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Challenging NICO again? Oral Dis 2023; 29:1885-1886. [PMID: 34614291 DOI: 10.1111/odi.14041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/30/2021] [Accepted: 10/02/2021] [Indexed: 11/29/2022]
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Abstract
The fate of orally administered [(14)C]cephalothin has been studied in the rat. This antibiotic undergoes degradation in the gut followed by the subsequent absorption of a portion of the degradation products. About 50% of the administered radioactivity appears in the urine as a mixture of thienylacetylglycine, thienylacetamidoethanol and an unidentified polar metabolite. Evidence is presented indicating that thienylacetamidoethanol arises by the enzymic reduction of a metabolic intermediate, thienylacetamidoacetaldehyde. The metabolic fate of cephalothin is very similar to that of cephaloram reported earlier. The fate of [(14)C]cephaloridine and 7-phenoxy[1-(14)C]acetamidocephalosporin was also investigated. In addition to the expected metabolites, about 5% of the cephaloridine dose is absorbed unchanged. With 7-phenoxy[1-(14)C]acetamidocephalosporin, 15% of the dose is recovered in urine as deacetyl-7-phenoxy[1-(14)C]acetamidocephalosporin.
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Bone Marrow Edema: Mild or Nascent Variant of Ischemic Bone Disease. J Oral Maxillofac Surg 2008; 66:205-8. [DOI: 10.1016/j.joms.2007.08.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Accepted: 08/22/2007] [Indexed: 10/22/2022]
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Staging Bisphosphonate-Related Osteonecrosis of the Jaw Should Include Early Stages of Disease. J Oral Maxillofac Surg 2007; 65:1899-900. [PMID: 17719423 DOI: 10.1016/j.joms.2007.04.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Accepted: 04/28/2007] [Indexed: 10/22/2022]
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Charlatans in dentistry: ethics of the NICO wars. THE JOURNAL OF THE AMERICAN COLLEGE OF DENTISTS 2003; 70:38-41. [PMID: 14977380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
The scientific and diagnostic status of neuralgia-inducing cavitational osteonecrosis, NICO, has not been definitively established. A case is presented in favor of this diagnosis based on published literature. It is argued that the case against NICO has been made largely based on personal experiences, by innuendo, and through personal attacks rather than in scientific debate.
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The Kinetics and Mechanism of the Reaction of Diphenyldiazomethane with 2,4-Dinitrophenol in Ethanol1. J Am Chem Soc 2002. [DOI: 10.1021/ja01150a030] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Hepatic microsomal N-dealkylation reaction. Molecular oxygen as the source of the oxygen atom. J Am Chem Soc 2002. [DOI: 10.1021/ja01040a060] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Piperidine Derivatives. XXI. 4-Piperidone, 4-Piperidinol and Certain of their Derivatives. J Am Chem Soc 2002. [DOI: 10.1021/ja01171a038] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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The Kinetics and Mechanism of the Reaction of Diphenyldiazomethane and Benzoic Acid in Ethanol1. J Am Chem Soc 2002. [DOI: 10.1021/ja01146a078] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Exogenous estrogen may exacerbate thrombophilia, impair bone healing and contribute to development of chronic facial pain. Cranio 1998; 16:143-53. [PMID: 9852807 DOI: 10.1080/08869634.1998.11746052] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A 32 year old white female, in apparently good health, failed to respond to conservative wound care for alveolar osteitis after a routine mandibular first molar extraction. Curettage and biopsy of necrotic alveolar bone from the #30 socket escalated her pain such that hospitalization was necessary for pain management with intravenous morphine. Twelve months prior to admission she had been placed on exogenous estrogen (Premarin, 0.625 mg/day) after a partial oophorectomy. While hospitalized, she was found to have resistance to activated protein C (APCR). Premarin was discontinued. After discharge, weekly changes of an antibiotic impregnated dressing allowed for progressive regeneration of bone and epithelium with gradual reduction in her pain. She was found to be heterozygous for the mutant Factor V Leiden, a heritable factor for increased tendency to form thrombi, so-called thrombophilia. We speculate that the exogenous estrogen administration exacerbated the thrombophilia associated with the Factor V Leiden mutation by compounding the patient's resistance to activated protein C thereby contributing to her development of osteonecrosis and severe alveolar neuralgia.
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A preliminary pilot study of treatment of thrombophilia and hypofibrinolysis and amelioration of the pain of osteonecrosis of the jaws. ORAL SURGERY, ORAL MEDICINE, ORAL PATHOLOGY, ORAL RADIOLOGY, AND ENDODONTICS 1998; 85:64-73. [PMID: 9474617 DOI: 10.1016/s1079-2104(98)90400-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVES In a preliminary pilot study of 30 treatments in 26 patients with osteonecrosis of the jaws and chronic disabling facial pain, our specific aim was to determine whether, to what degree, and how safely therapy of hypofibrinolysis and thrombophilia would ameliorate the chronic pain associated with osteonecrosis of the mandible and maxilla. STUDY DESIGN Thrombophilia was treated with Coumadin (DuPont) in 10 patients; hypofibrinolysis was treated with Winstrol (Sanofi-Winthrop) in 20 patients, including 4 who had mixed thrombophilia and hypofibrinolysis and had previously been treated with Coumadin. The initial treatment period was targeted to be 4 months. Each patient was asked to keep a daily written pain-relief numeric rating score and side-effects diary and to provide a summary pain-relief numeric rating score and side effects compilation for the total treatment period. RESULTS There were 4 men and 22 women in the study group; their mean age was 49 +/- 11 years. The mean onset of their osteonecrosis pain was at age 45 +/- 12 years, and the mean duration of their facial pain prior to therapy was 4.5 +/- 4.2 years. Ten patients had one or more thrombophilic traits (there were two patients with protein C deficiency, five with resistance to activated protein C and/or the mutant Factor V Leiden gene, and four with high anticardiolipin antibodies). The 10 patients who were thrombophilic were treated with Coumadin (the international normalized ratio was targeted to 2.5-3.0) for 22 +/- 9 weeks. By self-reported pain-relief numeric rating scores, 6 of the 10 patients with thrombophilia (60%) had > or = 40% pain relief, 2 (20%) had no change, and 2 (20%) had increased pain (30% and 80% worse). Nine of the 10 patients with thrombophilia (90%) had no Coumadin-related side effects; 1 patient (10%) stopped Coumadin therapy (after 28 weeks) because of nosebleeds. Winstrol (6 mg per day) was used for 16 +/- 9 weeks in 20 patients with hypofibrinolysis, some of whom had one or more hypofibrinolytic traits (10 had high levels of plasminogen activator/inhibitor activity, usually accompanied by low stimulated tissue plasminogen activator activity; 13 had high Lp[a] lipoprotein). Of these 20 patients with hypofibrinolysis, 9 patients (45%) had > or = 40% pain relief, 3 patients (15%) had 20% to 30% relief, 5 patients (25%) had no improvement, and 3 patients (15%) had increased pain (30% worse, 60% worse, and 70% worse). Six of the 20 patients with hypofibrinolysis (30%) had no Winstrol-related side effects, while 14 (70%) had side effects that could be attributed to Winstrol, including weight gain, peripheral edema, increased facial and body hair, and acne--all of which were reversed within 6 weeks of stopping Winstrol therapy. CONCLUSIONS We postulate that thrombophilia and hypofibrinolysis lead to impaired venous circulation and venous hypertension of the mandible/maxilla with subsequent development of osteonecrosis and chronic facial pain. In many patients, facial pain can be ameliorated by treating the pathogenetic coagulation defects with Coumadin or Winstrol. Large, double-blind, placebo-controlled crossover studies will be required in the future to validate these preliminary results and to determine whether pain relief with Coumadin or Winstrol justifies the risks and side effects associated with these medications, especially for long-term use, in osteonecrosis of the jaws.
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Heterozygosity for the Leiden mutation of the factor V gene, a common pathoetiology for osteonecrosis of the jaw, with thrombophilia augmented by exogenous estrogens. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 1997; 130:540-3. [PMID: 9390643 DOI: 10.1016/s0022-2143(97)90132-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We assessed whether heterozygosity for the thrombophilic Leiden mutation of the factor V gene (MFV) was pathogenetic for alveolar osteonecrosis of the jaw and chronic facial pain (neuralgia-inducing cavitational osteonecrosis (NICO)) in 89 patients with NICO. A second specific aim was to assess for thrombophilic synergism between exogenous estrogens and MFV for development of osteonecrosis of the jaw. MFV was found in 24% of the patients, 16 (21%) of 76 women and 5 (39%) of 13 men. The mutation was much less common in healthy normal controls: 3 (3%) of 101 women (chi2 = 14.8, p = 0.001) and 4 (3.7%) of 108 men (chi2 = 20.4, p = 0.001). Patients with and without MFV did not differ in tissue plasminogen activator activity, plasminogen activator inhibitor activity, proteins C and S, lipoprotein (a), or anticardiolipin antibodies (p > 0.05). Use of standard-dose oral contraceptives and/or postmenopausal estrogens before the development of NICO was more common in female patients with MFV (13 (81%) of 16) than in those without it (23 (38%) of 60; chi2 = 9.33, p = 0.002). When the thrombophilic effects of such exogenous estrogens were superimposed on the familial resistance to activated protein C associated with MFV, thrombophilia was augmented and the risk of osteonecrosis was increased. Since heterozygosity for this mutation occurs in at least 3% of unselected, healthy women, measurement of resistance to activated protein C and MFV would identify women at high risk for venous thrombosis and osteonecrosis, in whom use of oral contraceptives or postmenopausal estrogens might be contraindicated, while identifying a much larger group of women (approximately 97%) without the mutation whose risk from exogenous estrogens would be low.
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Alveolar osteonecrosis. ORAL SURGERY, ORAL MEDICINE, ORAL PATHOLOGY, ORAL RADIOLOGY, AND ENDODONTICS 1997; 84:229-30. [PMID: 9377182 DOI: 10.1016/s1079-2104(97)90334-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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The pathophysiology of alveolar osteonecrosis of the jaw: anticardiolipin antibodies, thrombophilia, and hypofibrinolysis. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 1996; 127:481-8. [PMID: 8621985 DOI: 10.1016/s0022-2143(96)90065-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We studied 55 patients (50 women, 5 men) with severe facial pain and biopsy-proven neuralgia-inducing cavitational osteonecrosis (NICO) of the alveolar bone of the jaws. Our aim was to assess the pathophysiologic contributions to NICO of anticardiolipin antibodies (aCLA), thrombophilia (increased tendency to intravascular thrombi), and hypofibrinolysis (reduced ability to lyse thrombi). Of the 55 patients, 43 (78%) had one or more tests positive for thrombophilia or hypofibrinolysis (or both), and only 12 (22%) were normal. Eighteen of 55 (33%) patients had high aCLA (> 2 SD above mean value for control subjects); immunoglobulin G (IgG) (p = 0.01) and immunoglobulin A (IgA)(p = 0.001) levels were higher in patients than in controls. The distribution of elevated aCLA immunoglobulin classes among patients was as follows: IgG alone, 5 (9%); IgA alone, 7 (13%); and IgM alone, 3 (5%). Three patients (5%) had high levels of both IgG and IgA aCLA. Other defects of the thrombotic or fibrinolytic systems in the 55 patients included high lipoprotein(a) in 36% (vs 20% in control subjects (p = 0.03)), low stimulated tissue plasminogen activator activity (tPA-Fx) in 22% (vs 7% in control subjects (p = 0.08)), high plasminogen activator inhibitor activity (PAI-Fx) in 18% (vs 8% in control subjects (p = 0.03)), resistance to activated protein C in 16% (vs 0% in control subjects (p = 0.007)), low antigenic protein C in 4+ (vs 0% in control subjects (p > 0.2)), and low antigenic protein S in 4% (vs 0% in control subjects (p > 0.2)). Anticardiolipin antibodies and other defects of the thrombotic and fibrinolytic systems appear to be common, potentially reversible pathogenetic risk factors associated with osteonecrosis of the jaw.
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Thrombophilia, hypofibrinolysis, and alveolar osteonecrosis of the jaws. ORAL SURGERY, ORAL MEDICINE, ORAL PATHOLOGY, ORAL RADIOLOGY, AND ENDODONTICS 1996; 81:557-66. [PMID: 8734702 DOI: 10.1016/s1079-2104(96)80047-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVES Our specific aim in 49 patients (42 women, 7 men) with osteonecrosis of the jaw was to determine whether thrombophilia (increased tendency to intravascular thrombosis) or hypofibrinolysis (reduced ability to lyse thrombi) were associated with this regional avascular necrosis. STUDY DESIGN Determinants of thrombosis and fibrinolysis were compared in healthy controls and in 42 women and 7 men who had biopsy-proven idiopathic osteonecrosis of the jaw with severe chronic jaw or facial pain syndromes and failure to respond to conventional medical and dental treatments. RESULTS Of the 49 patients, 35 (71%) had thrombophilia or hypofibrinolysis and only 14 were normal. Thrombophilia as a sole coagulation defect was found in 10 patients, 7 with resistance to activated protein C and 3 with low protein C (deficiency of an antithrombotic protein). Hypofibrinolysis with low stimulated tissue plasminogen activator activity and high lipoprotein (a) (an atherogenic, hypofibrinolytic lipoprotein) were found as sole coagulation defects in seven and eight patients, respectively. Ten patients had mixed defects; 7 of these 10 had thrombophilia with resistance to activated protein C. Sinusoidal dilatation was a constant feature in maxillary and mandibular bone biopsies, suggesting venous occlusion with intramedullary hypertension. Marrow fibrosis and occasional fibrin plugs were additional microscopic features believed to impair venous drainage and to contribute to ischemic necrosis of the alveolar bone. CONCLUSIONS Primary thrombophilia and hypofibrinolysis appear to be common, heritable, pathophysiologic risk factors for idiopathic osteonecrosis of the jaws. These coagulation defects may also contribute to alveolar neuralgia, atypical odontalgia and facial neuralgia, idiopathic trigeminal neuralgia, and to treatment failures so often encountered in patients with alveolar osteonecrosis and disabling chronic facial and jawbone pain syndromes.
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Local anesthetic effects in the presence of chronic osteomyelitis (necrosis) of the mandible: implications for localizing the etiologic sites of referred trigeminal pain. Cranio 1995; 13:212-26. [PMID: 9088162 DOI: 10.1080/08869634.1995.11678072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The aims of this study were: (1) to demonstrate how reproducible variations in incomplete anesthesia of the inferior alveolar nerve can be used as a guide to locate the etiologic sites of referred trigeminal pain emanating from the mandible; (2) to describe the salient histopathologic features of a lowgrade, nonsuppurative osteomyelitis seen in this patient population. Forty-six patients with idiopathic facial pain were subjected to a specific protocol of local anesthetic injections to sequentially block branches of the mandibular nerve to determine the effects on his/her pain. If this significantly reduced or altered the pain on three separate appointments, then exploratory surgery was conducted near identified zones of unanesthetized gingiva. Blocking (92%), bridging (4%), and divergence (4%) were observed patterns of anesthetic resistance of the mucogingival tissues used to categorize the incomplete anesthesia. A 100% correlation was found between the identified zones of unanesthetized gingiva and the discovery of intramedullary pathology. Medullary fibrosis with ischemic and degenerative changes in the cancellous bone were common findings, along with chronic inflammatory cell infiltrates and clusters of lymphocytes. It is concluded that Ratner's method of diagnostic anesthesia be implemented when searching for occult pain producing pathology of the jaws.
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Diagnostic anesthesia for referred trigeminal pain: Part 2. COMPENDIUM (NEWTOWN, PA.) 1992; 13:980, 983, 986, passim. [PMID: 1291072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Diagnostic anesthesia for referred trigeminal pain: 1. COMPENDIUM (NEWTOWN, PA.) 1992; 13:870, 873-4, 876 passim. [PMID: 1423400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Compatibility of premixed theophylline and methylprednisolone sodium succinate intravenous admixtures. AMERICAN JOURNAL OF HOSPITAL PHARMACY 1987; 44:1620-4. [PMID: 3307397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The stability of theophylline supplied as a premixed injection and of methylprednisolone sodium succinate in admixtures containing both drugs was studied. Solutions containing theophylline in concentrations of 4.0 mg/mL and 0.4 mg/mL were used. Methylprednisolone sodium succinate was added to each solution to produce a final concentration of 0.5 mg/mL and 2.0 mg/mL of methylprednisolone alcohol, a pharmacologically active form of methylprednisolone sodium succinate. Each admixture was prepared in triplicate, and samples were kept at room temperature in glass containers. Immediately after admixture and at 3, 6, 12, and 24 hours, samples were visually inspected, tested for pH, filtered, and assayed in duplicate by high-performance liquid chromatography for theophylline concentration and for both methylprednisolone sodium succinate and methylprednisolone alcohol content. Control solutions containing only one of the two drugs were also tested. No visual changes were observed. The addition of theophylline in 5% dextrose injection to the methylprednisolone sodium succinate solutions resulted in decreased pH values for all solutions, which did not vary significantly throughout the study period. Theophylline concentrations did not change significantly compared with baseline. In solutions containing theophylline 0.4 mg/mL with either 2.0 or 0.5 mg/mL of methylprednisolone sodium succinate, less than 90% of the initial methylprednisolone sodium succinate concentrations remained at 24 hours. However, within three hours after admixture preparation, methylprednisolone alcohol was detected in those solutions in increasing concentrations. A commercial preparation of premixed theophylline in 5% dextrose injection in a concentration of 4 mg/mL or less can be mixed with methylprednisolone sodium succinate in a final concentration of 2 mg/mL or less and administered intravenously within 24 hours after mixing.
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Maternal and fetal blood/brain distribution of d-propoxyphene and norpropoxyphene in rat and dog. Toxicol Appl Pharmacol 1981; 58:194-202. [PMID: 7245195 DOI: 10.1016/0041-008x(81)90423-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Deuterium-isotope effect in the biotransformation of 4-ethynylbiphenyls to 4-biphenylylacetic acids by rat hepatic microsomes. Biochem Biophys Res Commun 1981; 99:662-7. [PMID: 7236291 DOI: 10.1016/0006-291x(81)91795-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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The mutagenicity of dialkylaminoalkyl chlorides in a battery of short-term assays. ENVIRONMENTAL MUTAGENESIS 1981; 3:33-43. [PMID: 7021143 DOI: 10.1002/em.2860030104] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Dialkylaminoalkyl chlorides, valuable chemical manufacturing intermediates, were evaluated for their mutagenicity in several short-term assays: The concentration gradient bacterial mutagen assay, the Ames test, the L5178Y mouse lymphoma cell assay, and the hepatocyte primary culture-DNA repair test. The dialkylaminoethyl chlorides were active in all test systems. The relative mutagenic potencies of the ethyl chlorides were similar in the bacterial tests and the genic potencies of the ethyl chlorides were similar in the bacterial tests and the L5178Y cell assay. The dialkylaminopropyl chlorides were weakly mutagenic in two Salmonella strains but were inactive in the other test systems. The purpose of the test battery used in these studies is to generate data on a test compound which could be used to make a rational prediction of the carcinogenic potential of the compound in test animals. On this basis, the results with the dialkylaminoethyl compounds suggest that if these agents which can form the aziridinium ion were evaluated in in vivo test there is a reasonable chance some would be found to be carcinogenic. Alternatively, the data on the dialkylaminopropyl chlorides indicate that they have a rather low carcinogenic potential.
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Chemically-induced unscheduled DNA synthesis in primary rat hepatocyte cultures: a comparison with bacterial mutagenicity using 218 compounds. ENVIRONMENTAL MUTAGENESIS 1981; 3:11-32. [PMID: 7021142 DOI: 10.1002/em.2860030103] [Citation(s) in RCA: 307] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The autoradiographic identification of unscheduled DNA synthesis (UDS) in primary cultures of adult rat hepatocytes (HPC) has been proposed as a predictive test for mutagens/carcinogens. To assess the predictive value of this test, results in the hepatocyte UDS assay were compared with data for bacterial mutagenicity using a modified Ames test. Over 200 compounds representing a variety of chemical classes consisting of procarcinogens, ultimate carcinogens, and noncarcinogens were tested in each system. The accurate discrimination of many carcinogens/noncarcinogens was demonstrated by both systems. The induction of UDS in hepatocytes showed an excellent correlation with bacterial mutagenesis in response to polycyclic aromatic hydrocarbons, aromatic amines, biphenyls, nitrosamines, carbamates, azo-compounds, acridines, halogenated compounds, nitrosureas, quinolines, pyridines, purines, pyrimidines, esters and carbamates. Nitrocompounds, although active in bacteria, were poor inducers of UDS. The results support the complementary and confirmatory nature of these tests for genotoxic chemicals and indicate the usefulness of the hepatocyte UDS system as a component in a battery of short-term predictive tests for mutagens/carcinogens.
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The N-hydroxylation and ring-hydroxylation of 4-aminobiphenyl in vitro by hepatic mono-oxygenases from rat, mouse, hamster, rabbit and guinea-pig. Xenobiotica 1980; 10:469-81. [PMID: 7445518 DOI: 10.3109/00498258009033782] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
1. An analytical h.p.l.c. method has been developed which permits the separation and quantification of the in vitro metabolites of 4-aminobiphenyl (4-ABP). The method employs gradient elution from a reverse phase column. 2. The major metabolite in vitro of 4-ABP in liver fractions from rat, mouse, guinea-pig, rabbit and hamster was N-hydroxy-4-aminobiphenyl. 3. The observation that liver fractions from the guinea-pig are very effective in the n-hydroxylation of 4-ABP is in excellent agreement with the 1966 report from Kiese's laboratory, showing that the N-hydroxylation of 4-ABP is an important metabolic pathway in vivo in this species. 4. The ortho-phenol, 3-hydroxy-4-aminobiphenyl was also an important metabolite in each species except guinea-pig and rabbit. 5. Hydroxylation at the 4' and 2' positions was a minor pathway in all species studied. 6. Aroclor 1254 was a potent inducer of N-hydroxylation in rat, mouse and guinea-pig but not hamster and rabbit. Phenobarbital induced N-hydroxylation in rabbit and guinea-pig but not rat, while methylcholanthrene induced in rat and guinea-pig but not rabbit.
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The stereoselective enzymic reduction of the synthetic 9-ketocannabinoid, nabilone, in vivo, in isolated liver cells and in liver homogenate. Xenobiotica 1980; 10:33-6. [PMID: 6247856 DOI: 10.3109/00498258009033728] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
1. The enzymic reduction of the two optical isomers of nabilone, 6aR, 10aR and 6aS, 10aS, has been studied separately in the rat, in isolated hepatocytes, and in the 9000 g supernatant fraction of rat liver homogenate. The SS-nabilone was the more active substrate in all three cases. 2. In all three systems, the only carbinol formed from SS-nabilone was the S-(equatorial)-carbinol. In contrast, the reduction of RR-nabilone gave only S-(axial)-carbinol in the intact rat and in the isolated hepatocyte, but gave in the liver homogenate fraction a mixture of S-(axial)-carbinol and R-(equatorial)-carbinol. 3. The results show that the reduction of nabilone in vivo in the rat proceeds with rigid stereochemical control and that only the S-carbinols are formed. 4. The results also suggest that observations made with the intact liver cell may be more predictive of events in vivo than are those made with broken cell preparations.
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Mechanism of the dealkylation of tertiary amines by hepatic oxygenases. Stable isotope studies with 1-benzyl-4-cyano-4-phenylpiperidine. J Med Chem 1979; 22:1100-3. [PMID: 490556 DOI: 10.1021/jm00195a018] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The microsomal oxidative dealkylation of 1-benzyl-4-cyano-4-phenylpiperidine has been studied and the source of oxygen shown to be molecular oxygen. The rate of debenzylation was decreased by substituting deuterium for hydrogen in the methylene portion of the benzyl group. The isotope effect was measured by comparison of the reaction rates of the d0 and d2 compounds 1a and 1b and also of the d5 and d7 compounds 1c and 1d. Determination of the reaction rates for various mixtures of labeled and unlabeled species allowed the rates for 0 (kH) and 100 mol % (kD) to be accurately obtained. A primary isotope effect of 1.46 was observed when the methylene hydrogens of benzyl were replaced by deuterium. No secondary isotope was observed when the aromatic hydrogens of benzyl were replaced by deuterium. The results of this study are consistent with a mechanism involving direct hydroxylation at the benzyl methylene position in a rate-determining step.
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Assay of 855 test chemicals in ten tester strains using a new modification of the Ames test for bacterial mutagens. Cancer Res 1979; 39:682-93. [PMID: 371791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Determination of mutagenic activity in bacterial systems has become accepted as an initial step in the evaluation of the carcinogenic potential of new chemicals. In this paper, a bacterial mutagen screening technique is described in which chemicals can be tested in 10 tester strains over a 10,000-fold concentration gradient both with and without metabolic activation. Using this assay, 855 chemicals were tested, and 182 were found to be mutagenic in one or more of the tester strains. Included were 299 chemicals used in chemical manufacturing or laboratory synthesis. Of these, 20% gave a positive response in one or more strains. The high rate of positives undoubtedly reflects the high chemical reactivity of compounds in this group. In contrast, when 261 organic chemicals which were synthesized for evaluation as potential pharmaceutical or agricultural products were tested, only 8% were identified as mutagenic. The Salmonella typhimurium tester strains TA98 and TA1538 proved to be very reliable and efficient in detecting and identifying frame-shift mutagens. TA100 was the most sensitive tester strain, detecting 142 of the 182 mutagens encountered in the study. However, since TA100 detected both base substitution mutagens and frame-shift mutagens, this tester strain was not suitable for the specific identification of base substitution mutagens. Base substitution mutagens were more reliably detected by Escherichia coli tester strains WP2 and WP2 uvrA- than they were by S. typhimurium strains G46 and TA1535. The data obtained when mutagens are tested by the concentration gradient procedures can include (a) the activity spectrum in tester strains, (b) identification as either frame-shift or base substitution mutagens, (c) the minimal concentration at which auxotroph growth is inhibited, and (d) mutagenic potency in terms of minimal concentration at which mutagenicity is observed. The data obtained have been found to be of immediate use. For example, with manufacturing intermediates the data have been combined with other toxicity data and used as a basis for setting safety standards for handling such compounds in the workplace. In addition, positive bacterial mutagenicity data on selected members of new series of organic compounds can serve to alert the chemist early to the possibility that the compounds may possess undesirable toxic properties, particularly carcinogenicity. Also, this type of data should be of great value both in the planning and in the interpretation of other in vitro tests designed to evaluate the potential carcinogenicity in mammals of chemicals found to be positive in bacterial tests.
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Biotransformation of 4'-ethynl-2-fluorobiphenyl in the rat. In vitro and in vivo studies. DRUG METABOLISM AND DISPOSITION: THE BIOLOGICAL FATE OF CHEMICALS 1979; 7:76-80. [PMID: 38077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The absorption, metabolism, and plasma pharmacokinetics of a novel anti-inflammatory agent, 4'-ethynyl-2-fluorobiphenyl, was studied in the rat. 4'-[1-14C]Ethynyl-2-fluorobiphenyl was quantitatively absorbed from the gastrointestinal tract. Excretion of radiocarbon into urine was greater than excretion into bile. Appreciate amounts of radiocarbon remained in the carcass 24 hr after dosing. The only metabolite in plasma was (2-fluoro-4'-biphenylyl)acetic acid, which also possessed anti-inflammatory activity. Unchanged 4'-ethynyl-2-fluorobiphenyl was present after administration of higher doses. Peak plasma concentrations of (5-fluoro-4'-biphenylyl)acetic acid were observed within 1 hr of administration. The apparent plasma half-life of this acidic metabolite was 4 hr. The major eliminated metabolite was (4-hydroxy-2-fluoro-4'-biphenylyl)acetic acid. In vivo and in vitro metabolism studies suggest that the major metabolic pathway involves microsomal hydroxylation of the C-H bond of the ethynyl moiety to yield, after rearrangement, a highly reactive intermediate metabolite, 2-fluoro-4'-biphenylylketene.
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Antitumor activity of deacetyl vinblastine amide sulfate (vindesine) in rodents and mitotic accumulation studies in culture. Cancer Res 1978; 38:2886-91. [PMID: 679195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Isopropylbiphenyl metabolism in the rat. Relationships between metabolism, pharmacology and toxicology. Xenobiotica 1978; 8:333-40. [PMID: 676340 DOI: 10.3109/00498257809070016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Aromatic hydroxylation of amphetamine with rat liver microsomes, perfused liver, and isolated hepatocytes. Biochem Pharmacol 1978; 27:2525-9. [PMID: 215158 DOI: 10.1016/0006-2952(78)90320-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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48
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Microsomal biphenyl hydroxylation: the formation of 3- hydroxybiphenyl and biphenyl catechol. Mol Pharmacol 1978; 14:145-54. [PMID: 625282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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The metabolism of drugs in isolated rat hepatocytes. A comparison with in vivo drug metabolism and drug metabolism in subcellular liver fractions. DRUG METABOLISM AND DISPOSITION: THE BIOLOGICAL FATE OF CHEMICALS 1977; 5:518-26. [PMID: 21776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The metabolism of drugs in isolated rat hepatocytes has been investigated. Drugs which are metabolized by aromatic hydrolation, aliphatic hydroylation, N-demethylation, or glucuronidation have been used as substrates. With some substrates the rate of metabolism in isolated hepatocytes compares with that in hepatic 900g supernatant fraction or microsomes, but other substrates are metabolized at a slower rate in isolated hepatocytes. For example, the rate of butamoxane hydroxylation in isolated hepatocytes is slower than that in microsomes. However, the rate of hydroxylation is hepatocytes is identical to that in perfused liver. The metabolism of drugs in isolated hepatocytes correlates with in vivo drug metabolism better than does metabolism in the hepatic 9000g supernatant fraction or microsomes.
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Disposition and tissue levels of [3H]vindesine in rats. Cancer Res 1977; 37:3053-6. [PMID: 884663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The excretion, blood levels, and tissue distribution of [3H]vindesine have been studied in the rat. After an i.v. administration of 500 microgram/kg. [3H]vindesine was found to be distributed very rapidly to tissues. After the distribution phase, blood levels declined with a half-life near 10 hr. Excretion was mainly via the bile, and [3H]vindesine and its metabolites in bile were poorly reabsorbed in the gastrointestinal tract. Levels were relatively high in most tissues studied but appeared to be efficiently cleared from all tissues except thymus and testes. Uptake into peripheral nerves was considerably higher than into the central nervous system.
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