CD BR Research Articles

Synthesis and spectral studies of cadmium(II) complexes derived from di-2-pyridyl ketone and N4-phenylsemicarbazide: First structural report of a cadmium(II) complex of semicarbazone

A new semicarbazone (HL) based on di-2-pyridyl ketone and its three cadmium(II) complexes [CdL(CH 3COO)] 2 · 2CH 3OH ( 1), Cd(HL)Br 2 ( 2) and [Cd 2L 2N 3] 2 · H 2O ( 3) were synthesized and characterized by different physicochemical techniques. The complex, [CdL(CH 3COO)] 2 · 2CH 3OH ( 1) is having a dimeric structure. In complexes 1 and 3, the ligand moieties are coordinated as monoanionic (L −) forms and in complex 2, the ligand is coordinated as neutral (HL) one. The coordination geometry around cadmium(II) in 1 is distorted octahedral, as obtained by X-ray diffraction studies.

Syntheses, Structures and Luminescent Properties of Metal Complexes with Imidazole‐Containing Polyamine Ligand

AbstractFour novel metal complexes [Cd(L)Cl](BF4)·H2O (1), [Cd(L)Br]2[CdBr4]·2H2O (2), [Cu(L)Br]Br (3), and [Cu(L)](NO3)2 (4) were prepared by the reactions of ligand N1‐(2‐aminoethyl)‐N1‐(2‐imidazolethyl)‐ethane‐1,2‐diamine (L) with metal salts under different reaction conditions. All of these complexes exhibit 1D chains, but different structures. The results showed that the pH value of the reaction solution and counter ions have remarkable impact on the structure of the complexes. Furthermore, complexes 1 and 2 represent fluorescence properties in the solid state at room temperature.

High-resolution slice imaging of quantum state-to-state photodissociation of methyl bromide

The photodissociation of rotationally state-selected methyl bromide is studied in the wavelength region between 213 and 235 nm using slice imaging. A hexapole state selector is used to focus a single (JK=11) rotational quantum state of the parent molecule, and a high speed slice imaging detector measures directly the three-dimensional recoil distribution of the methyl fragment. Experiments were performed on both normal (CH(3)Br) and deuterated (CD(3)Br) parent molecules. The velocity distribution of the methyl fragment shows a rich structure, especially for the CD(3) photofragment, assigned to the formation of vibrationally excited methyl fragments in the nu(1) and nu(4) vibrational modes. The CH(3) fragment formed with ground state Br((2)P(3/2)) is observed to be rotationally more excited, by some 230-340 cm(-1), compared to the methyl fragment formed with spin-orbit excited Br((2)P(1/2)). Branching ratios and angular distributions are obtained for various methyl product states and they are observed to vary with photodissociation energy. The nonadiabatic transition probability for the (3)Q(0+)-->(1)Q(1) transition is calculated from the images and differences between the isotopes are observed. Comparison with previous non-state-selected experiments indicates an enhanced nonadiabatic transition probability for state-selected K=1 methyl bromide parent molecules. From the state-to-state photodissociation experiments the dissociationenergy for both isotopes was determined, D(0)(CH(3)Br)=23 400+/-133 cm(-1) and D(0)(CD(3)Br)=23 827+/-94 cm(-1).

A critical evaluation of homo- and hetero-leptic cadmium complexes using bond valence sums

The effect of the donor atoms in Cd complexes on the determination of R0 values for the bond valence sum (BVS) is reported. A total of 1321 CdXmYn fragments with X and Y = O, N, S, Cl, Br, and I were used to calculate the R0 values for Cd—X bonds from both homoleptic and heteroleptic fragments. The R0 values determined from mixed CdXmYn fragments agree with those determined from the homoleptic species, with no significant differences in the values as a function of either electronegativity or hard–soft character of the atoms. The new R0 values derived from the homoleptic series recommended for use in calculating the BVS are as follows: Cd(II)—O of 1.875(13) Å, Cd(II)—N of 1.951(15) Å, Cd(II)—S of 2.279(7) Å, Cd(II)—Cl of 2.216(17) Å, Cd(II)—Br of 2.334(7) Å, and Cd(II)—I of 2.525(7) Å. These R0 values can be used to calculate the oxidation state of Cd in complexes where Cd is bonded to any combination of O, N, S, Cl, Br, and I donor atoms. Cases where the BVS does not agree with the expected oxidation state are discussed. In particular, the planarity of Cd porphyrins is discussed in terms of the BVS.Key words: bond valence sums, cadmium complexes, cadmium porphyrins, cadmium distances.

An oral carcinogenicity and toxicity study of senna (Tinnevelly senna fruits) in the rat

Senna (Tinnevelly senna fruits), a known laxative derived from plants, was administered by gavage to Sprague-Dawley (Crl:CD (SD) BR) rats once daily at dose levels of 0, 25, 100 and 300 mg/kg/day for up to 104 consecutive weeks. Based upon clinical signs related to the laxation effect of senna, the highest dose (300 mg/kg/day) was considered to be a maximum tolerated dose. Sixty animals per sex were assigned to the control and dose groups. Assessments included clinical chemistry, hematology, full histology (control and high-dose groups; in addition, low and mid dose: intestinal tract, adrenals, liver, kidneys, brain and gross lesions) and toxicokinetics. The primary treatment-related clinical observation was mucoid feces seen at 300 mg/kg/day. When compared to controls, animals administered 300 mg/kg/day had slightly reduced body weights, increased water consumption and notable changes in electrolytes in serum (increases in potassium and chloride) and urine (decreases in sodium, potassium and chloride). The changes in electrolytes are most likely physiologic adaptations to the laxative effect of senna. At necropsy, dark discoloration of the kidneys was observed in animals in all treated groups. Histological changes were seen in the kidneys of animals from all treated groups and included slight to moderate tubular basophilia and tubular pigment deposits. In addition, for all treated groups, minimal to slight hyperplasia was evident in the colon and cecum. These histological changes, together with the changes seen in the evaluation of clinical chemistry and urine parameters, have been shown to be reversible in a previous 13-week rat study of senna. No treatment-related neoplastic changes were observed in any of the examined organs. Based upon these data, it is concluded that senna is not carcinogenic even after daily administration for 2 years at dosages of up to 300 mg/kg/day in Sprague-Dawley rats.

Vibrational spectra of phthalazine by density functional theory calculations and assignment of its metal complexes

The molecular geometry and vibrational frequencies of phthalazine (=Ph) in the ground state have been calculated by using density functional methods (B3LYP and BLYP and B3PW91) with 6-31G (d) as the basis set. The optimized geometric parameters obtained by using DFT/6-31G (d) basis set show the best agreement with the experimental values. Comparison of the observed fundamental vibrational frequencies of phthalazine and calculated results by density functional methods indicates that these methods give good results for molecular vibrational problems. Complexes of the type Zn (ph) 2 Cl 2, Zn (ph) 2 Br 2, Cd (ph) Br 2 and Co (ph) Cl 2 have been studied 4000–400 cm −1 region and assignment of all the observed bands were made. The analysis of the infrared spectra indicates that there are some structure-spectra correlations.

Toxicological profile of hydrofluoropolyethers

Hydrofluoropolyethers (HFPE) are a family of linear oligomeric fluorinated fluids comprising a chain of difluoromethoxy and tetrafluoroethoxy repeating units with terminal OCF 2H end groups, each of which contains an isolated hydrogen atom. These fluids have been designed as low environmental impact substitutes for perfluorinated organic substances in a number of applications including heat transfer and fire suppression agents, and as a solvent. The toxicological profile of these new fluids has been evaluated and is presented in this paper. Acute toxicity tests have been performed on Sprague–Dawley Crl: CD (SD) BR rats using oral, dermal, and inhalation routes. No deaths were recorded even at the highest tested concentrations, and the resultant LD 50/LC 50 values were >5000 mg/kg (oral), >2000 mg/kg (dermal), and >26,411 ppm (inhalation: reversible anaesthetic effects, e.g., lethargy, seen at this exposure concentration). Other short-term tests (skin and eye irritation, skin sensitisation, genotoxicity tests in vitro and in vivo, cardiac sensitisation) were also performed, and no hazardous properties were identified. Effects of repeated exposure by inhalation were examined in rats over test periods of 5, 14, 28, and 90 days. Effects on embryo–foetal development in the rat have also been studied. The 28-day, 90-day and developmental studies were performed using nominal HFPE concentrations of 1000, 3300, and 10,000 ppm (6 h/day: actual exposures confirmed by test atmosphere analysis), and the highest tested concentration proved to be an NOAEL in each study. Major observed effects were elevated urinary (inorganic) fluoride levels and increased liver weights with centrilobular hepatocyte hypertrophy (considered an adaptive response, linked to hepatic metabolism of absorbed material).

Spectral and structural studies of Zn and Cd complexes of 2-pyridineformamide N(4)-ethylthiosemicarbazone

Reduction of 2-cyanopyridine in the presence of N(4)-ethylthiosemicarbazide produces 2-pyridineformamide N(4)-ethylthiosemicarbazone, HAm4E. Complexes with various zinc(II) and cadmium(II) salts have been prepared and characterized using physical and spectral methods. In addition, the crystal and molecular structure of [Zn(Am4E)(OAc)] 2 ( 1), [Zn(HAm4E)I 2] ( 4a), [Cd(Am4E) 2] ( 5a), [Cd(HAm4E)Br 2] · DMSO ( 7a) and [Cd(HAm4E)I 2] · DMSO ( 8a) have been obtained. Coordination is via the pyridyl nitrogen, imine nitrogen and thione or thiolato sulfur when coordinating as the neutral and anionic ligand, respectively. [Zn(Am4E)(OAc)] 2 is the first example of a binuclear complex with a 2-pyridineformamide thiosemicarbazonato ligand in which the two acetate bridging groups are equivalent resulting in a center of symmetry.

Male reproductive tract lesions at 6, 12, and 18 months of age following in utero exposure to di(n-butyl) phthalate.

In utero exposure of male rats to the antiandrogen di(n-butyl) phthalate (DBP) leads to decreased anogenital distance (AGD) on postnatal day (PND) 1, increased areolae retention on PND 13, malformations in the male reproductive tract, and histologic testicular lesions including marked seminiferous epithelial degeneration and a low incidence of Leydig cell (LC) adenomas on PND 90. One objective of this study was to determine the incidence and persistence of decreased AGD, increased areolae retention, and LC adenomas in adult rats following in utero DBP exposure. A second objective was to determine whether AGD and areolae retention during the early postnatal period are associated with lesions in the male reproductive tract. Pregnant Crl:CD(SD)BR rats were gavaged with corn oil or DBP at 100 or 500 mg/kg/day, 10 dams per group. Three replicates of rats (n = 30 rats per replicate) were exposed from gestation day 12 to 21 and the male offspring allowed to mature to 6, 12, or 18 months of age. Gross malformations in the male reproductive tract and histologic lesions in the testes were similar to those previously described. However, testicular dysgenesis, a lesion of proliferating LCs and aberrant tubules that has not been previously described in DBP-exposed testes, was diagnosed. The incidence of this lesion was approximately 20% unilateral and 7-18% bilateral in the high-dose group and was similar among all ages examined, implicating a developmental alteration rather than an age-related change. AGD and areolae retention were found to be permanent changes following in utero exposure to 500 mg/kg/day of DBP. Decreased AGD was a sensitive predictor of lesions in the male reproductive tract, relatively small changes in AGD were associated with a significant incidence of male reproductive malformations. In utero DBP exposure induced proliferative developmental lesions, some of which would have been diagnosed as LC adenomas by the morphological criteria set forth by the Society of Toxicologic Pathology. However, these lesions were dissimilar to traditional LC adenomas as the LCs were poorly differentiated and the lesions contained aberrant seminiferous tubules. While the morphology and incidence of this DBP-induced testicular developmental lesion has been fully characterized by this study, the detailed pathogenesis warrants further investigation.

Effects of in utero exposure to finasteride on androgen-dependent reproductive development in the male rat.

Finasteride is a specific inhibitor of type II 5alpha-reductase, the enzyme that converts testosterone (T) to the more potent androgen receptor agonist dihydrotestosterone (DHT). In utero exposure to androgen receptor antagonists and T biosynthesis inhibitors have induced permanent effects on androgen-sensitive end points such as anogenital distance (AGD), nipple retention, and malformations of the male rat reproductive tract. The objectives of this study were to (1) characterize the dose response of finasteride-mediated alterations in androgen-dependent developmental end points, (2) determine whether prenatal exposure to finasteride permanently decreases AGD or results in nipple retention, and (3) evaluate whether AGD or nipple retention is predictive of adverse alterations in the male reproductive tract. Pregnant Crl:CD(SD)BR rats (n=5-6/group) were gavaged with either vehicle or finasteride at 0.01, 0.1, 1.0, 10, or 100 mg/kg/day on gestation days 12 to 21. All male offspring were monitored individually until necropsy on postnatal day (PND) 90. The present study design has been used previously for other antiandrogens and is sensitive to perturbations of the male rat reproductive tract. Decreases in AGD on PND 1 and increases in areolae-nipple retention on PND 13 were significantly different from controls in all finasteride-exposed male rats. Finasteride-induced changes in AGD and nipple retention were permanent in male rats exposed to finasteride at and above 0.1 mg/kg/day. On PND 90, dorsolateral and ventral prostate lobes were absent in 21 to 24% of rats exposed to 100 mg/kg/day finasteride and weighed significantly less at and above 10 mg/kg/day. In the highest dose group, 73% of animals had ectopic testes, much higher than previously reported. The most sensitive malformation other than decreased AGD and nipple retention was the dose-dependent increase in hypospadias. The lowest observed adverse effect level (LOAEL) for finasteride-induced permanent effects in this study was 0.1 mg/kg/day based on permanent changes in AGD and nipple retention. Finasteride-induced changes in AGD and retention of nipples were highly predictive of hypospadias, ectopic testes, and prostate malformations even though some animals with retained nipples or decreased AGD may not have had other reproductive tract malformations. In summary, prenatal exposure to finasteride specifically inhibited DHT-mediated development with little to no change in T-mediated development.

Quantitative changes in gene expression in fetal rat testes following exposure to di(n-butyl) phthalate.

Di(n-butyl) phthalate (DBP) alters male reproductive development by decreasing testicular testosterone (T) production when fetuses are exposed on gestation days (GD) 12-21. Previous studies have shown altered gene expression for enzymes in the T biosynthetic pathway following exposure to DBP. The objectives of this study were to develop a more detailed understanding of the effect of DBP on steroidogenesis, using a robust study design with increased numbers of dams and fetuses, compared with previous studies, and to explore messenger RNA (mRNA) expression for other critical genes involved in androgen biosynthesis and signaling. Additionally, immunohistochemical localization of protein expression for several key genes was performed to further confirm mRNA changes. Fetal Leydig cell lipid levels were also examined histochemically, using oil red O. Six to seven pregnant Crl:CD(SD)BR rats per group were gavaged with corn oil or DBP at 500 mg/kg/day on GD 12-19. Testicular RNA isolated from three randomly selected GD 19 fetuses per litter was used for real-time RT-PCR for the following genes: scavenger receptor class B-1 (SRB1), steroidogenic acute regulatory protein (StAR), P450 side-chain cleavage enzyme (P450scc), 3beta-hydroxysteroid dehydrogenase (3beta-HSD), P450c17, 17beta-hydroxysteroid dehydrogenase (17beta-HSD), androgen receptor (AR), luteinizing hormone receptor (LHR), follicle-stimulating hormone receptor (FSHR), stem cell factor tyrosine kinase receptor (c-kit), stem cell factor (SCF), proliferating cell nuclear antigen (PCNA), and testosterone-repressed prostate message-2 (TRPM-2). mRNA expression was downregulated for SRB1, StAR, P450scc, 3beta-HSD, P450c17, and c-kit following DBP exposure, and TRPM-2 was upregulated. 17beta-HSD, AR, LHR, FSHR, and PCNA were not significantly changed. Immunohistochemical staining for c-kit was seen in fetal Leydig cells, which has not been previously reported. Downregulation of most of the genes in the T biosynthetic pathway confirms and extends previous findings. Diminished Leydig cell lipid content and alteration of cholesterol transport genes also support altered cholesterol metabolism and transport as a potential mechanism for decreased T synthesis following exposure to DBP.

Effects of in utero exposure to the organophosphate insecticide fenitrothion on androgen-dependent reproductive development in the Crl:CD(SD)BR rat.

Fenitrothion [0,0-dimethyl-O-(4-nitro-m-tolyl) phosphorothioate] is an organophosphate insecticide that has been shown to have antiandrogenic activity using in vitro and in vivo screening assays. Studies were performed to evaluate the ability of fenitrothion to disrupt androgen-dependent sexual differentiation in the male rat. Pregnant Crl:CD(SD)BR rats were administered fenitrothion by gavage at 0, 5, 10, 15, 20, or 25 mg/kg/day ( n = 6-11/group) from gestation day (GD) 12 to 21. Maternal toxicity was observed in the dams treated with 20 and 25 mg fenitrothion/kg/day based on muscle tremors and decreases in body weight gain from GD 12 to 21. Fetal death was increased in the 20 and 25 mg/kg/day exposure groups, as evidenced by a decrease in the proportion of pups born alive. Androgen-mediated development of the reproductive tract was altered in male offspring exposed in utero to maternally toxic levels of fenitrothion (25 mg/kg/day), as evidenced by reduction in anogenital distance on postnatal day (PND) 1 and retention of areolae on PND 13. However, these effects were only transient, and there were no indications of abnormal phenotypes or development of androgen-dependent tissues on PND 100. At the dose levels evaluated in this study, fenitrothion was only weakly antiandrogenic in vivo compared with other androgen receptor antagonists such as flutamide, linuron, and vinclozolin. Based on observed fetotoxicity at 20 mg/kg/day, the lowest observed adverse effect level (LOAEL) for developmental effects can be lowered from 25 to 20 mg/kg/day.

Coordination of ZnII, CdII, and HgII by 2-Pyridineformamide-3-piperidyl-thiosemicarbazone

Sodium in dry methanol reduces 2-cyanopyridine in the presence of 3-piperidylthiosemicarbazide and produces 2-pyridine-formamide-3-piperidylthiosemicarbazone, HAmpip. Complexes with zinc(II), cadmium(II), and mercury(II) have been prepared and characterized by elemental analyses and spectroscopic techniques. In addition, the crystal structures of [Zn(Ampip) 2], [Zn(Ampip)(Oac)] 2, [Cd(HAmpip)Cl 2]·(CH 3) 2SO, [Cd(HAmpip)Br 2]·(CH 3) 2SO, [Cd(HAmpip)I 2]·(CH 3) 2SO, [Cd(Ampip) 2] and [Hg(HAmpip)Br 2]·(CH 3) 2SO have been solved. Coordination of the anionic and neutral thiosemicarbazone ligand is via the pyridyl nitrogen, imine nitrogen and thiolato/thione sulfur atom, respectively. In [Zn(Ampip)(OAc)] 2 one of the bridging acetato ligands has monodentate coordination and the other bridges in a bidentate manner. 113Cd NMR studies were carried out on the [Cd(HAmpip)X 2] (X = Cl, Br or I) and [Cd(Ampip)(OAc)] 2 complexes. The 113Cd chemical shifts are affected by the halogen and range from 411 to 301 ppm, and the spectrum of [Cd(Ampip)(OAc)] 2 shows two signals at 450 and 251 ppm. The 199Hg NMR spectrum of [Hg(HAmpip)Cl 2] also is discussed.

A study of the developmental toxicity potential of pentachlorophenol in the rat.

Pentachlorophenol (penta, CAS #87-86-5) is primarily used as a wood preservative. As part of the USEPA pesticide reregistration process, the developmental toxicity (embryo-fetal toxicity and teratogenic potential) of commercially available penta was studied following oral gavage to presumed pregnant female Sprague-Dawley rats (Crl:CD BR VAF/Plus Subdivision F, 83-3). Both study design and penta purity met the requirements of the USEPA. Doses of 0 (corn oil), 10, 30, and 80 mg/kg/day were administered to the rats at concentrations of 0, 2, 6, and 16 mg/ml, respectively from day 6 to day 15 of presumed gestation. The dosage volume was 5 ml/kg, adjusted on each day of dosage based on individual body weights recorded immediately before intubation. The rats were sacrificed on day 20 of presumed gestation and necropsied. The number of corpora lutea in each ovary was recorded. The uterus was examined for pregnancy, number and distribution of implantations, early and late resorptions and live and dead fetuses. Each fetus was weighed, sexed, and examined for gross external, soft tissue and skeletal alterations. The no-observable-adverse-effect-level (NOAEL) for maternal toxicity in rats was determined to be 30 mg/kg/day of penta. The developmental NOAEL for penta in rats was also found to be 30 mg/kg/day. The lowest-observable-adverse-effect-level (LOAEL) for penta developmental toxicity (80 mg/kg/day) was associated with increased resorptions, reduced live litter size and fetal body weights, and caused increased malformations and variations. These NOAELs, derived using USEPA approved study designs, are higher than those previously reported using penta that is no longer commercially available in studies with non-approved experimental designs. Penta should not be identified as a selective developmental toxicant in the rat because adverse effects on development of rat conceptuses occurred only at maternally toxic dosages.

Induction of hepatic microsomal drug-metabolizing enzymes by inhibitors of 5-lipoxygenase (5-LO): studies in rats and 5-LO knockout mice.

The effect of 5-lipoxygenase (5-LO) inhibitors on the hepatic microsomal mixed-function oxidase (MFO) system of rodents was investigated. After establishing the relative in vitro and in vivo potencies of the 3 test compounds, male Crl:CD (SD) BR rats received CJ-11,802 (0, 10, 50, or 200 mg/kg/day), zileuton (0, 10, 60, or 300 mg/kg/day) or ZD2138 (0 or 200 mg/kg/day) once daily by oral gavage for 14 (zileuton and ZD2138) or 30 (CJ-11,802) consecutive days. Controls were given an equivalent volume of 0.5% methylcellulose vehicle. At necropsy, all livers were weighed, and sections from representative animals (control and highest dose for each compound) were utilized to prepare hepatic microsomal fractions, which were assayed for cytochrome P-450 (CYP) content and the activities of cytochrome c reductase (CRed), para-nitroanisole O-demethylase (p-NOD), ethoxyresorufin O-deethylase (EROD), and pentoxyresorufin O-dealkylase (PROD). A dose-related increase in liver weight occurred in rats given CJ-11,802 and zileuton, while animals administered ZD2138 were unaffected. Rats given CJ-11,802 (200 mg/kg/day) and zileuton (300 mg/kg/day) had increases in CYP, EROD, PROD, CRed and p-NOD compared to corresponding controls, while only the latter two activities were elevated in animals administered ZD2138. To determine if induction of the hepatic microsomal MFO system was related to 5-LO inhibition, male DBA wild-type and 5-LO knockout mice were administered either CJ-11,802 (200 mg/kg/day) or vehicle by oral gavage for 14 consecutive days. At necropsy, liver weight, CYP content, and CRed activity were measured and all were increased similarly in the treated wild-type and knockout mice compared to corresponding controls, indicating that induction was not related to inhibiting 5-LO.

Synthesis and characterization of Zn(II) and Cd(II) complexes of S-benzyl-β- N-(2-pyridyl)methylenedithiocarbazate (HNNS): bioactivity of the HNNS Schiff base and its Zn(II), Cu(II) and Cd(II) complexes and the X-ray structure of the [Zn(NNS) 2] complex

A tridentate Schiff base having HNNS donor sequence was prepared by condensing S-benzyldithiocarbazate (NH 2NHCSSCH 2Ph) with pyridine-2-carboxaldehyde. Complexes of this ligand, pyCHNNHCSSCH 2Ph(HNNS), with Cu(II), Cd(II) and Zn(II) were synthesized and characterized by elemental analyses and various physico-chemical techniques. X-ray crystallographic analysis shows that the Zn(II) complex, [Zn(NNS) 2], is six-coordinate and has a distorted octahedral structure with the ligand coordinated to the Zn(II) ion as a uninegatively charged tridentate chelating agent via the pyridine nitrogen, the azomethine nitrogen and the mercaptide sulfur atoms. Distortions from the regular octahedral geometry are attributed to the restricted bite angles of the planar NNS tridentate ligand. The Cu(II) complex, [Cu(NNS)Cl], was paramagnetic with a square-planar stereochemistry while the Cd(II) complex, [Cd(NNS)Br], was diamagnetic and is suggested to have a tetrahedral structure. The Schiff base and its complexes were screened for antimicrobial, cytotoxic and antioxidant activities. Disc diffusion methods were employed for antimicrobial assays against eight pathogenic microorganisms. The Schiff base and the complexes do not display activities against any of the microorganisms. The Schiff base was cytotoxic with a CD 50 value of 5.90 μg ml −1 against the T-lymphoblastic leukemic cells while the Cu(II) and Cd(II) complexes were strongly cytotoxic with CD 50 values of 2.20 and 2.30 μg ml −1, respectively. The Cu(II) and Cd(II) complexes were also effective against colon cancer cells with CD 50 values of 2.60 and 3.10 μg ml −1, respectively. SBDTC showed a higher antioxidant activity than the α-tocopherol (vitamin E) and was comparable with butylated hydroxytoluene (BHT), a commercially used synthetic antioxidant.

Safety Assessment of DHA-Rich Microalgae from Schizochytrium sp. : III. Single-Generation Rat Reproduction Study

Schizochytrium sp. dried microalgae (DRM) contains oil rich in highly unsaturated fatty acids (PUFAs). Docosahexaenoic acid (DHA n-3) is the most abundant PUFA component of the oil. DHA-rich oil extracted from Schizochytrium sp. is intended for use as a nutritional ingredient in foods. As part of a comprehensive safety assessment program, the reproductive toxicity of DRM was examined in Sprague–Dawley-derived rats Crl:CD(SD)BR (30/sex/group) provided DRM in the diet at concentrations of 0, 0.6, 6.0, and 30%. These dietary levels corresponded to overall average dosages of approximately 400, 3900, and 17,800 mg/kg/day for F 0 males (premating) and 480, 4600, and 20,700 mg/kg/day for F 0 females, respectively. Prior to mating, males and females of the F 0 generation were treated for 10 and 2 weeks, respectively. Treatment of males continued throughout mating and until termination (approximately 3 weeks after mating). Treatment of the females was continued throughout gestation and through lactation day 21. The females were killed after raising their young to weaning at 21 days of age. Food consumption was measured weekly throughout the study (except during mating) and body weights were recorded at least weekly during premating, gestation, and lactation. Reproductive parameters including estrus cycle duration, mating performance, fertility, gestation length, parturition, and gestation index were evaluated. Litter size and offspring body weights were recorded, offspring viability indices were calculated, and physical development (vaginal opening and preputial separation) was assessed for the F 1 generation. All adult F 0 and F 1 animals were subjected to a detailed necropsy. DRM treatment had no effect on estrus cycles or reproductive performance including mating performance, fertility, gestation length, parturition, or gestation index. Litter size, sex ratio, and offspring viability indices were similarly unaffected and there were no effects of DRM treatment on the physical development of F 1 animals.

Safety Assessment of DHA-Rich Microalgae from Schizochytrium sp.: I. Subchronic Rat Feeding Study

The purpose of this study was to determine the potential toxicity of docosahexaenoic acid-rich microalgae from Schizochytrium sp. (DRM), administered in the diet to rats for at least 13 weeks. DRM was administered in the diet to groups of 20 male and 20 female Sprague–Dawley derived rats (Crl:CD(SD)BR) to provide dosages of 0, 400, 1500, and 4000 mg/kg/day for at least 13 weeks. DRM contained high levels of fat (approximately 41% w/w) of which long-chain highly unsaturated fatty acids (PUFAs) were a major component. Vitamin E acetate was added to DRM at manufacture to provide supplementary dietary antioxidant given the highly unsaturated fat content of DRM. Untreated controls received the basal diet only. An additional group of 20 males and 20 females received basal diet mixed with fish oil (Arista) to provide a target dosage of 1628 mg/kg/day, an amount of fat comparable to that received by rats administered the highest dose of DRM. Vitamin E acetate was also added to the fish oil to provide a comparable level of dietary antioxidant provided to high-dose DRM rats. There were no treatment-related effects in clinical observations, body weights or weight gains, food consumption, hematologic or urinalysis values, gross necropsy findings, or organ weights and there were no deaths. The only treatment-related changes in clinical chemistry parameters were decreases in high-density lipoproteins and cholesterol in the DRM and fish oil groups when compared to the untreated controls. These changes were expected based on the high PUFA content of DRM and fish oil. There were no microscopic findings suggestive of toxicity. Periportal hepatocellular fat vacuolation (accumulation of fat) was observed only in the livers of female rats in both the DRM (all dosages) and fish oil groups. This finding was expected given the higher fat content of both the DRM and the fish oil diets compared to the basal diet fed to the untreated controls. A slight increase in the incidence, but not severity, of cardiomyopathy was observed only in the 4000 mg/kg/day DRM males. This finding was not considered adverse because cardiomyopathy occurs spontaneously in rats and especially male rats of the Sprague–Dawley strain when fed high levels of fat. Since cardiomyopathy does not develop in other species including primates fed high-fat diets, its occurrence in rats is considered to have little relevance to human health. This study demonstrates that administration of DRM did not produce any treatment-related adverse effects in Sprague–Dawley rats of relevance to humans at dosages up to 4000 mg/kg/day for 13 weeks.

EFFECT OF 4-VINYLCYCLOHEXENE ON MICRONUCLEUS FORMATION IN THE BONE MARROW OF RATS AND MICE

This study was conducted to evaluate the potential of 4-vinylcyclohexene (VCH) to induce micronuclei in the bone marrow of mice and rats. Male and female Cr1:CD BR (Sprague-Dawley) rats and B6C3F1/CrBR mice were exposed to VCH 6 hr/day for 2 days or for 13 weeks. In the 2-day study, mice were exposed by inhalation to 0, 250, 500, or 1000 ppm, and rats were exposed to 0, 500, 1000, or 2000 ppm. In the 13-week study, mice were exposed to 0, 50, 250, or 1000 ppm, and rats were exposed to 0, 250, 1000, or 1500 ppm. In each study, a separate group of mice was exposed to 1000 ppm 1,3-butadiene (BD) so that a comparison could be made between the two compounds. Likewise, cyclophosphamide was also included for rats as a positive control. Bone marrow was collected from VCH-exposed animals approximately 24 h and 48 h after the final exposure. There were no statistically significant increases in micronucleatedpolychromatic erythrocytes (MN-PCEs) among VCH-treated mice and rats at any dose level or sampling interval at either 2-days or 13-weeks. Also, no statistically significant difierences in the polychromatic erythrocytes (PCE) to normochromatic erythrocytes (NCE) ratios were observed 273 in any of the VCH-treated mice and rats compared to air-exposed animals. As expected, both the butadiene-treated mice and the cyclophosphamide- treated rats showed significantly more MN-PCEs than the control animals.

CROSS-FOSTERING INHALATION TOXICITY STUDY WITH HCFC-123 IN LACTATING SPRAGUE-DAWLEY RATS

A study was performed in Sprague-Dawley rats (Crl:CD BR) to differentiate between effects of hydrofluorocarbon 123 (HCFC-123) on the lactating dam or on the fetus using fostering and cross-fostering of the offspring. Pregnant and/or lactating dams without the pups present were exposed to the test substance (1000 ppm) or clean air by whole-body inhalation for 6 h/day from day 6 to 19 post conceptionem (p.c.) and from day 5 to 21 post partum (p.p.). Pups were cross-fostered to new dams within the first 2 days after birth. Treatment of the mothers with HCFC-123 led to decreases in serum glucose, cholesterol, and triglycerides and increases in absolute and relative maternal liver weights. Decreased litter and individual pup weight and decreased serum triglycerides were observed in the pups of treated foster mothers. Treatment of the mothers with HCFC-123 did not influence milk production based on the body weight difference of the dam before suckling and 60 min after beginning of suckling using 12-pup "standard litters" of untreated dams. Total fat, glucose, and protein contents in the milk were also not influenced by the treatment. Trifluoroacetic acid (TFA), a main metabolite of HCFC-123, was observed in urine samples of standard litters that had been nursed by treated dams. In conclusion, the effects on offspring due to HCFC-123 treatment consisted of decreased pup weight and decreased serum triglycerides at weaning. All effects were due to treatment of the lactating dams, as no prenatally induced effects were found. Since milk production and nutritional constituents of the milk were not influenced, but significant amounts of the main metabolite were found in pup urine, an effect of HCFC-123 or its metabolite on the pups via maternal milk is considered to be a possible cause for their decreased weight gain.