Carcinogenicity of 2-amino-4-(5-nitro-2-furyl) thiazole in rats by oral and subcutaneous administration

Female Fischer rats were divided into two groups and fed either basal diet or basal diet containing 0.166% 2-amino-4-(5-nitro-2-furyl) thiazole for 52 weeks followed by basal diet for an additional 16 weeks. Our of the 24 rats fed 2-amino-4-(5-nitro-2-furyl) thiazole, 23 had forestomach tumors, four had fibroadenomas and two had adenocarcinomas in the mammary glands, two had renal pelvic carcinomas, five had papillomas and six had carcinomas in the bladder, and two had cutaneous tumors. None of the 10 rats fed basal diet developed tumors. In another study, two-week-old Fischer rats of both sexes were injected s.c. once a week for the first eight weeks with 2-amino-4-(5-nitro-2-furyl) thiazole at a dose of 10 mg/kg and then 1.4 mg/rat for an additional 46 weeks. The control rats were injected with solvent (dimethyl sulfoxide: water, 1:1) only. The experiment was terminated at the end of 58 weeks. Malignant fibrous histiocytomas were found in five out of eight male rats and four out of 11 female rats, and an angiosarcoma was found in one out of eight male rats injected with 2-amino-4-(5-nitro-2-furyl) thiazole. None of the control rats developed tumors.

Flow through collapsible tubes at high Reynolds numbers

The pressure-flow relationships of collapsible tubes were studied utilizing the Starling resistor model. Reynolds numbers much higher than previously reported were used to simulate high cardiac output states. Alterations which occur in vivo, including longitudinal tension, stretch, tubing diameter, length, and outflow resistance were also simulated and systematically investigated. The pressure-flow curves showed an initial rising phase, a plateau phase, as well as a late-rising phase which has not been reported previously. Self-induced oscillations occurred during the plateau phase and persisted throughout the late-rising phase. These perturbations were markedly increased by longitudinal tension and stretch, but were attenuated by increased diameter, length, and outflow pressure. These instabilities may prove to be an explanation for the "venous hum."

Activation of N-hydroxyphenacetin to mutagenic and nucleic acid-binding metabolites by acyltransfer, deacylation, and sulfate conjugation

N-Hydroxyphenacetin was activated to a mutagen in the Salmonella-Ames test by rabbit liver acyltransferase, rat liver cytosol, and rat liver microsomes. N-[ring]3H]-Hydroxyphenacetin was bound to transfer RNA when activated by acyltransferase from rabbit or rat liver or rat liver microsomes. The acyltransferase-catalyzed binding was not inhibited by paraoxon, a deacetylase inhibitor. The use of N-hydroxyphenacetin radioactively labeled in the acetyl group, as well as the ring, indicated that deacetylation was involved in the microsome-catalyzed binding reaction. In addition, the microsome-catalyzed binding was inhibited 90% by paraoxon. p-Nitrosophenetole, a deacetylated derivative of N-hydroxyphenacetin, was synthesized and bound to transfer RNA without enzymatic activation. Activation of N-hydroxyphenacetin by sulfate conjugation was also found to lead to binding to transfer RNA. The data implicated acyl transfer, deacetylation, and sulfate conjugation as possible routes for the activation of N-hydroxyphenacetin.

Subpicosecond-time-domain reflectometry

We demonstrate a new method of optical time-domain reflectometry using subpicosecond pulses and nonlinear detection. The high-spatial-resolution ( approximately 15-microm) temporal resolution and sensitivity put new limits on the size and nature of defects that can be detected, localized, and analyzed in optical fibers.

Activation of autologous reactive helper T lymphocytes for differentiation of human B lymphocytes

We present experimental evidence that autologous reactive T cells are triggered to proliferate by HLA-D or Ia-like antigens on pokeweed mitogen-pulsed non-T cells and that a subpopulation of these proliferating cells in turn helps PWM-primed B cells to differentiate into immunoglobulin-secreting cells. These helper T cells displayed a proliferation kinetics different from that of other autologous reactive T cells in peaking on the second day of culture and were relatively resistant to irradiation or treatment with mitomycin C. Since heterologous anti-Ia antibody (F(ab')2 reagent) inhibits proliferation of helper T cells and the generation of plaque-forming cells, Ia antigen is an essential component in PWM-stimulated B cell differentiation. Anti-Ia reagent was shown to interfere with B cell differentiation in 2 ways. First, it abrogates the ability of PWM-primed non-T cells to activate helper T cells. Second, it directly affects a differentiation of B cells into Ig-secreting cells even in the presence of the activated helper T cells.

Activation of autologous reactive helper T lymphocytes for differentiation of human B lymphocytes

We present experimental evidence that autologous reactive T cells are triggered to proliferate by HLA-D or Ia-like antigens on pokeweed mitogen-pulsed non-T cells and that a subpopulation of these proliferating cells in turn helps PWM-primed B cells to differentiate into immunoglobulin-secreting cells. These helper T cells displayed a proliferation kinetics different from that of other autologous reactive T cells in peaking on the second day of culture and were relatively resistant to irradiation or treatment with mitomycin C. Since heterologous anti-Ia antibody (F(ab')2 reagent) inhibits proliferation of helper T cells and the generation of plaque-forming cells, Ia antigen is an essential component in PWM-stimulated B cell differentiation. Anti-Ia reagent was shown to interfere with B cell differentiation in 2 ways. First, it abrogates the ability of PWM-primed non-T cells to activate helper T cells. Second, it directly affects a differentiation of B cells into Ig-secreting cells even in the presence of the activated helper T cells.

Effects of partial hepatectomy and dietary phenobarbital on liver and mammary tumorigenesis by two N-hydroxy-N-acylaminobiphenyls in female CD rats

The objective of this study was to investigate the induction of liver tumors by arylhydroxamic acids. The potential involvement of sulfate conjugation was minimized by the administration of a N-hydroxy-4-acylaminobiphenyl to female CD rats. This experimental design provided for the exposure of a target organ that has only a low capacity for activation of hydroxamic acids by sulfate conjugation, with a carcinogen that does not induce tumors in liver that possess a high sulfotransferase activity. A single dose of the N-formyl or N-acetyl derivatives of N-hydroxy-4-aminobiphenyl was given i.p. at 0.4 mmol/kg body weight to 34-day-old animals. In attempts to amplify the hepatocarcinogenic potential of the compounds, partial hepatectomy 24 hr before the chemical injection and subsequent long-term treatment with phenobarbital in the diet were carried out. For comparative purposes, other animals were subjected to three additional partial hepatectomies subsequent to the carcinogen administration instead of the phenobarbital treatment. The experiments were terminated 64 weeks after injection. Both the N-formyl and N-acetyl derivatives of N-hydroxy-4-aminobiphenyl, in conjunction with partial hepatectomy and subsequent treatment of dietary phenobarbital, induced a high incidence of neoplastic nodules and gamma-glutamyltranspeptidase-positive foci in the liver. Only one hepatocellular carcinoma was observed in each treatment group. Repeated partial hepatectomies enhanced the yield of gamma-glutamyltranspeptidase-positive foci but were ineffective in producing neoplastic nodules. In addition to the liver lesions, mammary tumors were also induced. Importantly, an inhibitory effect of the subsequent administration of phenobarbital was observed on mammary tumor formation, possibly because of alterations in hormone metabolism resulting from the induction of microsomal enzymes by phenobarbital, which resulted in a decreased promoting effect. There was no difference in the tumorigenicity of the formyl and acetyl derivatives in these experiments.

13-cis-retinoic acid: effect on urinary bladder carcinogenesis by N-[4-(5-nitro-2-furyl)-2-thiazolyl]-formamide in Fischer rats

The failure of 13-cis-retinoic acid to inhibit either the incidence or severity of bladder carcinoma in female Fischer rate initiated with N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) suggests that inhibition of bladder carcinogenesis by natural and synthetic retinoids is carcinogen-class specific, and adds an element of complexity to approaches in chemoprevention.

Synthetic retinamides: effect on urinary bladder carcinogenesis by FANFT in Fischer rats

The failure of N-ethylretinamide and N-(2-hydroxyethyl)retinamide to inhibit the incidence or severity of bladder carcinoma in female Fischer rats initiated with N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide supports the concept that the inhibition of bladder carcinogenesis by natural and synthetic retinoids is carcinogen-class specific.

O-esters of N-acylhydroxylamines: toxicity and enhancement of sister-chromatid exchange in Chinese hamster ovary cells

2-Naphthohydroxamic acid, 4-n-butoxyphenylacetohydroxamic acid, and their O-sulfonate, O-formate, O-acetate, and O-propionate derivatives were studied for cytotoxicity and sister chromatid exchange (SCE) induction in Chinese hamster ovary (CHO) cells. 2-Naphthylisocyanate, 2-aminonaphthalene (2 Lossen rearrangement products of the O-sulfonate derivative of 2-naphthohydroxamic acid), and N-methyl-2-naphthohydroxamic acid were also studied. All of these chemicals were cytotoxic and significantly increased SCE frequency, although there was a lack of correlation between these 2 effects. 2-naphthylisocyanate and 2-aminonaphthalene were not as cytotoxic nor as active in inducing SCEs as the O-sulfonate ester of 2-naphthohydroxamic acid suggesting that the cytotoxicity and SCE induction of the latter are not due to its decomposition products.

Carcinogenicity of benzidine, N,N'-diacetylbenzidine, and N-hydroxy-N,N'-diacetylbenzidine for female CD rats

To evaluate the role of metabolism in benzidine (BZ) carcinogenesis, BZ and 2 or its metabolites, N,N'-diacetylbenzidine and N-hydroxy-N,N'-diacetylbenzidine (NOHDABZ), were given by i.p. injection to female CD rats twice weekly for 4 weeks beginning at 30 days of age. A preliminary dose-response test showed that NOHDABZ was the most toxic compound; it caused chemical peritonitis and death in each of 4 animals given 70 mumol/kg body weight/injected. Toxicity was low in a 46-week carcinogenicity test which used either 10 or 30 mumol of each compound/kg body weight/injection; of 30 treated animals per groups, the effective number of rats was at least 28 per group. In the high dose BZ rats, the incidences of mammary gland and Zymbal's gland tumors were 41% (fibroadenoma plus adenocarcinoma) and 21% (adenoma plus carcinoma), respectively, and these incidences were significantly greater than those in control animals. The metabolites were approximately equipotent with BZ in mammary and Zymbal's gland, but the amount of NOHDABZ actually reaching these organs may have been diminished by local reactions of NOHDABZ within the peritoneum. Thus, of 60 NOHDABZ-treated rats, there were 2 toxicity-related early deaths, 6 rats with adhesions between visceral organs, and 5 tumors in tissues exposed directly to the compound. Since these effects were not present in other treatment groups, NOHDABZ may present an activate carcinogenic form of BZ.

Hepatitis A virus infection in Taiwan. A hospital-based study

One hundred and thirty-four healthy subjects and 220 patients with liver diseases were studied for antibody to hepatitis A virus (anti-HAV) with radio-immunoassay. The frequency of anti-HAV related closely to the age of healthy subjects; the rate of positivity increased with age, being 5.9% in those under four years, 13.3% in the late first decade and over 90% after the third decade. Taking meals at stalls with poor sanitary standards is suspected to cause the prevailing infection in teenagers, although a cohort effect due to environmental and socio-economic improvement can not be excluded. Anti-HAV was present in most patients with frequencies comparable to healthy subjects of the same age. It is concluded that in Taiwan the prevalent chronic liver diseases and hepatocarcinoma are unrelated to HAV infection and the patients are infected to an extent similar to healthy people of the same age.

Enhancement of sister-chromatid exchange in Chinese hamster ovary cells by nitrofurans

The nitrofurans, N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT), N-[4-(5-nitro-2-furyl)-2-thiazolyl]acetamide (NFTA), 2-amino-4-(5-nitro-2-furyl)thiazole (ANFT), 2-methyl-4-(5-nitro-2-furyl)thiazole (MNFT), 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (AF-2), nitrofurantoin, 5-nitro-2-furfurylidene diacetate and 5-nitro-2-furamidoxime were assayed for the enhancement of sister-chromatid exchange (SCE) in Chinese hamster ovary (CHO) cells and for the mutagenic activity in Salmonella typhimurium strain TA100. All of the nitrofurans significantly increased the frequency of SCE in CHO cells, and they were mutagenic for Salmonella. The increases in the frequencies of SCE were well correlated with the mutagenic activities in Salmonella.

Ethylene Production by Chilled Cucumbers (Cucumis sativus L.)

Chilling at 2.5 C accelerated the synthesis of 1-aminocyclopropane-1-carboxylic acid (ACC) and C(2)H(4) production in cucumber fruit. Skin tissue contained higher levels of ACC and was more sensitive to chilling than was cortex tissue. Accumulation of ACC in chilled tissue was detected after 1 day of chilling and remained elevated even after C(2)H(4) production started to decline. These data suggest that ACC synthesis is readily stimulated by chilling, whereas the system that converts ACC to C(2)H(4) is vulnerable to chilling injury. Chilling-induced C(2)H(4) production was inhibited by amino-ethoxyvinylglycine, sodium benzoate, propyl gallate, 2,4-dinitrophenol, carbonyl cyanide m-chlorophenylhydrazone, and cycloheximide. The utilization of methionine for ACC formation and chilling-induced C(2)H(4) biosynthesis was established using l-[3,4-(14)C]methionine. Chilled tissue had a higher capacity to convert l-[3,4-(14)C]methionine to ACC and C(2)H(4) than did nonchilled tissue.

Carcinogenicity of tannin and tannin-free extracts of bracken fern (Pteridium aquilinum) in rats

F344 inbred and Sprague-Dawley noninbred rats were fed a basic diet (groups 1 and 7) or a basic diet supplemented with 0.1% (later, 0.2 and 0.4%) tannin (group 2) isolated from bracken fern (Pteridium aquilinum) (BF), 33% BF (groups 3 and 6), 2% chloroform fraction of BF (group 4), or 4% tannin-free fraction of BF (group 5). The following incidences of intestinal or bladder tumors were observed: group 1, intestinal and bladder, 0/16; group 2, 0/21; group 7, 0/16; groups 4 and 5, intestinal, 7/15, bladder, 0/15; group 3, intestinal, 19/20, bladder, 12/20; and group 6, intestinal, 22/30, bladder, 15/30. The chloroform-methanol fraction prepared from urine of rats fed BF, chloroform fraction of BF, or tannin-free fraction of BF demonstrated mutagenicity for Salmonella typhimurium TA 100 but not for TA 98. No mutagenicity was detected in other prepared fractions. F344 rats in group 8 received weekly sc injections of tannin solution (0.1 g/kg body wt) for 38 weeks, and 16/20 developed palpable tumors that were malignant fibrous histiocytomas at the injection site. No tumor was present in any rat of control group 9.

Flow through collapsible tubes at low Reynolds numbers. Applicability of the waterfall model

The applicability of the waterfall model was tested using the Starling resistor and different viscosities of fluids to vary the Reynolds number. The waterfall model proved adequate to describe flow in the Starling resistor model only at very low Reynolds numbers (Reynolds number less than 1). Blood flow characterized by such low Reynolds numbers occurs only in the microvasculature. Thus, it is inappropriate to apply the waterfall model indiscriminately to flow through large collapsible veins.

Identification of a p69,71 complex expressed on human T cells sharing determinants with B-type chronic lymphatic leukemic cells

In the course of generating monoclonal antibodies to human thymus-dependent differentiation antigens, we were able to define specificities shared by T cells and by cells from patients with chronic lymphatic leukemia that were not detectable on normal B cells. In particular, one of these antibodies was reactive by indirect immunofluorescence with greater than 95% of the thymocytes and 80--95% of nonadherent sheep erythrocyte-rosetting peripheral blood lymphocytes (PBL), but was unreactive with normal B cells or cell lines derived from PBL by Epstein-Barr virus transformation. However, the leukemic cells from 11 of 14 patients with B-type chronic lymphatic leukemia were found to express detectable concentrations of this surface determinant. The target antigen recognized by this monoclonal antibody was shown by immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be a p69,71 complex. Our findings suggest a possible relationship between this antigen and the previously described GIX system in the mouse.

Ethchlorvynol: potential of metabolites for adverse effects in man

Identification of low levels of a metabolite of unaltered skeletal structure, 1-chloro-3-ethynylpent-1-en-3,4-diol (VII), detected in biological specimens of both nonfatal and fatal poisonings with DL-1-chloro-3-ethylpent-1-en-4-yn-3-ol (ethchlorvynol, la), has been achieved by high-resolution GC/MS. Corroborative evidence for the assigned structure (VII) was provided by synthesis, the design of which included as a central objective, concurrent access to 1-chloro-3-ethynyl-3,4-epoxy-1-pentene (VI), the putative direct precursor of VII. The diastereomeric epoxide mixture (VI) is mutagenic toward Escherichia coli WP2 try-hcr-, a UV-deficient repair strain. By contrast, neither Ia, VI, nor VII proved to be mutagenic toward Salmonella typhimurium (TA98, TA100, TA1535, and TA1539) with or without a liver postmitochondrial fraction. However, the epoxides (VI) proved cytotoxic to, for example, TA100, which apparently overlies its potency as a mutagen. The cytotoxicity of VI was also apparent in an in vitro culture system.

Isolation and immunological characterization of a major surface glycoprotein (gp54) preferentially expressed on certain human B cells

A major membrane glycoprotein with mol wt of approximately 54,000 has been isolated from membrane preparations of B-type lymphoid cell lines. Antiserum prepared against the isolated material specifically precipitated this glycoprotein from membranes labeled by surface radioiodination or by metabolic labeling. This antiserum was shown by complement-mediated cytotoxicity assay, membrane immunofluorescent staining, and by quantitative absorption analysis to react preferentially with certain B-lymphoblastoid cell lines, with a minor population of peripheral blood B lymphocytes, and a major population of tonsillar B lymphocytes. Certain B-cell leukemias also expressed the antigen, whereas others did not. Considerable variability was observed among positive B cells in the intensity of fluorescent staining even among the leukemic cells from a single individual. Although T cells, including T cells, were negative by direct immunofluorescent and cytotoxicity assay, evidence for low levels of the antigen on the cells of T cell lines was obtained. The whole specific antiserum and its F(ab')2 fragments stimulated B lymphocytes to proliferate. This proliferation did not produce differentiation to plasma cells and was T-cell independent. The monovalent Fab fragments had no effect. None of these preparations timulated T cells. The possibility that this antigen, termed gp54, may play some role in B-cell activation is discussed.

Expression of Ia-like antigens on cultured human malignant melanoma cell lines

Human malignant melanoma cell lines were found to bear Ia-like cell surface determinants demonstrable by hetero- or alloantisera and by direct identification of the characteristic bimolecular glycoprotein complex. Immunoprecipitation confirmed the presence of Ia determinants on the bimolecular complex. The quantity of Ia molecules determined by these methods and by absorption experiments was relatively constant for each cell line. Among different lines, however, the amount of Ia antigens ranged from a level equal to that expressed by B-cell lines to a small fraction of this amount. This variation in level of Ia contrasted with the more uniform amount of beta2-microglobulin detected on the cell surface. The Ia alloantigen specificity DRw2 was the most frequently encountered specificity. Ia determinants were also found on the surface of an epidermoid carcinoma line, but not on various other cell lines of normal or neoplastic origin.

Ia-bearing T lymphocytes in man. Their identification and role in the generation of allogeneic helper activity

The presence of Ia-like antigens was demonstrated on a small population (2-6%) of highly purified human circulating T lymphocytes by immunofluorescence with a rabbit anti-Ia serum raised against the isolated bimolecular Ia structure. The Ia+ T lymphocytes have no surface or intracellular immunoglobulins. The expansion of this Ia+ T-cell population was encountered in certain patients. Ia antigens were also found on T blasts grown in long-term cultures with conditioned medium generated by phytohemagglutinin-stimulated lymphocytes. In addition, leukemia blasts which stained for Ia antigens and formed E rosettes were identified in the peripheral blood of two leukemic patients. This evidence further supports the existence of Ia-bearing T cells in man. The Ia+ T-lymphocyte population was shown to contain cells responsible for the generation of allogeneic helper activity. Elimination of Ia+ lymphocytes from a purified T-cell population by the anti-Ia antiserum and complement abolished its ability to help an allogeneic B-cell preparation to generate plaque-forming cells against sheep erythrocytes in vitro in the presence of the antigen.

Mutagenicity of some commercially available nitro compounds for Salmonella typhimurium

Benzoyl chloride and 53 commercially available aromatic heterocyclic and aliphatic nitro compounds were tested for mutagenicity in Salmonella typhimurium TA98 and TA100. 34 of 53 nitro compounds (64%) were mutagenic, 4 in TA100 only, 15 in TA98 only, and 15 in both strains. 13 of the heterocyclic derivatives of pyridine, indole, indazole, quinoline, and benzimidazole were mutagenic. 21 of 34 mutagenic nitro compounds were bactericidal. Nitromethane was the only aliphatic tested and was not mutagenic. Benzoyl chloride, a human carcinogen, was mutagenic for TA98.

Inhibition of human erythropoietic colony formation in culture by treatment with Ia antisera

Incubation with Ia antiserum, followed by complement, markedly inhibited erythroid colonies arising from hematopoietic cells present in the nonadherent low density fractions of normal bone marrow. Both erythropoietin-dependent colonies and bursts were eliminated at dilutions of antiserum equivalent to, or greater than the dilutions required to abolish the granulocyte-macrophage colony formation. The inhibitory effect of the Ia antiserum was abolished by absorption with B but not T cells from lymphoid lines. Available evidence suggested that Ia determinants are expressed on the erythropoietin-sensitive progenitors of the erythroid series in precise analogy to their sequence of expression on the granulocyte lineage. In both lineages, as shown previously, the Ia determinants become undetectable during subsequent stages of differentiation.

A computer program for stepwise logistic regression using maximum likelihood estimation

A computer program has been written which performs a stepwise selection of variables for logistic regression using maximum likelihood estimation. The selection procedure is based on likelihood ratio tests for the coefficients. These tests are used in a forward selection and a backward elimination at each step. The use of the program is illustrated by several examples.

Patterns of expression of human "Ia-like" antigens during the terminal stages of B cell development

The "Ia-like" antigens characteristically present on the membrane of B lymphocytes were shown to be absent in most terminally differentiated Ig-producing plasma cells. This was most evident in analyses of myeloma plasma cells that uniformly lacked the Ia-antigens. Also, in B lymphoid cell lines, the lymphoblasts were uniformly Ia-positive but the plasma cells were negative. In contrast, however, the majority of plasma cells produced after pokeweed mitogen stimulation remained positive. Plasma cells in tonsil and in the tissue of peripheral blood of patients with Wladenström's macroglobulinemia were also sometimes Ia-positive although the majority were negative. Studies of membrane IgM and IgD indicated a similar loss in some instances. However, the SIg and Ia antigens were not invariably associated. These results lead to the conclusion that Ia-antigens are differentiation antigens for B cells and are usually lost by the end stage cells in this series.

Expression of Ia-like antigen molecules on human granulocytes during early phases of differentiation

Human B lymphocyte antigens analogous to the murine Ia determinants were found on myeloblasts and promyelocytes but not on more mature granulocytes. This was apparent by fluorescent staining with both human alloantisera and rabbit antisera to the isolated Ia-like proteins. The cells of patients with chronic myelocytic leukemia showed this difference especially clearly. Separation of the myeloblasts and promyelocytes by multistep density gradient fractionation produced a marked enrichment of the positive cells. The remaining cells from higher density fractions were more-mature neutrophils that were essentially negative. In acute myeloid leukemia, in which myeloid cells early in differentiation predominate, the vast majority of cells were strongly positive. Similar results were obtained with normal bone marrow cells. Here also, only the early forms of the myeloid series separated by gradient centrifugation had Ia antigens. Evidence was also obtained for the presence of Ia determinants on cells with the appearance of early erythroid precursors. Support for the presence of the Ia determinants on granulocyte-macrophage committed stem cells was provided by the inhibition of granulocyte colony formation in agar cultures following preincubation of normal bone marrow with antiserum and complement. Cross absorptions with purified preparations of immature cells provided evidence for the close similarity of the antigenic determinants on both myeloblasts and B cells. A 28,000-37,000-dalton bimolecular complex obtained from myeloblast membranes contained the Ia determinants and was similar to that obtained from peripheral blood B cell membranes.

Mutagenicity of hydroxamic acids for Salmonella typhimurium

P-Butoxyphenylacethydroxamic acid, benzohydroxamic acid, salicylhydroxamic acid, 2-naphthohydroxamic acid, indole-2-carbohydroxamic acid and benzoylaminoacethydroxamic acid were synthesized, and their mutagenicity for Salmonella typhimurium strains TA98 and TA100 were determined. Except for p-butoxyphenylacethydroxamic acid, all the hydroxamic acids were mutagenic for both strains. The mutagenicity progressed in the following order: 2-naphthohydroxamic acid greater than benzohydroxamic acid and salicylhydroxamic acid greater than benzoylaminoacethydroxamic acid and indole-2-carbohydroxamic acid. The starting materials for the synthesis of these acids including hydroxylamine were not in themselves mutagenic for TA98 and TA100. Thus, while the mutagenicity may require the hydroxamic acid as a whole, the acyl group may determine the mutagenic potency.

Effect of aminoethoxy analog of rhizobitoxine on ripening of pears

Ripening reactions in pears (Pyrus communis L.) were differentially affected by an aminoethoxy analog of rhizobitoxine (l-2-amino-4-[2-aminoethoxy]-trans-3-butenoic acid) (AAR). Ethylene production of both ;Anjou' and ;Bartlett' pears was inhibited by AAR. Decrease in firmness, increase in protein N and soluble pectin were delayed by AAR in ;Anjou' but not in ;Bartlett' pears. While loss in malic acid was retarded in ;Anjou' pears, rates of citric acid accumulation and malic acid reduction were not affected by AAR in ;Bartlett' pears.

Mutagenicity and antibacterial activity of hydroxamic acids

Hydroxamic acids demonstrated mutagenic and antibacterial activities. These activities appear to be dependent on the hydroxamic acid function and are probably due to the interaction with deoxyribonucleic acid.

Mutagenicity for Salmonella typhimurium of urine obtained from humans receiving nitrofurantoin

Urine samples from 12 humans receiving oral therapeutic doses of nitrofurantoin were mutagenic for Salmonella typhimurium strain TA 100 and nonmutagenic for strain TA 100-FR1. Mutagenic activity of the urine was not increased by treatment with beta-glucuronidase. Spot mutation assay of the chromatogram of urine revealed that the mutagenic activity of the urine was mainly due to unmetabolized nitrofurantoin.

Mutagenic activity of carcinogenic and noncarcinogenic nitrofurans and of urine of rats fed these compounds

The nitrofurans, 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (AF-2), N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT), nitrofurantoin, 5-nitro-2-furoic acid, 5-nitro-2-furamidoxime, 5-nitrofurfurylidene diacetate and the urine of rats fed these compounds, were assayed for mutagenic activity in Salmonella typhimurium strains TA100 and TA100FR1. All the nitrofurans were mutagenic in the order: AF-2 and FANFT greater than nitrofurantoin greater than 5-nitro-2-furamidoxime greater than 5-nitrofurfurylidene diacetate greater than 5-nitro-2-furoic acid. Strain TA100 was more sensitive than TA100FR1 to the mutagenic influence of these nitrofurans. Only the urine of rats fed AF-2, FANFT and nitrofurantoin had mutagenic activity. Again, TA100 was more sensitive than TA100FR1. The mutagenicity of the urine was not increased by treatment with beta-glucuronidase. AF-2, 2-amino-4-(5-nitro-2-furyl)thiazole (deformylated product of FANFT) and nitrofurantoin were excreted in the urine of rats fed these compounds; whereas the other nitrofurans were not excreted.