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PubMed1994

Mechanism-based comparisons of acute toxicities elicited by industrial organic chemicals in procaryotic and eucaryotic systems.

Comparisons of toxicities elicited by nonpolar and polar narcotics, weak acid uncouplers of oxidative phosphorylation, and bioreactive chemicals between the eucaryotic systems Pimephales promelas and Tetrahymena pyriformis and the procaryotic systems Escherichia coli and Photobacterium phosphoreum were performed. Each chemical had been a priori assigned a mechanism/mode of action based on the results from previous studies with eucaryotic systems. Hydrophobicity-dependent QSARs for nonpolar narcosis for both the E. coli and the P. phosphoreum endpoints was developed. However, due to the lack of a significant relationship between P. phosphoreum toxicity and log Kow, such a QSAR for polar narcosis was developed only for the E. coli endpoint. Except for 4-nitroaniline (the only chemical in the examined group that required activation to become the Michael receptor), all chemicals containing reactive substructures revealed excess toxicity over polar narcosis QSAR for E. coli endpoints. Moreover, chloroacidic acid and ethyl chloroacetate in this system also appear to be bioreactive. The only mechanism that seemed to not exist in the procaryotic system was uncoupling of oxidative phosphorylation. Chemicals from this group, except 2,4-dinitroaniline, did not exhibit excess toxicity over polar narcosis QSAR. This was thought to be explained by the lack of mitochondria in procaryotes, the target site of uncoupling agents in eucaryotes. In addition, evaluation of toxicities of halogen-substituted short-chain carboxylic alcohols indicated that their mechanisms vary, depending upon the type of substitution and the system.

Alcohols↗
PubMed1982

Mutagenic evaluation of carcinogens and non-carcinogens in the L5178Y/TK assay utilizing postmitochondrial fractions (S9) from normal rat liver.

As part of continuing effort to investigate various metabolic activation procedures in the L5178Y TK +/- leads to TK -/- mutation assay, a series of 18 chemicals including both carcinogens and non-carcinogens selected from 7 chemical classes were tested in the presence of 5% (v/v) 9000 x g postmitochondrial supernatant fraction (S9) prepared from the livers of untreated Sprague-Dawley rats. Excepting ethyl carbamate and thioacetamide, 8 of 10 carcinogens tested produced mutant counts significantly greater than controls when the results were analyzed by a 2-sample loge t-test. Of 8 non-carcinogens assayed, treatment with p-aminophenol and chloroacetic acid yielded mutant counts significantly greater than control levels in at least one test with S9 while styrene oxide, an Ames positive mutagen, produced mutagenic activity in the absence of S9. These results indicate the L5178Y TK +/- leads to TK -/- mutation assay coupled with 5% (v/v) liver homogenate from normal rodent liver and applied to 18 chemicals correctly distinguished the majority of carcinogens from structurally related non-carcinogens on the basis of chemically-induced gene mutations.

Animals↗
PubMed1987

Cytogenetic studies on 1,1-dichloroethylene and its two isomers in mammalian cells in vitro and in vivo.

Chromosomal aberration and sister-chromatid exchange (SCE) tests in vitro on 1,1-dichloroethylene (1,1-DCE), its two isomers, cis- and trans-1,2-DCE, and two possible metabolites of 1,1-DCE, chloroacetyl chloride and chloroacetic acid, were carried out using a Chinese hamster cell line, CHL. 1,1-DCE induced chromosomal aberrations in the presence of S9 mix prepared from the rat liver, but not in the absence of S9 mix. SCEs were also slightly induced by 1,1-DCE only in the presence of S9 mix. On the other hand, two isomers and two metabolites of 1,1-DCE induced neither chromosomal aberrations nor SCEs with and without S9 mix. 1,1-DCE, however, was negative even at a sublethal dose in the micronucleus test using mouse bone marrow, fetal liver and blood.

Animals↗
PubMed1982

Bovine costimulator. II. Generation and maintenance of a bovine costimulator-dependent bovine lymphoblastoid cell line.

Bovine peripheral blood leukocytes, activated with concanavalin A, were cultured in bovine costimulator-containing conditioned medium prepared in a totally defined, serum-free medium. A population of leukocytes subsequently grew exponentially. These bovine cells had the morphology of lymphoblasts, were negative for chloroacetate esterase, slightly positive for conspecific esterases, and highly peanut agglutinin-positive. These data suggested that the bovine leukocytes were of the T-cell lineage and that the active factor in the costimulator-containing conditioned medium might be the bovine equivalent of interleukin 2. A quantitative microassay, subsequently developed, revealed that the lymphoblastoid cell line was costimulator-dependent and lectin-independent. Further utilization of the microassay supported this contention and strengthened the concept of a bovine interleukin 2-dependent bovine T-cell line: Phytohemagglutin-M, phytohemagglutinin-P, and concanavalin A induced active factor from peripheral blood leukocytes, while lipopolysaccharide, a potent inducer of Interleukin 1 in other systems, failed to induce activity; and both T-cells and macrophages were required for optimal factor activity. Finally, a means by which to optimize production of the active moiety, utilizing lymph node cells, as opposed to peripheral blood leukocytes, was examined.

Animals↗
PubMed1982

Characterization of a new chromosomal marker for acute lymphoblastic leukemia from a long-term cell line.

A bone marrow aspirate from a child with acute lymphoblastic leukemia (ALL) at first relapse was used to establish cell line # 697. The cultured line and marrow aspirates taken at initial diagnosis and first relapse were examined and compared. Similarities in all patterns evaluated confirmed the leukemic origin of the line. Morphologically, the cells were typically lymphoblastic. Cytochemically, they were slightly acid phosphatase-positive and negative for peroxidase, ASD chloroacetate esterase, and nonspecific esterase. Immunologically, they were found positive for common-ALL antigen (CALLA), Ia-associated antigen, terminal deoxynucleotidyl transferase (TdT), and cytoplasmic IgM (cIgM) and slightly positive for surface IgM (sIgM). Testing for Epstein-Barr virus (EBV) capsid antigen was also positive. Cytogenetic evaluations performed on initial, relapse, and cell line specimens each revealed the presence of a pseudodiploid cell line characterized by a consistent marker chromosome. GTG-, QFQ-, and RF-banding identified the marker as being derived from a translocation involving chromosomes #7 and #19: t(7;19) (q11;q13). Iso 7q, -5, -9, and +2 were also found in significant association with the marker and were viewed as demonstrating continued karyotypic evolution within the cell line. From these data, cell line #697 has been classified as a leukemic line of B-cell lineage in a transitional stage between pre-B and mature B cells.

B-Lymphocytes↗
PubMed1990

Identification of IgE-positive cells and mast cells in frozen sections of multiple sclerosis brains.

There is evidence that nervous system mast cells may be involved in the pathogenesis of experimental demyelinating diseases, and that their involvement may be mediated by IgE. In order to examine the possible relevance of these observations to human demyelinating diseases, we have histologically and immunocytochemically examined multiple sclerosis (MS) and control brains for the presence of mast cells and IgE. Using a highly specific antiserum, we found IgE-positive cells in MS brains, but not in controls. IgE-positive cells could be detected in all regions of MS lesions, but were far more frequent in areas of active infiltration. Immunopositive staining was only observed when sections were pretreated with a methanolic peroxide solution, suggesting that the IgE was cytoplasmic. Positive cells typically exhibited plasma cell morphology. Mast cells were identified using chloroacetate esterase (CAE) staining, and we were able to confirm previous reports of an increased association of mast cells with MS lesions. Mast cells were seen in 7/14 MS brains compared with 1/8 controls. They were most commonly observed in demyelinated areas, but were also seen in association with infiltrate. Mast cells and IgE-positive cells were also observed in areas of perivascular infiltration in other inflammatory central nervous system diseases (subacute sclerosing panencephalitis, herpes encephalitis). Mast cells may represent a route for infiltrating cells to enter the brain in inflammatory disorders.

Brain↗
PubMed1990

Ethylene dichloride: the influence of disulfiram or ethanol on oncogenicity, metabolism, and DNA covalent binding in rats.

Male and female Sprague-Dawley rats were exposed to 50 ppm ethylene dichloride (EDC) for 7 hr/day, 5 days/week, for 2 years by inhalation. Additional rats were exposed to 50 ppm EDC either with 0.05% disulfiram in the diet or with 5% ethanol in the drinking water. Histopathologic lesions related to the combination of inhaled EDC and dietary disulfiram were observed in the liver, mammary, and testicular tissues of rats. This combined exposure resulted in a significant increase in the incidence of intrahepatic bile duct cholangiomas in both male and female rats. Male rats exposed to both EDC and disulfiram also had an increased incidence of subcutaneous fibromas, neoplastic nodules, and interstitial cell tumors in the testes. The female rats exposed to EDC and disulfiram also had a higher incidence of mammary adenocarcinomas. No significant increase in the number of any tumor type was observed in rats exposed to only EDC, disulfiram, or ethanol. Similarly, no significant increase in the number of tumors was observed in rats exposed to inhaled EDC and ethanol in water. At the end of the 2-year period animals from each group were evaluated for EDC metabolism and DNA binding. Blood levels of EDC at the end of a 7-hr exposure period were significantly higher for rats exposed to both EDC and disulfiram than for rats exposed to EDC alone. In addition, the elimination of a single oral dose of radiolabeled EDC was affected. The urinary excretion of 14C from control rats was 47 to 55% of the administered dose with 28 to 30% detected as unchanged EDC in the breath. In disulfiram-treated rats, only 35 to 36% of the administered 14C was eliminated in the urine with 41 to 55% as unchanged EDC in the breath. The urinary metabolite HPLC profile was qualitatively unchanged by long-term EDC, disulfiram, or ethanol treatment, either alone or in combination, and consisted primarily of thiodiglycolic acid, thiodiglycolic acid sulfoxide, and chloroacetic acid.

Animals↗
PubMed1991

The acute effects of S-(1,2-dichlorovinyl)-L-cysteine and related chemicals on renal function and ultrastructure in the pentobarbital-anesthetized dog: structure-activity relationships, biotransformation, and unique site-specific nephrotoxicity.

S-(1,2-Dichlorovinyl)-L-cysteine (L-DCVC), a substrate for the renal cysteine conjugate beta-lyase, and other related chemicals were administered intravenously to pentobarbital-anesthetized dogs. Six pertinent findings emerged regarding their nephrotoxicity. (1) L-DCVC was acutely nephrotoxic in the dog. (2) The earliest indicator of L-DCVC-induced renal damage was an increase in the urinary excretion rate of protein. (3) Contrary to results from other species, L-DCVC induced renal ultrastructural lesions only in the S1 and S2 cells of the proximal tubule. (4) The toxicity of L-DCVC (23.15 mumol/kg, iv) to S1 and S2 cells resulted from a direct tubular insult and not from overlapping episodes of hypoxia or ischemia. (5) L-DCVC could be detected in plasma only during the first 30 min after its injection. In addition, no L-DCVC and only small amounts of N-acetyl-L-DCVC and S-(1,2-dichlorovinyl)mercaptoacetic acid (DCV-MAA) (1.5% and less than 1% of the administered dose, respectively) were detectable in urine during the 6 hr following L-DCVC administration. (6) DCV-MAA and chloroacetic acid as well as other compounds that are not substrates for the renal cysteine conjugate beta-lyase (i.e., S-allyl-L-cysteine, vinthionine, and S-(1,2-dichlorovinyl)-D,L-alpha-methylcysteine) were not acutely nephrotoxic. These findings provide indirect evidence for the involvement of beta-lyase in the toxification of L-DCVC in the dog.

Anesthesia↗
PubMed1992

Time course of permeability changes and PMN flux in rat trachea following O3 exposure.

Changes in rat tracheal epithelial permeability and polymorphonuclear leukocyte (PMN) populations during a 24-hr time period following a 3-hr exposure to 0.8 ppm ozone (O3) were investigated. An increase in permeability to 99mTc-diethylene-triaminepentaacetate (DTPA) occurred immediately after the exposure, peaked at the 8-hr time point and decreased to control level by 24 hr. For correlation with tracheal permeability, tracheal cross sections were stained with naphthol AS-D chloroacetate and PMNs were scored by their location as well as staining characteristics (positive or negative). The total PMN population remained at the control value at the 0-, 4-, and 8-hr time points, and increased at 12 hr, followed by a rapid decline to below the control value for the remaining time points. There was a shift at the 8-hr time point in the population location, from the vasculature to the interstitium, which returned to control values at 12 hr. The percentage stained PMNs increased significantly at 16 hr while remaining at control values for all other time points. The data reveal that there is a significant increase in tracheal epithelial permeability immediately after the exposure, but the overall increase in the PMN population is preceded by a lag phase. A decrease in the vascular pool of PMNs concomitant with an increase in the interstitial pool of PMNs suggests their migration from blood to the interstitium after ozone exposure. These data indicate that while PMNs may play a role in permeability changes of tracheal epithelium, the initiation is most likely due to other factors.

Animals↗
PubMed1990

Prediction of the developmental toxicity hazard potential of halogenated drinking water disinfection by-products tested by the in vitro hydra assay.

A series of seven randomly selected potential halogenated water disinfection by-products were evaluated in vitro by the hydra assay to determine their developmental toxicity hazard potential. For six of the chemicals tested by this assay (dibromoacetonitrile; trichloroacetonitrile; 2-chlorophenol; 2,4,6-trichlorophenol; trichloroacetic acid; dichloroacetone) it was predicted that they would be generally equally toxic to both adult and embryonic mammals when studied by means of standard developmental toxicity "teratology" tests. However, the potential water disinfection by-product chloroacetic acid (CA) was determined to be over eight times more toxic to the "embryonic" developmental portion of the assay than it was to the adults. Because of this potential selectivity, CA is a high-priority item for developmental toxicity tests in pregnant mammals to confirm or refute its apparent unique developmental hazard potential and/or to establish a NOAEL by the route of most likely human exposure.

Animals↗
PubMed1984

Inhibition of non-specific leukocyte esterase activity. Absence of monocyte esterase activity due to phosphoric and thiophosphoric acid ester intoxication.

In vitro evaluation of the effect of five insecticidal phosphoric and 11 thiophosphoric acid esters on different, non-specific human leukocytes esterases indicated that most of the organic phosphor compounds studied inhibited the activity of neutral alpha-naphthylacetate esterase, alpha-naphthylbutyryl esterase, and naphthol AS acetate esterase, i.e. the monocyte esterases. The extent of inhibition was dose dependent; the inhibiting dose being identical for the various non-specific esterases. Reactivation with Obidoxim was not successful. Monocyte esterase activity in a human survivor of E 605 intoxication was detectable only after serum acetylcholinesterase had returned to normal levels. The organic phosphor compound studied, however, inhibited neither acid alpha-naphthylacetate esterase nor naphthol AS-D chloroacetate esterase activity.

Adolescent↗
PubMed1989

The changing role of ultraviolet spectroscopy in drug analysis.

New applications in the identification of minor components in drugs by rapid scanning diode-array UV spectrophotometers as high-performance liquid chromatographic (HPLC) detectors are exemplified by (a) identification and quantification of alpha-chloro-4-methoxycinnamic acid methyl ester as the byproduct of the Darzens reaction between 4-methoxybenzaldehyde and chloroacetic acid methyl ester; and (b) identification of 4-androsten-17-one and 3 beta-phenyl-5 alpha-androstan-17-one as impurities in 5 alpha-androst-2-en-17-one. The advantages of the use of derivative spectrophotometry are illustrated by the following examples: (a) determination of flumecinol (3-trifluoromethyl-alpha-ethylbenzhydrol) in an oily emulsion formulation; (b) determination of RGH-6148 (2-benzylthiazolidinone) in a suspension used in toxicological studies; and (c) determination of mestranol as an impurity in norethisterone.

Androstenes↗
PubMedDate not supplied

Pathophysiological mechanisms of HIV-induced defects in haematopoiesis: pathology of the bone marrow.

Bone marrow biopsies of 96 HIV1-infected patients were analysed histologically and by immuno- and enzyme histochemical techniques. Independently of the stage of disease, the bone marrow frequently exhibits hypercellularity and features of dysplastic haemopoiesis combined with mesenchymal alterations. In situ immunohistochemical analysis shows that there is a marked reduction in expression of the proliferation-associated nuclear antigen recognized by the Ki67 antibody. Comparison with non-infected controls reveals that there is a reduction in CD34+/myeloperoxidase-/naphthol AS-D chloroacetate- progenitor cells and an overproportional decrease in CD8+ lymphocytes in the bone marrow. Double staining revealed the presence of gag-coded HIV1 proteins in the above-mentioned CD34+ progenitor cells, in myelopoiesis cells, megakaryocytes and above all, in CD68+/acid phosphatase+ and alkaline phosphatase+ bone marrow reticular cells. From the latter results, it was concluded that HIV1-infected reticular cells may be disturbed in their ability to produce factors responsible for the short-range regulation of haemopoietic activity.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Two karyotypically unrelated clones with 5q- and 20q- in a primary myelodysplastic syndrome patient evolving into acute nonlymphocytic leukemia.

We describe a patient with primary myelodysplastic syndrome (MDS) evolving into acute nonlymphocytic leukemia (ANLL) who had two cytogenetically unrelated abnormal clones. A 68-year-old man presented with refractory anemia with excess of blasts (RAEB) and developed overt ANLL. Two cytogenetically independent clones, one with 5q- and the other with 20q-, were observed when the patient developed ANLL. The clones carrying both 5q- and 20q- were not detected. Leukemic blast cells were positive for peroxidase, naphtol ASD chloroacetate esterase, CD13, CD33, CD34 and HLA-DR, but negative for alpha-naphthyl butyrate esterase, CD14, CD10, CD19, CD20, CD1, CD2, CD3, CD5 and CD7. Although there have been a few reports describing the presence of multiple cytogenetically unrelated clones in one patient with MDS, this is the first case report that the 5q- and 20q- anomalies are derived from independent clones.

Aged↗
PubMed2005

Organic secretory products, adaptive responses and innervation in the parotid gland of ferret: a histochemical study.

To qualify cellular events of possible pathophysiological significance in the parotid of ferret, tissue obtained post-mortem from mature animals of either sex was examined by light microscopical histochemistry for calcium, protein, amino acids, mucosubstances and hydrolases, and by neurohistology. Calcium was localised in acinar cells replete with granules containing protein, disulphides and usually carboxylated mucosubstances. Acid phosphatase activity was basally concentrated in the acinar cells. The granular luminal region of striated ductal cells showed protein, tryptophan, disulphides, neutral mucosubstances, and E600-sensitive esterase and Naphthol AS-D chloroacetate esterase activities, whereas their basal region showed acid phosphatase activity. Strong periluminal activity of acid phosphatase and E600-resistant esterase characterised the collecting ducts. Cholinesterase activity was associated with an extensive network of nerve fibres embracing parenchyma. Catecholamine fluorescence was not seen. beta-glucuronidase reactive macrophages abounded in the interstices. The results suggest that while the acini in the parotid of ferret secrete polyionic glycoproteins, shielded by calcium, the striated ducts secrete tryptophan-rich products comprising neutral glycoproteins and showing proteolytic activity. Innervation is of the cholinergic type and parenchymal lysosomal activity, possibly related to autophagy of stored secretory products and heterophagy of luminal material, is brisk. Macrophages contribute to maintaining the glandular microenvironment, wherein secretory activity appears to be lethargic.

Acid Phosphatase↗
PubMed2004

Syntheses and evaluation of antioxidant activity of sydnonyl substituted thiazolidinone and thiazoline derivatives.

3-Aryl-4-formylsydnone 4'-phenylthiosemicarbazones (3a-d) and 3-aryl-4-formylsydnone thiosemicarbazones (3e-h), which are precursors of 3-aryl-4-heterocyclic sydnones, are prepared by the condensation of 3-aryl-4-formylsydnones (1a-d) with 4'-phenylthiosemicarbazide (2a) and thiosemicarbazide (2b), respectively. The thiosemicarbazones 3 reacted with cyclic reagents such as ethyl chloroacetate (4a), ethyl 2-chloroacetoacetate (4b) and 2-bromoacetophenone (4c) to produce heterocyclic substituted sydnone derivatives 5-7 that possess 4-oxo-thiazolidine and thiazoline groups. The antioxidant activity of synthesized compounds 5a-7h was evaluated. Among these compounds, 4-methyl-2-[(3-arylsydnon-4-yl-methylene)hydrazono]-2,3-dihydro-thiazole-5-carboxylic acid ethyl ester (6e-h) and 4-phenyl-2-[(3-arylsydnon-4-yl-methylene)hydrazono]-2,3-dihydro-thiazoles (7e-h) exhibit the potent DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity, comparable to that of vitamin E.

Animals↗
PubMed2005

Synthesis of 2-(aminocarbonylmethylthio)-1H-imidazoles as novel Capravirine analogues.

Different analogues of Capravirine (AG-1549) or S-1153 were prepared by synthesis of 2-(5-benzyl-4-isopropyl-1-methyl-2,3-dihydro-1H-imidazol-2-ylthio)acetamide (3a-c), ethyl [5-benzyl-1-(ethoxymethyl)-4-ethyl-1H-imidazol-2-ylthio]acetate (10), 2-[5-alkyl-4-substituted 1-(pyridin-4-ylmethyl)-1H-imidazol-2-ylthio]acetamides (12a-f), and 2-[5-benzyl-1-(benzyloxymethyl)-4-isopropyl-1H-imidazol-2-ylthio]acetamides (14a-l) from their corresponding amino acids through a sequence of reactions: Dakin-West reaction, hydrolysis, condensation with thiocyanate derivatives, alkylation with 2-iodoacetamide and ethyl chloroacetate, and coupling with 4-pyridylmethyl chloride, ethoxymethyl chloride and benzyloxymethyl chloride. All the synthesized compounds were screened for their activity against HIV-1 (wild type) and some of them (especially Capravirine like structures) were found active.

Anti-HIV Agents↗