Search PubMed⌕ Search

Biomedical subjects

Y F Wang

Publications and source records attributed to Y F Wang.

At least 145 records · Page 8Linked to original sources
PubMed1994

Studies on the aluminium content in Chinese foods and the maximum permitted levels of aluminum in wheat flour products.

Four hundred and six food samples of 64 food items, as well as 19 samples of aluminum (Al) containing food additives, were collected from Guangdong, Hunan, Shanghai and Beijing, and their Al contents were determined. The migration of Al from cooking aluminium-utensils into foods was also studied. The results show that the average daily dietary intake of Al in Chinese population was 9-12 mg. The dietary intake of migrated Al from Al-containing cooking utensils was approximately 4 mg per person per day. However, the use of Al containing food additives in the preparation of certain wheat flour products (e.g. steamed bread, deep-fried dough sticks) caused significant increase of dietary Al intake (> 1 mg/kg/day, the ADI proposed by WHO.) It is suggested that the content of Al in wheat flour products should not exceed 100 mg/kg, in order to meet the WHO ADI.

Aluminum↗
PubMed1994

[Lymphokine-activated killer cell induced from cord blood].

In this article, the studies on the method of inducing lymphokine-activated killer (LAK) cells from cord blood lymphocytes, the killing ability of LAK cells to tumor subculture cells K562 and Raji, the comparison of the killing activity to tumor subculture cells among LAK cells from cord blood lymphocytes, adult's Peripheral blood lymphocytes (PBL) and gynecologic cancer patient's PBL was presented. The changes of the OKT antigens on the surface of cord blood LAK cells tested with monoclonal antibodies was described. The morphologic changes resulted from the killing activity of LAK cells to target cells were observed by microscopy and electron-microscopy after a definite time co-incubation of the LAK cells and Raji cells. The results showed that: (1) LAK cells could be induced from cord blood and the induced LAK cells could remarkably kill the tumor subculture cell lines including nature killer (NK)-sensitive K562 cells as well as NK-insensitive Raji cells; (2) The activity of cord blood LAK cells is higher than that of the LAK cells from gynecologic cancer patient's PBL, But no significant difference with that of the LAK cells from normal adult's PBL; (3) T+3, T+8, the OKT antigens of cord blood LAK cells are just the same as human LAK cells from other sources; (4) After a definite time co-incubation, the cord blood LAK cells and Raji cells could form atypical rosette-circles under light microscopy. In the field of transmission electron-microscopy, the cord blood LAK cells had a certain active mobility. Raji cells, when incubated with the cord LAK cells for 4 hours, would become apoptosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[Estrogen and progesterone cytosol receptor concentrations in patients with endometriosis and their changes after gossypol therapy].

UNLABELLED: Estrogen and progesterone cytosol receptor (ERc, PRc) concentrations of endometrium biopsied during different phases of menstrual cycle were measured by dextran-coated charcoal method in 27 normal fertile women and 24 patients with endometriosis. 15 out of 24 endometriotic patients were put on gossypol for 2 months thereafter. After discontinuation of the drug, ERc, PRc contents of endometrium were reexamined during the same cycle day. Serum estradiol (E2) and progesterone (P) levels were also compared before and after gossypol treatment. In addition, endometriotic tissue and intrauterine endometrium were immediately obtained from the same patient after surgery in 16 cases with endometriosis, and their ERc, PRc concentrations were also compared. RESULTS: endometrium ERc, PRc concentrations of normal controls fluctuated during the menstrual cycle, with the peak at late follicular phase. In endometriosis group, the ERc, PRc contents and cyclic changes of endometrium in situ were not significantly different from the normal controls. However, the ERc, PRc contents of endometriotic tissue were significantly lower than those of endometrium in situ (P = 0.0036 and < 0.0001 respectively) without cyclic changes during menstrual cycle. After 2 months of gossypol therapy, serum E2 and P levels tended to decrease but the differences were not significant. Glandular secretion of endometrium decreased in only 4 out of 15 cases under pathological examination. In contrast, the ERc, PRc concentrations of endometrium in situ differed significantly from the pretreatment values (P = 0.0217 and 0.01 respectively). These data indicated: (1) The response of endometriotic tissue to estrogen and progestin was lower than that of endometrium in situ.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Clinical significance of elevated serum soluble interleukin-2 receptor in gastric cancer.

This is China's pilot study in the assessment of the diagnostic value of serum soluble IL-2 receptor (sIL-2R) in gastric cancer. We measured its level by ELISA method in 45 patients with gastric cancer (without metastasis: 32; with metastasis: 5; recurrence: 8) 27 gastric ulcer, 27 superficial gastritis and 44 healthy controls. The mean-serum sIL-2R levels were significantly elevated in cancer patients, those with metastasis showed even higher levels than those without metastasis. These results suggested that sIL-2R can be used as a marker of host biological response in gastric cancer patients as well as a tumor marker for the diagnosis of the disease.

Adult↗
PubMed1993

PYY: a neuropeptide in the canine enteric nervous system.

This study re-examined the anatomical locations of PYY in the canine gastrointestinal tract. Immunohistochemical studies with two relatively selective PYY antisera demonstrated PYY-LI immunoreactivity in nerve cell bodies and nerve fibres in the intestinal and gastric myenteric plexus and the intestinal submucosal plexus and in nerve fibres of the intestinal deep muscular plexus. Immunoreactive PYY-LI was also present in ileal endocrine cells. All PYY-LI immunoreactivity was completely abolished by pre-incubation of the antibodies with synthetic PYY but was unaltered by pre-incubation with synthetic NPY. Individual synaptosomal preparations obtained from canine intestinal and gastric myenteric plexus, and intestinal deep muscular plexus and submucous plexus, contained considerable quantities of PYY-LI which, on reverse-phase HPLC, co-eluted with a synthetic canine/porcine PYY standard. In contrast, isolated myenteric ganglia from rat and guinea pig did not contain detectable amounts of PYY-LI. These studies demonstrate that PYY is not confined to distal intestinal endocrine cells in the dog but is also an enteric neuropeptide with maximal concentrations being present in the intestinal myenteric plexus.

Animals↗
PubMed1993

Antitumor effects of GBS toxin: a polysaccharide exotoxin from group B beta-hemolytic streptococcus.

A group B streptococcus (GBS) isolated from human neonates diagnosed with sepsis and respiratory distress ("early-onset disease") produces a polysaccharide exotoxin (GBS toxin) that, when infused in sheep, causes lung pathophysiology similar to that seen in humans. Histological studies have demonstrated that GBS toxin induces a strong inflammatory response in the lung, with pulmonary sequestration of granulocytes and extensive capillary endothelial damage. The susceptibility of humans to GBS toxin is age-dependent and limited to about 4 days after birth. It is rarely evident thereafter. This suggests that the binding of GBS toxin to the target endothelium occurs via specific components in the developing lung endothelial cells of the newborn that are later lost. We report here that GBS toxin can also bind to developing endothelium associated with neoplasia and induce an inflammatory response. GBS toxin was shown by immunohistochemistry to bind to capillary endothelium of human large-cell carcinomas. In nude mice bearing human tumor xenografts, intravenously administered GBS toxin caused tumor necrosis and hemorrhagic lesions, and substantially inhibited the rate of growth of the tumors. In BALB/c mice bearing Madison lung tumors, GBS toxin induced an inflammatory response resulting in marked changes in tumor morphology, including vasodilation, endothelial and tumor cell necrosis, invasion of lymphocytes and macrophages, and capillary thrombosis. In these tumor models, no evidence of toxicity to the vasculature of other tissues was observed. The reported pathophysiology of GBS in human neonates, the lack of disease in non-neonates colonized with GBS, and these results suggest that GBS toxin may have potential as a well tolerated agent in cancer therapy of some human tumors.

Adenocarcinoma↗
PubMed1993

A study of blood supply of liver tumors using duplex Doppler ultrasound and color Doppler flow imaging.

With the use of duplex Doppler ultrasound and color Doppler flow imaging (CDFI), the characteristics of blood supply in neoplasma were studied in 51 cases of 60 liver tumors, and compared with the results of surgery, pathological examination and hepatic arterial angiography. The result showed that: 1. Doppler blood flow signals could be detected in all hepatic carcinomas, and in 10 cases of 18 hemangiomas, significant difference was observed (P < 0.001); 2. Doppler blood flow spectra showed pulsatile pattern in 41 of 42 hepatic carcinomas, and in 6 of 10 hemangiomas (P < 0.01); and 3. the peak flow velocity was obviously lower in hemangioma group than in hepatic carcinoma group (20.34 +/- 23.93 vs 64.74 +/- 30.18 cm, P < 0.001). The characteristics of CDFI show that hemangiomas and hepatocellular carcinomas are different. It can, therefore, be concluded that the blood supply of hepatic carcinomas mainly comes from hepatic arterial system, and is of value in duplex Doppler ultrasound and CDFI.

Adult↗
PubMed1993

Distribution and characterization of vasoactive intestinal polypeptide binding in canine lower esophageal sphincter.

BACKGROUND: Vasoactive intestinal polypeptide (VIP) may be a nonadrenergic, noncholinergic inhibitory transmitter in the lower esophageal sphincter (LES). There is no biochemical evidence of VIP receptors in the LES. METHODS: Using membranes from canine LES, VIP receptor distribution and characterization were analyzed by radioligand binding and cross-linking experiments. RESULTS: High densities of saturable VIP receptors were found (maximum bound [Bmax], 539.2 fmol/mg in the synaptosome-enriched fraction [P2] and 732.7 fmol/mg in the smooth muscle, plasma membrane-enriched fraction [Mic II]), with high affinity for 125I-VIP (dissociation constant [Kd], 1.38 nmol/L in P2 and 1.40 nmol/L in Mic II). Competition binding studies suggested the presence of two binding sites, a high-affinity (inhibitor constant [Ki1], 0.064 nmol/L) and a low-affinity (Ki2, 2.68 nmol/L) binding site in P2 membranes, but only one binding site (Ki, 1.18 nmol/L) in Mic II membranes. Guanosine triphosphate-gamma-s pretreatment eliminated high-affinity binding in P2 membranes by conversion to binding sites of lower affinity (Ki, 2.82 nmol/L). Studies with a cross-linking agent identified VIP receptors in synaptosomal and smooth muscle plasma membrane fractions; a single polypeptide of approximately 60 kilodaltons was found in each membrane. CONCLUSIONS: Specific VIP receptors exist in both synaptosomal and smooth muscle plasma membrane of canine LES.

Animals↗
PubMed1993

A cross-national prevalence study of children with emotional and behavioural problems--a WHO collaborative study in the Western Pacific Region.

Emotional and behavioural problems in primary school children were investigated with Rutter's questionnaires, in Japan (N = 2638), China (N = 2432) and Korea (N = 1975). The prevalence rates of children with deviant scores on the teachers' and parents' scales were 3.9 and 12.0% in Japan, 8.3 and 7.0% in China and 14.1 and 19.1% in Korea, respectively. Deviance of the antisocial type was more frequent than the neurotic type in Japan and China. Both types were almost equally frequent in Korea. The prevalence of deviance was higher in boys, and also higher in those children with poor school achievement. In China and Korea, the prevalence was higher in children from one-parent families. Although other family background factors had major effects on deviant behaviour in these two countries, the number of siblings and birth order had only a limited effect on the deviant behaviour of children in Japan, China and Korea.

Age Factors↗
PubMed1993

Dephosphorylation of standard prolactin produces a more biologically active molecule: evidence for antagonism between nonphosphorylated and phosphorylated prolactin in the stimulation of Nb2 cell proliferation.

Charge isomers of monomer PRL have been described for all species thus far examined. For the rat, cow, and chicken, at least a major proportion of the more acidic isomers have been shown to be phosphorylated. The physiological relevance of this posttranslational phosphorylation, however, remains unclear. In this study we have compared the growth-promoting activities of dephosphorylated and standard rat PRL (partially phosphorylated) in the widely used Nb2 bioassay. Dephosphorylated PRL was produced by treatment of standard rat PRL with acid phosphatase, resulting in the conversion of a 91.9% nonphosphorylated/8.1% phosphorylated preparation to a 98.6% nonphosphorylated preparation. These two preparations were added separately or in combination to stationary Nb2 cells. Cell number was assessed 3 days later using a colorimetric assay. Dephosphorylated PRL showed significantly higher growth-promoting activity than standard PRL at concentrations up to 10 ng/ml. In the 1-5 ng/ml concentration range, dephosphorylated PRL was twice as active. Given that the conversion of 6.7% phosphorylated PRL to nonphosphorylated PRL resulted in a doubling of activity, one can deduce not only that phospho-PRL acted as an antagonist to nonphosphorylated PRL in this assay, but also that it did not do so on an equimolar basis. Titration of the two PRL preparations produced data confirming this latter deduction. These data are of importance in our understanding of PRL-promoted cell proliferation.

Acid Phosphatase↗
PubMed1993

[Quick immunotherapy for pollinosis].

A preliminary analysis of 47 cases of pollinosis undergone rush immunotherapy revealed that such a protocol not only greatly shortened the time-course of treatment, but also diminished the number of injections required to reach the maintenance dose significantly, thus provided a better compliance of treatment. A two-year observation showed an effective rate of 91.3%. Adverse reactions though occurred, in no case was the reaction strong enough that a discontinuation of the treatment was warranted. The present status of rush immunotherapy has been reviewed and discussed also.

Adult↗
PubMed1993

The production of monoclonal antibody to androstenedione and the effect of passive immunization on Xinjiang fine-wool sheep with it.

Five hybridomas stably secreting monoclonal antibodies (McAbs) to androstenedione were prepared by using artificially synthesized androstenedion-11 alpha-succinyl conjugate with bovine serum albumin (BSA) as antigen. These McAbs showed slightly high cross-reactivity with testosterone (8.1-12.3%) and estrone (0.8-2.5%) and high affinities ranging from 2.0 x 10(7) to 2.8 x 10(8) L/M. They were all of the IgG1 subclass. Xinjiang finewool ewes which were passively immunized with McAbs had higher circulating levels of progesterone (P) and luteinizing hormone (LH) than those of control ewes in two oestrous cycles and these changes led to increased ovulation rate and twin lambs born in young ewes.

Androstenedione↗
PubMed1992

K-current mediation of prolactin-induced proliferation of malignant (Nb2) lymphocytes.

The effects of different concentrations of various K-current blockers on prolactin-induced proliferation and membrane K-currents in malignant lymphocytes (Nb2 cells) were investigated. Membrane currents were measured with the whole cell patch-clamp technique, and lymphocyte density was quantified by both spectrophotometric and conventional methods. K-current blockers tested (quinidine, 4-aminopyridine, barium, and tetraethylammonium) exhibited similar rank order potency for K-current block and inhibition of prolactin-induced proliferation of malignant lymphocytes. Because Nb2 cells proliferate independently of a transmembrane Ca-influx, these results suggest that K-currents per se rather than K-current modulation of Ca-influx is an essential event for lymphocyte proliferation.

4-Aminopyridine↗
PubMed1992

Prolactin isoform 2 as an autocrine growth factor for GH3 cells.

Because PRL has growth factor activities in several tissues, we have asked whether it also has autocrine growth factor activity in pituitary GH3 cells. GH3 cells were grown at increasing densities in the presence or absence of antirat PRL (polyclonal and monoclonal) or nonspecific antibodies. Cell proliferation increased with increasing cell density, as did the concentration of PRL in the medium. Antirat PRL, but not control antibody, markedly inhibited but did not eliminate cell proliferation, and this effect was diminished with increasing PRL concentration in the medium. PRL receptors were demonstrated on 40-50% of the cells by indirect immunofluorescence using a specific antirat PRL receptor monoclonal antibody. Cell surface PRL was colocalized to the same 40-50% of the cells and copatched or cocapped along with the receptors. Absence or presence of PRL receptors did not correlate with stage of the cell cycle, as judged by ethidium bromide dual labeling. Cell surface PRL was found to be on PRL-containing cells. These data have fulfilled four criteria necessary for establishment of a substance as a secreted autocrine growth factor: 1) the factor must be secreted; 2) in log growth phase, increased cell proliferation should occur at increased cell densities; 3) the cells must display a receptor for the factor; and 4) there must be a growth response to the factor. Thus we have established that PRL is an autocrine growth factor for at least 40-50% of the GH3 cell population. This, to our knowledge, is the first example of autocrine growth factor activity of a major hormone normotopically expressed.

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

[Excitant effect of sodium suberogorgin on isolated rabbit ileum].

Suberogorgin was isolated from Gorgoniae suberogorgia sp from South China Sea. The isolated rabbit ileum contracted in a concentration-dependent manner by suberogorgin-Na (Sub) 2.13 mumol.L-1 or higher. Sub 213 mumol.L-1 had no effect on the relaxation induced by norepinephrine and isoprenaline 10-100 mumol.L-1 on ileum. The stimulation of Sub on ileum was antagonized by atropine 56 mumol.L-1 or indometacin 0.35 mmol.L-1 and was partly blocked by indometacin 0.17 mmol.L-1, but was not affected by diphenhydramine 10 mumol.L-1. On the contracted ileum induced by neostigmine 1.7 mumol.L-1, acetylcholine 0.1 mumol.L-1 increased the tension but Sub 213 mumolL-1 did not. Sub obviously inhibited the acetylcholinesterase (AChE) from mouse brain hemogenates in vitro. Its pI50 (negative logarithm of molar concentration causing 50% inhibition of AChE) was 4.18, while the pI50 of neostigmine was 4.75. The results indicated that the ileum-excitant action of Sub was chiefly related to the inhibition of AChE.

Acetylcholinesterase↗
PubMed1992

An experimental study of pituitary transplantations in rabbits.

Experimental pituitary transplantations were carried out between the New Zealand white and American chinchilla rabbits. These two kinds of experimental rabbits were of different genotypes. The grafts were transplanted underneath the median eminences of the recipients after hypophysectomy. The rabbits with the transplants were treated with cyclosporine (CsA) and prednisone for the first month. Blood samples were taken at regular intervals for the determinations of serum thyroxine, prolactin and luteinizing hormone. The results suggested that neonatal grafts could survive and function almost normally with the aid of CsA and prednisone, but not without them. The results also disclosed that the interrelationship between the pituitary graft and the host's hypothalamus could be established. Pituitary transplantation from adult rabbit donors failed even though the recipients had been treated with CsA and prednisone in our experiment.

Animals↗