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PubMed2004

Effect of dibromoacetic acid on DNA methylation, glycogen accumulation, and peroxisome proliferation in mouse and rat liver.

Dibromoacetic acid (DBA) is a drinking water disinfection by-product. Its analogs, dichloroacetic acid (DCA) and trichloroacetic acid (TCA), are liver carcinogens in rodents. We evaluated the ability of DBA to cause DNA hypomethylation, glycogen accumulation, and peroxisome proliferation that are activities previously reported for the two other haloacetic acids. Female B6C3F1 mice and male Fischer 344 rats were administered 0, 1,000, and 2,000 mg/l DBA in drinking water. The animals were euthanized after 2, 4, 7, and 28 days of exposure. Dibromoacetic acid caused a dose-dependent and time-dependent decrease of 20%-46% in the 5-methylcytosine content of DNA. Hypomethylation of the c-myc gene was observed in mice after 7 days of DBA exposure. Methylation of 24 CpG sites in the insulin-like growth factor 2 (IGF-II) gene was reduced from 80.2% +/- 9.2% to 18.8% +/- 12.9% by 2,000 mg/l DBA for 28 days. mRNA expression of the c-myc and IGF-II genes in mouse liver was increased by DBA. A dose-dependent increase in the mRNA expression of the c-myc gene was also observed in rats. In both mice and rats, DBA caused dose-dependent accumulation of glycogen and an increase of peroxisomal lauroyl-CoA oxidase activity. Hence, DBA, like DCA and TCA, induced hypomethylation of DNA and of the c-myc and IGF-II genes, increased mRNA expression of both genes, and caused peroxisome proliferation. Again like DCA, DBA also induced glycogen accumulation. These results indicate that DBA shares biochemical and molecular activities in common with DCA and/or TCA, suggesting that it might also be a liver carcinogen.

Acetates↗

PubMed1976

Characterization of cardiac sarcoplasmic reticulum ATP-ADP phosphate exchange and phosphorylation of the calcium transport adenosine triphosphatase.

1. The terminal phosphate of (gamma-32P)ATP is rapidly incorporated into cardiac sarcoplasmic reticulum membranes (0.7--1.3 mumol/g protein) in the presence of calcium and magnesium. Cardiac sarcoplasmic reticulum membranes catalize an ATP-ADP phosphate exchange in the presence of calcium and magnesium. 2. Half-maximum activation of the phosphoprotein formation and ATP-ADP phosphate exchange is reached at an ionized calcium concentration of about 0.3 muM. The Hill coefficients are 1.3. 3. Transphosphorylation and ATP-ADP phosphate exchange require magnesium and are maximally activated at magnesium concentrations close to or equal to the ATP concentration. 4. The phosphoprotein level is reduced to about 45% at an ADP/ATP ratio of 0.1. The rate of calcium-dependent ATP splitting declines, whilst the rate of the calcium-dependent ATP-ADP phosphate exchange increases when the ADP/ATP ratio is varied from 0.1 to 1. The sum of both, the rate of ATP splitting and the rate of ADP-ATP phosphate exchange remains constant. 5. Phosphoprotein formation and ATP-ADP phosphate exchange are not affected by azide, dinitrophenol, dicyclohexyl carbodiimide and oubain, whilst both activities are reduced by blockade of -SH groups localized on the outside of the sarcoplasmic reticulum membrane. 6. The isolated phosphoprotein is acid stable. The trichloroacetic acid denatured 32P-labelled membrane complex is dephosphorylated by hydroxylamine, which might indicate that the phosphorylated protein is an acyl-phosphate. 7. Polyacrylamide gel elctrophoresis (performed with phenol/acetic acid/water) of phosphorylated sarcoplasmic reticulum fractions demonstrates that the 32P-incorporation occurs into a protein of about 100000 molecular weight. 8. It is suggested that the phosphoprotein represents a phosphorylated intermediate of the calcium-dependent ATPase which formation occurs as an early step in the reaction sequence of calcium translocation by cardiac sarcoplasmic reticulum similar as in skeletal muscle.

Adenosine Diphosphate↗

PubMed2006

Superficial chemical peels.

Superficial chemical peeling (SCP) involves the application of a peeling agent to the skin, resulting in destruction of part or all of the epidermis. SCP is mainly recommended for facial rejuvenation, photoaging and superficial rhytides, pigmentary dyschromias and acne. It can be used on all Fitzpatrick skin types, no sedation is needed, and the desquamation is usually well accepted. Overpeel and complications are very rare. The most commonly used SCP agents are glycolic acid 20-70%, trichloroacetic acid 10-35%, Jessner's solution, salicylic acid, pyruvic acid, resorcinol 30-50% preparations, and solid carbon dioxide. The careful selection of patients is critical for the outcome of a SCP and contraindications must be seriously considered. The peel procedure is generally common for all SCP agents but a good knowledge of the specific characters of each agent is of great importance in order to decide which to use for each individual patient.

Chemexfoliation↗

PubMed1986

Medium-depth chemical peeling of the skin: a variation of superficial chemosurgery.

Medium-depth chemical peeling of the skin is an intermediate procedure between superficial trichloroacetic acid application and deep phenolic cauterant application. Combining solid carbon dioxide with trichloroacetic acid promotes both epidermal and dermal regeneration. The technique for treatment of actinic degeneration, acne scarring, rhytids, and pigmentary aberrations is presented.

Adult↗

PubMed1970

Preparation of Cell Wall Antigens of Staphylococcus aureus.

Cell walls were prepared from Staphylococcus aureus strains Copenhagen and 263 by high-speed mixing in the presence of glass beads followed by differential centrifugation. Insoluble peptidoglycan complexes were derived from cell walls by extraction of teichoic acid with 10% trichloroacetic acid. Intact teichoic acid was prepared from each strain by digestion of cell walls with lysostaphin and isolated by column chromatography. Soluble glycopeptide (peptidoglycan in which only the glycan has been fragmented) and the stable complex of teichoic acid with glycopeptide were prepared by digestion of cell walls with Chalaropsis B endo-N-acetylmuramidase and were separated by column chromatography. Amino acid and amino sugar contents of walls and subunits of walls were comparable to those reported by others.

Journal Article↗

PubMed2006

Isolation and characterization of a bluegill-degrading microorganism, and analysis of the root hair-promoting effect of the degraded products.

Bluegill-degrading bacteria were isolated from various environmental sources. Brevibacillus sp. BGM1 degraded bluegill efficiently at 50 degrees C, and its culture supernatant showed the highest peptide and amino acid concentrations as trichloroacetic acid (TCA) soluble fraction (ASF) (10.7 mg/ml) of all supernatants obtained with bluegill as a substrate. Strain BGM1 secreted a protease(s) into the medium, and the concentration of peptides and amino acids gradually increased. The fertile effect of the degraded bluegill products (DGP) on Brassica rapa was also investigated. The root hair density of B. rapa grown with DGP at a concentration of 30 mug peptides and amino acids/ml was about 1.7 times higher than when grown with the same concentration of undegraded bluegill. DGP was shown to increase root hair numbers and adventitious root formation. The results of this study suggest that a specific peptide(s) for promotion of root hair is produced from the order Perciformes with a protease(s) from BGM1.

Animals↗

PubMed2006

[Analysis of haloacetic acids in drinking water by gas chromatography-mass spectrometry].

Based on liquid-liquid micro-extraction and acidic methanol derivatization methods from EPA Method 552.3, a gas chromatographic-mass spectrometric (GC-MS) method has been studied for determining haloacetic acid (HAAs) in drinking water using ultrapure water instead of methyl tert-butyl ether (MTBE) as solvent for preparing standard stock solution. The results showed that the peaks of 1,2-dibromo propane (internal standard) and HAAs were separated very well. With the improved method, the recoveries for HAAs (82% - 103%) were high at concentrations ranging from 5 to 80 microg/L, the detection limits for dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) were 0.72 and 0.44 microg/L. With the improved method, the runtime could be also significantly reduced without compromising the analytical resolutions. It is also demonstrated that the stock standard was stable under storage for 2 month at 4 degrees C.

English Abstract↗

PubMed2000

Regulation of protein synthesis in lactating rat mammary tissue by cell volume.

The effect of changing cell volume on rat mammary protein synthesis has been examined. Cell swelling, induced by a hyposmotic challenge, markedly increased the incorporation of radiolabelled amino acids (leucine and methionine) into trichloroacetic acid (TCA)-precipitable material: reducing the osmolality by 47% increased leucine and methionine incorporation into mammary protein by 147 and 126% respectively. Conversely, cell shrinking, induced by a hyperosmotic shock, almost abolished the incorporation of radiolabelled amino acids into mammary protein: increasing the osmolality by 70% reduced leucine and methionine incorporation into mammary protein by 86 and 93% respectively. The effects of cell swelling and shrinking were fully reversible. Volume-sensitive mammary tissue protein synthesis was dependent upon the extent of the osmotic challenge. Isosmotic swelling of mammary tissue, using a buffer containing urea (160 mM), increased the incorporation of radiolabelled leucine into TCA-precipitable material by 106%. Swelling-induced mammary protein synthesis was dependent upon calcium: removing extracellular calcium together with the addition of EGTA markedly reduced volume-activated protein synthesis. Cell swelling-induced protein synthesis was inhibited by the Ca(2+) ATPase blocker thapsigargin suggesting that volume-sensitive protein synthesis is dependent upon luminal calcium.

Animals↗

PubMed1979

Leishmanial excreted factor: protein-bound and free forms from promastigote cultures of Leishmania tropica and Leishmania donovani.

Leishmania spp. growing in culture produce an immunologically active substance called excreted factor (EF), which precipitates antibodies raised against intact cells and has been implicated as the conditioning agent for parasite infection of host macrophages. An improved method for isolation of the material is described, based on Sephadex column chromatography of growth medium which had been boiled at pH 5.0. This procedure allows the detection of differences among the EF molecules of different species, and it overcomes previous shortcomings through the monitoring of immunological activity throughout. Analysis of the products of this procedure revealed that EFs from Leishmania tropica and Leishmania donovani share a common carrier protein, identified as rabbit serum albumin, and are chemically quite similar. Growth medium from L. tropica boiled at acidic pH contains primarily an EF-albumin complex of 75,000 molecular weight. Treated growth medium from L. donovani, on the other hand, contains both the albumin complex and a smaller molecule (less than 27,000 molecular weight) that is not associated with rabbit protein. This material accounts for nearly 20% of the EF of one L. donovani strain, but constitutes only a minute fraction of L. tropica EF. Treatment of the EF-albumin complex with trichloroacetic acid separates the molecule into two major subunits, one having a molecular weight of about 61,000 (without anti-Leishmania activity) and the other having a molecular weight of about 18,000 (with no anti-rabbit activity). The protein-free EF of L. tropica differs from that released by trichloroacetic acid extraction in that it is capable of precipitating antisera of nonhomologous serotypes, whereas the albumin complex and the trichloroacetic acid-treated EF fragment are not. EFs from both species display pH-dependent affinity for certain lectins.

Carrier Proteins↗

PubMed1986

Extrahepatic organs metabolism of inhaled trichloroethylene.

An extrahepatic circulation system for dogs was developed using a portal vein to right femoral vein bypass procedure. This system maintained nearly normal biochemical and physiological parameters, i.e. arterial blood pressure, heart rate, electrocardiogram, leukocyte and erythrocyte count, hematocrit, alkaline phosphatase, blood urea nitrogen, ammonia and creatinine, for 2 h. Thus, the system appears to be a valid technique for investigating extrahepatic metabolism. Dogs were exposed for 1 h to 500, 700 and 1500 ppm of trichloroethylene. Free-trichloroethanol, trichloroacetic acid and conjugated-trichloroethanol appeared in the blood and urine after 30 min of exposure. The amounts of metabolite formed by dogs with hepatic bypass were less than by similarly exposed dogs without hepatic bypasses, specifically 50-80%, 10% and 10-20% for free-trichloroethanol, trichloroacetic acid and conjugated-trichloroethanol, respectively. In addition, trichloroethylene exposure produced a smaller decrease in leukocyte counts in the hepatic bypass dogs than in the non-bypass dogs. This observation may indicate that the liver itself played some role in the elimination or increment of leukocyte counts in the blood.

Administration, Inhalation↗

PubMedDate not supplied

Extraction and estimation of ATP from human spermatozoa.

This study attempts to provide guidelines for the extraction and estimation of ATP from spermatozoa. The conditions of extraction of ATP from spermatozoa using trichloroacetic acid were optimized. The efficiency of this extraction procedure was compared to that using boiling Tris buffer. Three commercially available kits which use the firefly luciferase assay for ATP and two luminometers were evaluated for the measurement of the spermatozoa extracts. Elevated levels of Mg2+ and/or Ca2+ did not interfere with the extraction of ATP by trichloroacetic acid or with the subsequent estimation of the nucleotide.

Adenosine Triphosphate↗

PubMedDate not supplied

Interferences in the delta-aminolevulinic acid dehydratase (ALA-D) assay.

A systematic study of the effect of procedural variables on the ALA-D assay has been carried out. Because of metal content in vacutainers, artifactual results are obtained on blood samples drawn by this method and the method of choice is the use of plastic syringes and tubes. The use of isopropyl alcohol as a skin sterilizing agent, although it gives measurable blood alcohol readings, does not affect the ALA-D assay. The handling of the whole blood has been investigated and the two methods of hemolysis compared. Trichloroacetic acid, a reagent used in the final assay of porphobilinogen, has been found to be a serious interference in the method, making it essential for this reagent to be kept in a securely sealed container. The deterioration of the trichloroacetic acid--mercuric chloride reagent is also a potential procedural problem that must be considered.

1-Propanol↗

PubMed1997

Acquired dyschromatopsia in combined exposure to solvents and alcohol.

HYPOTHESIS: Does occupational exposure to solvents in combination with alcohol intake give rise to acquired color vision defects? METHOD: A total of 138 individuals exposed to solvents (toluene, xylene, trichloroethylene, tetrachloroethylene) were examined using Lanthony's D-15 test and compared with 100 nonexposed controls. The extent of color vision loss was quantitatively assessed based on Bowman's color confusion index (CCI). A cumulative exposure index was calculated from the hours of exposure per day and the years of exposure. In 30 persons who were exposed to trichloroethylene and tetrachloroethylene, urinary trichloroacetic acid was assessed as a parameter of exposure. Alcohol intake was calculated as based on interviews of patients in grams of ethyl alcohol per week. RESULTS: Individuals who consumed more than 250 g alcohol/week and were simultaneously exposed to solvents showed a significantly elevated CCI (P = 0.0044). No significant correlation emerged between trichloroacetic acid excretion in the urine or the cumulative exposure index and the CCI. CONCLUSION: The combination of alcohol intake and occupational exposure to solvents discloses the risk of acquired subclinical color vision defects.

Adult↗

PubMed2000

Chemical peel of nonfacial skin using glycolic acid gel augmented with TCA and neutralized based on visual staging.

BACKGROUND: Until recently, standard techniques for laser or chemical peeling have not always provided consistent results when applied to the nonfacial skin. OBJECTIVE: The author describes a more controlled chemical peel technique for nonfacial skin using 70% glycolic acid gel combined with 40% trichloroacetic acid (TCA). The method has given consistently good results on the skin of the neck, chest, arms, hands, back, and other nonfacial skin. METHODS: More than 3100 patients were given skin peels of the neck, chest, and other areas of the body as indicated. Seventy percent glycolic acid gel was applied to the areas to be peeled, then immediately augmented with 40% TCA. Each area was carefully monitored for the end point and then neutralized with copious amounts of 10% sodium bicarbonate solution. The end point was determined by visual observation using a six-stage classification to determine the degree of peeling. RESULTS: Clinical results were excellent, with smoother skin texture, decreased wrinkling and striae, and fading of lentigines and other pigmentary abnormalities. There was excellent blending into peeled facial skin and into adjacent areas of nonpeeled skin. Complications were minimal. CONCLUSION: This technique can provide the benefits of skin peeling to nonfacial skin with excellent cosmetic results and minimal complications.

Chemexfoliation↗

PubMedDate not supplied

Macrophage oxidation of low density lipoprotein generates a modified form recognized by the scavenger receptor.

Incubation of low density lipoprotein (LDL) with endothelial cells or smooth muscle cells overnight has resulted in an oxidative modification of LDL that results in its recognition by macrophages by way of the acetyl LDL receptor. In the present study, we examined whether macrophages themselves can oxidize and modify LDL in a manner similar to that of endothelial cells. Incubation of 125I-labeled LDL with resident or thioglycollate-elicited macrophages for 24 hours in Ham's F-10 medium resulted in the appearance of thiobarbituric acid (TBA) reactive materials and trichloroacetic acid (TCA) soluble radioactivity in the medium. The LDL harvested from these incubations showed increased electrophoretic mobility and was degraded rapidly when added to fresh macrophages as compared to LDL previously incubated in the absence of cells. These macrophage-induced modifications could be prevented if the first incubation was carried out in the presence of the antioxidant butylated hydroxytoluene (BHT) or in Dulbecco's modified Eagle's medium (DMEM). The degradation of 125I-labeled macrophage-modified LDL by macrophages was competitively inhibited by unlabeled acetyl LDL or unlabeled endothelial cell-modified LDL but not by native LDL, indicating that the degradation was mediated by the acetyl LDL receptor.

Animals↗

PubMed1989

Degradation of insulin and insulin-like growth factors by enzyme purified from human erythrocytes. Comparison of degradation products observed with A14- and B26-[125I]monoiodoinsulin.

An insulin-degrading enzyme has been purified from human erythrocytes. This enzyme degraded 125I-labeled insulin-like growth factor I (IGF-I) more slowly than 125I-IGF-II and degraded IGF-II more slowly than 125I-insulin. The time course of 125I-insulin degradation suggested the presence of intermediates, each of which was itself shown to be a substrate for the enzyme. One of these intermediates appeared to be made up entirely of B-chain residues and had HisB10 as its NH2-terminal. The final major radiolabeled degradation product of A14-[125I]monoiodoinsulin was a peptide with TyrA14 at the A-chain NH2 terminal. This peptide could be reduced with dithiothreitol, suggesting that it contained amino acid residues from both A- and B-chains. It was partially precipitated by trichloroacetic acid and anti-insulin antibody but bound poorly to IM-9 lymphocytes. The final major degradation product of B26-[125I]monoiodoinsulin was a peptide whose NH2-terminal was TyrB26 and could not be reduced by dithiothreitol. It was partially precipitated by anti-insulin antibody but was precipitated poorly, if at all, by trichloroacetic acid and bound poorly to IM-9 lymphocytes. The results show that this enzyme degraded insulin by sequential cleavage of peptide bonds on both A- and B-chains. We identified LeuA13-TyrA14, SerB9-HisB10, and PheB25-TyrB26 as three of the bonds that are cleaved.

Chromatography, Gel↗

PubMed1991

Hydrolysis of Protein and Model Dipeptide Substrates by Attached and Nonattached Marine Pseudomonas sp. Strain NCIMB 2021.

Rates of substrate hydrolysis by nonattached bacteria and by bacteria attached to particles derived from marine diatom frustules were estimated by using two substrates, a dipeptide analog and a protein. Adsorption of the two substrates onto the particles was also evaluated. Methyl-coumarinyl-amide-leucine (MCA-leucine) was used to estimate hydrolysis of dipeptides by measuring an increase in fluorescence as MCA-leucine was hydrolyzed to leucine and the fluorochrome methylcoumarin. To examine hydrolysis of a larger molecule, we prepared a radiolabeled protein by C-methylation of bovine serum albumin. The rate of protein hydrolysis in samples of particle-attached or nonattached bacteria was estimated by precipitating all nonhydrolyzed protein with cold trichloroacetic acid and then determining the trichloroacetic acid-soluble radiolabeled material, which represented methyl-C-peptides and -amino acids. About 25% of the MCA-leucine adsorbed to the particles. MCA-leucine was hydrolyzed faster by nonattached than attached bacteria, which was probably related to its tendency to remain dissolved in the liquid phase. In contrast, almost 100% of the labeled protein adsorbed to the particles. Accordingly, protein was much less available to nonattached bacteria but was rapidly hydrolyzed by attached bacteria.

Journal Article↗

PubMed2006

Facial resurfacing for nonmelanoma skin cancer prophylaxis.

OBJECTIVE: To determine the effect of facial skin resurfacing for treatment of actinic keratoses (AKs) and prophylaxis against new primary basal and squamous cell carcinomas in individuals with previous nonmelanoma skin cancer (NMSC) or severe photodamage. DESIGN: Randomized, prospective 5-year trial. SETTING: Dermatology and otolaryngology clinics of a Veterans Affairs hospital. PATIENTS: Thirty-four patients with a history of facial or scalp AKs or basal or squamous cell carcinoma were enrolled. Five of 7 eligible patients who declined study-related treatment were used as controls. Twenty-seven patients were randomized to 3 treatment arms; 3 patients were discontinued from the study. INTERVENTIONS: Carbon dioxide laser resurfacing, 30% trichloroacetic acid peel, or 5% fluorouracil cream applied twice daily for 3 weeks. MAIN OUTCOME MEASURES: Reduction in the number of AKs was measured 3 months after treatment. The incidence of new NMSC in treated areas was assessed between January 1, 2001, and June 30, 2005. Times from baseline to diagnosis of first skin cancer were compared between the treatment and control groups. RESULTS: Treatment with fluorouracil, trichloroacetic acid, or carbon dioxide laser resulted in an 83% to 92% reduction in AKs (P< or =.03), a lower incidence of NMSC compared with the control group (P<.001), and a trend toward longer time to development of new skin cancer compared with the control group (P=.07). However, no significant differences were noted among the treatment groups. CONCLUSION: All 3 modalities demonstrated benefit for AK reduction and skin cancer prophylaxis compared with controls and warrant further study in a larger trial.

Aged↗