Phosphatidylethanolamine synthesis in ethanolamine-responsive and -nonresponsive cells in culture

Mammalian cells can be classified into two types based upon whether or not they show growth response to ethanolamine (Etn) in culture. The content of phosphatidylethanolamine (PE) in phospholipid and incorporation of radioactive Etn into the cells were examined in the Etn-responsive and -nonresponsive cells in order to elucidate the mechanisms of growth stimulation by Etn. In all Etn-responsive cells tested, 5 microM Etn significantly altered the composition of cellular phospholipid compared to that grown without Etn, while Etn-nonresponsive cells had a similar phospholipid composition whether the growth medium contained Etn or not. Using two rat mammary carcinoma cell lines, 64-24 (responsive type) and 22-1 (nonresponsive type), further studies were carried out. In 64-24 cells there was a proportional increase in PE content as the dosage of Etn in the medium was increased. The increase in PE content leveled off at 10 microM. Further, the increase in PE content was correlated with increased rate of growth. In contrast, PE content or growth rate did not change at all in 22-1 cells. In 64-24 cells radioactive Etn (0.1-50 microM) was incorporated four- to five-fold more efficiently into phospholipid, and the aqueous pool of precursors of PE was ten times less as compared to 22-1 cells, indicating that Etn-responsive cells utilize Etn supplied in the medium to synthesize PE far more efficiently than Etn-nonresponsive cells. De novo synthesis of PE must not be sufficient to support optimum growth in Etn-responsive cells.

Dexamethasone suppression tests in antidepressant treatment of melancholia. The process of normalization and test-retest reproducibility

Pilot studies suggest that changes in response to the dexamethasone suppression test (DST) in melancholic patients receiving antidepressants might represent a laboratory marker of clinical progress. We performed weekly DSTs in 31 hospitalized patients with major depressive disorder, primary and endogenous subtypes, during drug-free and subsequent treatment periods. Most nonsuppressors had progressive normalization of DST responses in conjunction with clinical improvement, DST normalization usually preceded or coincided with good clinical response, and failure to normalize was often associated with poorer clinical outcome. Occasional patients with baseline dexamethasone suppression become nonsuppressive after withdrawal from medication, but the DST has no apparent value as a serial marker in patients with well-documented normal DST findings. Our results extend the construct validity of the DST as a state-related marker in nonsuppressors and suggest future clinical applications.

Primary herpes simplex pneumonia in a neonate

A 6-day-old male infant was treated for rapidly progressive pneumonia. The infection was not responsive to antibiotic and symptomatic treatment, and the infant died within 48 hours of admission. Herpes simplex type II grew from premortem respiratory and postmortem lung cultures, and immunoperoxidase staining confirmed the presence of this organism in lung tissue. Pathologic findings were limited to the lungs. A maternal origin for the virus was suspected but could not be proved. We believe this patient represents the first reported case of isolated herpes simplex type II pneumonia in a neonate.

Bipolar outcome in the course of depressive illness. Phenomenologic, familial, and pharmacologic predictors

Twenty percent of a cohort of 206 outpatient depressives with no past bipolar history switched during prospective observation. These 41 probands developed manic periods on the average of 6.4 years (median 4, range 1-25) after their first depressive episode. The change in polarity occurred throughout the life span, but was most common in adolescence and early adulthood. The following variables were found useful in predicting this outcome: onset less than or equal to 25 years, bipolar family history, loaded pedigrees, precipitation by childbirth, hypersomnic-retarded phenomenology, and pharmacologically-mobilized hypomania. Although the respective sensitivities of these findings were relatively low (32-71%), their specificities ranged from 69% to 100% for bipolar outcome; the diagnostic specificity of any 3 of these variables when combined was 98%. When compared with nonbipolar depression, bipolar disorder was seldom chronologically secondary to nonaffective psychiatric disorders. These findings suggest that many young depressives with lethargy and oversleeping are not manifesting a "neurotic" disorder, but rather a precursor of primary bipolar affective disorder. Finally, a psychotically depressed adolescent or young adult with positive bipolar family history should be observed for eventual bipolar outcome, especially when the clinical presentation is that of stupor.

A cluster of repetitive elements within a 700 base pair region in the mouse genome

Approximately 39% of the clones from a BALB/c mouse genomic library hybridized with polyadenylated cytoplasmic RNA extracted from anemic mouse spleen. The DNA sequence of a portion of one such clone revealed the presence of three repetitive sequence elements within a 700 bp span. All three elements contain putative RNA polymerase III control regions oriented in the same direction and oligo(dA) tracts at their 3' ends. The first element is a member of the murine B1 family. A comparison of this element with other B1 family members indicates that the B1 family can be divided into two subclasses based on commonly held base changes and deletions. The second element within this 700 bp region may be a member of a new murine Alu family. Its structure is analogous to other murine Alu-equivalent sequences with respect to overall length, the presence of a 3' oligo(dA) tract and putative RNA polymerase III control regions. The third element is a murine type 2 Alu-equivalent sequence.

Response to dexamethasone suppression and total night sleep deprivation in an affectively disordered Klinefelter patient

A 50-year-old Klinefelter patient acutely developed a psychotic depression which rapidly responded to treatment with amitriptyline. This patient exhibited an early escape from dexamethasone suppression and became hypomanic the morning after total night sleep deprivation. The findings suggest that the use of biological tests to study affective syndromes occurring in Klinefelter patients might yield clues regarding the existence of pathophysiological common denominators of primary and Klinefelter-associated affective disorders.

The dexamethasone suppression test as a predictor of sleep deprivation antidepressant effect

An abnormal dexamethasone suppression test (DST) result, a sensitive and specific marker for endogenous depression, was found to be associated with an antidepressant response to sleep deprivation in patients who met DSM-III criteria for Major Depressive Episode regardless of whether they met criteria for melancholia or psychotic subtypes of this disorder. These findings support previous reports of an association between an abnormal DST result and antidepressant effects of sleep deprivation in depressed patients. Our results extend the positive association between an abnormal DST result and the antidepressant response to sleep deprivation to include depressed patients who are clinically nonmelancholic during their current episode but who have an abnormal DST result.

The utility of the REM latency test in psychiatric diagnosis: a study of 81 depressed outpatients

To examine the utility of the REM (rapid eye movement) latency test in identifying outpatient primary depressions, 81 consecutive referrals to a sleep disorders center were evaluated in a phenomenologic, sleep polygraphic, and psychometric study. Modified Feighner (St. Louis) diagnoses were definite primary depression (n = 19), probable primary depression (n = 30), depression chronologically secondary to preexisting psychiatric disorders (n = 19), and nonaffective psychiatric disorder (n = 13). There were 18 nonpsychiatric controls. REM latency less than 70 minutes on 2 consecutive nights detected 62% of primary depressions, discriminating them from the other diagnostic groups with 88% specificity. There were no false positives among controls. These data provided a 90% confidence for the diagnosis of primary depression in this outpatient sample. Requiring 2 consecutive nights of shortened REM latency appears to improve significantly the specificity of a test previously considered to have high sensitivity but relatively low specificity for depressive disorders.

H(2) and CO(2) Evolution by Anaerobically Adapted Chlamydomonas reinhardtii F-60

Using manometric and enzymic techniques, H(2) and CO(2) evolution in darkness and light has been studied in the green alga Chlamydomonas reinhardtii F-60. F-60 is a mutant strain characterized by an incomplete photosynthetic carbon reduction cycle but an intact electron transport chain.In the dark, starch was broken down, and H(2) and CO(2) was released. The uncoupler, carbonyl cyanide m-fluorophenylhydrazone with an optimum concentration of 5 to 10 micromolar, increased the rate of CO(2) release and starch breakdown but depressed H(2) formation. It was suggested that carbonyl cyanide m-fluorophenylhydrazone increased the rate of starch breakdown by making the chloroplast membrane permeable to H(+), removing a rate-limiting step, and leading to an altered fermentative pattern.Photoevolution of H(2) and CO(2), but not starch breakdown, was stimulated by acetate. Maximum stimulation occurred at concentrations from 1 to 10 millimolar. Carbonyl cyanide m-fluorophenylhydrazone stimulated starch breakdown and CO(2) and H(2) release in the light, but not to the extent of acetate. Inasmuch as the uptake and subsequent metabolism of acetate required ATP, it was suggested that acetate, like carbonyl cyanide m-fluorophenylhydrazone, stimulated H(2) photoproduction by removing ATP which limited the sequence of reactions. The contribution of photosystem II to the photoproduction of H(2), as judged from the effect of 10 micromolar 3-(3,4-dichlorophenyl)-1, 1-dimethylurea, was at least 80%.CO(2) photoevolution increased linearly with time, but H(2) photoevolution occurred in two phases: a rapid initial phase followed by a second slower phase. The rate of H(2) release increased hyperbolically with light intensity, but the rate of CO(2) production tended to level off and decrease with increasing light intensity, up to 145 watts per square meter. It was proposed that a changing CO(2) and H(2) ratio is the result of interaction between the carbon and hydrogen metabolism and the photosynthetic electron transport chain.

Stimulus and response contingencies in the misbehavior of rats

Misbehavior by rats, in the form of unnecessary and species-typical pawing, nosing, carrying, chewing, and retrieving a rolling ball bearing, was produced by pairing the ball bearing with food (Pavlovian procedure, Experiments 1 and 2) or by requiring contact with the ball bearing for food (operant procedure, Experiments 4 and 5). Misbehavior occurred both before and after eating the food pellet. The frequency, complexity, and duration of pre-pellet misbehavior was increased by delay of food until after the ball bearing exited (or was programmed to exit) and by requiring contact with the bearing to obtain food. Alternative goal-directed behavior, in the form of nosing, gnawing, and licking the food tray, occurred in Pavlovian contingencies in which food was delivered before the bearing was programmed to exit. Post-pellet misbehavior tended to occur when food was delivered before the bearing was programmed to exit and, in the case of required contact, before the animal released the bearing. Omission of food delivery on contact reduced the duration, complexity, and frequency of misbehavior, though experienced animals continued to contact (Experiment 3). In general, misbehavior was affected by both stimulus- and response-reward contingencies but showed characteristic organization and topography under both types of contingency.

REM density in the differential diagnosis of psychiatric from medical-neurologic disorders: a replication

The discriminatory power of rapid eye movement (REM) density in 61 outpatients with medical, neurologic, and psychiatric disorders and 8 noncase controls was assessed. REM density was significantly lower in a group of patients with medical-neurologic disease as compared with psychiatric and control subjects without evidence for such disease. Furthermore, low scores discriminated depressions occurring in the context of somatic disease when compared with those in the absence of such disease. The differences between groups were not accounted for by age or sex. The cutoff REM density score of 12.56, based on the 99% lower confidence limit of the noncase controls, provided the highest sensitivity (0.82) without loss of specificity (0.80). It was concluded that REM density may have merit as a general measure of diffuse central nervous system pathology, whether primary or secondary to widespread systemic disease. The findings of Kupfer's group are upheld and extended to a broader medical and neuropsychiatric population than in the original Pittsburgh study.

Chronic depressions. Part 1. Clinical and familial characteristics in 137 probands

Factors associated with chronicity in 137 probands with 2 or more years of low-grade intermittent depression were evaluated in a naturalistic setting. Four groups were tentatively identified and chronicity related to: (1) early onset (less than 25 years) intermittent subsyndromal or dysthymic depressions with positive family history for both unipolar and bipolar illness; (2) a spectrum of 'unstable' characterologic disorders with history for childhood object loss; (3) pre-existing non-affective psychiatric or incapacitating medical disorders, especially in combination; (4) incomplete remission from late-onset primary unipolar episode(s) with strong familial background for affective illness, multiple object losses, alcohol and sedative hypnotic dependence, superimposed incapacitating medical disorders, use of depressant antihypertensive agents, disabled spouses, and 'marital deadlock'. Beneficial effects of thymoleptic drugs and practical psychotherapy occurred in 45% of the total sample and were largely limited to groups 1 and 4. These findings argue against a common clinical stereotype that equates all chronic depressions with character disorder.

Difference between influences of homologous and heterologous maternal antibodies on response to serotype-2 and serotype-3 Marek's disease vaccines

Marek's disease (MD) vaccines representing serotypes 2 (SB-1 strain of MD virus) and 3 (FC-126 strain of turkey herpesvirus) were administered to 1-day-old MD-susceptible chicks that either were free of antibodies or carried maternally derived antibodies against SB-1, FC-126, or a serotype-1 MD virus, CU-2 strain. Homologous antibodies delayed the development of vaccine virus viremias and inhibited vaccinal immunity, as judged by protection against challenge with the virulent JM-10 strain of MD virus 7 days postvaccination. Heterologous antibodies had little effect on vaccine responses. Antibodies were shown to interfere with both cell-associated and cell-free vaccine virus.

Three cheers for conflict!

Conflict is pervasive and an inevitable part of life--at work and elsewhere. But author Dennis King, organizational consultant for The Procter & Gamble Manufacturing Company, adds that it is also a functional part of the social process. Managing conflict on the job involves the ability to identify, seek out, and utilize the functions of conflict and its outcomes. He identifies fifteen functions of conflict in three major categories: maintaining or reinforcing identity and innate strength, increasing operational effectiveness, and dealing with others. For example, conflict can lead to minor clashes that actually strengthen a relationship because they function as safety valves--preventing the buildup of tension to the stage of explosion. (Note, however, that a conflict over the basic foundation of a relationship spells trouble.) Similarly, in the union-management relationship, both negotiations and grievance handling focus on adjusting or eliminating problem elements so that the employer-employee relationship can exist satisfactorily. Recognizing and exploiting the functions of a conflict situation--that is, functional conflict management--can work to our benefit. If we develop a "functional mind-set," looking for the positive aspects of conflict will become natural.

Traumatic aneurysm of the descending geniculate artery: a complication of suction drainage in synovectomy for hemophilic arthropathy

A traumatic false aneurysm of the descending genicular artery developed as a complication of suction drainage of a knee following synovectomy in a patient with hemophilic arthropathy. The aneurysm enlarged in spite of Factor VIII replacement therapy, and surgical resection was required. As a precautionary measure, in knee arthrotomy operations, trocar-tipped catheters could be passed through the lateral side of the suprapatellar pouch.

Inactivation of Hydrogenase in Cell-free Extracts and Whole Cells of Chlamydomonas reinhardi by Oxygen

O(2) irreversibly inactivates hydrogenase from Chlamydomonas reinhardi. The mechanism for the inactivation involves the reaction of one molecule of hydrogenase with one molecule of O(2) (or two oxygen atoms) in the transition complex of the rate-limiting step. The second order rate constant for this reaction is 190 atmospheres(-1) minute(-1) (1.4 x 10(5) molar(-1) minute(-1)). At levels above 0.01 atmosphere O(2), the increased numbers of O(2) molecules may compete for the site of inactivation hindering the proper orientation for inactivation of any one O(2) molecule and resulting in lowered rates of inactivation.CO is a reversible inhibitor of hydrogenase acting competitively against H(2). The K(i) for CO is 0.0010 atmosphere. CO antagonizes O(2) inactivation. In a period when complete inactivation by O(2) would usually occur, the presence of CO greatly reduces the inactivation rate.After 3 hours of adaptation in whole cells, the presence of H(2) lowers the rate of deadaptation of hydrogenase. Inasmuch as H(2) promotes increased O(2) uptake the cellular concentration of O(2) is likely to be lower. After 48 hours of adaptation O(2) uptake is reduced even when H(2) is present and the pattern of deadaptation under O(2) with and without H(2) and CO is qualitatively the same as observed for the inactivation of cell-free hydrogenase. The mechanism of inactivation of cell-free hydrogenase by O(2) may be the same as the mechanism for loss of hydrogenase during deadaptation in whole algal cells.

Karyotypic Studies on Cyclorana and Associated Genera of Australian Frogs

The taxonomic relationships of frogs from the genus Cyclorana are uncertain, for they share similarities with both the Leptodactylidae and the Hylidae. Karyotypic comparisons were made between seven species of Cyclorana and three species from the leptodactylid genera Notaden, Neobatrachus and Heleioporus. All Cyclorana species have 2n = 26, whereas the other species have 2n = 24. The position and type of secondary constrictions subdivide the species of Cyclorana into three groups. The similarity of chromosome morphology in these three groups with that of hylids suggests a close phylogenetic relationship. The major chromosome differences between Cyclorana and representatives from the leptodactylid genera suggests a fundamental dichotomy masked by adaptation to a fossorial mode of life.

The theory of tree bole and branch form

Working from the general postulate that natural selection of plant form operates so as to maximize the survival potential of a species, this paper examines the hypothesis that the mechanical support of tree foliage must approach optimality in the use of wood, i.e., that tree stems and branches will have "optimal form" with respect to the amount of support tissue. Mathematical models of bole and branch form are presented, based on the proposition that either wind or gravity are the primary limiting factors for tree size and shape. Predictions of trunk and branch diameter as a function of tree size were tested with dimensional measurements of Populus tremuloides. The individual stems were selected from close-grown stands of differing ages. For small and intermediate trees, trunk diameter is such that stems have only 1.6 times as much wood as the minimum required to keep the tree from buckling under its own weight due to elastic instability. Branch diameters are shown to be close to the minimum required to maintain the spatial position of growing branches, as well as withstand wind forces. This minimal branch cost not only reduces the load which the stem must support against elastic instability, but allows the crown to flex in high winds. The flexing, in turn, reduces the drag force exerted by the wind on the trunk. Thus, the hypothesis that the observed tree form is an optimal design cannot be rejected on the basis of these results. Additional studies are planned with respect to optimal foliage distribution.

Steroid priming of the luteinizing hormone response to luteinizing hormone releasing hormone

Perifusion experiments were performed to study the stimulatory effects of luteinizing hormone releasing hormone (LH-RH) on the release of LH from anterior pituitary tissue. Exposure of pituitary tissue from normal male rats to LH-RH (5 ng/ml for 5 min) induced a small release of LH; in tissue from ovariectomized rats receiving no pretreatment, the release was more than three times greater and in tissue from gonadectomized male or female rats pretreated with oestradiol benzoate and progesterone, the release was six times greater than that observed in normal rats. Further exposure of pituitary tissue from gonadectomized steroid-pretreated male and female rats to LH-RH (5 ng/ml) induced an increase in the level of LH even greater than that seen after the initial exposure (priming action of LH-RH); in tissue from ovariectomized rats receiving no pretreatment, less LH was released than after the first exposure to LH-RH and in tissue from normal male rats the response was unchanged.

Home Range and Activity Patterns of the Sand Goanna, Varanus gouldii (Reptilia: Varanidae)

The movements of two subspecies of the sand goanna, V. gouldii, were studied at two localities in South Australia. The estimated home ranges of individuals of V.g. rosenbergi differed considerably, the largest area being 25 times the size of the smallest. Daily activity areas varied with the season, being largest in summer and smallest in winter. There were distinct differences between the two subspecies in their activity patterns, V. g. rosenbergi being active throughout the year whereas Kg. gouldii remained underground during winter.

Ocean Wave Patterns Under Hurricane Gloria: Observation with an Airborne Synthetic-Aperture Radar

Surface imagery of ocean waves under Hurricane Gloria (September 1976) has been obtained with an airborne synthetic-aperture imaging radar. Observations were obtained over most of the area within a radius of 150 kilometers around the center of the eye. These direct observations made it possible to derive the wave patterns in the region around a hurricane eye.

Pathological and therapeutic consequences of sleep loss: a review

Until recently sleep deprivation has been studied from the point of view of determining whether or not it produces deleterious effects. Evidence, however, has begun to accumulate indicating that both REM deprivation and single night sleep deprivation may have antidepressant effects. Although beneficial effects are found primarily in endogenously depressed patients, variable results have been obtained in both "endogenous" and "reactive" depressions, suggesting that these diagnostic categories include biologically heterogeneous populations.

The adverse effects of elemental diets on tolerance for 5-FU toxicity in the rat

The effects of a group of elemental diets on the gastrointestinal toxicity of 5-FU in the Sprague-Dawley rat were evaluated. Diarrhea, stomatitis, hypoalbuminemia, and early deaths were more frequent in the animals on elemental diets than in those consuming standard rat chow. Sepsis and hypoalbuminemia were directly related to the extent of protein hydrolysis of the particular elemental diet.

An additional chromosome race of Phyllodactyllus marmoratus (Gray) (Reptilia : Gekkonidae) and its phylogenetic implications

This paper describes a fourth chromosome race of P. marmoratus. Specimens from this race have 2n = 32 chromosomes and occur in an isolated pocket in the south-west of Western Australia. It is believed that this race has been derived from the 2n = 34 form by an additional chromosome fusion.

Season of birth in schizophrenia: an Australian study

The authors have studied the season of birth in schizophrenics comparing those born in both southern and northern hemispheres. Their findings do not support the notion of seasonal variations claimed by other authors. The clinical significance of reports published in the literature is questioned.

Traumatic dislocation of the hip joint in children

Between 1949 and 1972, 24 children under the age of 16 years were admitted to Middlemore Hospital with traumatic dislocation of a hip. Half of these were between 12 and 15 years of age, and there was a predominance of boys in the ratio of 7:1. A survey of these children supports the view that the hip joint of a child becomes dislocated more readily than that of an adult.

Conduction velocity in the proximal segments of a motor nerve in the Guillain-Barré syndrome

Conduction velocity from spinal cord to axilla (estimated using the F wave) has been compared with conduction velocity from axilla to wrist (measured in the conventional manner) in the motor fibres of the ulnar nerve in 17 controls subjects and in 11 patients with the Guillain-Barré syndrome (GBS). In the patients with GBS the conduction velocity was, in general reduced to a similar extent in both the proximal and the distal portions of the motor fibres, suggesting that the disease process is usually diffuse. In two patients, however, the conduction velocity in the proximal segment was disproportionally reduced and in one of these the conduction velocity in the distal segment was normal. It is concluded that the estimation of conduction velocity in the proximal segments of motor nerves may be of value in the assessment of patients with GBS.

Woman and work — two extracts from an EEC bulletin

The current issue of Vocational Training, Information Bulletin No 2/3, published by the Commission of the European Communities, contains two interesting items on women's employment. The first of these, by Deborah King, is reproduced in full below. The second item appears on page 15 under the heading ‘A survey of the situation and problems concerning the education, training and employment of women in the EEC’. This is a lengthy treatment of the subject, running to 18 pages of A4, of which we have reproduced the summary here. Although we now have equal opportunities legislation and sex discrimination legislation, the reports highlight areas in which there is much room for improvement — for example in the provision of day care facilities for children. Lack of this provision can be one of the main factors preventing a woman from returning to work while her family is young, yet where is the lobby for day nurseries in the UK? The report also draws attention to the hidden pool of female unemployment. Many married women who would enter employment if suitable job opportunities existed are unemployed, yet they do not claim unemployment benefit and so do not appear in the statistics. Readers wishing to read this report in full can obtain single copies of the Bulletin, price 65p, from HMSO, PO Box 569, London SE1 9NH. 01–928 6977, ext 365. The Bulletin appears four times a year and a subscription costs £2.00. When ordering, it is necessary to specify in which language you wish to receive the publication.

Lung biopsy in immunocompromised hosts

Ninety-five lung biopsy procedures in 78 immunocompromised patients yielded treatable diagnoses in 35 per cent of the needle aspirates, 46 per cent of the cutting needle biopsies and 65 per cent of the open thoracotomies. Complication rates of bleeding or pneumothorax were comparable to those previously described in nonimmunocompromised patients. In patients with coagulation defects, the risk of having bleeding complications was high. Among 44 patients with primary lymphoma, 22 (50 per cent) had a lymphomatous infiltrate in the lung. Twenty-two patients with severe hypoxemia were studied and their mortality, although significantly greater than in the patients without hypoxemia, was marginally improved when a treatable lung lesion was found. The over-all recovery rate was 70 per cent when a treatable diagnosis was made in contrast to 25 per cent when there was no specific diagnosis. Hence lung biopsy, particularly by thoracotomy, appears to be a valuable procedure in immunocompromised patients who have otherwise undiagnosable lung lesions.

Dumbbell neuroblastomas in children

A "dumbbell" neuroblastoma is a malignant neoplasm usually primary in the mediastinum or retroperitoneum with posterior extension through an intervertebral foramen to additional tumor within the spinal canal. Neurologic deficits are found in almost all cases. Nineteen patients with such tumors were reviewed with respect to diagnosis, management, and results. Treatment consisted of prompt laminectomy with total or subtotal excision of the extradural tumor. The primary tumor in the mediastinum or retroperitoneal area was removed at a second stage. All patients received postoperative radiation therapy. Eleven of the 17 patients observed more than two years are free of disease, a cure rate much higher than the overall experience with neuroblastoma. Substantial recovery of neurologic function occurred in most, but kyphoscoliotic deformities were a disturbingly frequent late complication.

Spontaneous and estrogen-produced tumors in Nb rats and their behavior after transplantation

Tumors in rats of the Nb strain, arising either spontaneously or after prolonged treatment with s.c. pellets of estrogen, were transplanted to establish whether hormone conditioning was required for their growth. Whereas all spontaneous tumors arising in males and many of those in females were autonomous on transplant, most of those arising in estrogenized rats continued to require hormones for growth after transplantation. The latter included carcinomas of the adrenal cortex, breast, pituitary ectopic tissue, ovary (thecomas), Leydig cells of testis, thymus, pancreas,salivary glands, oribital gland (fibroadenoma), liposarcoma, and lymphoma. Many of the tissues of origin of the tumors have not been considered to be under theinfluence of estrogens. A type of hormone-responsive tumor that was inhibited by estrogen and that grew only in normal rats is described. Ali estrogens tested, including estriol , were interchangeable in action. The incidence of the more common tumors of the adrenal, breast, and pituitary was very low in normal rats, but higher in females. All tumors were more common after estrogenization in both sexes, particularyly in older animals. The secretion of steroids and pitiutary hormones by many tumors led to obvious biological effects. Pituitary secretion led to severe lesions frequently associated with diseases in humans, but the signs of such diseases in the rat apparently were hormone dependent and disappeared if the tumor was removed. The overall results raised the possiblity that estrogens were not carcinogenic per se but stimulated the growth of previously altered cells and that, following their transplantation, this hormone requirement was retained. Irrespective of the mechanism of carcinogenesis, hormone-dependent tumor growth was not irreversible but was controlled in an unexpectedly wide spectrum of organs by exogenous estrogen. Host factors may play a major role in controlling the growth of many tumors and the ultimate course of the disease.

Chromosomal evolution in the lizard genus Varanus (reptilia)

The karyotypes have been determined of 16 of the 32 species of the genus Varanus, including animals from Africa, Israel, Malaya and Australia. A constant chromosome number of 2n = 40 was observed. The karyotype is divided into eight pairs of large chromosomes and 12 paris of microchromosomes. A series of chromosomal rearrangements have become established in both size groups of the karyotype and are restricted to centromers shifts, probably caused by pericentric inversion. Species could be placed in one of six distinct karyotype groups which are differentiated by these rearrangements and whose grouping does not always correspond with the current taxonomy. An unusual sex chromosome system of the ZZ/ZW type was present in a number of the species examined. The evolutionary significance of these chromosomal rearrangements, their origin and their mode of establishment are discussed and related to the current taxonomic groupings. The most likely phylogenetic model based on chromosome morphology, fossil evidence and the current distribution of the genus Varanus is presented.