Trichloroethylene (TRI), administered orally at high doses for 18 months has been shown to increase the incidence of hepatocellular carcinoma in B6C3F 1 mice but not Osborne-Mendel rats (NCI, 1976). The interpretation of these studies has been confounded due to the presence of epoxide stabilizers in the TRI. However more recent studies have demonstrated that pure TRI also causes hepatocellular carcinoma in B6C3F mice (NTP, 1983) and Aldedey Park (Swiss) mice (Elcombe 1 and Pratt, unpublished data). Furthermore, no increase in the incidence of hepatocellular carcinoma was observed in Fisher 344 rats administered pure TRI (NTP, 1983). TRI has been extensively examined for mutagenic potential, but many studies were bedeviled by the presence of mutagenic epoxide stabilizers. However, in general, TRI has been found to be only 'marginally' mutagenic or non-mutagenic (Greim et ai., 1975; Simmon et ai., 1977; Bronzetti et ai., 1978; Waskell, 1978; Bartsch et ai., 1979; Slacik-Erben et ai., 1980). Covalent binding of trichloroethylene or its metabolites to protein, RNA and DNA has been illustrated in vitro (Van Duuren and Banerjee, 1976; Bolt et ai., 1977; Bolt and Filser, 1977; Uehleke and Poplawski-Tabarelli, 1977; Banerjee and Van Dauren, 1978). However, in vivo, only extremely low (indistinguishable from protein binding) or zero binding of TRI metabolites to DNA has been reported (Parchman and Magee, 1982; Stott et ai., 1982).

Many chemotherapeutic agents introduced for use in humans are carcinogenic in laboratory animals (Conklin et al. 1965; Shimkin et al. 1966; Griswold et al. 1968; Harris 1976). However, initially their beneficial effect in disseminated cancer was of such short duration that the inevitable death of the patient from his primary disease precluded any clinical manifestation of the carcinogenic potential. During the last decade, chemotherapy has radically changed the outlook for many patients with cancer. Combinations of drugs, administered as the primary treatment, have resulted in high rates of cure in patients with disseminated malignancies, such as stage IV Hodgkin's disease or childhood acute lymphocytic leukemia. In other disseminated forms of neoplasia, induction of a remission, a substantial palliation and a prolongation of survival have been achieved. In many instances of localised disease, where surgery with or without radiotherapy are the primary form of treatment, anticancer drugs have been used with success as adjuvant therapy for distant microscopic disease. With these spectacular achievements, secondary malignancies, in particular acute non-lymphocytic leukemia (ANLL), has become of major concern. Incidence Acute leukemia is the most frequent form of secondary neoplasia in patients treated for cancer (Penn 1981). In one large series, 5. 9% of all ANLL could be attributed to previous chemotherapy (Kapadia et al. 1980).

Nervous system is in the most cases a likely target for the untoward effects of chemicals. The harmful consequences affect primarily the individual but may also considerably strain the whole society. The consumption of ethanol is a glaring example (National Institute on Alcohol Abuse and Alcoholism 1978). As ethanol, many organic liquids have similar immediate effects on the nervous system. The rapidity of the response suggests the involvement of the neuronal communication. The nervous system is also vulnerable to the depletion of oxygen, another common cause for the rapid deterioration of the brain function. It is quite impossible to list all the effects produced by the very large number of the individual chemicals. It would be more fruitful to try to understand the characteristics of the nervous system and the biochemical toxic mechanisms in the evaluation of the neurotoxicity of chemicals. Transfer of Xenobiotics in the Brain The adult central nervous system displays a functional barrier toward the blood-borne chemicals so that water-soluble compounds with an approximate molecular weight above 100 are largely prevented from directly entering the brain (Bradbury 1979). The functional barrier has morphological features typical to it and has a very close association of adjacent capillary cells separated by clefts of 12 A wide (Jacobs 1978). The nervous system capillaries are enveloped by glial cell tongues, and these pericytes contain contractile elements (Le Beux and Willemot 1978a, b) so that the capillaries can be constricted.

The first oral contraceptive became available in 1960 and since then these sub stances, which have been used by millions of women, have probably been the most widely studied group of drugs in medical history (Drill, 1966, 1977). Part of the evaluation oCoral contraceptives has involved their effect on the reproductive organs of women, with particular attention directed to evaluation of a possible carcinogenic effect of these steroids. To the extent that cancer of the reproductive organs is a common finding in women, the endogenous female sex hormones have been implicated in the occur rence of the cancer. The administration of estrogen has also been reported to in crease the incidence of cancer of the breast, cervix or endometrium in some strains or species of animals. Thus, because of the possible tumorigenic effect of estrogens there has been considerable interest in the relationship of oral contraceptives to cancer of the breast and genital tract."

The second year of Latin instruction can be the most difficult for student and teacher alike. Students must remember a seemingly endless array of grammatical rules and vocabulary, and often the material to be translated seems dull and lengthy beyond endurance. P. L. Chambers has found a way to overcome these problems, with the help of one ancient Roman. Aulus Gellius, a well-educated nobleman, is best known today for a collection of observations titled Noctes Atticae, a project he began during the long winter nights he spent in Attica, the region of Greece where Athens is located. The selections chosen for this reader touch on diverse aspects of Roman culture and can be easily understood and translated by intermediate students. For the Second Edition, Chamber added three new chapters, one of which centers on Aulus Gellius's translation of a letter to Aristotle by Philip of Macedon announcing the birth of his son Alexander. A classroom-tested book, The Attic Nights of Aulus Gellius, Second Edition, will motivate second-year students to continue their course of study while providing a much-needed alternative for Latin instructors seeking accessible textbooks for their students. A Teacher Key accompanies the text.

For students of Latin - even those at an advanced level - reading original works by Latin authors can be daunting. Students must remember a seemingly endless array of grammatical rules and vocabulary, and often the material to be translated seems dull and lengthy beyond endurance. Here P. L. Chambers overcomes these challenges through her engaging presentation of the writings of Pliny the Elder. Pliny the Elder (23-79 a.d.) was a military officer and imperial administrator of the early Roman Empire. His avid interest in natural phenomena led him to write the Natural Histories, an encyclopedic work encompassing subjects as diverse as astronomy, geography, biology, zoology, botany, medicine, and gemology. The passages from the Natural Histories included here for translation are enjoyable to read and revealing of what first-century Romans thought about their world. Accompanying the Latin texts are the following features: Quick grammatical reviews at the start of each chapter Examples from the Latin passages that demonstrate relevant grammatical topics Sentence exercises based on the original text End-of-chapter vocabulary lists specific to the chapter readings Grammatical tables at the end of the book for quick reference A glossary that includes basic vocabulary A teacher's key, available to instructors upon request Classroom-tested by the author, this appealing reader motivates students to continue their study of Latin and provides a welcome alternative for instructors seeking accessible textbooks for their students.

A student-friendly introduction to LatinLearning Latin can prove daunting even to the brightest students. But this innovative text draws students into the story of Rome and lets Virgil and Livy lead the way in learning declensions and conjugations. Latin Alive and Well is a classroom-tested textbook consisting of 36 units. It is designed for both high school and university classes, in both two-semester courses and intensive one-semester courses. Clear and direct, it avoids lengthy explanations in teaching grammar, instead introducing modern students to this venerable language by focusing on exercises and translations that make fine points of grammar more readily understandable. P. L. Chambers presents essential elements of grammar in a way that enables students to read classical authors immediately, introducing them to a passage from Virgil as early as the fifth chapter. In addition to using selected readings in Roman mythology, history, and philosophy to illustrate grammatical points, she has adopted an informal, encouraging tone, with a healthy dose of humor when appropriate. Latin Alive and Well is written so simply that students with no previous exposure to a foreign language can understand and learn the grammatical concepts. Previously available only in privately published editions, it has been used nationwide.