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Biomedical subjects

Y F Hu

Publications and source records attributed to Y F Hu.

At least 55 records · Page 3Linked to original sources
PubMed1993

[Radioimmunoassay of plasma endothelin in maternal and fetal umbilical cord vein in pregnancy induced hypertension].

Endothelin (ET) level was measured in 48 cases of normal pregnancies and in 29 cases of pregnancy induced hypertension (PIH) by radioimmunoassay (RIA). The results indicate that the difference of ET values between maternal and fetal umbilical cord vein was nonsignificant in normal pregnancy. Though a slight increase in maternal ET level was found in mild and moderate PIH, however the difference was nonsignificant when compared with normal pregnancy. ET increased significantly in plasma of patients with severe PIH. ET levels of fetal umbilical cord vein in different groups showed no much change. It suggests that ET increasing in plasma of patients with PIH may play a role in pathogenesis of PIH.

Adult↗
PubMed1993

Antiproliferative and antimetastatic effects of gossypol on Dunning prostate cell-bearing Copenhagen rats.

Gossypol, a polyphenolic aldehyde naturally present in cottonseed, has long been recognized as a male contraceptive and recently as a potential anticancer agent. Our study used a rodent model to evaluate gossypol's potential for the treatment of human prostatic carcinoma. Two-month-old Copenhagen male rats received subcutaneous implants of a subpassage of MAT-LyLu prostatic cancer line, a highly metastatic, androgen-independent Dunning prostate tumor subline that specifically metastasizes to lymph nodes and lungs of recipients. After 2 weeks of gossypol treatment (0 or 12.5 mg/kg B.W./day S.C.) initiated immediately after transplantation, the rats were sacrificed and evaluated for prostate tumor growth and metastasis. Testosterone and gossypol levels in tumor tissue and various reproductive organs and serum potassium level were measured by radioimmunoassay (RIA), high pressure liquid chromatography (HPLC) and atomic emission spectroscopy (AES), respectively. Gossypol-treated rats exhibited weight reductions in developed MAT-LyLu prostate tumor mass and prostate of 24% (p < 0.05) and 31% (p < 0.05), respectively; whereas testicular and epididymal weights were not significantly affected. Few metastases (20%) were observed in either lymph nodes or lungs of gossypol-treated recipients. The control rats, however, had a much higher rate of lung (60%) and lymph node metastasis (40%). Testicular testosterone levels, as measured by RIA, were significantly lower in gossypol-treated rats than in controls (p < 0.05), but serum testosterone levels were not different. Extractable gossypol content in the prostate tumor, as measured by HPLC, reached 19.67 ng/gm and was 1.28 times higher than in liver, 1.98 times higher than in testes, but was 3.3% of that in prostate. Moreover, serum had the highest gossypol content (10.7 micrograms/ml). Serum potassium levels, as measured by AES, were significantly higher in gossypol-treated individuals than controls (p < 0.05). Our results indicate for the first time that gossypol has antiproliferative and antimetastatic effects on MAT-LyLu prostate cancer cells and can be explored as a potential therapeutic agent for androgen-independent human prostatic carcinoma.

Androgens↗
PubMed1992

Transfer of 3H-gossypol to neonatal rats via milk of nursing dams.

Gossypol is a naturally occurring toxin with potent antifertility action in both males and females. Transfer of gossypol via milk from lactating mother to neonates has not been documented. One theory for the lack of such a finding is that gossypol, once tightly bound to milk proteins, is not extractable by conventional extraction methods for HPLC analysis. This study was designed to examine the possibility and dynamics of transmammary transfer of radioactively-labelled gossypol to neonates through nursing. Nursing rats were dosed with fifty microCi of 3H-gossypol in 0.5 ml of dimethyl sulfoxide via oral intubation on Day 10 post-partum. Six hours after treatment, significant amounts of 3H-gossypol were detected in the coagulated milk collected from the stomachs of the neonates as well as in the blood, liver, lung, spleen and a number of other tissues of these pups. While most neonatal tissues showed a steady decline in 3H-gossypol retention over time regardless of neonatal gender, adrenal glands and gonads preferentially accumulated 3H-gossypol in a time- and sex-dependent manner during the 24-hour sampling period. The results demonstrate that 3H-gossypol is transferred via milk from the nursing dams to their neonates. Thus, the gossypol content of milk presents a conceivable threat to neonatal health, especially to the normal function of steroidogenic organs.

Animals↗
PubMed1992

Effect of human growth hormone on the proliferation of human fetal islet cells in vitro.

In this study it was shown that 1000 micrograms/L hGH in serum-free medium promoted the attachment, spreading and formation of monolayer of islet cells. The radioactivity test indicated that hGH significantly stimulated the DNA synthesis of islet cells (P < 0.001). Furthermore, after 48 h exposure to hGH (1000 micrograms/L), both the insulin contents and release of islet cells significantly increased (P < 0.001); hGH also enhanced the responsiveness of fetal islet cells to high-concentration glucose plus theophylline stimulation (P < 0.001). However, the effect of hGH in the medium containing 10% newborn calf serum was not so prominent in comparison with that in the serum-free medium. The morphologic assay for mitotic cells showed a combination of 1000 micrograms/L hGH and 10% serum was the most efficient for inducing the mitosis, the mitotic index being 5.95%. We conclude that hGH is an important growth factor for human islet cells.

Cell Division↗
PubMed1992

[The effect of transfused marrow monocytes on Masugi nephritis in rabbits with radiation injury].

Sheep anti-rabbit glomerular basement membrane serum (NTS) was given to 2 groups of rabbits with a dosage of 0.8ml/kg for establishing model of crescentic glomerulonephritis. Seven days after the inoculation each rabbit received 800 rad whole body gamma-radiation in order to deplete the circulating leukocytes. Another 2 days later, all of the rabbits in group 1 received 10(8) cultivated rabbit marrow monocytes, while in group 2 nothing was given. In group 1, predominant infiltration of macrophages and cellularly crescents were obtained in the glomeruli 7 days after the administration of the cultivated cells. The Bowman's capsules were broken with crescents formation. In rabbits of group 2, there were swellings of some epithelia and endothelial cells and crescents were scanty. The result proves that the macrophages are the main factors during the formation of crescent.

Animals↗
PubMed1991

Calcium metabolism and osteopathy in diabetes mellitus.

To assess the changes of calcium metabolism and osteopathy in patients with diabetes. Serum Ca, P, AKP, PTH, CT, plasma fasting blood glucose (FBG) and HbA1 as well as X-ray film of the lumbar spine were measured in 30 diabetes patients; 11 were IDDM and 19 were NIDDM as compared to controls matched for age and sex. There were no significant differences in Ca, P, and CT values in serum between the IDDM and NIDDM patients and controls, whereas the serum levels of PTH and AKP were significant increased in IDDM patients. The incidence of osteoporosis which was shown by X-ray film in NIDDM patients was higher than in those of controls. No correlation between PTH value and osteoporosis or clinical control of diabetes was observed.

Adult↗
PubMed1990

Transcription factor AP-4 contains multiple dimerization domains that regulate dimer specificity.

Enhancer binding protein AP-4 is a transcription factor that activates both viral and cellular genes by binding to the symmetrical DNA sequence, CAGCTG. Here, we report the molecular cloning and characterization of human AP-4 cDNAs. The deduced amino acid sequence reveals that AP-4 is a helix-loop-helix (HLH) protein. Like other members of this family, the AP-4 HLH motif and the adjacent basic domain are necessary and sufficient to confer site-specific DNA binding. However, unlike other HLH proteins, AP-4 also contains two additional protein dimerization motifs consisting of leucine repeat elements LR1 and LR2. The analysis of various deletion and point mutants for their ability to dimerize in the presence or absence of DNA reveals several unusual features. Although the HLH basic region is sufficient for DNA recognition and binding, dimer formation between different truncated versions of AP-4 in solution requires an intact LR1 or LR2 domain. AP-4 is unable to form heterodimers with other helix-loop-helix family members such as the immunoglobulin enhancer binding factor, E12. In contrast, an AP-4 derivative, delta C222, which lacks LR1 and LR2 but retains an intact HLH, can form heterodimers with E12. Moreover, AP-4 molecules containing LR2 or LR1 are unable to form mixed dimers with carboxy-terminally truncated AP-4 molecules such as delta C222, but retain the ability to form complexes with longer versions of AP-4 that contain LR1 and/or LR2. Our findings strongly suggest that AP-4 contains multiple protein-protein interfaces that function to promote homodimer formation and restrict heterocomplexes. These findings provide a mechanism by which different members of the helix-loop-helix family of transcription factors can form functional dimers in a specific fashion with their appropriate partners to control transcriptional networks during cellular differentiation.

Amino Acid Sequence↗
PubMed1989

The influences of islet transplantation on metabolic abnormalities and diabetic complications.

To assess the long-term effect of islet transplantation on metabolic abnormalities and chronic complications of diabetic recipients, the long-term follow-up data of 36 type 1 diabetic subjects with functioning islet grafts for more than 1 year were analysed in this article. 36 type 1 diabetics, with mean age of 34.30 +/- 12.05 yr and mean duration of 11.53 +/- 5.29 yr, were followed up for a mean period of 29.39 +/- 9.50 mo after successfully transplanting with short-term cultured islet tissue of human fetal pancreases. The effect of islet transplants was identified as excellent in 13 subjects, good in 12 and fair in 11. The comparative studies were carried out of the mean levels of serum C-peptide, plasma glucose, GHb and GPP, serum lipids, and mean excretion of urine sugar, and the diabetic retinopathy, nephropathy as well as the autonomic neuropathy before transplantation in comparison with those of the present. The results of the study demonstrated that islet transplants could improve the function of islet B cells and the glucose metabolism, and might delay the development of diabetic retinopathy, nephropathy and autonomic neuropathy in successfully transplanted diabetic recipients, but not exert any influences on those of patients in fair group.

Adolescent↗
PubMed1988

Replacement of the macronuclear ribosomal RNA genes of a mutant Tetrahymena using electroporation.

The macronucleus of the ciliate Tetrahymena contains approx. 10(4) ribosomal RNA gene molecules (rDNA) in the form of linear, autonomously replicating palindromes. Previous studies have shown that macronuclear rDNA molecules derived from wild-type (wt) inbred strain C3 out-replicate those derived from wt inbred strain B, in macronuclei initially heterozygous for both, leading to the complete loss of the B rDNA. However, rmm-1, a cis-acting laboratory-induced mutation obtained previously by mutagenesis of inbred strain C3, causes the mutant rmm-1 rDNA to be completely out-replicated by B rDNA. These findings suggest the following hierarchy of replication potential: wt C3 greater than wt B greater than C3-rmm-1. We used electroporation to test whether cells containing only rmm-1 macronuclear rDNA are favorable recipients for transformation with either wt B or C3 donor rDNA molecules. The donor rDNA molecules carried the selectable marker Pmr (paromomycin resistance) located in the coding region of the 17S rRNA. Transformants were obtained, at a frequency greater than 1 in 10(5), by electroporation under a wide range of electrical discharge parameters. The fraction of cells surviving electroporation varied between 2 and greater than 95% in successful experiments. Replacement ('transplacement') of the recipient rDNA was observed, consistent with the prediction that B and C3 rDNA should out-replicate rmm-1 rDNA. These findings are also consistent with the previous conclusion that the differential replication determinants reside in the 5'-nontranscribed spacer of the rDNA.

Animals↗