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Biomedical subjects

Z Huang

Publications and source records attributed to Z Huang.

520 records · Page 29Linked to original sources
PubMed1988

Studies on the origin of the follicle associated epithelial cells of bursa Fabricii.

The present paper, by using interspecific chimera of chick and quail and submicroscopic study on the bursal follicle associated epithelium (FAE) cells during differentiation, indicates that FAE cells of the bursa of Fabricius are formed not by differentiation of the epithelial cells but originate from the mesenchymal cells after invading the bursal anlage, and then differentiate into FAE cells. A new suggestion is given on the interpretation of the mechanism of the invasion of hemopoietic stem cells into the bursal epithelium.

Animals↗
PubMedDate not supplied

HPLC method for the determination of paeoniflorin in Paeonia Lactiflare Pall and its preparations.

An HPLC method was described for the determination of Paeoniflorin in Paeonia Lactiflare Pall and its set prescription preparations, Paeoniflorin was separated on an ODS column with a mobile phase of methanol-tetrahydrofuran-water (17:3:80, v/v/v) and detected at 230 nm. The result was calculated by external standard method. The recovery of Paeoniflorin in Paeonia Lactiflare Pall is 96.2% with relative standard deviation of 0.76%.

Benzoates↗
PubMedDate not supplied

Inhibition of estrone sulfatase in human liver microsomes by quercetin and other flavonoids.

Inhibition of estrone sulfatase activity offers the potential for breast cancer prevention therapy by blocking a route to estrogen synthesis. We have investigated the inhibition of this activity by natural flavonoids in a human hepatic microsomal preparation in vitro. The majority of studies were performed with a male liver, but male and female livers exhibited comparable estrone sulfatase activities. The natural flavonoids, quercetin, kaempferol, and naringenin, significantly inhibited estrone sulfatase activity with I50 < 10 microM for the most potent, quercetin. Estrone sulfatase activity in the liver microsomes was biphasic, with a high affinity, low capacity, low concentration activity (Km 14.3 microM, Vmax 0.5 nmol/min/mg protein), probably steroid sulfatase-catalysed, and a low affinity, high capacity, high concentration activity (Km 1.5 mM, Vmax 21.5 nmol/min/mg protein), probably arylsulfatase C or E-catalysed. The former activity was inhibited uncompetitively by quercetin, the latter competitively. Quercetin, a natural dietary constituent, is a potent inhibitor of estrone sulfatase in vitro, and thus has the potential to express antiestrogenic activity in vivo.

Aged↗
PubMedDate not supplied

The second national growth and development survey of children in China, 1985: children 0 to 7 years.

To evaluate the normal physical growth and development of Chinese children and to compare the nutritional status of today with that of ten years ago, a second national cross-sectional growth survey was undertaken in the same urban and suburban rural areas of nine main cities in China in 1985 as in 1975. In this survey 152,874 boys and girls from birth to age 7.0 years were measured for weight, height, sitting height, and chest, head and upper arm circumferences. Compared with the results in 1975, the condition of growth and development of children for both boys and girls from urban or suburban rural areas has been relatively much improved. Average weight and height had increased in the past 10 years by 0.40 kg and 1.8 cm respectively, in 6-7-year-old children. The greater part of the increase in height has been due to increase in leg length. The urban-rural difference in stature has become smaller, as the increase has been greater in rural areas. The data from this survey can be used as a new growth standard for Chinese children.

Anthropometry↗
PubMedDate not supplied

Serum alkaline phosphatase activity and skeletal maturation in Guatemalan adolescents.

Serum alkaline phosphatase activity (AP), stature and Tanner-Whitehouse-2 RUS skeletal age (SA) were determined for 873 rural Guatemalan youth and young adults 11-25 years of age. Mean AP decreases systematically with chronological age (CA) in girls, while an adolescent increase in mean AP occurs at 14 years in boys. When mean AP is calculated within SA groups, clear adolescent increases are apparent in girls, peaking at 11 years SA, and at 14 years SA in boys. Correlations between AP and relative skeletal age (SA-CA) decrease systematically from moderately positive at the youngest CA groups to moderately negative at the older ages, crossing zero at the chronological ages of maximum adolescent AP values. Analyses suggest the patterns of mean AP in adolescence follow closely the timing and patterns of growth velocity in stature in each sex, and are only indirectly related to SA as it is a proxy for the maturational timing of the adolescent spurt in stature.

Adolescent↗
PubMedDate not supplied

Flat-panel digital radiology with amorphous selenium and active-matrix readout.

Future imaging techniques will be capable of high image quality, fast acquisition, compactness, and versatile operation. A flat-panel imager that is expected to achieve these goals is under development. It consists of a thin layer of amorphous selenium that converts x rays directly to an electric charge and a thin-film electronic circuit, or active matrix, to read out the electronic signal directly to a computer host. The advantages of amorphous selenium include high resolution and low noise without loss of signal strength. The advantages of the active matrix are real-time readout, flexible design parameters, and compactness of the readout structures. A prototype of this imager has been built and operated, and initial images (of an x-ray test bar pattern and a hand phantom) have been acquired. Although the prototype was built to test scientific principles and many possibilities for optimization remain, the images already possess the quality necessary for many radiographic procedures. A large range of current and new applications exist for this imager.

Hand↗
PubMedDate not supplied

Modulation of apoptosis, tumorigenesity and metastatic potential with antisense H-ras oligodeoxynucleotides in a high metastatic tumor model of hepatoma: LCI-D20.

BACKGROUND/AIMS: To investigate the effect of antisense H-ras DNA on tumorigenesity, apoptosis and metastasis of a high metastatic tumor model of human hepatocellular carcinoma in nude mice LCI-D20. METHODOLOGY: LCI-D20 cells in primary culture were treated with 10 microns/L antisense oligodeoxynucleotide (ODN) drugs in vitro. 1.5 x 10(6) LCI-D20 cells with or without pretreatment were inoculated into each elevated subcutaneous (s.c.) flap in 14 nude mice, 6 animals for antisense H-ras oligodeoxynucleotide treated cells, 4 for H-ras non-specific antisense oligodeoxynucleotide treated cells, and the rest 4 for cells without pretreatment. RESULTS: In in vitro cell culture study, 5-day continuous suppression of H-ras expression by antisense H-ras oligodeoxynucleotide resulted in significant inhibition of the proliferation of LCI-D20 cells (t = 31.529, P < 0.01). In situ end-labeling detection showed that apoptotic cell death was significantly increased in cells with 5-day treatment of antisense H-ras oligodeoxynucleotide (34.0 +/- 4.5%) in comparing with cells without treatment (2.5 +/- 1.2%, t = 13.434, P < 0.01) or treated with non-specific antisense oligodeoxynucleotide (4.8 +/- 1.4%, t = 12.453, P < 0.01) at the corresponding time. In the in vivo experiment, at week 6, no palpable tumor could be found in 50% (3/6) of animals receiving cells with pretreatment of antisense H-ras oligodeoxynucleotide, while 100% (4/4, 4/4) of animals in the 2 control groups developed palpable tumors. Tumor growth in antisense H-ras treated animals was significantly retarded in comparison with that of the untreated (t = 3.509, P < 0.01) or non-specific antisense oligodeoxynucleotide treated animals (t = 3.452, P < 0.01). 75% to 100% of animals in the 2 control groups developed lung metastases, while in antisense H-ras treated animals lung metastasis foci could not be found by random serial section and microscopy (u = 2.536, P < 0.01; u = 3.162, P < 0.01, respectively). CONCLUSIONS: Specific inhibition of H-ras expression by antisense H-ras oligodeoxynucleotides could not only induce apoptotic cell death, inhibit the growth rate of LCI-D20 cells in vitro and in vivo, but also alter in vivo tumorigenesity and metastatic potential of LCI-D20 cells.

Animals↗
PubMedDate not supplied

A novel kind of antitumour drugs using sulfonamide as parent compound.

To obtain potent antitumour agents with low toxicity, sulfonamide derivatives containing 5-flurouracil and nitrogen mustard, respectively are designed and synthesised. 1-(3-(4-Acetylaminobenzenesulfonamido)-3-oxopropyl)-5-fluoropyrimidine-2,4-dione (4) was obtained by the coupling of p-acetamidobenzenesulfonamide with 3-(5-fluorouracil-1-yl) propionic acid. The hydrolysis of 4 led to 1-(3-(4-aminobenzenesulfonamido)-3-oxopropyl)-5-fluoropyrimidine-2,4-dione (5). Treatment of p-acetamidobenzenesulfonyl chloride with bis(2-chloroethyl) amine led to 4-acetylamino-N,N-bis(2-chloroethyl)benzenesulfonamide (6). Subsequent hydrolysis of 6 in hydrochloric acid led to 4-amino-N,N-bis(2-chloroethyl)benzenesulfonamide hydrochloride (7). Two different synthetic route were investigated in the synthesis of 2-[N(1)-2-pyrimidyl-aminobenzenesulfonamido] ethyl 4-bis(2-chloroethyl) aminophenyl butyrate (12b). Carbobenzyloxy was proved to be unsuitable for the protection of the aromatic amino group of sulfadiazine since the pyrimidine ring was also hydrogenated at the last step of the first route under the deprotection condition. In another route, acetyl was firstly used as the protective group, then it was replaced by the Schiff's base. The reaction of chlorambucil with 2-[N(1)-2-pyrimidinyl-(p-acetyl)aminobenzenesulfonamido] ethanol (10b) afforded 2-[N(1)-2-pyrimidinyl-(p-benzylidene)aminobenzenesulfonamido] ethyl 4-bis(2-chloroethyl) aminophenyl butyrate (11b). Compound 12b was obtained by the hydrolysis of 11b. The acute toxicity and antitumour activity of 5, 7 and 12b have been investigated in mice. Compound 12b exhibited high antitumour activity and low toxicity with a therapeutic index (TI) of 47.55.

Animals↗
PubMedDate not supplied

Topochemical design of bioactive peptides and peptidomimetics.

For the studies of bioactive peptides, our laboratories have been employed an integrated approach including synthesis, bioassays, and conformational analysis. To obtain highly potent, selective and metabolically stable analogs, peptidomimetics such as peptide backbone modifications (retro-inverso structures), constrained amino acids, and cyclic structures have been incorporated into many bioactive peptide sequences. The conformational studies of the resulting analogs have led to topochemical models for the bioactivities of those peptides. This lecture will be focused on the results of such studies on opioids and somatostatin. We have synthesized numerous opioid analogs with various peptidomimetics based on three classes: enkephalins, dermorphin-deltorphins, and morphiceptins. Many of these analogs exhibit high potency, selectivity, and metabolic stability. Conformational studies of these analogs have enabled us to define the structural characteristics necessary for bioactivities of morphiceptins, dermorphins, enkephalins, and deltorphins. From these results, we can propose conformational models responsible for bioactivities at the mu- and delta-receptors. Our studies of cyclic somatostatin analogs are based on the highly active Merck analog c(-Pro6-Phe7-D-Trp8-Lys9-Thr10-Phe11-) (where the superscripts denote position in native somatostatin). To investigate the topochemical preference of backbone and side chains, unusual amino acids, including beta-methylphenylalanine7 or 11, beta-methyltryptophan8, as well as backbone modifications such as retro-inverso structures have been incorporated. The bioactivity profiles of these peptidomimetic molecules provide much information on the effects of backbone and side chain constraints on bioactivity.

Amino Acid Sequence↗