Extensive transcription of foreign DNA in a crown gall teratoma.
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Base Sequence↗
Biomedical subjects
F Yang
Publications and source records attributed to F Yang.
Plasmid DNA of Agrobacterium tumefaciens detected in a presumed habituated tobacco cell line.
'Tabac anergié' tissue has been used by many investigators as a habituated tobacco cell line. In this study, we have found sequences which are homologous to approximately 9 megadaltons of an Agrobacterium octopine-type plasmid in DNA isolated from 'Tabac anergié' tissue. These T-DNA sequences were shown to be the same 'core DNA' sequences found to be present in several other unorganized tumor lines which have been studied in our laboratory. The T-DNA was also shown to be integrated into plant DNA. Thus, the 'Tabac anergié' tissue is a crown gall tumor induced by a strain of Agrobacterium tumefaciens containing an octopine-type plasmid. These results indicate that the plants regenerated from 40 clones of the 'Tabac anergié' line by Sacristán and Melchers (1977) were actually reverted plants obtained from an unorganized crown gall tumor, kept in culture for more than 25 years. It is necessary to re-evaluate observations and conclusions which have been based upon 'Tabac anergié' being a habituated tissue.
Cell Line↗
Foreign DNA sequences in crown gall teratomas and their fate during the loss of the tumorous traits.
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Cell Line↗
Estradiol and progesterone binding in uterine leiomyomata and in normal uterine tissues.
To explain the sensitivity of uterine leiomyomata to endogenous and exogenous estrogens, specific cytosol receptor proteins for estradiol-17 beta and progesterone were found in tissue from uterine leiomyomata and compared with the concentrations of receptors in normal myometrium and endometrium from the same patient. The concentration of cytoplasmic estrogen receptors in leiomyomata (40.5 +/- 7.6 cytoplasmic estrogen receptors in leiomyomata (40.5 +/- 7.6 fmole/mg cytosol proteins, mean +/- SEM) was significantly greater than that found in myometrium (16.5 +/- 1.5) and significantly less than that found in endometrium (131 +/- 15.1). The concentration in leiomyomata of cytoplasmic progesterone receptors (104.4 +/- 41.2 fmole/mg cytosol protein, mean +/- SEM) was also greater than that found in myometrium (80.8 +/- 29.9) and less than that of endometrium (194.7 +/- 5.5); however, individual variation precluded statistical significance. The presence of cytoplasmic receptor proteins in myomatous tissues explains the sensitivity of the leiomyoma to endogenous or exogenous steroids and may provide information useful in the clinical management of this neoplastic disorder.
Adult↗
Iodinated neurohypophyseal hormones as potential ligands for receptor binding and intermediates in synthesis of tritiated hormones.
[3-Iodo-Tyr2]oxytocin (MIOT), [3,5-diiodo-Tyr2]oxytocin (DIOT), [3-iodo-Tyr2,Lys8]vasopressin (MILVP), [3,5-diiodo-Tyr2,Lys8]vasopressin (DILVP), [3-iodo-Tyr2,Arg8]vasopressin (MIAVP), and [3,5-diiodo-Tyr2,Arg8]vasopressin (DIAVP) were synthesized by iodination of the respective hormones, pruified, and characterized. All the monoiodo hormones had to be freshly prepared prior to bioassays, since on storage they gave rise to hormonal-like biological activity. The biological activities of these iodo analogues were measured in an adenylate cyclase assay employing neurohypophyseal hormone (NHH) sensitive bovine renal medullary membranes, and/or the rat oxytocic assay. In the cyclase assay, DIOT, DILVP, and DIAVP were inactive as agonists or antagonists. MIOT shows no agonistic activity in the renal cyclase system and uterus, but is a weak reversible inhibitor of oxytocin (OT) in both systems. When MIOT (10(-4) M) was preincubated with renal membranes for 10 min at 37 degrees C before addition of OT, it behaved as a noncompetitive inhibitor of NHH-stimulated adenylate cyclase. MILVP and MIAVP appear to be partial agonists with Km (half maximal response) 3 X 10(-6) and 3 X 10(-7) M, respectively, as determined in the cyclase assay. Upon preincubation with renal medullary membranes, MILVP (10(-6) M) behaves as a more potent noncompetitive inhibitor of OT than MIOT. Accordingly, iodo derivatives of NHH do not exhibit sufficient affinity to serve an specific ligands to measure OT, LVP, or AVP receptors in the uterus and kidney. Study of the specificity of inhibition produced by MIOT revealed that this analogue does not act selectively upon NHH receptors. Thus, MIOT modified adenylate cyclase systems which do not have NHH receptors, e.g., the PTH-sensitive adenylate cyclase in bovine renal cortex and the glucagon-sensitive adenylate cyclase in rat liver. DIOT, DILVP, and DIAVP were subjected to catalytic tritiation (employing carrier free tritium) and were converted to [3H]OT (25, 31, and 25 Ci/mmol), [3H]LVP (26 and 23 Ci/mmol), and [3H]AVP (17 Ci/mmol), respectively. These tritiated ligands have been successfully used to measure NHH receptor sites both in kidney and uterine membranes as described in other studies.
Adenylyl Cyclases↗
Tuberculous infection in a vascular prosthesis: a case of aortic graft infection resulting from disseminated tuberculosis.
Insertion of an aortic prosthetic bypass graft in a patient with untreated disseminated tuberculosis resulted in graft infection with formation of a pseudoaneurysm. Microbiologic cultures implicated Mycobacterium tuberculosis as the causative agent, and a subsequent review of the literature indicated this report to be the first clinical demonstration of the susceptibility of vascular prosthesis to M tuberculosis infection to our knowledge.
Aorta↗
Retro analogs related to oxytocin.
[D-alle3]-retro-D-deaminotocinamide (I), retro-L-deaminotocinamide (III) and their respective N-formyl derivatives (II and IV) were synthesized by the stepwise active ester method: deaminotocinamide was prepared by the solid-phase method. The retro-analogs of deaminotocinamide, tested at concentrations up to 10)-5)M, were found to be without activity as agonists or antagonists in the oxytocic assay. At 10(-4)M,[D-alle]-retro-D-deaminotocinamide is a weak competitive inhibitor of oxytocin. [D-alle3, Gly7]-retro-D-deaminooxytocin (V) was synthesized either by the active ester method or by a fragment condensation method employing the retro-D-RING, [D-alle3]-retro-D-deaminotocinamide, and D-tail, Boc-Gly-D-Leu-Gly, as the fragments...
Amino Acids↗
Contribution of the peptide backbone to the action of oxytocin analogs.
This investigation was undertaken to evaluate the functional contribution of the peptide backbone of oxytocin in its interaction with receptor. Corey-Pauling-Koltun models of (Gly-7) deaminooxytocin, deaminotocinamide, and their respective retro-D-analogs built in any specific conformation (e.g., the Walter-Urry model for oxytocin) have a quai-equivalent topochemical arrangement of amino-acid side chains; however, the CO and NH elements of the peptide backbone of the retro-D-analog are reversed. The retro-D-analogs of deaminotocinamide and (Gly-7) deaminooxytocin (prepared using D-alle for L-Ile) and their respective N-formyl derivatives were assayed for uterotonic activity relative to related L-peptides. All retro-D-analogs (tested at concentrations ranging from 10-10 to 10-5 M) were devoid of angonistic (or antagonistic) activity in the isolated rat uterus, except for the retro-D-(D-alle-3, Gly-7) deaminooxytocinamine, which retains a terminal NH-2 group on the tail; the latter is a partial agonist with very low affinity. The results obtained with retro-D-analogs indicate that one or more of the elements of the peptide backbone of the tocinamide ring are essential for "occupation" and "activation" of uterine receptors. Oxytocin action may be the resultant of multiple hydrogen-bonding interactions between CO, NH, NH-2, and OH groups of the hormone with complementary groups on receptor, made possible by appropriate hydrophobic bonding.
Amino Acid Sequence↗
Effects of commonly used mitogens on the cytotoxicity of 4-tertiary butylphenol to human melanocytes.
In the search for environmental compounds responsible for contact or occupational vitiligo, it was found that the most potent was 4-tertiary butylphenol (4-TBP). Exposure to 4-TBP is widespread both in industry and in consumer items including synthetic leather, plastic, glues, and germicidal phenolic detergents. How 4-TBP causes depigmentation and the death of melanocytes is currently unclear. Growth mitogens for human melanocytes include alpha-melanocyte stimulating hormone (alpha-MSH), basic fibroblast growth factor (bFGF) and 12-o-tetradecanoylphorbol-13-acetate (TPA). The former two mitogens are physiological growth factors for melanocytes. We have studied the effects of these mitogens on the cytotoxicity of 4-TBP in human melanocytes. Our results demonstrated that deprivation of alpha-MSH or bFGF from melanocyte cultures resulted in reduced cytotoxicity to 4-TBP. Similar results were obtained upon treatment of melanocytes with an inhibitor of cAMP-dependent protein kinase A (PKA), that is known to be activated by alpha-MSH, or with an inhibitor of the tyrosine kinase bFGF receptor. In contrast, removal of fetal bovine serum or TPA from the culture medium did not influence the susceptibility of melanocytes to 4-TBP. These results suggest that activation of the cAMP and tyrosine kinase signaling pathways, both of which are involved in the mitogenic response of melanocytes, increase the susceptibility of these cells to the cytotoxic effects of 4-TBP.
Animals↗
Carboxy terminal of beta-amyloid deposits in aged human, canine, and polar bear brains.
Immunocytochemistry, using antibodies specific for different carboxy termini of beta-amyloid. A beta 40 and A beta 42(43), was used to compare beta-amyloid deposits in aged animal models to nondemented and demented Alzheimer's disease human cases. Aged beagle dogs exhibit diffuse plaques in the absence of neurofibrillary pathology and the aged polar bear brains contain diffuse plaques and PHF-1-positive neurofibrillary tangles. The brains of nondemented human subjects displayed abundant diffuse plaques, whereas the AD cases had both diffuse and mature (cored) neuritic plaques. Diffuse plaques were positively immunostained with an antibody against A beta 42(43) in all examined species, whereas A beta 40 immunopositive mature plaques were observed only in the human brain. Anti-A beta 40 strongly immunolabeled cerebrovascular beta-amyloid deposits in each of the species examined, although some deposits in the polar bear brain were preferentially labeled with anti-A beta 42(43). beta-amyloid deposition was evident in the outer molecular layer of the dentate gyrus in the aged dog, polar bear, and human. Within this layer, A beta 42 was present as diffuse deposits, although these deposits were morphologically distinct in each of the examined animal models. In dogs, A beta 42 was cloud-like in nature; the polar bear demonstrated a more aggregated type of deposition, and the nondemented human displayed well-defined deposits. Alzheimer's disease cases were most frequently marked by neuritic plaques in this region. Taken together, the data indicate that beta-amyloid deposition in aged mammals is similar to the earliest stages observed in human brain. In each species, A beta 42(43) is the initially deposited isoform in diffuse plaques.
Aged↗
Rodent models of Alzheimer's disease: rat A beta infusion approaches to amyloid deposits.
The development of rodent models for Alzheimer's disease is a critical step for both understanding the disease and developing therapeutic drugs. Transgenic and knockout mouse models will elucidate some important aspects of the etiology of the disease and the development of pharmaceutical treatments. Here, we will focus on the advantages of nontransgenic models. In nontransgenic rat models, intraventricular infusion of A beta 1-40 (alone) generally results in diffuse deposition of A beta with very few focal plaque-like amyloid deposits after a 30-day intraventricular infusion. However, we have recently found that large numbers of scattered A beta immunoreactive plaque-like deposits can be produced in retired female Sprague-Dawley rat breeders using intraventricular infusion of A beta combined with neuropil injection of transforming growth factor beta 1(TGF beta). A beta that was not associated with the large deposits was often immunolocalized with neurons and cell processes. Immunogold electron microscopy demonstrated the presence of A beta in endosome/lysosomes of neuronal processes and glia and basal lamina. In some cases this labeling was clearly in lysosomes of degenerating neurites. This model allows one to introduce A beta and other plaque-associated factors without overexpression of potentially confounding APP domains. We conclude that A beta infusion models will be a useful complement to transgenic approaches to Alzheimer's pathology.
Alzheimer Disease↗
Keratin in cutaneous amyloidoses.
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Amyloid↗
Ibuprofen effects on Alzheimer pathology and open field activity in APPsw transgenic mice.
We previously showed the non-steroidal anti-inflammatory drug (NSAID) ibuprofen suppresses inflammation and amyloid in the APPsw (Tg2576) Tg2576 transgenic mouse. The mechanism for these effects and the impact on behavior are unknown. We now show ibuprofen's effects were not mediated by alterations in amyloid precursor protein (APP) expression or oxidative damage (carbonyls). Six months ibuprofen treatment in Tg+ females caused a decrease in open field behavior (p < 0.05), restoring values similar to Tg- mice. Reduced caspase activation per plaque provided further evidence for a neuroprotective action of ibuprofen. The impact of a shorter 3 month duration ibuprofen trial, beginning at a later age (from 14 to 17 months), was also investigated. Repeated measures ANOVA of Abeta levels (soluble and insoluble) demonstrated a significant ibuprofen treatment effect (p < 0.05). Post-hoc analysis showed that ibuprofen-dependent reductions of both soluble Abeta and Abeta42 were most marked in entorhinal cortex (p < 0.05). Although interleukin-1beta and insoluble Abeta were more effectively reduced with longer treatment, the magnitude of the effect on soluble Abeta was not dependent on treatment duration.
Aging↗
Nonaqueous biocatalytic degradation of a nerve gas mimic.
Organophosphorus hydrolase has been shown to be an effective catalyst for the continuous decontamination of a nerve agent in a continuous gas phase reactor. Very small quantities of the enzyme are sufficient to enable detoxification of low concentrations of the nerve agent for extended periods of time. In the case where the nerve agent is at high concentrations (a liquid), the enzyme has also been shown to be active in biphasic mixtures of a solvent with water. The activity and specificity of the enzyme in both environments (continuous gas phase and biphasic mixture) obey classical models of enzyme kinetics. The activity of the enzyme in such extreme environments enables optimization of systems capable of continuous gas or liquid phase biocatalytic degradation of highly toxic chemicals.
Catalysis↗
Application of base cleavable safety catch linkers to solid phase library production.
We have used sulfide "Safety Catch" linkers to anchor typical medicinal chemistry functional groups to amine resins. Compounds are loaded as the ester, carbamate, or amine. At the end of the synthesis, the linker is activated by peracid. The sulfone resins are then cleaved by beta-elimination in the gas phase or in solution by secondary amines to produce acids and primary, secondary, or tertiary amines. Comparison of cleavage rates to other sulfone resins including SEM showed significantly faster cleavage for this system with conditions similar to Fmoc deprotection. Application of this strategy to a medicinal chemistry library gives good yields and purities of the resulting compounds.
Chemistry, Pharmaceutical↗
Duplication within the haptoglobin Hp2 gene.
DNA sequencing shows that the intragenic duplication within the human haptoglobin Hp2 allele was formed by a non-homologous, probably random, crossing-over within different introns of two Hp1 genes, probably in an Hp1F / Hp1S heterozygote.
Alleles↗
HMG CoA reductase-inhibitor-related myopathy and the influence of drug interactions.
We report four cases of rhabdomyolysis and severe, disabling myopathy associated with HMG CoA reductase-inhibitor therapy. Patient developed symptoms following the addition of roxithromycin to combination lipid-lowering therapy with simvastatin and gemfibrozil. Patients 2 and 3 became symptomatic after developing acute on chronic renal impairment while taking simvastatin. The muscle biopsy of patient 3 revealed a necrotizing myopathy and the presence of inclusion bodies. Patient 4 developed symptoms within 4 weeks of starting cerivastatin monotherapy. The four cases illustrate the importance of considering the potential for drug interactions and making appropriate dosage adjustments for renal insufficiency in patients receiving HMG CoA reductase therapy.
Aged↗
A method for the analysis of butyltin chlorides in air by gas chromatography with atomic emission detection.
An initial screening test compared the use of tropolone (2-hydroxy-2,4-6-cycloheptatrienone) in acetic acid with sodium diethyldithiocarbamate (NaDDC) as chelating agents for the extraction of butyltin chlorides from glass fiber filters and XAD-2 resin tube. NaDDC was chosen for subsequent analyses. Mono-, di-, and tributyltin chloride were spiked onto glass fiber filters and XAD-2 resin, extracted in toluene with NaDDC and derivatized with pentylmagnesium bromide. Derivatized butyltin species were determined by gas chromatography with plasma atomic emission detection. Glass fiber filters and XAD-2 resin were found to provide high retention of butyltin compounds during sampling and efficient recovery of butyltin compounds by extraction with NaDDC.
Air Pollutants, Occupational↗