摘要:

The objectives of this study were to determine the percutaneous absorption of alach‐lor relative to formulation dilution with water, and to determine the ability of soap and water, and of water only, to remove alachlor from skin, relative to time. Alachlor is a preemergence herbicide. The in vivo percutaneous absorption of alachlor in rhesus monkeys was 17.3 ± 3.3, 15.3 ± 3.9, and 21.4 ± 14.2% for 24‐h skin exposure to Lasso formulation diluted 1:20, 1: 40, and 1: 80, respectively. In vivo, there was no support for increased alachlor skin absorption with water dilution, as previously reported for in vitro absorption. The average in vivo absorption of 18% applied dose over 24 h (0.75%/h) was similar to the maximum in vitro rate of 0.8%/h using human skin and human plasma as receptor fluid. Dose accountability in vivo was 80.6–95.2%. [14CJAIachlor in Lasso diluted 1 : 20 with water was placed on rhesus monkeys at concentrations of 23 μg/10 μl/cm2. Skin decontamination at 0 h with soap and water (50% Ivory liquid 1:1 v/v with water) removed 73 ± 15.8% (n ‐ 4) of the applied dose with the first wash; this increased to a total of 82.3 ± 14.8% with two additional washes. Decontamination after 1 h removed 87.5 ± 12.4% with three successive washes. After 3 h decontamination ability decreased, and after 24 h only 51.9 ± 12.2% could be recovered with three successive washes. Using water only, at 0 h 36.6 ± 12.3% alachlor was removed with the first wash and the total increased to 56.0 ± 14.0% with two additional washes. At 24 h the total amount decreased to 28.7 ± 72.2% for three successive washes.

ISSN:0098-4108    

DOI:10.1080/15287399209531619

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Prompted by reports of sexual impotence among chemical factory workers exposed to amsonic acid (4,4'‐diaminostilbene‐2,2'‐disulfonic acid; CAS 81–11–8) and its synthetic precursors 4,4'‐dinitrostilbene‐2,2'‐disulfonic acid (DNSDSA; CAS 128–42–7), 2‐methyl‐5‐nitrobenzenesulfonic acid (MNBSA; CAS 121–03–09), and 4‐nitrotoluene (CAS 99–99–0), the uterine‐weight‐increasing actions of single intraperitoneal doses of these chemicals were determined at 24 h after treatment in weanling female rats and compared to the results of similar experiments with diethylstilbestrol (DES; CAS 56–53–01), a synthetic estrogen chemically related to amsonic acid and DNSDSA. Doses of 100 mg/kg or less of amsonic acid were either without effects or produced equivocal effects, while uterine weights were increased after doses of 300 and 1000 mg/kg; doses of 3000 mg/kg were clearly toxic. Neither DNSDSA nor MNBSA increased uterine weight after doses that were not overtly toxic. Doses of 10 mg/kg or less of 4‐nitrotoluene were without effect, but doses of 30 and 100 mg/kg increased uterine weights without producing overt toxicity; doses of 1000 mg/kg were clearly toxic. While both amsonic acid and 4‐nitrotoluene exhibited uterotropic effects, they were both much weaker than DES in this respect. Other experiments indicated that the time course of the effects of approximately equiactive doses of amsonic acid and DES were very similar, and that the responses to oral doses of amsonic acid were not appreciably different from the responses to the same doses given intra‐peritoneally. Finally, a sample of amsonic acid taken from the workplace of the complaining workers was also found to have uterotropic activity. These experiments suggest that amsonic acid and 4‐nitrotoluene have estrogenic activity, and thus provide a possible mechanistic explanation for the complaints of impotency in factory workers exposed to these substances.

ISSN:0098-4108    

DOI:10.1080/15287399209531620

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Trimethylamine (TMA) is an aliphatic amine, and its blood levels can increase after ingestion of certain foods, such as fish, and during disease states, such as chronic renal failure. We recently reported that TMA can inhibit fetal development in vivo and in vitro in mice. The present studies were done to find out if the inhibitory effects of TMA on embryonic development are caused by a decrease in macromolecular synthesis, using mouse embryo cultures as the experimental model. At a submaximally toxic concentration (0.75mM), TMA inhibited the growth of embryos to approximately 70% of control and caused neural‐tube defects in 73% of embryos. By 42 h of culture, DNA, RNA, and protein content of TMA‐treated embryos were approximately 50% of the control values. Embryotoxic effects of TMA were not caused by changes in pH and osmolarity of the culture media. The inhibitory effects of TMA on embryonic growth were time dependent and apparent at 2–4 h of culture. The inhibition of growth was accompanied by a decrease in the incorporation of tritium‐labeled thymidine, uridine, and leucine into DNA, RNA, and proteins, respectively. Thiols #OPL‐ and D‐cysteine, gluta‐thione) and the antioxidant L‐ascorbic acid did not cause significant antagonism of embryotoxic effects of TMA. It is concluded that TMA exerts teratogenic effects on mouse embryos in culture and inhibits their growth by reducing macromolecular synthesis; these effects may not involve glutathione depletion or generation of free radicals.

ISSN:0098-4108    

DOI:10.1080/15287399209531621

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A useful framework is proposed for unifying the synthesis of plasma proteins and their degradation by, or release from, liver cells of intact and partially hepatectomized rats, in which synthesis and release of acute‐phase plasma proteins occur in synchrony with the internalization and catabolism of plasma and extracellular proteins. The catabolism of proteins and other hepato‐intracellular glycoproteins during sepsis or trauma is essential to provide constituent amino acids and carbohydrates for the synthesis of acute‐phase plasma proteins. Increases in the plasma levels of acute‐phase response proteins in sham‐operated rats reached a maximum between 1 and 2 d after mock surgery, and had returned virtually to control levels within 6 d. By contrast, acute‐phase proteins in the plasma of partially hepatectomized rats were decreased by 10–20% of their initial values after 24 h. A maximum acute‐phase response on d 7 after the operation was characterized by an increase of 181, 445, and 19% for alpha‐1‐acid glycoprotein, hepatoglobin, and hemopexin, whereas other acute‐phase proteins remained below control levels, for example, by 11, 25, and 38% for albumin, transferrin, and prealbumin, respectively. This delayed response suggests that the nascent liver cells had inherited the capacity of the parent cells to respond to inflammatory signal and had synthesized acute‐phase plasma proteins. Accordingly, a time frame for the application of toxin to nascent hepatocytes is suggested. An increased activity (300 ± 50%) for both bound and free neuraminidase in remnant liver tissue 19 h post partial hepatectomy suggested that hepatic regenerating factor(s) were produced in liver tissue via the hepatic bound and/or free neuraminidase‐mediated de‐sialylation of humoral substrates. By contrast, circulating levels of lysosomal enzymes alpha‐fucosidase and beta‐N‐acetyl‐D‐glucosaminidase were increased marginally after 24 h but had returned nearly to control levels after 7 d, suggesting that lysosomal acid hydrolases do not play a major role in regenerative DNA synthesis, mitosis, or in the synthesis of acute‐phase plasma proteins.

ISSN:0098-4108    

DOI:10.1080/15287399209531622

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The objective of this in vitro study was to examine the response of mixed cultures of Sertoli and germ cells to treatment with thallium (Tl) at the range of concentrations that, in previous studies, was shown in vivo to affect reproduction. Cultures were prepared from the testis of Sprague‐Dawley rats. Cultures containing approximately 3.75 × 105cells/ml were treated with Tl concentrations corresponding to 35, 7, and 1.4 μg Tl/g testis, estimated from protein content of cultures. Observations at 24, 48, and 72 h after treatment showed a significant release of germ cells into the culture medium that was both concentration and time dependent. Cultures treated with 35 μg Tl/g testis showed a threefold increase in germ‐cell detachment compared with controls after only 24 h of exposure. As the treatment time increased to 48 h of exposure, even cultures exposed at the lowest Tl concentration (1.4 μg Tl/g testis) showed significant loss of germ cells. After 48 h, cultures exposed to 7 μg Tilg testis exhibited a 2.5‐fold increase in germ‐cell detachment, and those exposed to 35 μg Tl/g testis exhibited a 10‐fold increase over controls. Morphological investigations of cell cultures showed evident loss of germ cells with significant reduction in prepachytene and pachytene spermatocytes and changes in the shape of Sertoli cells. These results are in agreement with in vivo studies, in which thallium treatment at comparable exposure levels manifested its earliest toxic testicular effects in Sertoli and germ cells. They also demonstrate the usefulness of this in vitro culture technique to assess toxic testicular damage rapidly.

ISSN:0098-4108    

DOI:10.1080/15287399209531623

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

WILDLIFE TOXICOLOGYT. J. Peterle Van Nostrand Reinhold, New York, 1991. 322 pp., $59.95

ISSN:0098-4108    

DOI:10.1080/15287399209531624

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0098-4108    

DOI:10.1080/15287399209531618

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor