed on p+. The chromosomal in situ hybridization with tritium labelled rRNA gene probe demonstrated that the distribution of the silver grains was along the entire p+ of the marker chromosome. The number of silver grains on the short arm of the p+ was 3.9 times as that of any other normal acrocentric chromosomes. Two cases of female with repeated spontaneous abortions and 2 cases of male with gonadal dysgenesis were found by family study. Our studies, combining with previous literatures suggested that these abnormalities were probably in association with p+ marker chromosome.

Adult↗
PubMed1992

Chromosomal localization of the mouse prealbumin gene (Ttr) by in situ hybridization.

Prealbumin is a serum protein which plays an important role in plasma transport of retinol and thyroxine. The accumulation of a variant prealbumin is associated with a hereditary disorder, familial amyloidotic polyneuropathy (FAP). In situ hybridization with a mouse prealbumin gene cDNA probe was carried out in mouse fibroblasts. Analysis of 114 R-banded metaphases showed that 13% of the total grains were located on chromosome 4 and 46% of the grains on this chromosome were in the region C6-D1. Linkage and syntenic group analysis showed that the prealbumin gene (Ttr) is located between two syntenic groups on mouse chromosome 4, which corresponded to two syntenic groups present on human chromosomes 1 and 9.

Animals↗
PubMed1992

Human pituitary null cell adenomas and oncocytomas in vitro: effects of adenohypophysiotropic hormones and gonadal steroids on hormone secretion and tumor cell morphology.

Human pituitary null cell adenomas and oncocytomas are not associated with evidence of excess hormone secretion in vivo; their cellular derivation has not been clarified by morphologic investigation. In this study we examined 41 null cell adenomas and 58 oncocytomas in vitro to determine hormone release and its response to several adenohypophysiotropic hormones and gonadal steroids. In vitro, 96/99 tumors released LH, FSH, and/or alpha-subunit of glycoprotein hormones. TSH was released by 11 tumors. GH, PRL, and ACTH were found in small quantities in 11, 8, and 5 tumors, respectively. Only 3 tumors released no detectable hormones. Incubations with test substances were examined at 2- and 24-h periods for up to 72 h. All but 3 of 53 tumors showed marked and persistent increases in the release of LH, FSH, and/or alpha-subunit in response to GnRH in short and long duration experiments. Secretion of LH, FSH, or alpha-subunit was stimulated to more than 150% of control by TRH in 37/48 tumors, by CRH in 10/20, by GRH in 7/20. Estradiol, progesterone, and testosterone increased release of FSH, LH, and/or alpha-subunit in 23/32, 3/12, and 3/12 tumors, respectively, and reduced their release in 6/32, 5/12, and 7/12, respectively. In tumors which showed no response to gonadal steroids, GnRH in combination with estradiol, progesterone, or testosterone yielded the same result as GnRH alone; in tumors inhibited by gonadal steroids, GnRH in combination with one of those substances reduced the response to GnRH. No secretion of GH, PRL, ACTH, or TSH was detected after incubation with GRH, estradiol, CRH, or TRH except in the tumors which initially released GH, PRL, or TSH. Ultrastructural examination of cultured cells from 15 cases revealed morphologic alterations that correlated with changes in hormone release and could be quantified by morphometry. This study represents the largest analysis of hormone production and release in vitro and morphologic correlation of clinically nonfunctioning pituitary adenomas. The responsiveness of gonadotropin secretion by null cell adenomas and oncocytomas to GnRH and gonadal steroids resembles that of gonadotroph adenomas. However, the unexpected increases in gonadotropin release attributable to several other adenohypophysiotropic hormones and the release of multiple hormones suggests that null cell adenomas and oncocytomas may represent neoplasms derived from uncommitted or committed precursor cells that can undergo differentiation towards several cell lines.

Adenoma↗
PubMed1992

Molecular cytogenetic study of short arm aberrations in human D, G group chromosomes.

Six cases of Dp+/Gp+, 10 cases of D/G translocation, 1 case of supernumerary marker chromosome, and 1 case of Yqs were studied using molecular and cytogenetic techniques. The Ag-NOR frequencies of the Dp+ and Gp+ groups were found to be higher than those of normal controls, while their satellite association frequencies were lower. Autoradiographic silver grains were not significantly distributed along the p+ part of the marker chromosome as revealed by chromosomal in situ hybridization using an rRNA probe. This result differs from our previous report. It is suggested that there might be different mechanisms for the formation of p+ on acrocentric chromosomes. D/G translocation cases were found to have lost their NOR. A study of supernumerary marker chromosomes and Yqs cases suggested that the marker chromosome and Yqs exerted no phenotypic effect. The mechanism of their formation is discussed.

Adolescent↗
PubMed1992

[Molecular cytogenetic study of an extra small chromosome].

An extra small chromosome was observed in a three-generation family. Eight members of this family were involved, but their phenotypes were normal. Molecular cytogenetic study was carried out, using cytogenetic methods and chromosome in situ hybridization with 3H-labelled rDNA probe. The results showed that this chromosome was from the short arm of chromosome of D/G group. The origin and genetic effects of this chromosome and fertility of the carriers were also discussed were also discussed briefly.

Adult↗
PubMed1992

[Interphase cytogenetic studies of human X chromosome].

The chromosome in situ hybridization with human X chromosome alpha satellite DNA probe (pBamX7) on human lymphocyte metaphases and interphase nuclei was performed for interphase cytogenetic studies. The individuals with numerical or structural abnormalities of X chromosome were studied. The results showed that the probe hybridized specifically to the centromeric region (p11----q11) of X chromosome. The number of silver grain clusters in interphase nuclei was correlated with that of X chromosome. Most of the clusters located near the nuclear membrane where inactive X chromatins (Barr-bodies) were usually found. The method of ascertaining the number of X chromosomes by in situ hybridization was much more reliable than that by counting the number of Barr-bodies. The modified R-banding technique was introduced and the significance of this work was also discussed.

Chromosome Aberrations↗