Biomedical subjects

K M Flynn

Publications and source records attributed to K M Flynn.

12 recordsLinked to original sources

PubMed2005

Long term dietary methoxychlor exposure in rats increases sodium solution consumption but has few effects on other sexually dimorphic behaviors.

Methoxychlor is an insecticide with estrogen-like activity, thus exposure during development might cause sexually dimorphic behavioral alterations. To evaluate this, pregnant rats consumed diets containing 0, 10, 100 or 1000 ppm methoxychlor from gestational day 7, and offspring continued on these diets until postnatal day (PND) 77. Assessments of sexually dimorphic behaviors in offspring indicated that intake of a 3.0% sodium chloride solution was significantly increased (41%) in males and females of the 1000 ppm group. No treatment group differed from controls in open field nor running wheel activity, play behavior, nor 0.3% saccharin solution intake. Offspring of the 1000 ppm group showed significantly decreased body weight, reaching 17% less than controls at PND 77, but not clearly related to their salt solution intake. During pregnancy, 1000 ppm dams consumed 23% less food and weighed 10% less than controls, but this did not affect litter outcomes. These results indicate that in rodents, developmental and chronic exposure to dietary methoxychlor alters the sexually dimorphic behavior of salt-solution intake in young adults of both sexes. Similar behavioral alterations with other xenoestrogens, and the potential for interactions among xenoestrogens, suggest that this report may minimize the true effects of dietary methoxychlor exposure.

Animals↗

PubMed2004

Toxicity and apoptosis induced by the mycotoxins nivalenol, deoxynivalenol and fumonisin B1 in a human erythroleukemia cell line.

The toxicity of the mycotoxins nivalenol (NIV), deoxynivalenol (DON) and fumonisin B1 (FB1) were studied in the K562 human erythroleukemia cell line using the Trypan Blue, MTT and BrdU uptake analyses of cytotoxicity, cell metabolism and cell proliferation, respectively. Nuclear staining with propidium iodide and DNA analysis by flow cytometry were used to identify apoptosis and cell cycle distribution. By the MTT and BrdU tests, both NIV and DON were significantly more toxic than FB1 by at least one order of magnitude, with ID50s ranging from 0.5 microM for NIV to 70 microM for FB1. The MTT test indicated that NIV was significantly (approximately four times) more toxic than DON. In contrast, the Trypan Blue test did not reveal any effects of mycotoxin exposure suggesting that, at the concentrations tested, NIV, DON and FB1 did not induce cytotoxicity through plasma membrane damage. Cell cycle analysis suggested apoptotic cytotoxicity, revealing 100% cellular debris at the highest concentrations of NIV and DON and approximately 2.9 times more debris than control at the highest FB1 concentration. Morphological evidence of apoptosis was related to the toxicity of the substances, such that the more toxic NIV and DON resulted in more late stage apoptotic events than FB1. This study suggests that human blood cells are sensitive to mycotoxin exposure, that NIV is more toxic than DON which is more toxic than FB1, and that DNA damage and apoptosis rather than plasma membrane damage and necrosis may be responsible for the observed cytotoxicity.

Apoptosis↗

PubMed2001

Behavioral responses of rats exposed to long-term dietary vinclozolin.

Vinclozolin is a fungicide used on food crops with human exposure estimated at approximately 2 microg/kg/day from ingestion; occupational exposure, however, may be greater. The metabolites of vinclozolin have been reported to act as antiandrogens and have adverse effects on reproductive physiology and behavior in animals. Here, pregnant rats were fed soy-free diets containing 0, 10, 150, or 750 ppm of vinclozolin (approximately 0, 0.8, 12, and 60 mg/kg/day for an adult) beginning on gestational day 7, and offspring were continued on these diets through sacrifice at postnatal day 77. Male and female offspring were assessed for changes in several nonreproductive sexually dimorphic behaviors: open field and running wheel locomotor activity, play behavior, and consumption of saccharin- and sodium chloride-flavored solutions. There was a significant interaction of sex with vinclozolin exposure on running wheel activity, which indicated that females in the high-dose exposure group were hypoactive compared to same-sex controls. There was a significant overall effect of vinclozolin exposure on fluid consumption, and high-dose animals showed increased intake of the saccharin solution and decreased intake of plain water while saccharin was available. Effects were more pronounced in females, which drank 40.8% more saccharin than control females, whereas males drank 6.2% more than control males. There were no effects of vinclozolin treatment on play behavior or sodium solution intake. Gestational duration, total and live pups per litter, litter sex ratios, and birth weight were also not significantly affected, nor were body weight and food intake for dams and offspring. These results indicate that long-term dietary exposure to vinclozolin does not have severe toxicological consequences on the nonreproductive behaviors measured here. However, exposure may cause subtle alterations in locomotor activity and consumption of saccharin-flavored solution.

Administration, Oral↗

PubMed2000

Effects of genistein exposure on sexually dimorphic behaviors in rats.

The phytoestrogen genistein, the principal isoflavone in soybeans, has adverse effects on animal reproduction. As adult physiology and behavior are sensitive to perturbation by developmental estrogens, exposure to genistein during development may produce behavioral alterations as well. Pregnant rats were fed soy-free diets containing 0, 25, 250, or 1250 ppm genistein (approximately 0, 2, 20, or 100 mg/kg/day) beginning on gestational day 7, and offspring continued on these diets through postnatal day (PND) 77. Male and female offspring were assessed for levels of sexually dimorphic behaviors: open field activity, play behavior, running wheel activity, and consumption of saccharin- and sodium chloride-flavored solutions. Consumption of the salt solution was affected by genistein, with animals in the 1250-ppm group drinking significantly more than controls; consumption of plain water was unaffected. Genistein treatment also significantly affected play behavior; although no treated group was significantly different from controls, and the effect was not sexually dimorphic. Running wheel activity and saccharin solution consumption showed significant sex differences, but no effects of genistein treatment. Gestational duration, total and live pups per litter, and total and live litter sex ratios were not significantly affected by genistein. However, average weight per live pup at birth and offspring body weights from PND 42-77 were significantly decreased in the 1250-ppm group. Body weight and food intake for the dams were also significantly decreased in the 1250-ppm group. These results indicate that developmental genistein treatment, at levels that decrease maternal and offspring body weight, causes subtle alterations in some sexually dimorphic behaviors.

Animals↗

PubMed2000

Developmental neurotoxicity of endocrine disrupters: focus on estrogens.

A number of different environmental compounds are proposed to interact with the endocrine system (i.e., endocrine disrupters). Many of these have estrogenic effects in vitro and/or in vivo. Recent reviews have focused attention on the need for assessing the neurotoxicity of these compounds following developmental exposure. This attention comes in part from the literature on the effects of developmental exposure to exogenous estrogen on later behavioral and neuropathological alterations. A review of the ongoing neurobehavioral and neuropathological studies at the National Center for Toxicological Research on four such estrogen mimics (genistein, methoxychlor, nonylphenol, and ethinyl estradiol) is presented with results indicating that intake of a sodium solution is sensitive to these estrogen mimics. Developmental dietary exposure in male and female rats resulted in increased consumption of the sodium solution. Volume of the sexually dimorphic nucleus of the medial preoptic area was reduced by genistein, nonylphenol, and ethinyl estradiol exposure in males. The regulatory impact of these data and the directions for future research are discussed.

Animals↗

PubMed2000

Multigenerational exposure to dietary genistein has no severe effects on nursing behavior in rats.

The phytoestrogen and principal isoflavone in soy, genistein, has adverse effects on reproductive physiology in rodents. Since physiology and behavior are both sensitive to perturbations by estrogens, genistein may produce behavioral alterations as well. This paper reports one aspect of a study in which several adult rodent behaviors will be assessed following long term multigenerational dietary exposure to genistein. Since maternal care may affect offspring behaviors in adulthood, it is important to determine the potential for genistein to affect maternal behavior. Here, rats (F0 generation) were fed soy-free diets containing 0, 5, 100, or 500 ppm genistein (approx. 0, 0.4, 8, and 40 mg/kg/day for an adult) beginning on postnatal day (PND) 42. Two generations of offspring (F1 and F2) were continued on these diets and all treatment groups of the F3 generation were returned to 0 ppm at weaning (PND 22). In the first 3 weeks after parturition (for each generation), dams were assessed on 6 occasions for the presence of the arched back posture with at least one pup nursing. Data were analyzed by 3 way repeated measures analysis of variance (ANOVA) with generation, treatment, and postnatal day as factors, and p<0.05 required for significance. There were no significant interactions among treatment, generation, or day, and no overall effects of treatment or generation. As expected, there was a significant overall effect of day, with animals nursing less on later days (p<0.0001). As assessed here, these results suggest that lifelong and multigenerational exposure to dietary genistein has no severe effects on nursing behavior in rodents.

Animals↗

PubMed1999

Sexually dimorphic development and binding characteristics of NMDA receptors in the brain of the platyfish.

This study investigated age- and gender-specific variations in properties of the glutamate N-methyl-d-aspartate receptor (NMDAR) in a freshwater teleost, the platyfish (Xiphophorus maculatus). Prior localization of the immunoreactive (ir)-R1 subunit of the NMDAR protein (R1) in cells of the nucleus olfactoretinalis (NOR), a primary gonadotropin-releasing hormone (GnRH)-containing brain nucleus in the platyfish, suggests that NMDAR, as in mammals, is involved in modulation of the platyfish brain-pituitary-gonad (BPG) axis. The current study shows that the number of cells in the NOR displaying ir-R1 is significantly increased in pubescent and mature female platyfish when compared to immature and senescent animals. In males, there is no significant change in ir-R1 expression in the NOR at any time in their lifespan. The affinity of the noncompetitive antagonist ((3)H)MK-801 for the NMDAR is significantly increased in pubescent females while maximum binding of ((3)H)MK-801 to the receptor reaches a significant maximum in mature females. In males, both MK-801 affinity and maximum binding remain unchanged throughout development. This is the first report of gender differences in the association of NMDA receptors with neuroendocrine brain areas during development. It is also the first report to suggest NMDA receptor involvement in the development of the BPG axis in a nonmammalian vertebrate.

Animals↗

PubMed1997

Developmental changes in NMDA receptor expression in the platyfish brain.

We have examined the distribution of the N-methyl-D-aspartate (NMDA) receptor in the brain of a freshwater teleost using an antibody against the R1 subunit of the receptor (NMDAR1). The primary site of localization was the nucleus olfactoretinalis (NOR), a significant gonadotropin releasing hormone (GnRH)-containing brain nucleus. The number of cells expressing NMDAR1 in this nucleus was dependent upon developmental stage, with pubescent and mature animals displaying significantly more stained cells than immature and senescent animals. This is the first reported observation of age- and maturity-related NMDA receptor association with GnRH-containing brain areas.

Aging↗

PubMed1986

Tumor antigen on benign adenomas and on murine lung carcinomas quantitated by a two-site monoclonal antibody assay.

TSP-180 is a Mr 180,000 cell surface protein found on several murine lung carcinomas but not on fibroblast or sarcoma cell lines. Monoclonal antibody 135-13C binds to TSP-180 with high affinity but could not be used to quantitate the protein in tumors and normal tissue (Cancer Res., 41: 3465-3470, 1981). TSP-180 was purified from a transplantable BALB/c carcinoma (line 1 cells) by immunoaffinity chromatography and used as an immunogen to produce another monoclonal antibody (346-11A) to a different epitope on the molecule. A two-site solid-phase radioimmunoassay for TSP-180 was developed to quantitate TSP-180 in tissue extracts. The assay can detect as little as 3 ng of TSP-180 in samples up to 10 mg of protein. Analyses of several lung carcinoma cell lines confirmed that TSP-180 is present in all (five of five) cell lines ranging from 40 to 800 ng per mg of cell protein extract. Mouse tissues from normal and tumor-bearing mice were analyzed for TSP-180. Values for line 1 tumors growing i.m. were about 70 ng of TSP-180 per mg of protein. Normal tissue from normal and tumor-bearing mice contained low levels of TSP-180 from less than 0.3 ng/mg of protein for liver to a high of about 11 ng/mg of protein for leg muscle. Finally, small benign urethane-induced adenomas (1 to 2 mm) from BALB/c mice had moderate amounts of TSP-180 (11 ng/mg of protein), while two primary lung adenocarcinomas in the same animals had 20 and 47 ng/mg of protein, respectively, suggesting that TSP-180 expression may increase with increasing cancer of these tumors. Analyses of individual urethane-induced lung tumors from A/J mice showed that 11 of 13 carcinomas had high levels of TSP-180, while only 1 of 6 adenomas had a detectable amount of TSP-180, and that was at a moderate level. Specific quantitation of tumor markers in normal, benign, and malignant lung tissue may be helpful in identifying different levels of gene expression as tumors progress to more malignant states.

Adenoma↗

PubMed1985

Factors affecting passive monoclonal antibody therapy of Moloney sarcoma in BALB/c mice.

We have developed a syngeneic monoclonal antibody (MoAb) (244-19A) which retards growth and contributes to cures of BALB/c mice bearing Moloney sarcoma cell (MSC) tumors (S.J. Kennel, T. Lankford, and K.M. Flynn, Cancer Res., 43: 2843-2847, 1983). The 244-19A epitope has not been detected in normal tissue or in any cultured cell (other than MSC) tested, including 15 different BALB/c sarcomas. MoAb 244-19A remains in circulation for a relatively long time in normal mice (t1/2 = 3.8 days), but it is cleared faster from tumor-bearing mice (t1/2 = 1.7 days), indicating a specific interaction of the antibody with the tumor. The 244-19A epitope is very labile. Osmotic lysis of cells or fixation with ethanol abolishes antibody binding. Trypsin treatment or fixation with gluteraldehyde reduces activity by 80 to 90%. Results from immunoprecipitation of radioiodinated MSC surface proteins indicate that the 244-19A epitope may reside on a Mr 65,000 protein, distinct from the major C-type virus glycoprotein 70 of these cells. Several factors affecting passive MoAb therapy have been evaluated. Doses as low as 24 micrograms/ mouse demonstrated a significant therapeutic effect; however, larger doses up to 1.5 mg/mouse produced progressively more cures. Since MoAb 244-19A is syngeneic in BALB/c mice, fractionated doses of antibody can be given over long periods of time without a host response to the MoAb. Fractionated doses showed a slight advantage over single dose therapy, but the difference was not statistically significant (P less than 0.2). Passive MoAb therapy has been effective in nu/nu mice, in BALB/c mice depleted of complement with cobra venum factor, and in BALB/c mice irradiated with 399 rads of X-rays; thus, therapy did not require complement, B-cells, or a cytotoxic T- cell response. Although tumor growth was retarded in nu/nu mice (T-cell-deficient), complete cures of tumored animals could not be accomplished even with large, multiple doses of antibody, indicating that cytotoxic T-cells eliminate residual tumor cells resulting in cures of BALB/c mice. Treatment of BALB/c mice with silica to deplete macrophage function did not affect therapy with MoAb 244-19A; however, treated animals still retained about 30% of their original phagocytic function, so macrophages cannot be eliminated as a possible host effector function.

Animals↗

PubMed1983

Therapy of a murine sarcoma using syngeneic monoclonal antibody.

Syngeneic monoclonal antibodies (MoAb) to Moloney sarcoma cells (MSC) were produced by fusion of spleen cells from MSC regressor mice to myeloma SP2/0. MoAb 244-19A, an immunoglobulin G2b, bound to MSC cells and did not bind to two other sarcomas (K-BALB and Ha2), a carcinoma (Line 1), a fibroblast (A31) or a fibroblast infected with C-type virus (A31-Moloney leukemia virus). In contrast, MoAb 271-1A bound to the MSC and Ha2 sarcoma and line 1 carcinoma as well as to the normal and infected fibroblast cultures. Antibodies were tested for therapeutic effect using three schedules of antibody injection. Injection i.p. of ascites fluid containing 244-19A MoAb given on Days-1, 0, and +1 relative to tumor cell injection increased life span significantly over that of control animals given injections (P3, immunoglobulin G, or MoAb 271-1A) and produced some seven of 19, one of five, and one of five long-term survivors in three separate experiments. Antibody given to animals with established tumors (4 days after implantation) also prolonged life span significantly and produced three of nine long-term survivors. Antibody given to animals with very large tumor burdens (10 days after implantation) did not prolong life span significantly. Optimal dose, schedule, and mechanism studies concerning this therapy are in progress.

Animals↗

PubMedDate not supplied

Maternal and offspring toxicity but few sexually dimorphic behavioral alterations result from nonylphenol exposure.

Nonylphenol ethoxylates are used in the production of surfactants and are found in numerous manufactured substances. para-Nonylphenol (NP) is a suspected endocrine disruptor, exhibiting estrogen-like activity and might cause alterations with developmental exposure. To evaluate such effects, pregnant Sprague-Dawley rats consumed diets containing 0 (n = 11), 25 (n = 10), 500 (n = 10), or 2,000 (n = 9) ppm NP beginning on gestational day (GD) 7. At postnatal day (PND) 21, offspring continued on the same maternal diets until PND 77 and were evaluated for behavioral alterations (open-field activity at PNDs 22-24, 43-45, 64-66, play behavior at PND 35, running wheel activity at PND 63-77, flavored solution intake at PND 69-75). During pregnancy and lactation, dams in the 25-, 500-, and 2,000-ppm groups consumed 9 to 25% less food, which was associated with a 17% less weight gain during GDs 1 to 21 in dams of the 2,000-ppm group, although this effect was not statistically significant. Gestation duration, birth weight, sex ratio of live pups, and number of live or dead pups per litter did not differ between treatment groups. Offspring body weight and food consumption were decreased in the 2, 000-ppm group beginning at PND 28; however, an effect of feed aversion could not be eliminated. Behavioral assessments of offspring indicated no consistent NP-related effects in open-field activity at PNDs 22-24, 43-45, and 65-67 nor in running wheel activity at PNDs 63-75. Play behavior at PND 35 and intake of a 0.3% saccharin-flavored solution at PNDs 69-71 did not differ with respect to treatment groups. However, intake of a 3% sodium-flavored solution at PNDs 73-75 was significantly increased in offspring of the 2,000-ppm group and intake of regular water during this same time was also significantly increased. These results indicate that developmental NP treatment results in maternal and offspring toxicity as evidenced by decreased food intake and weight gain. However, behavioral alterations were evident only in increased intake of a sodium solution.

Animals↗