30-Day Oral Toxicity Study of L-Selenomethionine in Female Long-Tailed Macaques (Macaca fascicularis)

Twenty female long-tailed macaques received nasogastric intubationof 0–600 µg/kg-day L-sele-nomethionine for up to30 consecutive days. Selenium ingestion was well tolerated atall dose levels until the second to third week of the studyat which time two animals given 600 µg/kg-day died. Oneanimal from the 300 µg/kg-day group was removed from studyon Treatment Day 19 due to selenium-induced hypothermia. Insome cases, administered doses were reduced at the 300 and 600µg/kg-day levels such that the final time-weighted averagedoses were 0, 25, 62–117, 150, 188–203, and 300µg/kg-day. Six animals at the 188 µg/kg-day levelor greater required nonscheduled fruit and dietary supplementationto prevent their impending demise. As the dose and durationof exposure increased, the incidence of anorexia, gastrointestinaldistress, mucocutaneous toxicity, and frequency of reduced bodytemperature also increased. A dose-dependent reduction in bodyweight was also observed. At the greater doses, disturbancesin menstrual function were evident, and were accompanied bythe absence of serum progesterone concentrations above 1.0 ng/ml,reduced luteal phase lengths, increased intermenstrual intervals,and lowered estrogen excretion. A maximum tolerated dose of150 µg/kg-day L-seleno-methionine for 30 days was identifiedbased on mean body weight reduction, hypothermia, dermatitis,xerosis, cheilitis, disturbances in menstruation, and the necessityof dietary intervention to prevent death at doses of 188 µg/kg-dayor greater.     

Toxicity of 8-methoxypsoralen in cynomolgous monkeys (Macaca fascicularis)

Male and female cynomolgous monkeys were administered 0, 2, 6 or 18 mg/kg 8-methoxypsoralen (8-MOP) 3 times a week orally for 26 consecutive weeks. Dose-dependent emesis was the most sensitive indicator of 8-MOP toxicity. The lowest dose to elicit emesis was 3 x 6 mg/kg/week of 8-MOP. Among the histological findings proliferation of Kupffer cells was the only recurring observation. However, these finding as well as some hematological and serum electrolyte changes lacked a dose-response relationship. In the highest dosage group one female monkey was found in moribund condition on the 39th day of the study and was killed. Histopathological evidence indicated beginning shock as the cause of the rapidly deteriorating health of the monkey. Similar to effects in man and rats, 8-MOP displayed nonlinear pharmacokinetics in the cynomolgous monkey, saturation occurring between 3 x 2 and 3 x 6 mg/kg/week. Increased clearance of 8-MOP in the lowest dosage group after 26 test weeks was attributed to a combination of enzyme induction and saturable first pass effect. Since the plasma profile of 8-MOP at the lowest dose (3 x 2 mg/kg/week) in cynomolgous monkeys closely resembles that in humans after therapeutic doses (0.4-0.6 mg/kg) and because of other similarities (vomiting as earliest sign of toxicity, saturable first pass effect), it is reasonable to assume that chronic toxicity of 8-MOP as defined in this study is quite predictive for man.     

Toxicity of a GM3 cancer vaccine in Macaca fascicularis monkey: a 12-month study

GM3 is a ganglioside that has been biochemically identified as dominating the cell surface of several human tumours, but is also found on human normal cells at much lower density. Since GM3 is widely distributed in essentially all types of animal cells, there is a conflict with the concepts of tumour-associated antigen, immunogen, and toxicity. We have designed a GM3-based cancer vaccine for the treatment of human breast and melanoma tumours. Prior to the Phase I clinical trial, we carried out a 12-month dose repeated toxicity study in five male Macaca fascicularis monkeys. Four male monkeys were treated with placebo in a similar way. During the study, no differences were observed between control and treated monkeys related to daily clinical observations (other than local damage) including rectal temperature, blood pressure, respiratory and cardiac rates, weight gain, biochemical and hematological parameters (with the exception of transitory pathological changes), and anti-DNA and anti-nuclear antibodies, although treated monkeys consistently developed both IgM- and IgG-specific anti-GM3 antibodies. Sixty per cent of treated monkeys developed moderate local reactions at the injection site, which disappeared without sequels. We concluded that this GM3 cancer vaccine overcame in monkeys the natural tolerance to GM3 ganglioside evidenced by a strong immune response, while the local reactions elicited-were transitory without apparent important systemic toxicity effects.     

Visual recognition memory deficits in methylmercury-exposed Macaca fascicularis infants

Infant Macaca fascicularis exposed prenatally to maternal subclinical levels of methylmercury (MeHg) and their nonexposed controls were administered a test of visual recognition memory beginning at 210 days postconception (mean postnatal age = 51.88 days, SD = 5.30). The test consisted of a series of problems in which two identical 35 mm slides of a monkey's face were presented for a study period, followed by a test trial in which the previously exposed stimulus was paired with a novel one, and the looking time to each was recorded. The nonexposed group showed differential visual attention to the novel stimuli, indicating visual recognition abilities. The exposed group's visual attention to the novel stimuli was random. These results, in conjunction with earlier findings, suggest that prenatal MeHg exposure is associated with impaired visual recognition memory performance.     

Developmental toxicity assessment of tanezumab,an anti-nerve growth factor monoclonal antibody,in cynomolgus monkeys (Macaca fascicularis)

Two intravenous studies with tanezumab, an anti-nerve growth factor monoclonal antibody, were conducted in pregnant cynomolgus monkeys to assess potential effects on pregnancy and pre- and postnatal development. Study 1 evaluated infants up to 12 months of age following weekly maternal dosing (0, 0.5, 4 or 30 mg/kg; 18 per group) from gestation day (GD) 20 through parturition. Study 2 evaluated infants 2 months postnatally following weekly maternal dosing (0, 0.5 or 30 mg/kg; 20–21 per group) from GD 20 through 48. In the absence of maternal toxicity, tanezumab increased stillbirth and post-birth infant mortality/morbidity, decreased infant growth and resulted in microscopic changes in the peripheral sympathetic and sensory nervous system of the infants at all doses. Decreased primary antibody responses and increased incidences in skin changes in infants were also observed. The no-observed-adverse-effect-level for maternal toxicity was 30 mg/kg and <0.5 mg/kg for developmental toxicity.     

Acute trimethyltin intoxication in the monkey (Macaca fascicularis)

Adult cynomolgus monkeys were administered trimethyltin (TMT) iv in dosages ranging from 0.75 to 4.0 mg TMT/kg and observed for behavioral changes. Animals were subsequently killed for light and electron microscopic examination. TMT showed a dose-related toxicity, with high dose animals (4.0 and 3.0 mg/kg) dying within 24 hr, and low dose animals (0.75 mg/kg) surviving without morphological effects. Animals given 1.10 mg TMT/kg displayed a reproducible clinical course, characterized by tremor, hyperactivity, and ataxia which progressed to stupor and finally unconsciousness. By light microscopy, neuropathology was most pronounced in the CA-3 and CA-4 regions of Ammon's horn. Degenerating pyramidal neurons, micro- and astrogliosis, and neuronophagia were commonly observed. Mild degenerative changes were identified in amygdala, medulla, spinal cord, and Purkinje cells. The fascia dentata remained intact. Ultrastructurally, injured neurons contained accumulations of lysosomes and lysosome-like structures within perikarya and neurites. Demyelination or vascular damage was not observed. Data indicate the monkey to be highly sensitive to TMT, with morphological injury most severe in limbic structures.     

Effects of methyl mercury on testicular functions in Macaca fascicularis monkeys

These studies were performed to investigate the effects of MeHg on testicular function in Macaca fascicularis monkeys. In an in vivo study involving oral treatment of adult males Macaca fascicularis monkeys with MeHg for 20 weeks, changes in spermatozoal production, motility and morphology and in serum testosterone were followed before, during and after treatment. MeHg treatment significantly decreased % motile spermatozoa and scores for sperm speed and forward progression and increased % abnormal sperm tail forms, at sub-neurotoxic levels. The MeHg-induced increase in semen abnormalities was not accompanied by any significant changes in serum levels of testosterone. No consistent histological abnormalities were detected in testicular biopsies from the treated animals at the end of the treatment period. A good recovery pattern was observed for the MeHg effects on sperm motility while this was unclear for the effects on sperm morphology.     

Methylmercury effects on the social behavior of Macaca fascicularis infants

Observations of the social behavior of Macaca fascicularis exposed in utero to methylmercury (MeHg) and nonexposed control infants were performed as part of a study of the toxic, reproductive and developmental effects of maternal MeHg intake. Infants were tested twice weekly from 2 weeks to 8 months of age. Data were summarized into 6 categories of social behavior and 7 categories of nonsocial behavior. Analysis of the most prevalent behavior indicated that MeHg-exposed offspring exhibited a decrease in social play behavior and a concomitant increase in nonsocial passive behavior. The MeHg effect on social play behavior tended to decrease with age, while the group differences in nonsocial passive behavior tended to increase. The results indicate that maternal intake of MeHg during pregnancy can affect the social development of infant primates by suppressing social interactions and increasing nonsocial behavior.     

Pharmacokinetics of Methylmercury in the Blood of Monkeys (Macaca fascicularis)

Pharmacokinetics of Methylmercury in the Blood of Monkeys (Macacafascicularis). RICE, D. C., KREWSKI, D., COLLINS, B. T., ANDW1LLES, R. F. (1989). Fundam. Appl Toxicol. 12, 23–33.Statistical analysis of the blood mercury profiles of groupsof two and four adult female cynomolgus monkeys (Macaca fascicularis)given single oral doses of 500 µg and 50 µCi (25.3µg) methylmercury/kg body wt, respectively, indicatesthat a two-compartment model best describes the absorption andelimination of methylmercury in blood. Absorption was largelycomplete within 6 hr, and the half-time of methylmercury duringthe terminal elimination phase ranged from 10 to 15 days. Inaddition, three groups of five adult female cynomolgus monkeyswere dosed with methylmercury every Monday, Wednesday, and Fridayfor periods up to 2 years at effective doses of 10, 25, or 50µg methylmercury/kg body wt/day. The average blood levelsat steady state were estimated to be 0.27 ± 0.02, 0.69± 0.03, and 1.51 ± 0.08 ppm, respectively, withaverage time taken to achieve 95% of the steady-state bloodlevel being about 92 days. The steady-state blood levels obtainedvia extrapolation of the results from the two single-dose experimentswere significantly different from those actually achieved, indicatingthat the average steady-state blood levels under chronic dosingconditions may not be accurately estimated on the basis of short-termexperiments. The data were also used to examine the impact ofdifferent dosing intervals on variation in blood mercury levels.     

Chronic colitis in Macaca fascicularis: similarities with chronic colitis in humans

In recent years, a substantial number of macaques have died at the Southwest Foundation for Biomedical Research, USA, following protracted intractable diarrhea. The diarrhea could last for up to two years and occurred in infant, juvenile or young adult animals. The histopathological diagnosis at autopsy was chronic colitis. The histopathological subtype of chronic colitis is here assessed in a relatively large number of colonic specimens obtained at autopsy (n = 90). The colonic mucosa was well preserved for histological examination in 83 of the 90 macaques. At review, various histological phenotypes of chronic colitis were found. Chronic lymphocytic-plasmacytic colitis occurred in 78.3% (65 out of 83), chronic ulcerative colitis in 20.5% (17 out of 83) and Crohn's colitis in 1.2% (1 out of 83). In macaques, some histological phenotypes of chronic colitis (ulcerative and Crohn's colitis) closely mimic chronic colitis in humans. The awareness that chronic colitis in macaques is not one disease but a series of chronic inflammatory changes, with common clinical symptoms and similar gross appearances, may lead to the correct histological diagnosis of the subtype of the disease.     

Interaction of Zidovudine (Azidothymidine) with Isoprinosine and Probenecid in Macaca fascicularis

Pharmaceutical Research -     

The Fate of Chronically Consumed Caffeine in the Monkey (Macaca fascicularis)

The Fate of Chronically Consumed Caffeine in the Monkey (Macacafascicularis). GILBERT, S. G., STAVRIC, B., KLASSEN, R. D.,AND RICE, D. C. (1985) Fundam. Appl. Toxicol. 5, 578–587.The metabolic fate of chronically administered caffeine wasexamined in monkeys. Caffeine and equal parts of citric acidwere added to the drinking water of four female monkeys (Macacafascicularis). The concentration was gradually increased overa 10-week period to 0.35 mg/ml for three of the monkeys. A monkeythat was lactating, but had no infant, was exposed to caffeinein the drinking water at a concentration of 0.30 mg/ml. At thesedoses, administered for up to 50 weeks, there were no overtsigns of toxicity as indicated by food and fluid consumption,body weight, or general condition of the monkey. Mean plasmacaffeine concentrations were 3.8, 5.7, and 5.9 µg/ml,while mean plasma theophylline concentrations were 11.8, 13.0,and 20.1 µ/ml. respectively for the monkeys receiving0.35 mg/ml. Mean plasma caffeine and theophylline concentrationsfor the lactating monkey were 10.7 and 21.4 µg/ml, whilemean milk concentrations were 10.5 and 17.6 µ/ml, respectively,indicating that caffeine and its major metabolite theophyllineare readily excreted in milk. The high plasma theophylline levelsindicate that caffeine metabolism in the monkeys differs fromthat in humans. Theophylline was the main urinary metabolite.In addition, large amounts of 1,3-dimethyluric acid were excretedin the urine but only traces of this metabolite were found inthe plasma. After withdrawal of caffeine, plasma caffeine levelsdecreased to almost zero in the first 24 hr with a half-lifeof 5.5 hr, and plasma theophylline levels declined with a half-lifeof 12.7 hr     

Effect of polychlorinated biphenyls and polychlorinated quaterphenyls in Cynomolgus monkey (Macaca fascicularis)

Female Cynomolgus monkeys (Macaca fascicularis) with P-KC-400, Y-PCB, PY-PCB or polychlorinated quaterphenyls (PCQ) received a daily dose of 5 mg for 20 weeks, and some monkeys received a daily dose of 10 mg of Y-PCB or 0.5 mg of PCQ. The chemical compositions of the polychlorobiphenyls (PCB) used for the oral administration were as follows: P-KC-400, PCB from which polychlorodibenzofurans (PCDF) have been removed from Kanecklor 400, largely contains tri- and tetrachlorobiphenyls and no PCDF. Whereas, Y-PCB and PY-PCB, PCB with constituents similar to PCB ingested by yusho patients, largely contain penta- and hexachlorobiphenyls, in addition, PCDF of 400 ppm was present only in Y-PCB, but not in PY-PCB. There were immunosuppression, enlargement and histopathological changes of the liver (such as interstitial inflammation, and proliferation of epithelial cells of biliary duct, etc.) in the groups fed P-KC-400 and PY-PCB (free of PCDF). In the group fed Y-PCB (with PCDF), there were more apparent decreases in body weight, immunosuppression, fatty liver and histopathological changes than in the groups P-KC-400 and PY-PCB. In addition, there were hair loss, acneform eruptions, edema of the eyelid, congestion and abscess of the Meibomian gland, and cornifications of the skin, characteristic dermatological findings of yusho disease.     

Reproductive and Developmental Toxicity of Phthalates

The purposes of this review are to (1) evaluate human and experimental evidence for adverse effects on reproduction and development in humans, produced by exposure to phthalates, and (2) identify knowledge gaps as for future studies. The widespread use of phthalates in consumer products leads to ubiquitous and constant exposure of humans to these chemicals. Phthalates were postulated to produce endocrine-disrupting effects in rodents, where fetal exposure to these compounds was found to induce developmental and reproductive toxicity. The adverse effects observed in rodent models raised concerns as to whether exposure to phthalates represents a potential health risk to humans. At present, di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DBP), and butyl benzyl phthalate (BBP) have been demonstrated to produce reproductive and developmental toxicity; thus, this review focuses on these chemicals. For the general population, DEHP exposure is predominantly via food. The average concentrations of phthalates are highest in children and decrease with age. At present, DEHP exposures in the general population appear to be close to the tolerable daily intake (TDI), suggesting that at least some individuals exceed the TDI. In addition, specific high-risk groups exist with internal levels that are several orders of magnitude above average. Urinary metabolites used as biomarkers for the internal levels provide additional means to determine more specifically phthalate exposure levels in both general and high-risk populations. However, exposure data are not consistent and there are indications that secondary metabolites may be more accurate indicators of the internal exposure compared to primary metabolites. The present human toxicity data are not sufficient for evaluating the occurrence of reproductive effects following phthalate exposure in humans, based on existing relevant animal data. This is especially the case for data on female reproductive toxicity, which are scarce. Therefore, future research needs to focus on developmental and reproductive endpoints in humans. It should be noted that phthalates occur in mixtures but most toxicological information is based on single compounds. Thus, it is concluded that it is important to improve the knowledge of toxic interactions among the different chemicals and to develop measures for combined exposure to various groups of phthalates.     

Metabolic activity of fresh and cryopreserved cynomolgus monkey (Macaca fascicularis) hepatocytes

1. The effect of cryopreservation on the metabolic capacity of monkey hepatocytes over 4 h in suspension and 24 h in culture was determined. Hepatocytes were diluted in a buffer containing 10% DMSO and frozen in a computer-controlled chamber. 2. Initial ethoxyresorufin and ethoxycoumarin O     

Metabolic activity of fresh and cryopreserved cynomolgus monkey (Macaca fascicularis) hepatocytes

1. The effect of cryopreservation on the metabolic capacity of monkey hepatocytes over 4 h in suspension and 24 h in culture was determined. Hepatocytes were diluted in a buffer containing 10% DMSO and frozen in a computer-controlled chamber. 2. Initial ethoxyresorufin and ethoxycoumarin O-deethylase (ECOD) activities were the same in fresh and cryopreserved (CP) hepatocytes. ECOD activity in suspensions declined over 4 h but was the same in fresh and CP hepatocytes. 3. The formation of testosterone hydroxy (OHT) metabolites (namely 6beta-OHT, 2beta-OHT, 16beta-OHT, 16alpha-OHT, 15beta-OHT, 2alpha-OHT and 6beta-OHT) was unaffected by cryopreservation. The loss of OHT activities over 4 h in CP and fresh whole cell suspensions was attributed to a loss of cofactor. CP hepatocyte cultures had equivalent OHT activities to freshly isolated hepatocytes. 4. Initial UDP-glucuronyltransferase (UGT) activities, using the substrates 4-methylumbelliferone, ethoxycoumarin and hydroxycoumarin, were equivalent in fresh and CP whole hepatocytes. At later times, UGT activity was lower in CP than fresh hepatocytes but this was due to a loss of UDPGA. Initial sulphotransferase (SULT) activities, using the substrates 2-naphthol, ethoxycoumarin and hydroxycoumarin, were equivalent in fresh and CP hepatocytes. SULT activities were less stable than UGT activities but were the same in fresh and CP hepatocytes throughout the 4-h incubation. 5. Initial glutathione S-transferase activities (using 1-chloro-2,4-dinitrobenzene) were the same in fresh and CP hepatocytes and both did not decrease over 4 h. 6. CP monkey hepatocytes are a useful model for metabolic and cytotoxicity studies. These cells can be can be used either in suspension or in culture.     

Developmental Toxicity of 1,1,1-Trichloroethane in CD Rats

1,1,1 -Trichloroethane (TCEN), a major industrial and householdsolvent, was evaluated for pre- and postnatal developmentaleffects in SpragueDawley rats. This study was designed to assessthe repeatability of a report (S. C. Dapson, D. E. Hutcheon,and D. Lehr, Teratology 29, 25 A, 1984) that indicated that10 ppm TCEN in drinking water caused cardiac malformations indeveloping rats. In the present study, TCEN (97% pure) was administeredin the drinking water at target concentrations of 3, 10, and30 ppm, using 0.05% Tween 80 as an emulsifying agent Two controlgroups, one receiving deionized/filtered water and the otherreceiving a vehicle control solution containing 0.05% Tween80 and 0.9 ppm 1,4-dioxane, a stabilizing agent found in thebulk chemical, were also included. Male and female breeders(more than 30 per group) were exposed to the control solutionsor test compound for 14 consecutive days prior to cohabitationand for up to 13 days during the cohabitation phase. Sperm-positivefemales (24–29 per group) continued to be exposed to theseformulations during pregnancy and lactation to Postnatal Day(PND) 21. Parental animals exhibited a slight aversion to the30-ppm drinking water during the premating exposure. No significanteffect on reproductive competence of the parental animals orpostnatal growth and development of the offspring to PND 21was noted. A slight increase in mortality from implantationto PND 1, possibly due to high mortality in one litter, wasobserved in the 30-ppm dose group. There was no indication ofan increase in the incidence of cardiac or other malformationsin PND 21 pups. In summary, TCEN administered at 3, 10, and30 ppm in the drinking water had no significant effect on themorphological development of CD rats,