Effects of short-term estrogen treatment on the progression of N-methyl-N-nitrosourea-induced premalignant mammary lesions in female Lewis rats.

We studied the effects of short-term estrogen treatment (STET) on the progression of mammary lesions from ductal hyperplasia (DH) through ductal carcinoma in situ (DCIS) to invasive ductal carcinoma (IDC) in the N-methyl-N-nitrosourea (MNU)-induced rat mammary carcinogenesis model. Three-week-old female Lewis rats (n = 40) received an intraperitoneal injection of MNU (50 mg/kg). Three weeks later, a 3-week-release, 0.25-mg, 17ß-estradiol pellet was subcutaneously implanted for 2 weeks in 20 rats (STET); the remaining 20 rats did not receive the estradiol pellets (age-matched control). All rats were killed at 12 weeks of age, and their abdominal-inguinal mammary glands were histologically examined. The incidence and multiplicity of DHs were similar between groups (STET, 90% and 3.9 ± 0.6 vs. age-matched controls, 80% and 3.0 ± 0.5). However, DCIS and IDC did not develop in STET rats, whereas DCIS (25% and 1.4 ± 0.2) and IDC (35% and 1.4 ± 0.3) developed in the age-matched controls. Immunoscores of estrogen and progesterone receptors and positive rate of proliferative cell nuclear antigen (PCNA) in DH were similar in both groups, while the positive rate of cyclin D1 was significantly reduced in the STET group (P < 0.05). Thus, STET blocked the progression from DH to DCIS in MNU-induced mammary carcinogenesis, and decreased expression of cyclin D1 may play an important role in the blockade of cell transition from DH to DCIS.

Retinal degeneration induced in adult mice by a single intraperitoneal injection of N-ethyl-N-nitrosourea.

Seven-week-old female BALB/c mice received a single intraperitoneal injection of N-ethyl-N-nitrosourea (ENU) (50, 100, 200, 400, or 600 mg/kg), and retinal damage was evaluated after 7 days. Sequential morphological features of the retina and retinal apoptosis, as determined by the TUNEL assay, were analyzed 6, 12, 24, and 72 hr and 7 days after treatment with 600 mg/kg of ENU. Moreover, older mice (25 to 34 weeks of age) received an intraperitoneal injection of 600 mg/kg ENU and were sacrificed 7 days later. All animals were necropsied, and both eyes were examined histopathologically. Two of the 5 mice that received 600 mg/kg ENU died during the experimental period. Histopathologically, all mice that received 600 mg/kg of ENU experienced retinal degeneration characterized by the loss of photoreceptor cells (disappearance of the outer nuclear layer and photoreceptor layer) in both the central and peripheral retina within 7 days. One of 5 mice treated with 400 mg/kg ENU exhibited retinal damage that was restricted to the central retina. Older mice treated with 600 mg/kg ENU exhibited retinal damage that was similar to the retinal damage in younger mice. In the 600 mg/kg ENU-treated mice, TUNEL-positive photoreceptor cells peaked 72 hr after ENU treatment. Retinal thickness and the photoreceptor cell ratio in the central and peripheral retina were significantly decreased, and the retinal damage ratio was significantly increased 7 days after treatment. In conclusion, ENU induces retinal degeneration in adult mice that is characterized by photoreceptor cell apoptosis.

Anticancer effects of garlic and garlic-derived compounds for breast cancer control.

Garlic and garlic-derived compounds reduce the development of mammary cancer in animals and suppress the growth of human breast cancer cells in culture. Oil-soluble compounds derived from garlic, such as diallyl disulfide (DADS), are more effective than water-soluble compounds in suppressing breast cancer. Mechanisms of action include the activation of metabolizing enzymes that detoxify carcinogens, the suppression of DNA adduct formation, the inhibition of the production of reactive oxygen species, the regulation of cell-cycle arrest and the induction of apoptosis. Selenium-enriched garlic or organoselenium compounds provide more potent protection against mammary carcinogenesis in rats and greater inhibition of breast cancer cells in culture than natural garlic or the respective organosulfur analogues. DADS synergizes the effect of eicosapentaenoic acid, a breast cancer suppressor, and antagonizes the effect of linoleic acid, a breast cancer enhancer. Moreover, garlic extract reduces the side effects caused by anti-cancer agents. Thus, garlic and garlic-derived compounds are promising candidates for breast cancer control.

Cerebromalacia with epilepsy and cortical blindness in a laboratory Japanese macaque (Macaca fuscata).

The authors performed a pathological examination of a 5-year-old female laboratory Japanese monkey who developed cortical blindness and epileptic seizures. Generalized, tonic-clonic seizures started to occur during behavioral training to get the animal to enter a carrying cage for future psychological experiments. Blindness was suspected because of a lack of approaching behavior toward foods such as fruits. Although the monkey was extensively treated with anticonvulsants, the clinical signs did not improve. An increased serum creatine phosphokinase (CPK) level and bilateral occipital brain atrophy were detected. Histopathologically, a severe degree of cerebromalacia was detected bilaterally in the occipital lobe, and necrosis and gliosis were seen mainly in the temporal lobe. Focal inflammation was found in the meninges. No other changes were observed in other nervous tissues or organs, and no signs of a parasitic or viral infection were found in the systemic organs. Spontaneously occurring lesions in the central nervous system have been rarely reported in laboratory monkeys. In the present case, the cause of cerebromalacia could not be confirmed, but the relationship between symptoms such as abnormal vision and the presence of brain lesions was distinct. The authors believe that this case is a valuable historical control case for the laboratory Japanese macaque.

Short-term pregnancy hormone treatment of N-methyl-N-nitrosourea-induced mammary carcinogenesis in relation to fatty acid composition of serum phospholipids in female Lewis rats.

AIM: Short-term oestrogen and progesterone treatment (STEPT) mimics the pregnancy hormone milieu. This study compared the development of N-methyl-N-nitrosourea (MNU)-induced mammary cancer in female Lewis rats that received STEPT in early or later life. MATERIALS AND METHODS: Rats in Groups 1 and 2 received a single intraperitoneal injection of 50 mg/kg MNU at 4 weeks old. Pellets containing 0.5 mg 17beta-estradiol and 32.5 mg progesterone (EP) were subcutaneously implanted in rats in Group 1 during 6-9 weeks old. Rats in Groups 3 and 4 received 50 mg/kg MNU at 22 weeks old and again at 23 weeks old. EP pellets were implanted in rats in Group 3 during 24-27 weeks old. At the time of EP removal and 8 weeks afterward, 4 randomly selected rats in each group were sacrificed for blood sampling. The fatty acid composition of serum phospholipids was measured by capillary gas chromatography. The remaining rats were sacrificed when they developed mammary tumours >or=1 cm in diameter or at the termination of the experiment, which was at 18 weeks old for Groups 1 and 2 and at 64 weeks old for Groups 3 and 4. Mammary cancer was histologically confirmed. RESULTS: Group 1 had a significantly suppressed incidence of mammary cancer compared to Group 2 (7% vs. 90%), whereas the cancer incidence in Group 3 was similar to that of Group 4 (50% vs. 56%). Rats in Group 1 had significantly smaller n-6/n-3 polyunsaturated fatty acid (PUFA) ratios and higher levels of docosahexaenoic acid (DHA) than those in Group 2 at the time of EP removal but not 8 weeks after EP removal. Neither the PUFA ratios nor the DHA levels differed between Groups 3 and 4 at any time. These data suggest that the age at which STEPT is administered is important, since its mammary cancer-suppressing potential was lost in aged animals. CONCLUSION: DHA and the n-6/n-3 PUFA ratio may play a crucial role in mammary cancer suppression by STEPT.

Solitary fibrous tumor of soft tissue: a case report and immunohistochemical study.

A case of solitary fibrous tumor (SFT) arising in the soft tissue of the left inguinal region is reported. A 57-year-old Japanese woman presented with a nonadherent, well-defined, oval mass that was 2 x 3 cm in diameter and located in the inguinal soft tissue. Microscopic evaluation showed proliferation of spindle-shaped, fibroblast-like cells by the coexistence of hypo- and hypercellular areas with mast cell infiltration separated by hemangiopericytoma-like blood vessels. Immunohistochemistry revealed strong expression of CD34 and CD99 in the fibroblast-like cells, supporting the diagnosis of SFT. Although the patient was free of symptoms such as hypoglycemia, immunoreactive insulin-like growth factor (IGF)-II was localized in the socalled Golgi area of the spindle-shaped cells. In conclusion, immunoreactive IGF-II was detected in SFT that was not associated with hypoglycemia.

Ocular toxicity caused by Paclitaxel in neonatal sprague-dawley rats.

BACKGROUND: The toxic effects of paclitaxel (PTX) on neonatal eyes have not been evaluated. MATERIALS AND METHODS: PTX was dissolved in solvent containing polyethoxylated castor oil and intraperitoneally administered to male and female Sprague-Dawley rats at a dose of 0, 2, 4 and 8 mg/kg at 0 day of age, 4 mg/kg at 14 days of age, or 8 mg/kg at 12-18 weeks of age. Eyes were histologically examined 1 and/or 7 days after PTX. RESULTS: Male and female rats that received 4 mg/kg or more of PTX at 0 days of age developed cataracts and retinal dysplasias, while the rats that received other dosing regimens did not develop ocular lesions. Epithelial cells in the lens were apoptotic on day 1, and lens fibers were degenerative at day 7, indicating the development of cataracts. Scattered foci of apoptosis in the neuroblastic layer of the retina on day 1, and rosettes were seen on day 7, suggestive of retinal dysplasia. CONCLUSION: Neonatal rats that received a threshold dose of PTX (4 mg/kg) at a critical period (0 days of age) developed cataracts and retinal dysplasia; however, the 2 mg/kg dose at 0 days of age and the 4 or 8 mg/kg dose at 14 days of age or older caused no ocular damage. Thus, the determination of the dose and timing of PTX treatment administered during the early developmental stage requires great care to avoid ocular toxicity.

N-methyl-N-nitrosourea-induced retinal degeneration in mice is independent of the p53 gene.

PURPOSE: A single systemic administration of N-methyl-N-nitrosourea (MNU) causes retinal degeneration involving photoreceptor cell loss within 7 days. MNU-induced photoreceptor cell loss is due to apoptosis and is a reliable animal model for human retinitis pigmentosa. The purpose of this study was to determine if p53 contributes to the development of MNU-induced retinal degeneration in mice. METHODS: Eight-week-old p53(-/-), p53(+/-), and p53(+/+) mice received an intraperitoneal injection of 60 mg/kg bodyweight of MNU. Age-matched p53(+/+) mice received the vehicle only (physiologic saline containing 0.05% acetic acid). Mice were sacrificed and necropsied 7 days after the treatment. Both eyes were examined histologically and morphometrically to determine retinal thickness, photoreceptor cell ratio, and retinal damage ratio. RESULTS: No mice died during the experiment, but the p53 null mice treated with MNU had a statistically significant weight loss compared to the other groups. Histologically, all MNU-treated mice, regardless of p53 gene status, experienced retinal degeneration characterized by photoreceptor cell loss (the disappearance of the outer nuclear layer and photoreceptor layer) in both the central and peripheral retina. All MNU-treated mice had significantly decreased retinal thickness and photoreceptor cell ratios at the central and peripheral retina and an increased retinal damage ratio compared to the vehicle-treated control. The retinal changes caused by MNU in p53(+/+), p53(+/-), and p53(-/-) mice were not significantly different and hence were related to a p53-independent apoptotic mechanism. CONCLUSIONS: Because the absence of p53 did not prevent photoreceptor cell loss, we conclude that p53 is not essential for MNU-mediated photoreceptor cell degeneration.

An autopsy case of chronic progressive external ophthalmoplegia with renal insufficiency.

An autopsy of a 44-year-old Japanese woman with mitochondrial cytopathy confirmed the presence of chronic progressive external ophthalmoplegia (CPEO). Immunohistochemistry using antimitochondrial antibody was performed to observe the ultrastructure of the skeletal muscle and renal tissues. The patient was born of consanguineous parents, developed normally, and was of average intelligence. At 22 years of age, the patient noticed hearing loss, and subsequently, over time, developed a progressive generalized muscle weakness, which included limitation of eye movement and ptosis. At age 41, a muscle biopsy was performed using the modified Gomori trichrome method and demonstrated the presence of ragged red fibers. After the evaluation of her results in conjunction with her clinical course, she was diagnosed with CPEO. Renal insufficiency was discovered at age 30, and the patient died at the age of 44 of respiratory failure caused by respiratory muscle weakness and pneumonia. The autopsy revealed fiber size variation within the skeletal muscle, and an antimitochondrial antibody analysis demonstrated the accumulation of mitochondria between the bundles of myofibrils, as well as in subsarcolemmal locations. Ultrastructurally, abnormal mitochondria with disoriented cristae and paracrystalline inclusions were seen. Although no remarkable histological changes were noted in the kidneys, tubular epithelial cells exhibited accumulated abnormal mitochondria, similar to those seen in the skeletal muscle. Because mitochondrial diseases can affect other energy-dependent organs in addition to the skeletal muscle, immunohistochemical examinations employing an antimitochondrial antibody are useful for obtaining further ultrastructural observations that can assist in making a distinct diagnosis of this systemic disorder.