Odontomas in Peromyscus leucopus.

A colony of Peromyscus leucopus was established 15 years ago from animals trapped in the deciduous forest at Argonne National Laboratory, Argonne, Illinois. A roentgenographic survey of the skeletons of 189 of these untreated animals dying during a 13-month period disclosed 48 odontogenic growths in 21 of the mice. These growths were diagnosed on histopathologic examination as complex odontomas, the incidence of which was higher in males than in females. In this relatively small sample, these benign tumors appeared to be associated with youth rather than old age.

Increased incidence of malignant tumors in dogs after total body irradiation and marrow transplantation.

One hundred fifty-three dogs were given 6.1-21.3 Gy total body irradiation at 0.02-0.2 Gy/minute delivered from two opposing cobalt sources followed by allogeneic (131 dogs) or autologous (22 dogs) marrow grafts and observed for 6-127 (median 33) months. The incidence of malignant tumors in radiation chimeras was compared to that in 242 untreated dogs observed for 6-188 (median 81) months. Thirteen malignancies were observed in 11 radiation chimeras. These tumors included two leiomyosarcomas of the mesentery, four adenocarcinomas of the breast, prostate and ovary, two mastocytomas, one hypernephroma, perianal gland carcinoma, seminoma, Brenner tumor, and an oligodendroglioma. Fifty-four malignancies were seen in 44 control dogs. These included 12 mammary carcinomas, 12 thyroid carcinomas, six lymphomas, two malignant melanomas, and a number of other solid tumors. On the basis of time-dependent Cox regression analysis, radiation chimeras had an estimated relative risk of developing a malignancy that was 5-fold higher than in control dogs (p less than 0.001). No tumor has yet been observed in a group of 15 chimeras conditioned by cyclophosphamide or dimethyl busulfan and followed for 6-97 (median 24) months. The increased risk of cancer among canine radiation chimeras suggests that high-dose total body irradiation may increase the risk of developing a malignancy and should be avoided whenever possible in the conditioning for marrow transplantation of human patients with nonmalignant diseases.

The comparative tumorigenic effects of fission neutrons and cobalt-60 gamma rays in the B6CF1 mouse.

In the period from 1971 to 1986, both sexes of the B6CF1 (C57BL/6 x BALB/c) mouse were exposed at 110 +/- 7 days of age to single, 24 once-weekly or 60 once-weekly doses of fission neutrons or 60Co gamma rays. A small group of males was also exposed to gamma rays for 22 h/day, 5 days/week, for either 23 or 59 weeks, the elapsed times for the 24 and 60 once-weekly series. All mice were followed for their natural lifetimes. A gross pathology report is available on 32,000 animals, and a histopathology record is available on about 19,000. About 85% died with or from one or more neoplastic diseases. The principal tumors observed at death were of lymphoreticular (45-60%), vascular (20%), or pulmonary (35-50%) origin. From 4 to 10% died with fibrosarcomas, hepatocellular tumors, ovarian tumors, and tumors of the Harderian, adrenal, and pituitary glands. Dose-response equations (linear and linear-quadratic) were fitted to the data for deaths from and occurrences of eight different individual or groups of tumors. Equations were constrained through the control intercepts and fitted separately for the two sexes, the two radiation qualities, and all exposure patterns for the two intervals of 600-799 days and 800-999 days from first exposure. RBE values were derived from the ratios of linear coefficients of dose-response curves. RBE values increased as dose was protracted, largely due to the reduced effectiveness of protracted gamma irradiation; however, about 28% of the increase can be attributed to the increase in neutron-induced injury caused by dose protraction. Highest RBE values were seen for tumors of epithelial tissue origin and the lowest for tumors of connective tissue origin. The range for significant values was from about 2 to over 50. Nonneoplastic diseases accounted for about 5% of all deaths, and 10% were classified as from unknown causes. Neither category responded to differences in radiation quality or exposure patterns.

The role of imagery in self-hypnosis: its relationship to personality characteristics and gender.

30 volunteer Ss practiced self-hypnosis for approximately 4 weeks and wrote a record of their experiences in a diary following each session. Imagery produced during self-hypnosis was coded in 2 ways: the imagery was either reality oriented or it was fantastic and had primary process qualities. Levels of imagery production remained virtually the same over a 4-week period. Self-hypnotic imagery was significantly greater for the female Ss than for the male Ss, particularly primary process imagery. Verbal expressivity (measured as the average number of words per page of each S diary) was calculated to control for the effects of verbal production on Ss' imagery scores. When imagery scores were standardized based on verbal expressivity, female Ss still produced significantly more primary process imagery than male Ss. Personality characteristics (assessed by standardized personality inventories) were examined in relation to self-hypnotic imagery. "Impulse Expression" was positively related to primary process imagery for the female Ss. "Outgoingness" was positively related to primary process imagery for the entire sample, but especially for the female Ss.

The relation of self-reports of hypnotic depth in self-hypnosis to hypnotizability and imagery production.

The relationship of self-reports of hypnotic depth obtained during self-hypnosis to hypnotizability and to the kinds of imagery produced during self-hypnosis is investigated. The sample consisted of 22 highly hypnotizable Ss who practiced self-hypnosis in 1-hour daily sessions for 4 weeks and kept daily journals in which they detailed the contents of their self-hypnosis experiences. The journals were coded for imagery production by scoring for both reality-oriented and primary process imagery. Ss had been taught to monitor their hypnotic depth using a slightly revised version of the Extended North Carolina Scale (ENCS) of Tart (1979). Previously, ENCS has been used only with heterohypnotic Ss. The self-reports of depth using ENCS correlated highly with hypnotizability as measured by the Revised Stanford Profile Scale of Hypnotic Susceptibility. Form I of Weitzenhoffer and Hilgard (1967) and with imagery production. Results demonstrate that ENCS scores are also a valid indicator of self-hypnotic depth among highly hypnotizable Ss. Furthermore, they indicate that both hetero-hypnotizability and imagery production are related to self-hypnotic depth, but that the association between imagery and hypnotizability is due to their individual relationships to self-hypnotic depth.

Mouse ovarian tumors--a review including classification and induction of neoplastic lesions and description of several previously unreported types.

The purpose of this study is to review the pertinent literature on the incidence, methods of induction and pathogenesis of ovarian tumors of mice. Strains of mice with a high incidence of spontaneously occurring granulosa cell tumors (gct) and tubular adenomas (ta) are the C3HeB/Fe and C3HeB/De; strain HAN:NMRI developed Sertoli cell tumors and (DBA x Ce)F1 hybrids had a high incidence gct. Ninety-five percent of hybrid (C57BL/6J x C3H/HeJ)F1 WxWv mice which lack germ cells develop complex tubular adenomas. Strain LT, in which a high percentage of ovarian ova develop parthenogenetically, develops has a high incidence of teratomas. The use of hormones, castration and transplantation of the ovaries in a number of inbred strains results in a high incidence of ovarian tumors; in strain Maf/Sp gct and luteomas were induced in 82%. Irradiation with gamma rays produced a similar incidence of ovarian tumors in (C57L x A)F1 hybrids. The chemical inducing the highest incidence (92%) of ovarian tumors of mice is 9,10 Dimethyl 1,2 benzanthracene (DMBA). Recently, 4-Vinylcyclohexene was shown to induce a high incidence of ovarian tumors. A number of rare ovarian tumors were reported. Described are five androblastomas composed of either Leydig or Sertoli cells or a combination of the two cell types and a single undifferentiated androblastoma. Seven teratomas were described, three of which contained large amounts of neural tissue; another was classified as a teratoma with a parieto-visceral yolk-sac carcinoma component.

Acute monocytic leukemia in an irradiated Beagle.

A purebred female Beagle dog that had received 2,000 R of protracted wholebody gamma-irradiation from 60Co when 14 months old had hematologic changes consistent with a myeloproliferative disorder 3 years after the termination of radiation exposure. Peripheral blood and bone marrow findings during the 7-month period before death showed progressive anemia with increased numbers of platelets; immature granulocytes, monocytes and promonocytes. A period of partial remission occurred during which time the peripheral blood was aleukemic, although there was marked thrombocytosis and abnormal erythropoiesis which was evidenced by bizarre circulating nucleated red cells, anisocytosis, poikilocytosis and Howell-Jolly bodies. The dog had a terminal crisis with marked leukocytosis, most cells in the peripheral blood being bizarre monocytes and promonocytes. Tissues obtained at necropsy showed diffuse as well as focal infiltration of the spleen, liver, lymph nodes, heart, kidney and gastrointestinal wall with immature neoplastic cells resembling monocytes and monocytic precursors. The monocytic differentiation of the invasive cell population was confirmed by morphological, cytochemical, histological, ultrastructural and in vitro cell culture studies.

The ultrastructure of radiation-induced endosteal myelofibrosis in the dog.

A rapidly developing, progressive form of endosteal myelofibrosis (MF) (with myeloid metaplasia) has been shown to occur at low frequency (approximately 4%) in dogs exposed continuously to low daily doses (10 R/day) of whole-body gamma irradiation. We report in this study the morphological details of the endosteal surface during both preclinical and clinical phases of developing MF by combination light microscopy and scanning/transmission electron microscopy. Pronounced alterations of the endosteum were observed and included: (1) during the early preclinical phases, a progressive time-dependent transition of the endosteal surface from predominantly resting to actively formative and resorptive states; and (2) during the late preclinical phase, aberrant autonomous osteogenic process(es) characterized by a marked reduction in the resorptive, osteoclast-associated endosteal areas occurring concomitantly with further increases in formative areas of the endosteum. Localized patches of overlapping, morphologically transformed endosteal cells (i.e., round-osteoblastic to branched-reticular shaped) were observed within the morphologically reactive, formative endosteum. Osteogenic-endosteal changes coincided with major restructuring of the hematopoietic parenchyma and supporting stromal network. We discuss the possibility that the early occurring endosteal changes are causally linked to normal reparative functions that operate during regenerative hematopoiesis following local and systemic injury. Based on morphological data collected during the late preclinical phase, we speculate that the mechanism of myelofibrosis induction involves the failure to terminate early osteogenic-dependent repair sequences.