Effects of Riparian Buffer Vegetation and Width: A 12-Year Longitudinal Study

Agricultural contributions of nitrogen are a serious concern for many water resources and have spurred the implementation of riparian buffer zones to reduce groundwater nitrate (NO). The optimum design for buffers is subject to debate, and there are few long-term studies. The objective of this project was to determine the effectiveness over time (12 yr) of buffer types (trees, switchgrass, fescue, native, and a control) and buffer widths (8 and 15 m) by measuring groundwater NO-N and dissolved organic carbon (DOC) trends. At the intermediate groundwater depth (1.5-2.1 m), NO-N reduction effectiveness was 2.5 times greater (46 vs. 16%) for the wider buffer, and, regardless of width, buffer effectiveness increased 0.62% yr. Buffer vegetative type was never statistically significant. In the deep-groundwater depth (2.1-3.5 m), there was no change in NO-N removal over time, although the statistical interaction of width and vegetative type indicated a wide range of removal rates (19-82%). The DOC concentrations were analyzed at the field/buffer and buffer/stream sampling locations. Depending on location position and groundwater sampling depth, DOC concentrations ranged from 1.6 to 2.8 mg L at Year 0 and increased at a rate of 0.13 to 0.18 mg L yr but always remained low (≤5.0 mg L). Greater DOC concentrations in the intermediate-depth groundwater did not increase NO-N removal; redox measurements indicated intermittent reduced soil conditions may have been limiting. This study suggests that riparian buffer width, not vegetation, is more important for NO-N removal in the middle coastal plain of North Carolina for a newly established buffer.

Nonsteroidal progestins and antiprogestins related to flutamide

From the dual progestin/antiandrogenic properties of certain synthetic steroids (e.g. cyproterone acetate), it was apparent that the progesterone (P) and androgen (A) receptors must have some common ligand binding features. The nonsteroidal antiandrogen (aA) hydroxyflutamide was therefore considered a possible starting point for medicinal chemistry aimed at antiprogestin (aP) activity. Various modifications to the side chain and aryl ring substituents of flutamide yielded both P and aP activity, but always coupled with varying degrees of A or aA activity. Mineralocorticoid activity was present in some structures, but glucocorticoid and antiglucorticoid activities were not detected. Species (rat, rabbit and monkey) and chiral differences presented formidable difficulties in developing simple structure activity patterns, and low ( < 1%) in vitro uterine receptor binding belied in vivo potency of some aPs. One of the most active aPs, ZM172406, the R enantiomer of ZM150271, N-(3-chloro-4-cyanophenyl)-3,3, 3-trifluoro-2-hydroxy-2-methylpropanamide, had comparable oral potency to mifepristone in rats and monkeys. The racemate ZM150271 was an effective abortifacient during early pregnancy in pigtailed monkeys (3 x 10 mg/kg) but less effective in cynomolgus monkeys. One of the most active progestins (Pn), ZM182345, N-(4-nitro-3-trifluoromethylphenyl)-4-phenyl-2-hydroxy-2-trifluoromet hyl-pentanamide, was at least as potent as P in rats and rabbits but also possessed A activity.

ZD4190: an orally active inhibitor of vascular endothelial growth factor signaling with broad-spectrum antitumor efficacy

There is evidence that vascular endothelial growth factor (VEGF) contributes to solid tumor growth through the promotion of both angiogenesis and tumor vascular permeability. To abrogate VEGF signaling, we developed a small molecular weight inhibitor of VEGF receptor tyrosine kinase (RTK) activity that was compatible with chronic oral administration. ZD4190, a substituted 4-anilinoquinazoline, is a potent inhibitor of KDR and Flt-1 RTK activity, and VEGF stimulated HUVEC proliferation in vitro. Chronic once-daily oral dosing of ZD4190 to young rats produced a dose-dependent increase in the femoral epiphyseal growth plate area, which may be attributed to the inhibition of VEGF signaling in vivo because vascular invasion of cartilage is a prerequisite to the process of ossification. Once-daily oral dosing of ZD4190 to mice bearing established (approximately 0.5 cm3) human tumor xenografts (breast, lung, prostate, and ovarian) elicited significant antitumor activity and at doses that would not be expected to have any direct antiproliferative effect on tumor cells. Prolonged tumor cytostasis was further demonstrated in a PC-3 xenograft model with 10 weeks of ZD4190 dosing, and upon withdrawal of therapy, tumor growth resumed after a short delay. These observations are entirely consistent with the proposed mode of action. ZD4190 is one of a series of VEGF RTK inhibitors that may have utility in the treatment of a range of histologically diverse solid tumor types.

Design and structure-activity relationship of a new class of potent VEGF receptor tyrosine kinase inhibitors

A series of substituted 4-anilinoquinazolines and related compounds were synthesized as potential inhibitors of vascular endothelial growth factor (VEGF) receptor (Flt and KDR) tyrosine kinase activity. Enzyme screening indicated that a narrow structure-activity relationship (SAR) existed for the bicyclic ring system, with quinazolines, quinolines, and cinnolines having activity and with quinazolines and quinolines generally being preferred. Substitution of the aniline was investigated and clearly indicated that small lipophilic substituents such as halogens or methyl were preferred at the C-4' position. Small substituents such as hydrogen and fluorine are preferred at the C-2' position. Introduction of a hydroxyl group at the meta position of the aniline produced the most potent inhibitors of Flt and KDR tyrosine kinases activity with IC(50) values in the nanomolar range (e.g. 10, 12, 13, 16, and 18). Investigation of the quinazoline C-6 and C-7 positions indicates that a large range of substituents are tolerated at C-7, whereas variation at the C-6 is more restricted. At C-7, neutral, basic, and heteroaromatic side chains led to very potent compounds, as illustrated by the methoxyethoxy derivative 13 (IC(50) < 2 nM). Our inhibitors proved to be very selective inhibitors of Flt and KDR tyrosine kinase activity when compared to that associated with the FGF receptor (50- to 3800-fold). Observed enzyme profiles translated well with respect to potency and selectivity for inhibition of growth factor stimulated proliferation of human umbilical vein endothelial cells (HUVECs). Oral administration of selected compounds to mice produced total plasma levels 6 h after dosing of between 3 and 49 microM. In vivo efficacy was demonstrated in a rat uterine oedema assay where significant activity was achieved at 60 mg/kg with the meta hydroxy anilinoquinazoline 10. Inhibition of growth of human tumors in athymic mice has also been demonstrated: compound 34 inhibited the growth of established Calu-6 lung carcinoma xenograft by 75% (P < 0.001, one tailed t-test) following daily oral administration of 100 mg/kg for 21 days.

The relevance of preclinical models to the treatment of postmenopausal breast cancer

The predictive value of test results in animals when selecting a compound for potential therapeutic human use depends upon the relevance of the animal model to the human disease and the comparative pharmacokinetics of the compound in animals and man. The development of the aromatase inhibitor, anastrozole (Arimidex), illustrates the importance of these factors. In postmenopausal women with breast cancer, aromatase activity in the peripheral tissues is the main source of oestrogen for tumour growth. Only one form of the human enzyme is known, which is not subject to strong feedback control. Inhibition of aromatase therefore simply reduces oestrogen production. This situation is mimicked by assays of acute inhibition of ovulation in rats, chronic inhibition of androstenedione-induced uterine hypertrophy in sexually immature rats, and chronic inhibition of peripheral aromatase in monkeys. In all these assays, maximum anastrozole activity was consistently achieved at an oral dose of about 0.1 mg/kg, and the clearance half-life of 7-16 h indicated that once-daily dosing would be possible in humans. The clearance half-life in postmenopausal women is about 50 h, and with once-daily dosing the dose of anastrozole required for maximal inhibition is 1 mg/day. The rat 7,12-dimethylbenzanthracene tumour model, in contrast, is supported by ovarian oestrogen and chronic inhibition provokes positive feedback loops that try to restore oestrogen production, masculinise the animals and decrease the clearance half-life of anastrozole. Higher doses (10 mg/kg) of anastrozole are therefore needed. Variations in the dose of aromatase inhibitor required in different models, therefore, can be explained in terms of pharmacokinetics and do not reflect the effectiveness of anastrozole as an aromatase inhibitor.

The preclinical pharmacology of "Arimidex" (anastrozole; ZD1033)--a potent, selective aromatase inhibitor

Anastrozole is a comparatively simple, achiral benzyltriazole derivative, 2,2'-[5-(1H-1,2,4-triazol-1-ylmethyl)-1,3-phenylene]bis(2-++ +methylpropiononitrile), that inhibits human placental aromatase with an IC50 of 15 nM and elicits maximal activity in vivo in rats (inhibition of ovulation and androstenedione-induced uterine hypertrophy) and monkeys (lowering of plasma oestradiol) at 0.1 mg/kg p.o. At 30 times this dose, anastrozole does not elevate plasma 11-deoxycorticosterone in monkeys, and at 100 times this dose, does not affect plasma aldosterone levels or Na+/K+ excretion in rats, plasma K+ concentrations in dogs, or cause adrenal hypertrophy in rats or dogs. It therefore has no discernible effect on adrenocorticoid hormone synthesis in vivo at very large multiples of its maximally effective aromatase-inhibiting dose. At similar large multiples in rats it displays no oestrogenic, anti-oestrogenic, androgenic, anti-androgenic, progestogenic, glucocorticoid, antiglucocorticoid or mineralocorticoid activity. Anastrozole is thus a potent and highly selective aromatase inhibitor, with no intrinsic hormonal activities--a pharmacological profile particularly suitable for the treatment of breast cancer.

Effects of a non-steroidal pure antioestrogen, ZM 189,154, on oestrogen target organs of the rat including bones

ZM 189,154 ([1RS,2RS]-2-(4-hydroxyphenyl)-2-methyl- 1-[9-(4,4,5,5,5-penta-fluoropentyl)sulphinylnonyl]-1,2,3,4- tetrahydronaphth-6-ol) is a non-steroidal pure antioestrogen. It has a high relative affinity for the oestrogen receptor, completely blocks the trophic action of oestradiol (OE2) on the uterus in immature and ovariectomized (OVX) adult rats and, in the latter, also completely blocks the trophic action of OE2 on vagina, bone and growth rate. ZM 189,154 displays no intrinsic oestrogen-agonist activity on uterus, vagina, bone, LH secretion or growth rate in OVX rats. Differential sensitivity of OE2-regulated processes was more apparent in intact rats. Daily doses of 0.6 mg/kg per day of ZM 189,154 blocked ovulation; 2 mg/kg per day achieved maximal uterine atrophy but did not affect bone density or growth rate; 10 mg/kg per day produced a broader spectrum of effects (reduced bone density, increased basal LH, slightly increased growth rate), but the magnitude of these was smaller than after ovariectomy; the 10 mg/kg dose also produced multiple ovarian follicular cysts. The failure of ZM 189,154 to achieve complete ovariectomy-like effects in intact rats may be due to the action of ovarian factors other than OE2, or to the circulating OE2 levels resulting from the disturbance to ovarian function posing too strong a challenge to the antagonist.

Arimidex: a potent and selective fourth-generation aromatase inhibitor

Arimidex is a potent and selective aromatase inhibitor undergoing evaluation as a treatment for postmenopausal women with advanced breast cancer. Studies to determine the pharmacology of Arimidex were conducted in both animals and humans. In animals, Arimidex was selective for the aromatase enzyme, elicited maximal activity at about 0.1 mg/kg, did not interfere with steroid hormones produced by the adrenal glands, and, at a dose of 1 mg/kg, had no detectable pharmacologic activity other than aromatase inhibition. Absorption of ZD1033, the active component of Arimidex, was rapid and virtually complete after oral administration to animals. ZD1033 was extensively metabolized in animals after oral administration; the metabolites were excreted predominantly in urine. The pharmacodynamic, pharmacokinetic, and safety profiles of single and multiple daily doses of Arimidex were determined in humans. Doses of 1 to 10 mg of Arimidex suppressed estradiol to the maximum degree measurable. Arimidex had no clinically significant effects on key enzymes that regulate cortisol and aldosterone biosynthesis. Absorption of ZD1033 was rapid, with maximum plasma concentrations occurring within 2 hours after oral administration. Plasma concentrations of ZD1033 rose with increasing doses of Arimidex. The elimination half-life of ZD1033 in humans ranged from 30 to 60 hours. Urinary excretion accounted for a small percentage of each dose. A 3- to 4-fold accumulation of ZD1033 in plasma occurred after daily administration of 3-, 5-, or 10-mg doses. Arimidex was well tolerated. Phase III studies are under way to determine the efficacy and safety of Arimidex in postmenopausal women with advanced breast cancer.

Antiuterotrophic effects of the pure antioestrogen ICI 182,780 in adult female monkeys (Macaca nemestrina): quantitative magnetic resonance imaging

The antiuterotrophic efficacy of the pure antioestrogen ICI 182,780 has been demonstrated previously by magnetic resonance imaging (MRI) in ovariectomized oestrogen-treated monkeys (Macaca nemestrina). Further characterization of the effects of ICI 182,780 in intact adult female monkeys with normal menstrual cycles was undertaken to provide an indication of its potential actions in premenopausal women. Changes in the volume of uterine tissues were measured by MRI in early, mid and late cycle. The volume of the uterus varied up to fivefold between individual monkeys but serial observations in individuals provided sufficient precision to allow accurate assessments to be made of changes in the endometrium and myometrium during the course of the menstrual cycle and following ICI 182,780 administration. In comparison with its initial size in untreated monkeys, the endometrium increased in volume by 60% and 125% in the mid and late cycle respectively. In contrast, the size of the myometrium decreased significantly, by 16% from early to mid cycle and then recovered to near its initial volume in the late cycle. Treatment with ICI 182,780 beginning in the early part of the menstrual cycle prevented the growth of the uterus. The magnitude and duration of the response was dependent on whether or not ovulation occurred during treatment with ICI 182,780. In animals rendered anovulatory, growth of the endometrium was blocked completely by ICI 182,780 and the volume of the tissue declined below that present at the start of the menstrual cycle. Antiuterotrophic efficacy was significantly less in monkeys which ovulated during treatment with ICI 182,780.(ABSTRACT TRUNCATED AT 250 WORDS)

Antiuterotrophic effects of a pure antioestrogen, ICI 182,780: magnetic resonance imaging of the uterus in ovariectomized monkeys

ICI 182,780 is a potent specific pure antioestrogen which may offer advantages in breast cancer treatment compared with partial agonists like tamoxifen. To characterize further the potency and efficacy of ICI 182,780, its effects on the uterus of ovariectomized, oestrogen-treated monkeys (Macaca nemestrina) have been measured using magnetic resonance imaging (MRI). Quantitative MRI allows accurate non-invasive repetitive measurements of endometrial and myometrial volume following hormonal treatments, using each animal as its own control. Single i.m. injections of a long-acting oil-based formulation of ICI 182,780 sustained blockade of oestradiol action on the monkey uterus in a dose-dependent manner for 3-6 weeks. Repeated injections of 4 mg ICI 182,780/kg at 4-weekly intervals provided increasingly effective blockade of uterine proliferation. In a short-acting formulation, ICI 182,780 also completely blocked the trophic action of oestradiol, administered concurrently, in ovariectomized monkeys. Similarly, ICI 182,780 caused involution of the uterus stimulated by prior treatment with oestradiol. The rate and extent of uterine involution in monkeys treated with ICI 182,780 was similar to that seen following oestrogen withdrawal. These studies demonstrate that ICI 182,780 is a fully effective pure antioestrogen in a primate.

A case of endometriosis in the macaque diagnosed by nuclear magnetic resonance imaging

A case of spontaneous endometriosis was diagnosed in the pigtailed macaque (Macaca nemestrina nemestrina) with the aid of high-field (2.35 T), T2-weighted (TE50), C1H2-suppressed, oblique nuclear magnetic resonance imaging (MRI). Postmortem histology was obtained. A variety of endometriotic lesions was seen with MRI, including extrauterine hyperintense apparently cystic regions, extrauterine hypointense regions apparently associated with intracellular paramagnetic iron proteins, and an enlarged myometrium exhibiting adenomyosis foci.

A potent specific pure antiestrogen with clinical potential

Previous studies from this laboratory have described a series of 7 alpha-alkylamide analogues of estradiol with pure antiestrogenic activity, exemplified by ICI 164,384. A new compound, 7 alpha-[9-(4,4,5,5,5-pentafluoropentylsulfinyl)nonyl]estra-1,3,5(10 )- triene-3,17 beta-diol (ICI 182,780) has now been identified which has significantly increased antiestrogenic potency and retains pure estrogen antagonist activity. The antiuterotrophic potency of ICI 182,780 in the immature rat was more than 10-fold greater than that of ICI 164,384 (50% effective doses of 0.06 and 0.9 mg/kg, respectively). This order of magnitude increase of in vivo potency was also reflected, in part, by intrinsic activity at the estrogen receptor. The relative binding affinities of ICI 182,780 and ICI 164,384 were 0.89 and 0.19, respectively, compared with that of estradiol (1.0). Similarly, the in vitro growth-inhibitory potency of ICI 182,780 exceeded that of ICI 164,384 in MCF-7 human breast cancer cells, where 50% inhibitory concentrations of 0.29 and 1.3 nM, respectively, were recorded. ICI 182,780 was a more effective inhibitor of MCF-7 growth than 4'-hydroxytamoxifen, producing an 80% reduction of cell number under conditions where 4'-hydroxytamoxifen achieved a maximum of 50% inhibition. This increased efficacy was reflected by a greater reduction of the proportion of cells engaged in DNA synthesis in ICI 182,780-treated cell cultures compared with tamoxifen-treated cells. Sustained antiestrogenic effects, following a single parenteral dose of ICI 182,780 in oil suspension, were apparent in both rats and pigtail monkeys. In vivo, antitumor activity of ICI 182,780 was demonstrated with xenografts of MCF-7 and Br10 human breast cancers in nude mice. A single injection of ICI 182,780 provided antitumor efficacy equivalent to that of daily tamoxifen treatment for at least 4 weeks. The properties of ICI 182,780 identify this pure antiestrogen as a prime candidate with which to evaluate the potential therapeutic benefits of complete estrogen withdrawal in endocrine-responsive human breast cancer.

Oblique NMR imaging of the uterus in macaques: uterine response to estrogen stimulation

We report methods for quantitative NMR imaging of the primate uterus and the application of these methods of measuring the response of the monkey (Macaca nemestrina) uterus (endometrial volume, myometrial volume, T2 values, myometrial junction zone) to estrogen stimulation. High-field (2.35 T), fat-suppressed, T2-weighted (TE50) oblique methods were used. Slice thickness, location, and angle were varied on each examination to obtain six contiguous slices between the cervix and fundus, regardless of size or orientation of the uterus. Basal endometrial and myometrial volumes were 0.05 +/- 0.01 cm3 and 1.31 +/- 0.23 cm3 in chronically ovariectomized animals. These increased by 15.7 +/- 3.6-fold and 3.1 +/- 0.4-fold, respectively, during 7 days of estrogen stimulation (estradiol benzoate, 5 micrograms/kg sc daily) while myometrial T2 increased from 52 +/- 1 to 67 +/- 4 ms. These changes reversed following menstrual bleeding.

Comparison of the action of nonoxynol-9 and chlorhexidine on sperm

The effect on sperm motility of nonoxynol-9 chlorhexidine diacetate was compared in semen and cervical mucus. Both compounds had similar spermicidal potency in semen, abolishing sperm motility within 3 minutes at 0.5 mg/ml. When these compounds were allowed to diffuse into mucus, the subsequent survival of sperm in the mucus was different. Restricted penetration and loss of motility occurred rapidly after treatment with 0.1 mg/ml chlorhexidine, whereas sperm survived normally in mucus after prolonged contact with 200 mg/ml chlorhexidine. When the compounds were mixed directly with the mucus before sperm penetration was attempted, chlorhexidine still immobilized sperm, but concentrations of nonoxynol-9 that would be spermicidal in semen had no effect in mucus.

Fluprostenol-induced softening of the cervix of the pregnant rat

Fluprostenol, an analogue of prostaglandin F2 alpha, administered s.c. to rats on day 18 of pregnancy increased cervical creep, or softness, by the following day. Doses of fluprostenol 100-fold larger were necessary to increase uterine contractions. Fluprostenol produced falls in serum progesterone concentrations, increases in 20 alpha-dihydroprogesterone concentrations, no changes in oestradiol or relaxin concentrations and a reduction in the ovarian human chorionic gonadotrophin binding capacity in vitro. Fluprostenol was less potent in inducing cervical softness when administered per vaginam, and a dose which produced softening in pregnant rats was ineffective in ovariectomized steroid-maintained pregnant or pro-oestrous rats. The findings suggest that cervical softening by fluprostenol does not result from a simple direct action on the cervix or by increasing uterine contractions, but rather by an indirect hormonal action mediated by the ovaries. The results with the lowest dose of fluprostenol indicate that cervical softening could be produced without a sustained fall in serum progesterone concentrations. Fluprostenol is much more potent at increasing cervical softness in the pregnant rat than prostaglandin F2 alpha or prostaglandin E2. With fluprostenol the ratio of dose to induce uterine contractility relative to that to produce cervical softness was greater than with these natural prostaglandins, indicating the greater selectivity of fluprostenol in the pregnant rat.

Haemoglobin Hijiyama: a haemoglobin variant found in connection with glycosylated haemoglobin estimation in a Finnish diabetic boy

A variant of haemoglobin A, named earlier haemoglobin Hijiyama, was found in three generations of a Finnish family in connection with the determination of glycosylated haemoglobin of a diabetic patient. The biochemical abnormality is in the beta-chain at residue 120 where lysine is replaced by glutamic acid. In the heterozygote carriers of the abnormal haemoglobin there was no apparent association with clinical or haematological abnormalities. By isoelectric focusing in thin-layer polyacrylamide gels, haemoglobin Hijiyama could be distinguished with high specificity from haemoglobin A as well as from other haemoglobin variants earlier found in Finland. The glycosylated haemoglobin fractions (haemoglobin A1 and haemoglobin Hijiyama 1) in the diabetic patient sample could be determined by colorimetric and electrophoretic methods.

Changes of gap junctions in myometrium of guinea pig at parturition and abortion

Myometrial tissues from guinea pigs were quantitatively examined for gap junctions in electron micrographs. Small numbers of gap junctions were present between smooth muscle cells in myometria of pregnant guinea pigs at days 50 and 65 of gestation. The junctions increased in number and size at parturition on day 69 and decreased again to control levels 24 h after parturition. A similar increase in junctions occurred when abortion was induced by 16,16-dimethylprostaglandin E2 (PGE2) on day 65. There were no consistent or significant differences in number of gap junctions from myometrium taken over sites of placental attachment and from other sites. These results together with previous studies suggest that an increase in myometrial gap junction area is associated with and may be essential for parturition in guinea pigs, but the control of their development may differ from that in other mammals.

Dissociation of oocyte maturation and ovulation in mice pretreated with a derivative of dihydropyridazinone

Treatment of mice with a dihydropyridazinone derivative (6-(4'-aminophenyl)-4,5-dihydro-5-methylpyridazin-3-one; ICI 109,081) inhibited the maturation of oocytes in the presence of gonadotrophins without affecting ovulation. The spontaneous resumption of meiosis in oocytes cultured in vitro was reversibly inhibited. ICI 109,081 may therefore be useful for evaluating the relationship between follicular development and the resumption of meiosis.

A luteolytic effect of a prostaglandin F2 alpha analogue in non-pregnant women?

Four healthy non-pregnant volunteers with regular cycles were exposed to vaginal suppositories containing a PGF2 alpha analogue (ICI 81.008, 500-600 microgram) twice at 24-hour intervals in the early or mid-luteal phase. In comparison to serum progesterone levels of ovulatory control cycles, this treatment caused a significant decrease of serum progesterone combined with a shortening of the length of the luteal phase by 1.4 days. No gastrointestinal or other adverse effects were noticed during this treatment. Administration of ICI 81.008 in the follicular phase interfered neither with ovulation nor with the length or shape of the following luteal phase. Although limited, these data suggest a luteolytic effect of ICI 81.008 in women.