Residues of forestry herbicides in plants of importance to California Native Americans.
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California↗
Biomedical subjects
D Tran
Publications and source records attributed to D Tran.
Time course of inhibition of hypertension by antisense oligonucleotides targeted to AT1 angiotensin receptor mRNA in spontaneously hypertensive rats.
Antisense oligodeoxynucleotides (AS-ODN) can be designed to provide inhibition of a specific protein. Since angiotensin receptors are involved in blood pressure regulation we constructed AS-ODN to angiotensin II type-1 receptor (AT1) mRNA. When given centrally, the AS-ODN reduces blood pressure in spontaneously hypertensive rats (SHR) 24 h after injection. To study the time course of a single AS-ODN injection on blood pressure and heart rate, groups of SHR were injected intracerebroventricularly (icv) with either single dose of AS-ODN or scrambled (SC) ODN and blood pressure was recorded through implanted catheters daily for up to 9 days. Blood pressure decreased significantly in the AS-ODN treated rats compared to the SC-ODN rats for up to 7 days. The maximum decrease (38 mm Hg) occurred at 3 days. There appeared to be no toxic reaction or side effects and the blood pressure level had recovered by days 8 and 9. Heart rate was not altered by AS-ODN treatment. To test that the ODN was entering the brain tissue, fluorescein-isothiocyanate labelled (FITC) ODN was injected in Sprague-Dawley rats and the fluorescence detected 1 h later by confocal microscopy. Within 1 h there was rapid uptake into cells close to the site of injection and into brain parenchyma around the third and lateral ventricles. To test that the AS-ODN had reduced AT1 receptors, binding studies were carried out on membranes from hypothalamic tissue. There was a modest (approximately 20%) but significant (P < .05) decrease in the AT1 receptor binding after 25 microm or 50 microm AS-ODN. AT2 receptors were not altered by the AS-ODN, indicating its specificity for the AT1 receptor. The small decrease in receptor binding, relative to its large effect on blood pressure, is discussed in terms of the AT1 receptor life cycle. The mechanism for the long action of a single AS-ODN injection is hypothesized as resulting from the persistence of AS-ODN in the nucleus, preventing transport of the mRNA into the cytoplasm.
Animals↗
Expression of secretory group II phospholipase A2 by CD1a positive cells-in human atherosclerotic plaques.
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Antigens, CD1↗
Cyclin G1 and cyclin G2 comprise a new family of cyclins with contrasting tissue-specific and cell cycle-regulated expression.
We describe the isolation and characterization of cDNAs encoding full-length human and murine cyclin G1 and a novel human homologue of this cyclin designated cyclin G2. Cyclin G1 is expressed at high levels in skeletal muscle, ovary, and kidney. Following an initial up-regulation from early G1 to G1/S phase, cyclin G1 mRNA is constitutively expressed throughout the cell cycle in T and B cell lines. In contrast, in stimulated peripheral T cells, cyclin G1 mRNA is maximal in early G1 phase and declines in cell cycle progression. Cyclin G1 levels parallel p53 expression in murine B lymphocytes; however, in several human Burkitt's lymphomas, murine lymphocytes treated with transforming growth factor-beta, early murine embryos, and several tissues of p53 null mice, cyclin G1 levels are either inverse of p53 levels or expressed independent of p53. The cyclin G1 homologue, cyclin G2, exhibits 60% nucleotide sequence identity and 53% amino acid sequence identity with cyclin G1, and like cyclin G1, exhibits closest sequence identity to the cyclin A family. Distinct from cyclin G1, the amino acid sequence for cyclin G2 shows a PEST-rich sequence and a potential Shc PTB binding site. Cyclin G2 mRNA is differentially expressed compared to cyclin G1, the highest transcript levels seen in cerebellum, thymus, spleen, prostate, and kidney. In contrast to the constitutive expression of cyclin G1 in lymphocytes, cyclin G2 mRNA appears to oscillate through the cell cycle with peak expression in late S phase.
Amino Acid Sequence↗
A single MEF2 site governs desmin transcription in both heart and skeletal muscle during mouse embryogenesis.
Desmin, the muscle-specific intermediate filament protein is one of the earliest known myogenic makers both in heart and in somites. We have previously shown that high levels of desmin expression in the skeletal cell line C2C12 are due to a distal enhancer, which contains a muscle-specific factor-(2MEF2) binding site, adjacent to an E box, the binding site of the myogenic Helix-Loop-Helix (mHLH) regulators. We have further shown that MEF2C, a myocyte restricted member of the MEF2 family and all four mHLH factors can bind to their corresponding sites and through a cooperation with a second proximal E box can transactivate the desmin promoter. To study the significance of these regulatory elements in vivo, we have generated transgenic mice with desmin-lacZ reporters, intact or mutated at the MEF2 and E box of the enhancer. We show that the cis-acting DNA sequences within the 1-kb 5' flanking region of the mouse desmin gene are sufficient to direct appropriate temporal transcription both in heart and in skeletal muscle during mouse embryogenesis. Mutation at the MEF2 site completely suppressed transcription of the linked lacZ transgene in both developing heart and somites of the embryos. Mutation of the E box only suppressed activation in skeletal muscle precursors (somites and limb buds) but not in cardiac muscle. These data demonstrate that the MEF2 site is indispensable for the desmin enhancer function both in heart and in skeletal muscle. In addition, MEF2 cooperation with the mHLH regulators is absolutely necessary for proper transcriptional activity during embryonic skeletal muscle development.
Animals↗
Intracellular calcium stores and inositol 1,4,5-trisphosphate receptor in rat liver cells.
The D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] receptor was localized by immunofluorescence experiments in situ in liver cryosections. Two anti-Ins(1,4,5)P3 receptor antibodies (against the 14 C-terminal residues of the type 1 receptor or against the entire cerebellar receptor) weakly decorated the whole cytoplasm, and a more intense labelling was observed at the periphery of the hepatocytes, particularly beneath the canalicular and the sinusoidal domains of the plasma membrane (PM). Antibodies against calreticulin, the Ca2+ pump (SERCA2b) or endoplasmic reticulum (ER) membranes homogeneously labelled the cytoplasm and the subplasmalemmal area. These data indicate that the ER can be divided into at least two specialized subregions: one is located throughout most of the cytoplasm and contains markers of the rough ER (RER), calreticulin, SERCA2b and a low density of Ins(1,4,5)P3 receptor, and the other is confined to the periphery of the cells and contains calreticulin, Ca2+ pump, RER markers and a high density of Ins(1,4,5)P3 receptor. A membrane fraction enriched in Ins(1,4,5)P3 receptor and in markers of the PM was immuno-adsorbed with the antibody against the C-terminal end of the Ins(1,4,5)P3 receptor and pelleted with Sepharose protein A. The immuno-isolated material was enriched in Ins(1,4,5)P3 receptor, but none of the markers of the ER or of the PM could be detected. This suggests that the Ins(1,4,5)P3 receptor is localized on discrete domains of the ER membrane beneath the canalicular and the sinusoidal membranes, where it was found at higher densities than the other markers.
Animals↗
Disruption of muscle architecture and myocardial degeneration in mice lacking desmin.
Desmin, the muscle specific intermediate filament (IF) protein encoded by a single gene, is expressed in all muscle tissues. In mature striated muscle, desmin IFs surround the Z-discs, interlink them together and integrate the contractile apparatus with the sarcolemma and the nucleus. To investigate the function of desmin in all three muscle types in vivo, we generated desmin null mice through homologous recombination. Surprisingly, desmin null mice are viable and fertile. However, these mice demonstrated a multisystem disorder involving cardiac, skeletal, and smooth muscle. Histological and electron microscopic analysis in both heart and skeletal muscle tissues revealed severe disruption of muscle architecture and degeneration. Structural abnormalities included loss of lateral alignment of myofibrils and abnormal mitochondrial organization. The consequences of these abnormalities were most severe in the heart, which exhibited progressive degeneration and necrosis of the myocardium accompanied by extensive calcification. Abnormalities of smooth muscle included hypoplasia and degeneration. The present data demonstrate the essential role of desmin in the maintenance of myofibril, myofiber, and whole muscle tissue structural and functional integrity, and show that the absence of desmin leads to muscle degeneration.
Animals↗
Utility of Tc-99m mebrofenin scintigraphy in the assessment of infantile jaundice.
Technetium-99m mebrofenin hepatobillary excretory patterns were assessed in 36 infants with hyperbilirubinemia. Phenobarbital was administered to 22 patients before imaging. Final diagnoses included: intrahepatic cholestasis (14 patients), neonatal hepatitis (nine patients), biliary atresia (eight patients), alpha-1-antitrypsin deficiency (two patients), Alagille's syndrome (two patients), and cystic fibrosis (one patient). No patient with biliary atresia showed bowel activity by 24 hours. Of the 28 infants without biliary atresia, 23 (82%) had bowel activity visualized by 6-8 hours and 26 (90%) had bowel activity by 24 hours. Two had no bowel activity at 24 hours: one had cystic fibrosis and one had neonatal hepatitis. Of the 26 patients with bowel visualization, the time to visualize bowel did not differ between patient groups with and without phenobarbital induction. All of the patients with hepatitis, including those with marked dysfunction, showed good hepatic uptake. Mebrofenin scintigraphy is an important imaging technique in the diagnostic evaluation of infants with hyperbilrubinemia. In addition to biliary atresia, intrahepatic cholestasis due to cystic fibrosis and severe neonatal hepatitis may also cause bowel nonvisualization up to 24 hours. The results of this study suggest phenobarbital induction may not be needed when Tc-99m mebrofenin scintigraphy is used for the assessment of infantile jaundice.
Aniline Compounds↗
Synthesis and characterization of indolicidin, a tryptophan-rich antimicrobial peptide from bovine neutrophils.
Indolicidin, a novel tryptophan-rich microbicidal tridecapeptide amide isolated originally from granules of bovine neutrophils, has been prepared by optimized manual and automated protocols of stepwise solid-phase synthesis with N alpha-9-fluorenylmethyloxycarbonyl (Fmoc) amino acid derivatives. Both standard polystyrene (PS) and polyethylene glycol-polystyrene (PEG-PS) graft supports were used in combination with handles that provide C-terminal peptide amides: 5-(4-Fmoc-aminomethyl-3,5-dimethoxyphenoxy)valeric acid (PAL) or 5-(9-Fmoc-aminoxanthen-2-oxy)valeric acid (XAL). Final deprotection/cleavage was carried out with reagent K, trifluoroacetic acid-phenol-water-thioanisole-1,2-ethanedithiol (82.5:5:5:5:2.5), or reagent B, trifluoroacetic acid-phenol-water-tri(isopropyl)silane (88:5:5:2), and related cocktails. Initial purities as high as 93% were obtained immediately following cleavage. In the largest-scale synthesis carried out, 0.8 g of HPLC-purified indolicidin (> 99% pure) was obtained, representing a 39% overall yield based on C-terminal Arg(Pmc) anchored to PAL-PS-resin. The main synthetic product, and some by-products, were characterized by analytical high-performance liquid chromatography (HPLC), sequencing, and fast atom bombardment mass spectrometry (FABMS). The antimicrobial potencies of natural and synthetic indolicidin, as determined by in vitro antibacterial and antifungal assays, were identical. Further, the reactivities of natural and synthetic peptides with anti-indolicidin antibody were indistinguishable.
Animals↗
Medial collateral ligament injuries: evaluation of multiple signs, prevalence and location of associated bone bruises, and assessment with MR imaging.
PURPOSE: To investigate the multiple signs of medial collateral ligament (MCL) sprains, including the location and prevalence of associated bone bruises, and evaluate the accuracy of the criteria proposed for magnetic resonance (MR) imaging in grading these sprains. MATERIALS AND METHODS: MR images were evaluated for signs of MCL injury in 76 patients with MCL sprains and 25 asymptomatic volunteers. These signs were then correlated with standards used to determine MCL injury at clinical evaluation. The grade of MCL injury as determined with MR imaging criteria was compared with clinical findings. RESULTS: All signs demonstrated little interobserver variability and were specific. The most sensitive signs were fascial edema and loss of demarcation from adjacent fat. This MR imaging grading system was inaccurate for classification of grade 3 MCL tears and was only questionably accurate for grades 1 and 2. CONCLUSION: Multiple signs of MCL sprains on MR images have varying sensitivities. MR grading systems may not be accurate for classification of MCL injuries.
Adult↗
Anorexia nervosa in 'non-white' populations.
BACKGROUND: Comparisons were made between two groups of anorectic patients, 'non-white' and 'white', on a variety of clinical and social characteristics. METHOD: The study is based on a 34-year long database (1960-93) associated with a national tertiary referral centre. Thirty-six non-white patients meeting DSM-III-R criteria for anorexia nervosa (AN) and five with 'partial syndrome' are compared with a white group comprising 944 patients with full syndrome. RESULTS: The main finding is clinical similarity between the two groups, extending to social class and pathological patterns of family relationship. The non-whites are shorter in stature (P = 0.004) and report earlier menarche (P = 0.004); they are younger at presentation (P < 0.001), somewhat less emaciated, and practice veganism slightly more commonly; they less often acknowledge sensitivity to 'fatness' (P < 0.003). This sensitivity was exposed later whenever treatment involved substantial weight gain. The proportion of non-white cases accepted for assessment has not changed in respect of year of onset (around 6%) for the last 20 years, or year of presentation (around 6-7%) over the last 15 years. There was a tendency for non-white patients to be referred earlier in their illness. CONCLUSIONS: The clinical and background profiles of non-white and white anorectics are generally similar. The numbers arising and presenting have not changed recently. Non-white patients apparently have as ready access as white patients to assessment and treatment by us.
Adolescent↗
Ca(2+)-mobilizing hormones induce sequentially ordered Ca2+ signals in multicellular systems of rat hepatocytes.
The development of hormone-mediated Ca2+ signals was analysed in polarized doublets, triplets and quadruplets of rat hepatocytes by video imaging of fura2 fluorescence. These multicellular models showed dilated bile canaliculi, and gap junctions were observed by using an anti-connexin-32 antibody. They also showed highly organized Ca2+ signals in response to vasopressin or noradrenaline. Surprisingly, the primary rises in intracellular Ca2+ concentration ([Ca2+]i) did not start randomly from any cell of the multiplet. It originated invariably in the same hepatocyte (first-responding cell), and then was propagated in a sequential manner to the nearest connected cells (cell 2, then 3, in triplets; cell 2, 3, then 4 in quadruplets). The sequential activation of the cells appeared to be an intrinsic property of multiplets of rat hepatocytes. (1) In the continued presence of hormones, the same sequential order was observed up to six times, i.e. at each train of oscillations occurring between the cells. (2) The order of [Ca2+]i responses was modified neither by the repeated addition of hormones nor by the hormonal dose. (3) The mechanical disruption of an intermediate cell slowed down the speed of the propagation, suggesting a role of gap junctions in the rapidity of the sequential activation of cells. (4) The same multiplet could have a different first-responding cell for vasopressin or noradrenaline, suggesting a role of the hormonal receptors in the sequentiality of cell responses. It is postulated that a functional heterogeneity of hormonal receptors, and the presence of functional gap junctions, are involved in the existence of sequentially ordered hormone-mediated [Ca2+]i rises in the multiplets of rat hepatocytes.
Animals↗
The Caco-2 cell monolayers as an intestinal metabolism model: metabolism of dipeptide Phe-Pro.
The metabolism of Phe-Pro was investigated in Caco-2 cell monolayers, a model of small intestinal epithelium. The results indicate that the majority of Phe-Pro was hydrolyzed during passage from the apical (AP) to basolateral (BL) side. The enzyme responsible for the hydrolysis is prolidase, a cytosolic enzyme. Through kinetic studies of a supernatant enzyme preparation, a Km of 30.4 microM and Vmax of 38.9 nmol/min per mg of protein were obtained. The enzyme catalyzed hydrolysis was inhibited by proline (66%), Zn+ (86%), Cu++ (100%), Fe (100%), PCMB (89%), and captopril (66%), but not by leucine. We also studied the transcellular transport of Phe-Pro by measuring the amount of Phe in the receiver media. In the presence of a proton gradient (AP pH6, BL pH7.4), the appearance rate of Phe in the BL media after Phe-Pro was loaded apically was at least 100 times faster than that in the AP media after Phe-Pro was loaded basolaterally. The former is also higher than the appearance rate of Phe without a transepithelial proton gradient (pH 6-pH 6) or against a proton gradient (pH7.4-pH6). The rate of appearance of Phe in the BL media (pH7.4) after Phe-Pro was loaded on the AP side (pH 6) was decreased by the presence in the AP media of proline (42%), leucine (40%), and captopril (17%), but not by Zn++. In conclusion, the transmembrane uptake of Phe-Pro is dependent on a proton gradient, and the intracellular metabolism of Phe-Pro is complete via hydrolysis by prolidase.
Cell Division↗
Clentiazem given at reperfusion improves subendocardial reflow and reduces myocardial infarct size in the dog.
The postischemic cardioprotection by calcium antagonists and the interplay between neutrophils and regional myocardial blood flow were investigated further, using clentiazem, a new potent calcium channel blocker derived from diltiazem. A 90-min occlusion of the interventricular coronary artery was followed by 6 hr of reperfusion in anesthetized dogs. One group was given clentiazem: 100 micrograms/kg at 5 min before reperfusion followed by a perfusion of 1 microgram/kg/min until sacrifice; controls received saline. Infarct size (% of area at risk) estimated with triphenyltetrazolium staining and by histology was reduced by nearly 50% (P < .05) in treated (16.6 +/- 3.0%), as compared to control (31.6 +/- 6.3%) dogs. Regional and collateral myocardial flows estimated with radioactive microspheres were similar between groups before and during occlusion. However, after an initial recovery to preocclusion values at 30-min reperfusion in both groups, flow declined to 50% normal (P < .05) in control animals after 3 and 6 hr in midwall and subendocardium, but the change was remarkably attenuated (P < .05) in subendocardium of clentiazem-treated dogs. Also, neutrophil accumulation at the epicardial side of the infarct, at the edge of salvaged myocardium, and estimated by tissue myeloperoxidase measurement, was reduced by 50% in treated dogs (clentiazem: 17.2 +/- 2.8; controls: 32.3 +/- 2.7 x 10(6) neutrophils/g). We conclude that administration of clentiazem at reperfusion reduces infarct size by interfering with both neutrophil accumulation and development of subendocardial no reflow in reperfused myocardium.
Animals↗
ELISA regulatory application: compliance monitoring of simazine and atrazine in California soils.
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Atrazine↗
Cellular distribution of polyphosphoinositides in rat hepatocytes.
The distribution of total phospholipids, phosphatidylinositol 4-phosphate (PIP) and phosphatidylinositol 4,5-bisphosphate (PIP2) was studied in isolated rat hepatocytes: (i) by mass assay and isotopic labelling in the fractions of plasma membranes, microsomes, mitochondria and nuclei prepared from isolated hepatocytes and (ii) by immunolocalization of PIP2 with a specific antibody (kt3g) in whole hepatocytes and isolated nuclei. Mass measurement and isotopic labelling showed that PIP was distributed in all four fractions. PIP2 was present in the plasma membrane and the nuclei. In whole cells, PIP2 was also detected in the plasma membrane by immunolocalization with the anti-PIP2 antibody kt3g. In unpolarized single hepatocytes, PIP2 distributed evenly throughout the plasma membrane. However, in polarized cell couplets, PIP2 was the most often undetectable in the lateral domain between the cells, and distributed preferentially in the sinusoidal domain of the plasma membrane. These results suggest that hepatocytes segregate PIP2 in particular domains of their plasma membrane. In purified fractions of nuclei, immunolocalization experiments showed that PIP2 was present uniquely in the nuclear envelope.
Animals↗
Trans-bilayer distribution of phosphatidylinositol 4,5-bisphosphate and its role in the changes of lipid asymmetry in the human erythrocyte membrane.
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Calcium↗
ELISA of simazine in soil: applications for a field leaching study.
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Chromatography, Gas↗