PubMed Health⌕ Search

Biomedical subjects

T Peng

Publications and source records attributed to T Peng.

17 recordsLinked to original sources
PubMed1992

Effect of lithium chloride on ornithine decarboxylase activity in rat adrenal.

The effects of lithium chloride on ornithine decarboxylase (ODC) activity were compared in the adrenal and kidney of control (saline treated) and prolactin-treated rats. ODC activity was decreased in kidney of both groups of animals, the magnitude of the effect of lithium in the hormone-treated group varying with the time of administering the lithium relative to prolactin. The response in the adrenal was quite different. Following treatment with LiCl, there was a gradual increase in ODC activity from a low of 10-35 pmol CO2 x 30 min-1.mg protein-1 in control animals to values 20- to 30-fold greater at 5 h. In rats treated simultaneously with LiCl and prolactin, ODC activity was greater at 5 h than that observed in animals receiving either compound alone, indicating that their effects were additive. When LiCl was given 4 h after prolactin, i.e., 1 h before sacrifice, ODC activity decreased to a very low level at 5 h, as in other tissues. The increase in ODC activity in the adrenal following LiCl is of the same magnitude as the changes observed in tissues stimulated to undergo alterations in proliferation, differentiation, or metabolic or membrane activity by hormones and other external stimuli.

Adrenal Glands↗
PubMed1992

[The experimental studies of the effect of Forskolin on the lowering of intraocular pressure].

The effect of the domestic Forskolin on lowering the intraocular pressure (IOP) of rabbits was studied. The results showed that the Forskolin significantly lowered the normal IOP of rabbits and blocked the ocular hypertension induced by water load in rabbits (p < 0.01). The maximum decrease value of 2%, 1% and 0.5% of the Forskolin was 0.59. 0.36 and 0.19 kPa (1 kPa = 7.5 mmHg), which showed the noticeable dose-effect relationship. Topical ocular application of Forskolin lowered IOP in 1/2 hour, reached to a peak in 2-3 hours and remained significantly for 10 hours. The pupillary diameter did not change when IOP were reduced. Furthermore, the Forskolin had potent stimulative properties to adenylate cyclase (AC). The greater the ability of the Forskolin to stimulate AC, the stronger the effect of IOP lowering.

Adenylyl Cyclases↗
PubMed1991

[The distribution of apolipoproteins AI, CII and CIII mRNA in rat tissues].

It was demonstrated that apo AI, CII and CIII mRNA were distributed in rat (Sprague Dawley) liver, intestine, brain and kidney by RNA-dot blot analysis with apoAI, CII and CIII cDNA probes. The relative abundances of apoAI in liver, intestine, brain and kidney tissues are 100%, 212%, 170% and 224%, respectively, those of apoCII are 100%, 61%, 163% and 214%; and those of apoCIII 100%, 65%, 70% and 73%, respectively. The experiment was repeated for three times. The results were discussed in this paper.

Adult↗
PubMed1990

Inhibition of hormone-stimulated ornithine decarboxylase activity by lithium chloride.

Effects of Li+ on hormone-stimulated ornithine decarboxylase (ODC) activity were determined in kidney and liver of rats treated with dexamethasone or prolactin (PRL) and also in cultured, PRL-stimulated Nb2 lymphoma cells. In both systems, LiCl led to rapid and marked decreases in ODC activity. The inhibitory effect of Li+ in exponentially growing Nb2 lymphoma cell cultures, measured at 45 min, was dose-dependent, ranging from 10% at 0.1 mM LiCl to 95% at 10 mM LiCl. Surprisingly, on continued incubation with 10 mM LiCl, the lymphoma cells partially overcame the inhibition, showing ODC activities which reached a maximal value of ca 50% of the control at 4.5 h. The inhibition by Li+ could not be reduced by adding myo-inositol to the culture medium. LiCl did not inhibit ODC activity when added to cell-free extracts of rat tissues and Nb2 lymphoma cells indicating it did not act directly on the enzyme; however, there is evidence that, in intact cells, Li+ enhances the rate of inactivation of the enzyme.

Animals↗
PubMed1990

[Screening and identification of apolipoprotein CIII cDNA clones from human liver cDNA library and preparation of apolipoprotein CIII cDNA probe from the clones].

Four of positive clones were obtained by three runs of screening the cDNA library of human liver with rabbit antihuman apolipoprotein (apo) CIII IgG. One of them was identified to be the positive clone of apoC III cDNA by restriction endonuclease map studies of the cDNA insert fragment and by Western blot analysis of the expression products. The apoCIII cDNA-gamma gt11 recombinant DNA prepared from the positive clone can be used in RNA-dot blot analysis as apoCIII cDNA probe. And the apoCIII cDNA clone can be also used to produced apoCIII peptide under the induction of isopropyl-beta-D-thiogalactoside. The apoCIII peptide, after purification, has a lot of use in further studies.

Apolipoprotein C-III↗
PubMed1990

Retinitis pigmentosa associated with glaucoma--clinical analysis.

A clinical analysis of Retinitis Pigmentosa (RP) was made in 2,789 eyes of 1,400 patients seen over a 5 year period (1983-1987), 64 eyes of 32 cases (2.3%) of RP associated with glaucoma were investigated. Of these 32 cases, the angle closure glaucoma was much more than the open angle glaucoma (30/2). More than half of the 32 cases were without cupping of disk, 5 cases did not have the glaucomatous damage to disk in spite of persistent elevated intraocular pressure for 0.5-5 yrs under the maximum medical therapy. 31 cases (97%) had subnormal blood pressure compared with the normal blood pressure value in different age groups. Histopathologic changes of the trabecular meshwork (TM) of 14 eyes showed a little bit more pigment cells in the TM than normal subjects, no typical features that would obstruct the outflow channels.

Adolescent↗
PubMed1990

[Effect of high carbohydrate and high fat diets on plasma glucose, insulin and lipids in normal and hypertriglyceridemic subjects].

The fasting plasma glucose, insulin and lipids response to high-carbohydrate-low-fat diets and low-carbohydrate-high-fat diets in normal subjects and patients with endogenous hypertriglyceridemia was observed. The normal, high carbohydrate and high fat diets consisted of 60%, 80% and 40% carbohydrate, 25%, 5% and 45% fat and 15% protein of total calorie respectively. The fasting plasma glucose levels increased (P less than 0.01) on day 1, insulin increased on day 3 (P less than 0.01 and P less than 0.05) and TG levels increased on days 3 and 5 after taking high carbohydrate diets both in the normal and hypertriglyceridemic groups. The fasting plasma TC and HDL-C decreased on high carbohydrate diets mainly in the hypertriglyceridemic group. The fasting plasma glucose slightly decreased on day 5, TG decreased on day 1 (P less than 0.05) and TC increased on day 1 and 3 (P less than 0.01) after taking high fat diets, but no differences were observed in insulin levels. Fasting plasma HDL-C levels in the normal group remained unchanged, but significantly decreased 3 days after taking high fat diets in the hypertriglyceridemic group (P less than 0.001). Our results indicate that high carbohydrate intake may be an important cause of hypertriglyceridemia in our country. This diet may cause a slight increase in the blood glucose level, which in turn stimulates an increase in plasma lipids and decrease in HDL-C, which is associated with an increase in the incident of coronary heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Changes in antizyme-ornithine decarboxylase complexes in tissues of hormone-treated rats.

The presence of antizyme-ornithine decarboxylase complex in thymus and kidney of rats was demonstrated using the method of Y Murakami et al. [(1985) Biochem. J. 225, 689-697]. A very small amount of complex was found in kidney of control rats, accounting for only 1-3% of total enzyme in the tissue, while in thymus, approximately one-third of the total ornithine decarboxylase in thymus occurred as an antizyme-enzyme complex. After treatment with dexamethasone, both free ornithine decarboxylase and antizyme-ornithine decarboxylase decreased in thymus, the free enzyme activity decreasing more rapidly. In kidney, the concentration of the antizyme-ornithine decarboxylase complex increased after dexamethasone treatment, but only after the induction of free enzyme activity had reached its peak and begun to decrease. The pattern of the changes in amount of antizyme-ornithine decarboxylase complex after prolactin treatment differed from those observed in the dexamethasone-treated animals. In both kidney and thymus, the concentration of antizyme-ornithine decarboxylase complex increased concurrently with the induction of free enzyme activity. Both free and complexed ornithine decarboxylase had increased at 2.5 h after prolactin treatment and continued to increase to maximum specific activities at similar rates. In thymus, the amount of ornithine decarboxylase present as a complex reached 70% of the total in the tissue. In both thymus and kidney, the concentration of antizyme-ornithine decarboxylase complex decreased more slowly than did free enzyme activity. Free antizyme was observed only in thymus of dexamethasone-treated animals. The amount of measurable inhibitor was decreased if cycloheximide was given with dexamethasone.

Animals↗
PubMed1989

[Argon laser trabeculoplasty for open angle glaucoma--a four year follow-up].

79 patients (105 eyes) with uncontrolled open angle glaucoma underwent argon laser trabeculoplasty (ALT). The average pressure drop was 10.7 mmHg in 58 eyes at one year, 10.1 mmHg in 35 eyes at two years, 9.9 mm Hg in 48 eyes at three years and 10.2 mmHg in 24 eyes at four years. Teh mean success rate was 78%, failures occurred in the first six months in 21 of 23 eyes, the remaining eyes failed at three years, 18 eyes (17%) required filtering surgery. Average medication scores varied little from year 1 through year 4, 45 eyes (42.9%) were being treated with few medications after ALT. The results of ALT depend on the severity of glaucoma: the eyes with advanced disc damage (C/D greater than 0.9, visual field less than 20 degrees) had 59% rate of filtering surgery, while the eyes with C/D 0.6-0.8, visual field greater than 20 degrees at ALT had a filtering surgery rate of 3%.

Aged↗
PubMed1988

Multiple ionic forms of ornithine decarboxylase differ in degree of phosphorylation.

Two major ionic forms of ornithine decarboxylase were separated by column chromatography of extracts of kidneys from androgen-treated male CD-1 mice on DEAE-Sepharose CL-6B, and purified individually to apparent homogeneity. On SDS-PAGE, a single major protein band of Mr 50000 was present in each. When incubated with casein kinase II, purified from rat liver cytosol, only one form of the enzyme, which represented 20% of the total ornithine decarboxylase in the tissue, became phosphorylated. The major form, which was eluted later from the column, could be phosphorylated only after treatment with alkaline phosphatase, indicating that the phosphatase removed enzyme-bound phosphate already attached at the casein kinase II phosphorylation site. Evidence for the occurrence of a phosphorylated form of the enzyme in kidneys of dexamethasone-treated rats is also presented.

Alkaline Phosphatase↗
PubMed1986

An inhibitor of ornithine decarboxylase in lactogen-deprived Nb2 node rat lymphoma cells.

A previous study has shown that the activity of ornithine decarboxylase in cultured Nb2 node rat lymphoma cells falls to undetectable levels when cells become quiescent following incubation in lactogen (prolactin)-deficient medium. In the present study, it was found that addition of extracts of the lactogen-deprived, quiescent cells to extracts of log-phase cells markedly reduced the ornithine decarboxylase activity of the latter, the inhibitory activity being proportional to the amount of quiescent cell extract added. Evidence is presented that the ornithine decarboxylase-inhibitory activity in the quiescent cell extracts is due to an antizyme-like, polypeptide factor with an Mr of approx. 28,000. The activity of the inhibitor appears to be directed rather specifically against ornithine decarboxylase, since the activities of S-adenosylmethionine decarboxylase, thymidine kinase and uridine kinase were not affected. The Nb2 cell ornithine decarboxylase inhibitor may have an important role in modulating the cellular levels of ornithine decarboxylase as they change in response to the withdrawal and restoration of extracellular mitogenic lactogens.

Animals↗
PubMed1986

Gingival basement membrane antigens in desquamative lesions of the gingiva.

Desquamative gingival lesions are a clinical manifestation of several entities where histologic alterations in the gingival basement membrane are frequent. Normal and lesional gingival specimens from six patients with desquamative lesions of the gingiva associated with cicatricial pemphigoid or lichen planus and from one normal subject were examined by indirect immunofluorescence for immunologic alterations in basement membrane antigens. In four out of five desquamative gingival lesions from patients with lichen planus, type IV collagen and EBA basement membrane antigens were interrupted, thickened, or partially or completely absent as compared to normal gingiva. One specimen showed multiplication and duplication of the basement membrane. In the two desquamative gingival lesions from patients with cicatricial pemphigoid, type IV collagen was either partially absent or associated with the connective tissue side of the subepithelial bullae. These results suggest structural alterations in antigens within the basement membrane of patients with desquamative lesions of the gingiva.

Antigens↗
PubMed1985

An inhibitor of ornithine decarboxylase in the thymus and spleen of dexamethasone-treated rats.

A marked decrease in activity of ornithine decarboxylase in thymus and spleen occurs soon after treatment of rats with a glucocorticoid. In the present study, evidence was obtained that extracts of these tissues prepared 5 h after administration of dexamethasone, when the enzyme activity is very low, contain an inhibitor of ornithine decarboxylase. The inhibitor is also present at 12 h after treatment and, in lesser amount, at 2.5 h, but was not evident at 24 h. The inhibitory activity was destroyed by treatment with heat or with trypsin, and was not lost on dialysis of the extract. Preliminary experiments indicate that the Mr of the inhibitor is greater than 50 000, which differentiates it from antizyme, an inhibitor of ornithine decarboxylase found in several other cell types. The inhibitor seems to act by a non-catalytic and non-competitive mechanism. The inhibition is dependent on the amount of inhibitor and does not change with time. Since inhibition is not changed by dialysis of the inhibitory extract, its activity apparently does not require small-Mr substances. This differentiates it from inhibitors which inactivate ornithine decarboxylase by covalent modification, such as the polyamine-dependent protein kinase or transglutaminase. The formation of this inhibitor is an early event in lymphoid tissues in response to dexamethasone and may be important in causing the inhibition of cell division which precedes the destruction of lymphocytes.

Animals↗
PubMed1976

Emergency open lung biopsy.

Twenty-eight patients underwent open lung biopsy on an emergency basis. The clinical course in each case was deteriorating rapidly, and all were in respiratory failure. The correct diagnosis was established in 96% of the biopsies (27 of the 28 patients). The clinical diagnosis prior to biopsy was in error or incomplete in 15 (55%) of the patients. Specific therapy was lifesaving in 12 of the 28 patients. The value of the procedure outweighed the complications. Thrombocytopenia and positive end-expiratory pressure ventilation were not contraindications to biopsy.

Adult↗