Effects of estradiol on prostaglandin E2 biosynthesis and prostaglandin metabolic enzyme activity in rat kidneys.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
W C Chang
Publications and source records attributed to W C Chang.
Inhibition of human natural killer cell activity by platelet-derived growth factor. II. Membrane binding studies, effects of recombinant IFN-alpha and IL-2, and lack of effect on T cell and antibody-dependent cellular cytotoxicity.
We have previously reported that a 2-h pre-treatment with physiologic (nanogram) quantities of the naturally occurring biologic substance, platelet-derived growth factor (PDGF), significantly inhibits human NK cell activity (cytotoxicity) in a dose-dependent manner as measured against the NK-sensitive target K-562, as well as the single-cell binding of human NK cells to K-562 targets (i.e., conjugate formation). In this study, we have completed a more detailed and longer time course evaluation of PDGF-mediated human NK cell inhibition, and demonstrate a more marked inhibition of human NK cells at 8 to 20 h as compared to 2 h. We also show that either rIFN-alpha or IL-2 reverses the PDGF-mediated NK cell inhibition; and furthermore, that PDGF does not inhibit the lymphokine augmented NK activity of recombinant alpha-IFN or IL-2-activated human NK cells. In addition, we have further demonstrated that PDGF does not inhibit cytotoxic T cell activity as generated in the MLR, nor does PDGF significantly inhibit antibody-dependent cellular cytotoxicity. Finally, we have demonstrated that human NK cells have roughly 12,000 high-affinity, surface binding sites for PDGF, as determined by the competitive binding of 125I-labeled purified PDGF and unlabeled PDGF to B73.1+ FACS-sorted lymphoid (NK) cells, and Scatchard analysis of these data. The implications of these findings are discussed.
Adult↗
Carp gamma-crystallins with high methionine content: cloning and sequencing of the complementary DNA.
The nucleotide sequences of gamma-crystallin cDNAs cloned from the common carp (Cyprinus carpio) have been determined. The amino-acid sequences derived consist of two polypeptides with 177 and 172 amino-acid residues for gamma-m1 and gamma-m2, respectively. They exhibit unusually high methionine contents: 12.4% for gamma-m1 and 14% for gamma-m2. Comparison of both fish gamma-crystallins with bovine gamma-II crystallin reveals that they are similar in structure. The striking features of both fish gamma-crystallins are as follows. (1) Both of them retain the 'conserved' residues, i.e., Tyr-6, Glu-7, Gly-13, Ser-34 and their equivalents in other motifs. (2) they possess the second aromatic residue at position 11. Both of these structural features are considered to be the major factors in stabilizing the folded hairpin structure of the protein. (3) The variable residues in the core region of C-terminal domain are almost all sulfur-containing amino acids, i.e., methionine or cysteine. (4) 30% of the surface hydrophobic groups are composed of methionine. The last two unusual features have been found so far only in these two fish gamma-crystallins. The high methionine content may make an important contribution to the protein stability of fish gamma-crystallins.
Amino Acid Sequence↗
Nucleotide sequence of carp prolactin cDNA.
Explore the source record for details and available documents.
Animals↗
Cloning and sequencing of bullfrog growth hormone complementary DNA.
Total mRNA was isolated from the pituitary glands of bullfrog (Rana catesbeiana), purified by affinity chromatography with oligo(dT)-cellulose columns. The cDNA was synthesized and cloned in Escherichia coli using EcoRI linkers and pBR322 as vector. The cDNA library was screened by hybridization with 32P-labeled duck growth hormone (GH) cDNA. A positive clone was selected and sequenced. The full-length bullfrog GH cDNA contains 950 nucleotide pairs with an open reading frame coding for the precursor GH of 215 amino-acid residues. The partial amino-acid sequence from the protein confirms that derived from the cDNA, with Phe as the first residue in the mature bullfrog GH preceded by a 25-residue hydrophobic signal peptide. The bullfrog GH shares sequence homology with those of other vertebrate species in the following order: duck (61% protein sequence homology; 67% cDNA homology), rat (56%; 61%), human (47%; 57%) and salmon (42%; 50%).
Amino Acid Sequence↗
Purification of duck growth hormone and cloning of the complementary DNA.
Duck growth hormone (GH) was isolated and purified from duck pituitaries by salt precipitation and HPLC on reverse-phase C18 columns. The duck GH was homogeneous as shown by SDS-polyacrylamide gel electrophoresis with a molecular weight of 22,000. The cDNA was synthesized and cloned in Escherichia coli using EcoRI linkers and pBR322 as vector. The positive clones were selected and sequenced. The full-length duck GH cDNA contains 820 nucleotide pairs with an open reading frame coding for the precursor form duck GH of 216 amino-acid residues. The partial amino-acid sequence from the protein completely agrees with that derived from the cDNA, with Phe as the first residue in mature duck GH preceded by a 27-residue hydrophobic signal peptide. The duck GH is almost completely homologous to the chicken GH, with only three conservative substitutions (Ser for Thr, His for Tyr and Lys for Arg) and one deletion (Ala) in the duck GH sequence. Comparison of amino-acid sequence of duck GH with that of various species reveals 56%, 73% and 40% homologies with GHs of human, rat and salmon, respectively.
Amino Acid Sequence↗
[Effect of cigarette smoking on platelet-thromboxane A2 and arterial-prostacyclin synthesis in rats].
Explore the source record for details and available documents.
Animals↗
Stimulation of prostaglandin E2 biosynthesis by estradiol in rat kidneys.
The effect of estradiol administration on renal prostaglandin (PG) E2 biosynthetic activity in rats was studied. A specific radioimmunoassay for PGE2 was developed and applied in the quantitation of PGE2 biosynthesis in kidney. Conversion of exogenous arachidonic acid into PGE2 by renal microsomal fraction was assayed. Formation of PGE2 was linear in fashion up to 5 min incubation at 37 degrees C, and linear in fashion up to 3.5 mg of microsome used as enzyme source. The renal biosynthesis of PGE2 was significantly increased by estradiol treatment.
Animals↗
Cloning and sequencing of a carp beta s-crystallin cDNA.
The mRNAs were extracted from common carp (Cyprinus carpio) lenses, purified, reverse transcribed, dC tailed and cloned into Escherichia coli with pBR322 as vector. The cloning efficiency was around 1 X 10(7) colonies per micrograms of mRNA. A clone (pC20) was found by hybrid-arrested to contain the cDNA related to carp crystallins. However, comparison of the derived amino-acid sequence with bovine gamma-II and beta s-crystallins indicates that this carp crystallin sequence resembles closely the bovine beta s-crystallin and should be better classified as such except that this fish sequence does not contain the N-terminal 'arm' of four amino-acid residues present in bovine beta s-crystallin.
Amino Acid Sequence↗
Stimulation of 5-lipoxygenase activity in polymorphonuclear leukocytes of rats by caseinate treatment.
In the present study, the lipoxygenase activity in polymorphonuclear (PMN) leukocytes of rats was characterized, and the change in lipoxygenase activity in peritoneal and peripheral PMN leukocytes challenged by caseinate was investigated. Peritoneal PMN leukocytes produced 5-HETE and LTB4 as the major 5-lipoxygenase metabolites from arachidonic acid. The 5-lipoxygenase activity was calcium dependent. Caseinate treatment in rats significantly stimulated the 5-lipoxygenase activity in peripheral and peritoneal PMN leukocytes. Although it also stimulated the cyclooxygenase metabolic pathway, the effect was not as evident as that on the 5-lipoxygenase pathway. Since LTB4 is a potent chemotactic factor for PMN leukocyte migration, the present results might explain the mechanism on the PMN leukocyte infiltration caused by caseinate treatment.
Animals↗
GABA-dependent modulation of the Cl- ionophore by steroids in rat brain.
Steroids inhibit the binding of [35S]t-butylbicyclophosphorothionate ([ 35S]TBPS) to the GABAA-benzodiazepine receptor (GBR) linked Cl- ionophore in a GABA dependent manner but not through the GABAA receptor. The most potent steroid evaluated is a naturally occurring metabolite of progesterone, 3 alpha-hydroxy,5 alpha-dihydroprogesterone with an IC50 of approximately 17 nM. Structural requirements necessary for inhibitory activity coincide with those reported for anticonvulsant and anesthetic actions. Coupled with earlier evidence that these steroids do not act directly at the benzodiazepine receptor nor the [35S]TBPS labeled site to modulate the Cl- ionophore, the possibility is proposed that a distinct membrane-bound 'steroid site' coupled to the GBR-Cl- ionophore complex exists.
Animals↗
Natural killer (NK) cell immunodeficiency in patients with chronic myelogenous leukemia. II. Successful cloning and amplification of natural killer cells.
Defective natural killer (NK) cell populations from patients with chronic myelogenous leukemia (CML), that reacted with both HNK-1+ and B73.1+ antibodies, were obtained by a fluorescence-activated cell sorter (FACS). These fractions, along with NK fractions from normal donors which reacted with both antibodies, were expanded as bulk cultures or clones by limiting dilution, for 4 weeks in the presence of 10% interleukin 2 (IL 2), human type AB plasma, and irradiated human allogeneic mononuclear cells. Successfully established clones from patients with CML, with lytic activity against autologous and more differentiated neoplastic granulocytes, were generated more efficiently from B73.1+ than from HNK-1+ subsets. However, there were no significant differences among the generations of B73.1+ and HNK-1+ clones for both patients and normal donors with lytic activity against NK susceptible K-562 targets. Fresh myeloblast preparations from a blast crisis were found to be more susceptible to lysis by IL 2-proliferative B73.1+ and HNK-1+ clones than were fresh myelocyte preparations from a chronic phase CML patient, which were lytically susceptible to only B73.1+ clones. B73.1+ and HNK-1+ subsets from CML patients demonstrated major histocompatibility complex nonrestricted killing, and showed the following predominant phenotypes: B73.1+T3+T8+ or B73.1+T3+T8- from B73.1+ subsets; and HNK-1-T3+T8+ (initially HNK-1+) from HNK-1+ subsets. In contrast, B73.1+ and HNK-1+ clones from normal donors showed the following predominant phenotypes: B73.1+T3-T8-; and HNK-1-T3-T8- or HNK-1-T3-T8+ (initially all HNK-1+). Short-term in vitro IL 2 or interferon treatment of fresh NK defective subsets from CML patients resulted in minimal cytotoxic augmentation. In contrast, defective NK cells from CML patients, whether HNK-1+ or B73.1+ subsets, proliferated with complete regeneration of cytolytic activity after a 3-4 week exposure to IL 2, but differed in phenotypic profiles as compared to those of normal donors. These observations imply that not only fresh defective NK cells but also the cytotoxically restored clones from CML patients are derived from different NK subsets and may represent undifferentiated forms of NK cells that may be arrested at an early stage of development by yet unknown mechanism(s). In vitro substantiation of autologous leukemia cell killing by IL 2-proliferative NK cell clones is encouraging and may allow for new in vivo immunotherapeutic modalities in CML patients.
Antibodies, Monoclonal↗
Effects of steroids on renal NAD+-dependent 15-hydroxyprostaglandin dehydrogenase activity in ovariectomized rats.
It has been suggested that the circulating prostacyclin in primarily inactivated by renal NAD+-dependent 15-hydroxyprostaglandin dehydrogenase. Changes in the renal enzyme activity in response to hormones were studied. The renal 15-hydroxyprostaglandin dehydrogenase activity in female rats was lower than that in male rats, and was significantly increased by ovariectomy. The effect of sex steroids on the renal enzyme activity was then studied in ovariectomized rats. Estradiol administration induced a significant decrease in the renal enzyme activity, while testosterone did not show any significant effect. Kinetic parameters for the renal enzyme from control and estradiol-treated groups were compared. An identical apparent Km for prostaglandin E2 was obtained for the enzyme from both groups. Vmax in the treated group was progressively decreased. The enzyme from both groups decayed at the same rate. The results indicated that estradiol might be the major endogenous sex steroid regulating the renal NAD+-dependent 15-hydroxyprostaglandin dehydrogenase activity, and the inhibitory effect of estradiol on the renal enzyme might be due to the inhibition of the enzyme biosynthesis.
Animals↗
Physicochemical characterization of lens crystallins from the carp and biochemical comparison with other vertebrate and invertebrate crystallins.
Lens crystallins were isolated from the homogenate of carp (Cyprinus carpio) eye lenses by gel permeation chromatography and characterized by gel electrophoresis, immunodiffusion, amino acid analysis, circular dichroism, and protein sequence analysis. Three well-defined fractions corresponding to alpha/beta-, beta-, and gamma-crystallins were obtained in relative weight percentages of 26, 22, and 52%. The native molecular masses of the purified fractions were determined to be 410, 60, and 20 kDa, respectively. The polypeptide compositions as determined by SDS gel electrophoresis revealed the substantial presence of beta-crystallin polypeptides in the alpha-crystallin fraction; this is also evident in the fractionation of amphibian crystallins but is not common in the case of higher classes of vertebrates. The circular dichroism spectra indicate a predominant beta-sheet structure in all three fractions, albeit with some contribution of alpha-helical structure in the gamma-crystallin, the amino acid composition of which bears a resemblance to that of squid crystallin. Sequence comparison of carp gamma-crystallin with frog and calf gamma-crystallins indicates a high degree of homology in their N-terminal segments despite the dissimilarity of amino acid compositions and weak immunological cross-reactivity.
Amino Acids↗
Selective suppression of insulin-induced proliferation of cultured human hepatoma cells by somatostatin.
The effects of somatostatin (SRIF), insulin, and triiodothyronine (T3) on the growth of human hepatoma cells were investigated on the well-differentiated human hepatoma cell line Hep3B. Results showed that both insulin and T3 can stimulate cell growth of serum starved Hep3B cells at physiological concentrations. SRIF alone showed little growth-promoting activity. When added concurrently with insulin, however, SRIF suppressed the insulin-induced cell proliferation in a dose-dependent manner. On the other hand, SRIF had no inhibitory effect on T3-induced cell proliferation. SRIF is labile in the medium, with a half-life of about 2 h during culture incubation. SRIF did not disturb the insulin binding to its surface receptors nor inhibit the insulin-dependent receptor kinase activity of Hep3B cells in vitro. These results suggest that postreceptor regulation may be involved. The selective suppression by SRIF of insulin-induced cell growth provides an unique approach to the study of insulin actions on proliferation of human hepatoma cells.
Carcinoma, Hepatocellular↗
Electroelution of DNA and protein from polyacrylamide and agarose gels.
An electroelution method is described for the recovery of DNA and protein from agarose or polyacrylamide gels. The samples to be electroeluted are compartmentalized in a modified microcentrifuge tube fitted with dialysis membranes. This procedure is simple, rapid, inexpensive and efficient. Within 30 min to 2 hrs, the recovery of the sample is nearly quantitative. DNA fragments recovered can be directly subjected to DNA sequence analysis or enzymatic reactions after ethanol precipitation. Proteins can also be recovered after separation by acrylamide gel in the presence or absence of detergents and be ready for further analysis.
Animals↗
In vitro pollen plant induction and embryoid clone establishment of Panax ginseng.
In anther culture of Panax ginseng, its callus formation showed a wide adaptability to culture media. Large numbers of calli were induced on media exhibiting better effects of induction. Supplements of 5 mg 2,4-D/1 and 1 mg KT/1 to the media proved to be much effective. Regeneration of the whole plantlets from anther culture of Panax ginseng is usually quite difficult. During the past three years, however, sixteen of the 100 medium formulae tested were proved to be suitable. The formulae of MS + 0.5 mg BA/1 + 2 mg GA/1 + 1000 mg LH/1 + 3% sucrose were considered good and effective. A visibly differentiated body, which was light-milky white and later turned into a light green spot, was formed 40 days after the callus was transferred to the differentiation media. This body differentiated subsequently into buds, roots and, eventually, seedlings. The embryoid clones have been established in order to maintain its ability of continual differentiation into plantlets through successive culturings of many generations. The test-tube ginseng thus formed were transferred to regular flowerpots and grew well. Based upon chromosome examination of the callus cells and the root tips, we tentatively affirmed that the majority of these regenerated from anther of Panax ginseng were originated from pollen cells.
Methods↗
Suppressor T lymphocytes from lepromatous leprosy skin lesions.
The immune response in leprosy forms a spectrum with lepromatous leprosy patients exhibiting specific unresponsiveness to antigens of Mycobacterium leprae. This unresponsiveness is thought to be related to the prevalence of T8-positive lymphocyte in these lepromatous lesions. To analyze the immunoregulatory function of these T8 cells, we developed simple procedures to extract lymphocytes from skin biopsy specimens of patients with leprosy. These lymphocytes were sorted for T8 and T4 positive cells, and cell lines were established by expansion with interleukin 2 (IL 2) and irradiated feeder cells. All T8 positive lines tested were positive for IL 2 receptors and HLA-DR determinants. These lines were additionally assayed for lepromin-induced suppression of the normal peripheral blood lymphocyte Con A proliferative response. Thirteen of 32 lines from six lepromatous patients showed significant suppressor activity, whereas nine lines from six tuberculoid patients and one line from normal peripheral blood failed to show suppression (p less than 0.001). Taken together, the finding of M. leprae-triggered suppressor cells within lepromatous skin lesions may in part explain the M. leprae unresponsiveness of lepromatous leprosy patients.
Antigens↗