Some cases of lymphoid leukosis in captive wild birds

A total of 1,234 post mortem examinations of captive wild birds was carried out during a 5-year observation period. Six cases of lymphoid leukosis were found and their pathological features are described.

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.

Expression of growth factors and growth factor receptors in the liver of C57BL/10J mice following administration of phenobarbitone

Liver enlargement is a common feature of non-genotoxic rodent hepatocarcinogens administered at high doses. In the present study, the expression of growth factors and growth factor receptors was investigated in the C57BL/1OJ mouse during liver enlargement induced by the non-genotoxic rodent hepatocarcinogen, sodium phenobarbitone (PB). Male mice were dosed 0-2500 p.p.m. PB in the diet for 1, 4 and 13 weeks. There was a dose and time dependent increase in liver weight. Hepatocyte replication, assessed by incorporation of bromodeoxyuridine, was increased in a dose-dependent manner at week 1 only (18-fold increase at 2000 p.p.m.) and was predominantly localized in the centrilobular region. At week 1, PB (2500 p.p.m.) caused transient increases in transforming growth factor alpha (TGFalpha) and epidermal growth factor receptor (EGFR) and decreases in transforming growth factor beta1 (TGF-beta1) and mannose-6-phosphate receptor (M6PR) in centrilobular hepatocytes which correlated with the replication in this region. At week 1, there was an increase in both hepatocyte growth factor (HGF) and hepatocyte growth factor receptor (HGFR) which colocalized in centrilobular hepatocytes; in some mice or periportal hepatocytes in other mice. After 13 weeks, HGF and HGFR were localized in the cytoplasm of centrilobular hepatocytes of all mice but exhibited a differential intracellular distribution across the lobule. At 2500 p.p.m. PB, EGFR and HGFR mRNA were essentially unchanged over the 13 week dosing period whilst M6PR mRNA was increased 2- to 4-fold. At 2500 p.p.m. PB, EGFR protein levels from immunoblots showed a consistent decrease over the 13 weeks whilst M6PR and HGFR protein levels were essentially unchanged. The protein level and mRNA data for EGFR suggest post-transcriptional modification. Thus, phenobarbitone caused transient replication of hepatocytes and modulation of growth stimulatory and inhibitory factors and their associated receptors in terms of overall levels and regional distribution in the liver.

The topography, structure and incidence of mineralized bodies in the basal ganglia of the brain of cynomolgus monkeys (Macaca fascicularis)

Whole coronal slices from 6 levels of the brain of 16 cynomolgus monkeys (8 control and 8 treated by daily gavage with a novel pharmaceutical agent for one year) were examined histologically. Mineralized bodies were identified only in coronal sections passing through the optic chiasma and mammillary bodies. Identical mineralized structures were present in the basal ganglia of both control and treated animals. The majority were seen in the globus pallidus, occasionally in the putamen and once in the nearby caudate nucleus. These structures were partially ferruginated and also partially calcified. They appeared to arise in relation to small vessels. They are part of the naturally occurring background pathology of several species of non-human primates and the incidence in this study (3/8 control and 5/8 treated) was approximately what might be expected from reports in the literature. Mineralized bodies of the basal ganglia of primates represent a spontaneous lesion with a characteristic distribution. They may cause confusion in interpretation of toxicological studies if their natural occurrence is not appreciated.

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.

Neuron-specific enolase immunoreactivity in rat and mouse phaeochromocytomas

Neuron-specific enolase (NSE) was found to be consistently present in the rat and mouse adrenal medulla in the normal and neoplastic state. It is suggested that NSE immunoreactivity may be a useful tool in the differential diagnosis of phaeochromocytomas.

Tumours of the bone in C57BL/10J mice

Tumours of the bone were found in 17 (12 females and 5 males) of 6768 (0.25%) C57BL/10J mice (3384 males and 3384 females) pooled from 14 oncogenic studies carried out from 1973 to 1987. Tumours of bone were found predominantly in female mice and were age related. The tumours were classified histologically as osteosarcoma (5 osteoblastic, 6 mixed type and 1 fibroblastic), chondroma (2), chondromyxoid fibroma (1), chondrosarcoma (1) and periosteal fibroma (1).

A survey of the pathology of marmosets (Callithrix jacchus) derived from a marmoset breeding unit

The results of a survey of the major pathological conditions encountered in an established breeding colony of common cotton-eared marmosets (Callithrix jacchus) is presented. 265 home-bred and 70 imported wild-caught marmosets were examined. A Heinz body haemolytic anaemia and skeletal muscle myopathy were the most common pathological findings and were considered to be a result of a complex nutritional deficiency involving vitamin E, selenium and protein. Inflammatory disease of the intestinal tract was also a major feature. Chronic colitis was particularly common in older marmosets. Pneumonia, otitis media, meningitis and brain abscesses were important pathological findings in home-bred marmosets and were commonly associated with bacterial infections, particularly Bordetella bronchiseptica and Klebsiella species. Trichospirura leptostoma within pancreatic ducts of wild-caught marmosets was the only significant parasitic disease encountered. Mycotic infections of the upper alimentary tract with Candida species were occasional findings in debilitated animals. No pathological features suggesting viral diseases were found.

Haematological, coagulation and blood chemistry data in red-bellied tamarins Saguinus labiatus

Haematology, coagulation and clinical chemistry data are reported for a group of male and female red-bellied tamarins (Saguinus labiatus). The tamarins were juvenile and young adults and were bred in captivity. High mean values for activities of alkaline phosphatase, alanine amino-transferase, aspartate aminotransferase and creatine kinase were noted. The findings are compared with data obtained from other members of the family Callitrichidae.

Organ weight data in juvenile and adult marmosets (Callithrix jacchus)

Organ weight data from 167 (82 male and 85 female) juvenile and adult common cotton-eared marmosets ( Callithrix jacchus) is presented. The marmosets were bred in captivity and were used as untreated or vehicle control animals in safety evaluation studies carried out over an 8 year period.

Pancreatic atrophy in young Beagle dogs

Six young Beagle dogs had non-inflammatory pancreatic atrophy associated with lack of weight gain and low serum protein levels. Histologically there was severe atrophy with loss of acinar architecture and absence of islets of Langerhans (type 1), or partial atrophy with ppreserved islets (type 2). The correlation between histological type and clinical severity was poor.

The ultrastructural features of progestagen-induced decidual cells in the rhesus monkey (Macaca mulatta)

Five rhesus monkeys were treated with levonorgestrel-releasing intravaginal rings for 52 weeks. The rings were designed to provide a sustained release of ten times the human dose level of the hormone. Histological examination of the uterine endometrium showed widespread decidualisation of endometrial stromal cells. Ultrastructurally, two distinct cell types were identified: decidual and granular. Some of the decidual cells were ultrastructurally comparable with those reported elsewhere; however, in aproportion of these cells, intracisternal sequestration of the rough endoplasmic reticulum was widespread. The granular cells resembled those described in the metrial gland of rats and, as their name suggests, contained variable numbers of electron-dense granules.

The intravenous toxicity of dibekacin sulphate (DKB) to female beagle dogs

Dibekacin sulphate (DKB), a new aminoglycoside antibiotic developed on the theory of bacterial resistance, was given by intravenous injection to groups of female Beagle dogs at dosages of 2.5, 5.0, 10.0 or 25.0 mg/kg/day for 13 weeks. Physiological saline was given as a control. Some dogs given 5.0 or 10.0 mg/kg/day were retained undosed for a further 5 weeks in order to assess recovery. Premature deaths from acute renal tubular nephrosis occurred in dogs given 25.0 and 10.0 mg/kg/day. Dogs which survived treatment at 10.0 mg/kg/day showed marked elevation of circulating urea and creatinine concentrations after 4 weeks' treatment but thereafter the increases became less obvious. Varying degrees of renal cortical tubular dilatation, basophilia, degeneration or necrosis were seen in the kidneys of all dogs examined after 13 weeks treatment although no clinical impairment of renal function was detectable at dosages up to 5.0 mg/kg/day. These changes had essentially regressed in dogs examined 5 weeks after the last dose of DKB at 5.0 mg/kg/day. All the adverse clinical and histological effects noted, following any dose level of DKB tested, could be attributed to renal changes.

A renal carcinoma in an Augur buzzard (Buteo rufofuscus augur)

A renal carcinoma in a captive Augur buzzard (Buteo rufofuscus augur) is described.

Renal aplasia and hypoplasia in the rhesus monkey (Macaca mulatta)

Unilateral renal aplasia or hypoplasia was discovered in 3 wild-caught rhesus monkeys at the end of routine toxicological experiments. No clinical abnormalities were evident and the opposite kidneys had undergone compensatory hypertrophy and hyperplasia.

Interstitial cell tumour of the testis in a western lowland gorilla (Gorilla gorilla gorilla)

The post mortem in an adult male gorilla (Gorilla gorilla gorilla) aged approximately 33 years revealed very small testes, and the cut surface of the left testis appeared nodular. Microscopic examination showed a marked atrophy of seminiferous tubules and fibrosis together with a diffuse interstitial cell hyperplasia. Two interstitial cell adenomas were identified in the left testis.

Treatment of rhesus monkeys (Macaca mulatta) with intravaginal rings loaded with levonorgestrel

The effects of levonorgestrel-releasing intravaginal rings were investigated in 15 rhesus monkeys for 52 weeks. The intravaginal rings were designed to provide a sustained release of either three or ten times the human dose level of the hormone. Untreated placebo rings were used as a control. The devices were well retained. After insertion of the vaginal rings, a dose-related decrease in vaginal bleeding was observed. The vaginal microbial flora were assessed qualitatively and semi-quantitatively and although all groups including controls showed some changes in microbial populations, by the end of the study nearly all animals returned to a normal balanced microflora. Terminal studies showed that, at the high dose level, ovulation was suppressed and widespread atrophy of the uterine mucosal and glandular epithelium had occurred. A dose-related increase in mucus within the lumen of the endocervical canal was observed. Focal or diffuse atrophy of the vaginal mucosal epithelium was seen in the majority of levonorgestrel-treated animals.

Treatment of rhesus monkeys (Macaca mulatta) with intravaginal rings impregnated with either progesterone or norethisterone

The effects of both progesterone- and norethisterone-loaded intravaginal rings were investigated in twenty-five rhesus monkeys for 52 weeks. The intravaginal rings were designed to provide a sustained release of either the human dosage level of the hormone or ten times this level. Untreated placebo rings were used for control purposes. The devices were well retained. With the exception of increased plasma fibrinogen levels in animals treated with norethisterone, no marked differences in either local or systemic toxicity between the progesterone and norethisterone intravaginal rings were apparent. Following insertion of the hormone-treated intravaginal rings, a dose-related decrease in vaginal bleeding was recorded. The vaginal microbial flora were assessed qualitatively and semiquantitatively and all groups including the placebo controls showed a changes in mcirobial populations. Terminal studies indicated that at high dose levels, ovulation was suppressed and widespread atrophy of the uterine mucosal and glandular endometrial epithelium had occurred. An increase in cervical mucus was observed within the lumen of the endocervical canal in a proportion of hormone-treated animals. In the vagina, a dose-related focal or diffuse atrophy of the mucosal epithelium was found.

Treatment of rhesus monkeys (Macaca mulatta) with intrauterine devices loaded with levonorgestrel

The effects of levonorgestrel-loaded plastic intrauterine devices on endometrial morphology were investigated in 15 rhesus monkeys for 14 weeks. The devices were designed to release 25 microgram of the hormone per day and were inserted in the uterus by hysterotomy. Control animals were sham operated or received inert placebo devices. With the levonorgestrel-releasing devices, widespread changes in endometrial morphology were seen. These changes included atrophy of the endometrial mucosal and glandular epithelium and decidualization of the endometrial stroma. With the inert placebo control devices, only minor changes in endometrial morphology were observed.

Safety evaluation of toothpaste containing chloroform. III. Long-term study in beagle dogs

Beagle dogs were given chloroform in a toothpaste base orally in gelatin capsules on 6 d/wk for 7 1/2 yr, followed by a 20-24 wk recovery period. Groups of 16 males and females received 0.5 ml/kg/d of the vehicle (toothpaste without chloroform) and 8 dogs of each sex remained untreated. Treated groups comprised 8 dogs of each sex remained untreated. Treated groups comprised 8 dogs of each sex, receiving doses equivalent to 15 and 30 mg CHCl3/kg/d in the toothpaste vehicle; another group of the same size received an alternative non-chloroform toothpaste (0.5 ml/kg/d). Eleven of the 96 dogs died during the study, only two of these being in the CHCl3-treated groups. The only significant toxic response during treatment was a moderate rise in serum enzyme levels (e.g. SGPT), reaching a peak in the sixth year of the study and probably corresponding to minimal liver damage. Few Palpable growths were noted while the dogs were alive. "Fatty cysts" were seen in the liver of several dogs at post mortem possibly associated with the chloroform treatment but the distribution of a nodular change in the liver was not obviously dose related. A small number of macroscopic and microscopic neoplasms were seen; one dog in each chloroform-treated group had a malignant tumour but there were no tumours in the liver or kidney of any dog. Overall, exposure to chloroform in a toothpaste base was not associated with any effect on the incidence of any kind of neoplasm. From this and related studies in mice and rats, it is concluded that repeated exposure to chloroform (3.5 percent) in toothpaste is unlikely to result in any hazard to human health.

Segmental aplasia of the vagina in the beagle bitch

Segmental aplasia of the vaginal mucosa was discovered in 3 beagle bitches at the end of a routine toxicological experiment. Anomalies of Müllerian duct development in the bitch are discussed.

Toxicity of methyl testosterone in the beagle dog

When methyl testosterone was administered orally to beagle dogs at dosage levels of 2, 4 and 6 mg/kg per day for 27 weeks, hepatotoxicity was induced. The change induced was characterized by enlargement of periportal hepatocytes and the presence of haemosiderin within macrophages. There was some evidence of recovery over a 13-week period.