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An investigation was conducted of the effects of dietary nitrate on thyroid function in beagle dogs and their offspring. The dogs received 0 ppm, 300 ppm, 600 ppm or 1000 ppm sodium nitrate in drinking water under normal management and feeding conditions. Continuous consumption of these sublethal levels of nitrate did not produce a syndrome of chronic nitrate toxicosis characterized by thyroid dysfunction.

Excess fetal and newborn mortality have well-known associations with adequacy of maternal medical care during pregnancy as well as mother’s age, race, economic rank, marital status, and history of previous successful pregnancies. A study which included 783 consecutive autopsies on newborns delivered at a New York City Hospital provides the data for a multivariate analysis of these and other maternal factors on the incidence of specific disorders in newborn offspring.

Cyclophosphamide was administered to male and female rats at 1 or 3 mg/kg/day for 3 successive generations. Except for slight decreases in body weight gain, the general health of the rats, both parental and live offspring, appeared unaffected by treatment. There was a progressive decrease in the number of live births produced in the 3-mg/kg group. Mean total leucocyte values were decreased for both treated groups. Administration of cyclophosphamide to only the male or only the female produced effects which could be expected from cytotoxicity to spermatogenesis or embryonic or fetal toxicity. Although these rats were exposed to cyclophosphamide during embryonic development and for 30 weeks after birth, after 2 weeks' withdrawal from medication, practically complete recovery occurred in the males. A greater and longer residual effect was seen in females.

Synopsis Three generations of two‐way selection were conducted for the donor competence of graft‐versus‐host reaction. Selection was effective in changing the donor competence. The average realised heritability over three generations was determined to be 0.41 by measuring the difference between the high (H) and low (L) lines. Reciprocal crosses gave intermediate values compared with those for their respective line offspring. Changes of gene frequencies at the B blood group locus were examined. In the H line the frequency of B 11 allele increased and of B 9 decreased, as expected, after selection in each generation. In the L line, however, the expected change was observed only in the first two generations. The direction of change reversed in the latter two generations. Relationship between the B locus genotypes and the degree of splenomegaly was different according to the sex of donors. In male donors, the B 9 /B 11 induced larger spleen than the B 9 /B 9 did, but in females the B 9 /B 9 was generally larg...

SUMMARY Apterous exules of Rhopalosiphum padi which experienced short photoperiods only during the first half of their nymphal life all produced gynoparae which made up 57% of the offspring produced in the first 7 days of the mother's reproductive life. Short photoperiods during the second half of a mother's nymphal life did not induce the production of gynoparae. However, when short photoperiods were experienced throughout a mother's nymphal life significantly more gynoparae (82%) were produced. Ten per cent of the offspring of mothers that experienced short photoperiods only during their adult life developed into gynoparae. Of the offspring reared in short photoperiods, but born to mothers reared and kept in long photoperiods, 30% developed into gynoparae. When mothers were exposed to short photoperiods in their adult life and their offspring so treated, then 90% of the offspring developed into gynoparae. Males only occurred amongst the last offspring of mothers that experienced short photoperiods in either the first or the second half of their nymphal life.

A study of the sexual behavior of the male offspring of guinea pigs treated with cyproterone acetate (CA) is presented. CA was administered in doses of 50 mg/kg body weight from Day 30 to Day 45 of pregnancy. 15 male offspring were reared and their sexual behavior was studied in 4 experiments. No signs of masculine sexual behavior were observed in 11 of the males (73%) and only 1 animal showed complete male sexual behavior. Indications of female sexual behavior were observed in the test animals when in the presence of normal males though no spontaneous lordosis reaciton occurred. CA males that were subsequently castrated and treated with 50 mcg of testosterone propionate showed reduced masculine sexual behavior compared with control animals. CA males treated with 3 mcg of estradiol benzoate and .2 mg of progesterone had significantly longer lordosis reaction than control animals had though the reactions were significantly shorter than those observed in ovariectomized females treated with estradiol benzoate and progesterone. The reason for the altered sexual behavior is most likely the inhibition of endogenous androgen activity by CA during the differentiation of the hypothalamic centers that influence behavior. The results are at variance with other studies which did not find any feminizaiion of sexual behavior.

This survey research, using typological and cross-tabulation procedures with a randomly selected sample of 563 black and white, primarily Catholic-democratic middle-class, undergraduate students from a northern urban university, explored and analyzed the relationships between perceived parental permissiveness (laissez-faire, autocratic, quasi-democratic, and democratic) and the degree of marijuana usage (high, medium and low) among offspring. The following hypotheses were tested and found to obtain: (1) Perceived laissez-faire parent-child relationships lead to high marijuana usage by offspring; (2) Perceived autocratic parent-child relationships lead to medium use of marijuana by offspring; (3) Perceived quasi-democratic parent-child relationships lead to low marijuana usage by offspring; and (4) Perceived democratic parent-child relationships lead to low marijuana usage. In addition, a summary of four intervening variables, age (16-18, 19 and above) sex, race (black, white) and peer group orientation (strong, moderate, weak) were documented via the literature to correlate with marijuana usage, yielded 36 sub-hypotheses, of which 29 were confirmed.

The chronic ingestion of .5% butylated hydroxyanisole (BHA) or butylated hydroxytoluene (BHT) by pregnant mice and their offspring resulted in a variety of behavioral changes. Compared to controls, BHA-treated offspring showed increased exploration, decreased sleeping, decreased self-grooming, slower learning, and a decreased orientation reflex. BHT-treated offspring showed decreased sleeping, increased social and isolation-induced aggression, and a severe deficit in learning.

Adoption was studied inMacaca mulatta. Multiparous mothers were separated from their biological offspring within hours following parturition, and 2 1/2 days later, on the average, they were offered neonates for adoption. These foster infants had been separated from their biological mothers shortly after birth and averaged 2 3/4 days old when subjected to adoption. Mothers that were offered a single neonate immediately and completely adopted the foster infant. But mothers that were offered two infants at the same time were ambivalent. Many infants were rejected initially, although with one partial exception, the mothers eventually accepted and cared for two infants. It was concluded that the macaque maternal affectional system may be biased toward accepting and nurturing one infant at a time.

Playful contact interaction within a captive family of six meerkats was observed using a rotating focal animal observation method over a 5-month period. Ten interaction patterns are described. The mother interacted playfully with her family members at a low rate while the father and young initeracted together far more than with the mother. The parents sniffed all family members about equally, but all offspring sniffed the father far more than they sniffed the mother. Dyadic interaction sequences between the youngsters incorporated two patterns that infrequently occurred in fatheryoung sequences. Eighteen-week profiles of biting and forelimb contact displayed large oscillations in rate for each animal, but there was little inter-individual concurrence in each pattern and little similarity in profiles between patterns. Playful interaction was depressed and fluctuations dampened following the birth of an ill-fated litter. Sniffing fluctuated over a smaller amplitude than either of the other two patterns. During the 5-month observation period, only the father and one youngster were consistent in their choice of recipients of forelimb contact; the other three youngsters altered the proportion of contact delivered to their companions. The youngsters did not exhibit significant changes in the body targets of biting over the time period of the study.

THE hazard to man of environmental contamination by certain metals is of considerable importance and in this context the organic and inorganic compounds of lead are the subject of much current interest. The clinical effects on the individual of accidental overexposure to lead are well known. What is perhaps not so widely realised, however, is that there is the possibility that high lead levels may be hazardous to the foetus of exposed parents. “Intoxication with lead” is often quoted as “reducing fertility and increasing the frequency of abortions and miscarriages” in man1–5, and some animal studies have shown6 that administration of lead salts may result in an increase in congenitally malformed offspring. These findings, the reported carcinogenicity of lead salts in rats7, and the earlier reports that salts of a variety of heavy metals induce aberrations in plant chromosomes8,9, have stimulated a number of in vitro and in vivo studies into the possible mutagenic effects of lead which have yielded conflicting results.

Overwintering adults of the social wasp Polistes fuscatus (Fabricius) were collected in the early spring and placed in nest boxes under controlled conditions. Colonies were initiated, and one-, two-, and three-foundress associations were formed. Successful single-foundress colonies were similar to successful multiple-foundress colonies in developmental time for immatures, nest size, and total production of offspring. Multiple-foundress colonies were more likely to produce offspring than were single-foundress colonies. Half of the foundress wasps failed to reproduce, either because the colony failed or because they were non-reproductive subordinates. Apparently, wasps that were likely to fail at reproduction tended to join colonies rather than to initiate colonies. The relevance of this data to hypotheses on the selective advantage of foundress associations is discussed.

Offspring of heroin-addicted gravidae frequently show narcotic withdrawal after birth. Many clinical signs are indicative of hyperactivity of of the autonomic nervous system, generalized hyperhidrosis being one example. Since many of these infants are prematurely born, their capacity for reflex sweating is very unusual. Still, they show generalized sweating with significantly greater frequency than do healthy premature controls and even mature neonates. In response to local stimulation tests with sudorific drugs (epinephrine, acetylcholine, and nicotine), a significantly greater proportion of these addicted premature babies show sweat gland responsiveness than do controls, and minimal effective doses are lower.Accelerated development of sweating function in neonates ill with heroin withdrawal shows that the sweating deficit of healthy premature babies cannot be due to refractoriness of the sweat gland, but is, at least in part, attributable to immaturity of autonomic centers.

SUMMARYTwo surveys were conducted on commercial farms in England, Wales and Scotland to ascertain whether breeding contributed to variation in the number of lambs born per ewe, in lamb mortality and in the number of lambs remaining to be weaned per ewe. Each flock comprised two or more breed groups, but within flocks differences in breed were often quite small.In one survey of 74 flocks (average size 198 ewes, comprising 175 breed groups) the lambing percentage averaged around 150% and the lamb deaths to weaning (including stillbirths) around 9%. Within flocks there were statistically significant differences in the number of lambs born and weaned per ewe attributable to the breed of lamb and of its dam and sire. Crossbreeding was associated with a higher weaning percentage. Lamb mortality differed significantly among breeds and crosses of lamb. Lambing performance varied with type of farm.The second survey was a comparison of different crossbred types of dam, themselves the offspring of three breeds of sire and seven of ewe. Thirty flocks participated, providing 29 sets of records for 1-yearold females producing on average 120% lambs and losing through death (including stillbirths) 25 % of lambs born, and 10 sets at 2 years old, with 176 lambs per 100 ewes lambing and 11 % of the lambs born dying before 8 weeks old. Variation attributable to the crossbred type of the dam and to the breed of the dam's sire was significant for lambing and weaning percentage and the incidence of lamb mortality.

In field experiments designed to determine the nature and chronological development of chick recognition by natural-breeding Ring-billed Gulls, adults tending broods for a variable number of days were given recognition tests by replacing their own young with chicks from other nests. Introduced chicks of the same age as the resident brood were nearly always accepted during the first 5 days posthatching and usually rejected after the 7th day whether or not a resident chick remained on the territory. Adults with 7-day-old chicks presented with substitute 2-day-old broods either pecked or abandoned the younger chicks in almost all cases. Adults repeatedly presented with normally advancing-age substitute chicks each morning for the first eight days posthatching showed no signs of rejecting substitute chicks at any point. The pattern of parental activity shown by these birds resembled that of controls allowed to associate continuously with their own chicks. To examine the perceptual basis of recognition, a series of resident chicks 12-20 days old were surgically devocalized, and another series were marked with black ink to alter their individualistic plumage and facial patterns. No changes were observed in the behavior of parents toward muted or near-muted chicks, but over half of the parents attacked the visibly altered chicks. These attacks diminished within a few hours as the chicks persisted in showing positive approach responses to the attacking parent. In similar tests with 3- to 4-day-old chicks marked in the same way there were no rejections, suggesting that the markings did not, in themselves, constitute releasers for aggressive attack. The major findings of the study are interpreted as follows: a. Parent Ring-billed Gulls are able to recognize their own chicks after about 7 to 9 days posthatching, the stage at which increasing mobility terminates the family isolating mechanism provided by territorial boundaries. b. In identifying their own chicks, parent gulls can use individual variations in physical appearance. They may also respond positively to the relaxed comportment characteristic of chicks in familiar physical and social surroundings. c. In the social congestion that prevails in a gull breeding colony, individual recognition between parent and offspring provides the basis for a system of exclusive family units. This system, along with territorialism during the egg and early chick stages, permits a breeding bird to channel its reproductive energy to its own offspring exclusively, thereby promoting its own genes in contention with competing-gene carriers in the colony.

The effects of parenteral metal supplements on salicylate teratogenicity were studied in rats. Ferrous gluconate (16 mg/kg), manganous sulfate (10 mg/kg), cuprous sulfate (6 mg/kg), or deionized water were given ip on days 8, 9, and 10 of gestation, Sodium salicylate (250 or 500 mg/kg) or deionized water was administered po on day 9, l h after the metal-salt treatment. Mn significantly enhanced the teratogenic effects of salicylate, Fe potentiated the salicylate effect but to a lesser extent than Mn, and Cu had little or no effect on salicylate teratogenicity. Mn and Fe significantly increased total salicylate concentration in both embryos and maternal plasma at 6 h after salicylate treatment, with Mn having the greater effect. No interference with plasma-protem binding of salicylate could be detected. Posrnatal effects of possible salicylatemetal interactions were studied in 40-day-old offspring of animals treated with 125 mg/kg aspirin po and 16 mg/kg ferrous gluconate ip on days 8, 9, and 10. Increased exploratory activity and mean body weight were observed in both the aspirin-Fe and aspirin groups relative to vehicle controls, but maze learning was impaired only in animals exposed to both aspirin and Fe. The potentiation of the pre- and postnatal effects of salicylate by parenteral metal-salt treatment implies a salicylate-metal interaction in the maternal circulation and suggests chelation as a mechanism of the teratogenic action of salicylate.

Female rats with 30 to 70% of conditioned responses in an avoidance conditioning session in a Warner cage, were treated daily during pregnancy with 0.5 mg/kg of d,l-amphetamine administered subcutaneously. They had been mated with males selected with the same criterion who received no treatment.

Mother rats were either adequately fed or were undernourished during much of pregnancy and throughout lactation. Both control (C) and undernourished (UN) offspring had free access to food from weaning. Rats were tested between 15 and 27 weeks of age. During repeated exposures on the same day in a rectangular observation box, UN rats moved about more and reared on their hind legs more often than controls, but defecated less frequently. Two measures of exploratory behavior, tendency to emerge from a familiar to an unfamiliar area and responsiveness to a novel object, did not differentiate the 2 groups, nor did control and UN rats differ in the rate at which they pressed a lever to produce a light stimulus in a dark Skinner box. These and other long-term, activity studies indicate that previously undernourished rats are more active than controls in familiar, nonstressful situations.

SummaryIn order to rear diploid drones with larger testes, the inheritance of testis size was investigated. The genie balance hypothesis was tested in relation to the different additive effects of various X-alleles. Different levels of heterozygosity of multiple loci were also considered.Apis mellifera adansonii and A.m. ligustica were crossed to determine the X-allele composition of the offspring; this resulted also in different degrees of heterozygosity in the progeny. About 300 queens were instrumentally inseminated, and haploid and diploid drones originating from 23 queens were investigated; 1460 testes were measured.The size of the testes of haploid drones of various groups differed very little. The average volume of the testes of various groups of haploid drones was 2·7–6·5 times as large as that of diploids of the same groups. Diploid drones of African bees had larger testes (mean volume 4·14 mm3) than those of Italian bees (mean 1·82 mm3), and backcrosses to Italian queens resulted in medium-sized...

A survey of 621 female nurse-anesthetists in Michigan was performed to determine the incidence of birth defects among the offspring of this group. Two separate mailings and telephone interviews resulted in a response rate of 84.5 per cent. Of children whose mothers worked during pregnancy, 16.4 per

Seventeen-day-old and 38-day-old rats were compared on position habit reversal. Ss were drawn from the same litters and assigned randomly to either the 17-day-old or the 38-day-old test condition. The 17-day-old and the 38-day-old groups were matched on position habit acquisition. The 17-day-old group was significantly poorer on position habit reversal (p

Exposure of brook trout (Salvelinus fontinalis) to sublethal concentrations of copper from yearlings through spawning to 3-mo juveniles was found sufficient to establish a "no effect" concentration. No adverse effects were found on survival, growth, or reproductive capacity of trout exposed in a second generation from egg through spawning to copper concentrations (about 9.4, 6.1, and 4.5 μg/liter) which had caused no adverse effects on their parents when exposed to similar concentrations from yearlings to spawning. Nor were any adverse effects found on survival or growth of their offspring when exposed to the same concentrations from hatching to age 90 days. Tissue residue analyses indicated no copper accumulation in gill, liver, kidney, or muscle of either first- or second-generation trout exposed to the various copper concentrations, and residues in unfertilized eggs from exposed females were similar to those in females not exposed to added copper.

Many benthic marine animals release their gametes, embryos, or larvae into the water column. The offspring subsequently enter the adult population through settlement and metamorphosis. Sea urchins are one such animal. They have highly differentiated larvae that undergo a complex metamorphosis. The scant information on their metamorphosis has been reviewed by Hyman (1955). MacBride (1903) was the first to prepare a comprehensive description of metamorphosis. He used Echinus esculentus eggs that were fertilized in the laboratory. The larvae were fed on organisms collected along with the seawater in which they were raised. Earlier workers used field-collected larvae. Neither of these methods could have yielded consistently healthy and uniformly developing animals. With the development of a culture technique for sea urchins (Hinegardner, 1969), large and uniform populations of healthy animals became available for study.

UNTIL recent years, the strongest evidence for the importance of genetic factors in the etiology of schizophrenia came from twin studies. Early investigations reported concordance rates for monozygotic twin pairs that, from a genetic point of view, were most encouraging, but encountered methodological problems concerning sample acquisition, diagnosis of cotwins, and determination of twinship.1-5 The recent investigations of Tienari,6 Kringlen, ’ Gottesman and Shields,* and Fischer et ~1.~ have taken care to avoid the problems of the earlier studies and have obtained concordance rates for monozygotic twins that are appreciably less than those of the earlier studies. More recently, new methods have been employed to unconfound the possible effects of rearing and genes. These studies, using an adoption strategy, have incontrovertibly demonstrated the importance of the role of genetics in the etiology of schizophrenia. HestonlO and Rosenthal et aZ.ll evaluated the personalities of individuals born to a schizophrenic parent and reared in foster (Heston) or adoptive homes (Rosenthal et al.). In both studies the offspring were compared to an appropriate control group of foster and/or adoptive offspring whose biological parents had no record of psychosis and who were matched to the index group for age, sex and type of placement. All subjects were evaluated by a psychiatric interview and psychological tests. Heston reports that 5 of the 47 offspring of schizophrenic mothers had been hospitalized with a diagnosis of schizophrenia, and 8 were diagnosed as “schizoid psychopath,” for a total of 28 per cent of the index sample. None of the 50 controls was so diagnosed. In a still preliminary report, Rosenthal et al. found 3 diagnosed schizophrenics, 9 borderline schizophrenics, and 10 schizoid or “doubtful borderline” index cases among their sample of 69 offspring for a total of 32 per cent with a “schizophrenia spectrum diagnosis.” None of the 67 matched controls exhibited process schziophrenia, while 12 were diagnosed as borderline or schizoid for a total of 18 per cent. In both studies combined, 7 per cent of the index cases were chronic schizophrenics and 23 per cent were borderline or schizoid. Kety et a1.,1= using the adoption method in a different way, examined the prevalence of

Transplacentar administration of MNU to pregnant Wistar-R rats at the 16th day of gestation, while inducing cerebral malformations in all the offspring examined, produced only one nervous system tumor. This malignant neoplasm, diagnosed optically as a neuroblastoma, was also examined at the EM level. Although structures strongly suggestive of incipient or abortive synaptic formations were present, well developed synapses were not observed. Among the various neuronal features displayed by the tumor cells, notably some extensive Nissl arrays and numerous subsurface cisternae, several were indicative of maturing nerve cells: branching tumoral processes provided with typical growth cones and dense cored “neurosecretory” vesicles. These vesicles are now considered to be one of the characteristics of newly developing nerve fibers. The presence of these developmental features in a nerve cell tumor helps to substantiate the embryonic origin of neuroblastomas postulated as arising from immature forms and not from dedifferentiated cells.

Glutathione peroxidase (E.C. 1.11.1.9: glutathione: H 2 O 2 oxidoreductase) activity and selenium concentration were measured in lenses of female rats and their offspring after long-term feeding of either a selenium-supplemented ( 0·1 parts 10 6 ) or selenium-deficient ( 0·02 parts 10 6 ) diet. Long-term selenium deficiency decreased lens glutathione peroxidase activity in parent rats and their offspring to 15 and 14% respectively of supplemented controls. For comparison to lens, glutathione peroxidase was also measured in liver, heart, lung, erythrocytes, kidney, adrenal, testis, and brain of the offspring. Selenium deficiency caused the enzyme to decrease most dramatically in liver (to 0) and least in brain (to 62% of selenium supplemented controls). Although glutathione peroxidase in lens was lower than that in the other organs assayed, it was among the organs more sensitive to depletion caused by selenium deficiency. A short-term selenium deficiency of 8 weeks in newborn lambs had no effect on lens glutathione peroxidase, but the enzyme in organs such as liver was dramatically decreased. Therefore, an extensive period of selenium deficiency appears necessary to affect lens glutathione peroxidase activity, which probably relates to the relatively slow turnover and slow growth of the lens. The possible role of the seleno-enzyme, glutathione peroxidase, in the prevention of cataracts and the relationship of selenium to vitamin E and sulfur-containing amino acids in this regard are discussed.

Of 378 pregnant women with high initial toxoplasma antibody titers or seroconversion during pregnancy, 183 acquired the infection during pregnancy, a rate of 6.3 per 100 pregnancies. There were 11 abortions; seven infants were stillborn or died. Toxoplasmosis occurred in 59 of the nonaborted offspring. Among these, two died, and seven had severe disease with cerebral and ocular involvement. Of the remaining 50, 11 had mild, and 39 had subclinical illness. Severe disease was noted only when maternal infections were acquired during the first two trimesters. Later acquisition resulted in subclinical or no fetal infections. Parasites were isolated from the placentas of 25 per cent of those who acquired toxoplasma during pregnancy. Treatment with spiramycin during pregnancy reduced the overall frequency of the fetal infections but not of overt disease. Mothers with antibodies before they became pregnant had no infected infants.

Studies were conducted on the effects of supplemental selenium upon the performance of S.C.W.L. hens raised from hatching on selenium-low, semipurified diets (0.02 p.p.m. Se) containing adequate vitamin E. In hens continued on a Se-low laying diet, supplements of 0.015 p.p.m. Se and 0.030 p.p.m. Se as Na2SeO3 significantly increased egg production and hatchability. The Se concentration in the eggs was approximately equal to the dietary Se level throughout a 13 week period. When fed a selenium-low chick starter diet, offspring of the hens receiving 0.030 p.p.m. Se showed improved growth, but no protection against exudative diathesis and no improvement in hepatic glutathione peroxidase activity. When selenium-depleted hens were fed a low selenium (0.027 p.p.m.) practical diet, supplementation of 0.1 p.p.m. Se as selenomethionine significantly increased egg production. Hatchability of fertile eggs from the unsupplemented group fell to 42% after 6 weeks, while the values for the hens receiving either selenite or selenomethionine (0.1 p.p.m. Se) remained at approximately 90%. By 20 weeks, the hens receiving 0.1 p.p.m. Seas Na2SeO3 showed improved egg production as compared to those on the basal diet, and hatchability fell below 10% for the unsupplemented group but remained at 90% for the group receiving Se. The concentration of Se in eggs from hens fed the basal diet alone and supplemented with 0.1 p.p.m. as selenite and selenomethionine was 0.026, 0.121 and 0.124 p.p.m., respectively, after 3 weeks. After 15 weeks eggs from hens fed the basal diet alone and supplemented with 0.1 p.p.m. Se as selenite contained 0.035 and 0.138 p.p.m. Se, respectively. Both supplements of Na2SeO3 and selenomethionine delayed the onset of symptoms of exudative diathesis. The results indicate a nutritional requirement for selenium for normal hatchability, egg production and performance of progeny.

SummaryThe frequency of natural crossing in 1972 was estimated, in two subsets of a composite cross grown inF6in Nairn and in Fife, as 2·61±0·25% and 4·59±0·35% respectively. The estimated inbreeding coefficients of the parental generations were less than would be expected if all types of pollination were equally fertile and gave equally fertile offspring.

Treatment of female F-344 rats and C57B1/6 mice with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) during the latter half of gestation and in the postnatal period resulted in a severe depletion of lymphocytes in the thymic cortex of the offspring. Cellular immunity was impaired in these animals. Allograft rejection times were prolonged in rats and mice. Graft-versus-host (GVH) activity of spleen cells as well as the response of rat thymus and spleen cells to phytohemagglutinin (PHA) was reduced on a cell-for-cell basis. No reduction occurred in the response of thymus cells to concanavalin A (Con A). Maternal treatment postnatally on day 0, 7 and 14 with 5 μg TCDD/kg of body weight reduced total PHA and Con A response recoverable from the thymus by 91 and 74%, respectively. Histologically, depletion of thymic cortex was not due to lymphocyte destruction. There was no adrenal hypertrophy. Stress-induced release of glucocorticoids is not considered responsible for the immune suppression observed. In contrast to the marked effects in early life, reduced responsiveness of spleen cells to PHA in mice treated with TCDD when 1 month old was only seen at a dose level that was clearly toxic. In 4-month-old mice, PHA responsiveness as well as GVH activity were not decreased. Response of unstimulated and stimulated thymus and spleen cell cultures was not reduced by adding TCDD in vitro. In TCDD-exposed rats, decreased eosinophilia was observed in acidophilic cells in the adenohypophysis. This finding is discussed in view of the effect of TCDD on the thymus, and a possible mode of action of TCDD is proposed.

Attempts to recover XO offspring resulting from 600 R irradiation of spermatogonia proved negative. X-Rays were administered either in a single dose or in 100+ 500 R fractions separated by 24 h, and controls were strictly comparable in all respects. Altogether 14016 offspring were scored, including a small group derived from irradiated mature spermatozoa. The breeding scheme allowed phenotypic detection of paternal or maternal sex-chromosome loss, paternal nondisjunction, and certain translocations. All phenotypically exceptional mice were examined cytologically and through breeding tests. Similar tests of the mothers of presumed O/X p exceptionals revealed that in 9 of 14 cases there was a pre-existing XO condition, indicating the importance of performing such a test. Two of the 3a X m /O-appearing mice were probably X m /O///X m /X p mosaics, with the integument predominantly XO and the germinal tissue predominantly X/X. The frequency of paternal sex-chromosome loss was 2.4 · 10−3 in the controls and 2.0 · 10−3 in the two irradiated groups, where X m /O's must therefore be assumed to be of spontaneous origin. Since translocation experiments provide evidence that chromosome breaks are induced by irradiation of spermatogonia, the failure to recover XO's is explained in one of two possible ways. (1) Breakage in spermatogonia does not lead to recoverable single-chromosome loss, either because no sister-chromatid joining occurs, or, if it does, because this leads to cell-division failure. (2) Alternatively, sex chromosome loss does occur, but resulting X/O and O/Y cell progeny is inviable in the testis—a suggestion supported by evidence from natural and artificial mosaics. The results of the present experiment lend further support to our earlier suggestion that most spontaneously occurring X m /O mice are the result of events occurring after sperm entry into the egg. The spontaneous frequency of paternal sex-chromosome loss has ranged over two orders of magnitude in various reports. On the other hand, the frequencies of spontaneous X m loss (O/X p daughters of X/X females/total daughters) and of paternal nondisjunction (2 · X m /X p /Y frequency)

The number of fetuses in the rat has been operatively restricted between 50 and 90% of normal by destruction of the other implantation sites by cauterization on the 8th day of pregnancy. The surviving offspring had significant increases in placental weights, body weights, cerebral weights, cerebral protein and cerebral DNA (cell number). Placental weights followed the extent of restriction.

The successful hybridization of Anopheles litoralis King and Anopheles subpictus Grassi is reported. Reciprocal crosses with the 2 species produced viable progeny which appeared to develop normally to adults. Hybridized females laid fewer viable eggs in comparison with the parents. The F1 hybrids resembled the subpictus parent in most particulars. The spotting on the legs of the litoralis parent was suppressed in the offspring. Backcrosses of both litoralis parents with the hybrid were performed. The F1 hybrid ♀♀ × litoralis ♂♂ produced viable offspring. Since no cross in which the F1 male hybrids were involved produced viable eggs, they were assumed to be sterile.

Nursing rat mothers were given penfluridol 1.0 mg/kg on days 1, 3, and 5 after delivery. The male litter-mates were killed 4 weeks after birth 30 min after treatment with an inhibitor of aromatic l-aminoacid-decarboxylase, NSD-1015, and the concentrations of noradrenaline, dopamine, and 5-hydroxytryptamine were analyzed in regional brain areas. Additionally, the accumulation of Dopa and 5-hydroxytryptophan after administration of NSD-1015 was analyzed. In the offspring of mothers treated with penfluridol a marked decrease in the rate of tyrosine hydroxylation in specific brain regions was observed. The possibility that penfluridol interacts with the development of monoaminergic mechanisms in the brain at a sensitive developmental period, and thereby induces a decreased functional activity in central monoamine neurones, especially in the limbic system, is discussed.

Six experiments were conducted to assess the influence of duration of lactation, the presence of young, and the stimulus characteristics of intruder animals upon postpartum aggression of mice. The first experiment showed that postpartum aggression toward conspecifics was highest between Day 3 and Day 8, declined between Day 9 and Day 14, and was present toward males but absent toward females between Day 15 and Day 21 of the lactation period. Experiment 2 showed that lactating mice rarely attacked conspecifics to which they had been previously exposed but would readily attack strangers. Experiment 3 and 4 demonstrated that lactating animals never attacked intruders when tested 5 hr after pup removal. However, placement of young behind a wire partition in the home-cage for 5 hr or replacement of the offspring for as little as 5 min following 5 hr of separation restored postpartum aggression. The fifth experiment showed that 1- and 10-day old intruders were seldom attacked while intense aggression was directed against 14- and 20-day old intruders. Finally, Experiment 6 demonstrated that 14-day old intruders whose hair was removed were rarely attacked.

NAW-wa-2 + /Pr (NAW) mouse embryos and fetuses were relatively resistant to death caused by maternal injection of Cd on days 81–17 of gestation, and C57BL/10ChPr (B10) mouse embryos and fetuses were relatively susceptible, Crosses indicated that sensitivity to Cd-induced embryotoxicity was inherited by a complex pattern with a possible maternal effect. Studies using maternal injections of 109Cd at 10 days' gestation indicated that Cd crossed the placenta in both the sensitive and resistant strains since 109Cd was detected in embryos and placentas at 1–24 h postinjection. Fractionation of the tissue cytosol preparations by Sephadex gel G-200 filtration indicated that free Cd was absent from embryos and placentas of both strains. In embryonic cytosol of both strains 109Cd was associated with fractions showing elution characteristics indicative of Cd-binding protein (metallothionein, MW 10,000). In placental cytosol of both strains 109Cd was predominantly associated with fractions whose characteristics indicated a moiety of approximately 19,000 MW. The two strains differed only in the amount of Cd present in the embryonic cytosol — B10 embryos had more Cd in the binding-protein fractions than did NAW embryos. To evaluate the placental capacity for transfering Cd throughout gestation females were injected on day 13 and 17 of gestation; l09Cd was detected in embryos, fetuses, and placentas of both strains 4 and 24 h postinjection, In contrast with day-10 results gel profiles from offspring and placentas were qualitatively similar, i.e., the heavier (dimeric?) Cd-binding molecule was not present in placental cytosol. B10 embryonic mortality was greater at these later gestational times.

The heritabilitý of performance in thoroughbreds was studied using the Timeform Ratings for horses which raced during 1970. Timeform Ratings are based on the relative performance of all horses racing in a given year. 794 Individual three year old records, representing 96 sires which had five or more progeny, were used. The mean ratings for sires, dams and progeny were 128.5, 93.6 and 81.4 respectively; among the progeny the ratings for colts, fillies and geldings were 88.3, 79.1 and 77.1 respectively. Calculations made suggest that while stallion selection is effective in selecting sires with high performance ratings it does not appear that the selection of dams is very closely related to performance. There was no evidence of assortative mating. Paternal half sib and regression of offspring on sire analyses of the data yielded heritability estimates of 0.35 ± 0.11 and 0.74 ± 0.20 respectively. Further regression analyses on a reduced set of data (553 progeny records) of offspring on sire, offspring on dam and offspring on mid parent value gave heritabilities 0.56 ± 0.20, 0.36 ± 0.10 and 0.34 ± 0.08respectively. The possible reason for the substantially higher heritability estimates from the regressions of offspring on sire are discussed. It is concluded that the best measure of heritability of performance is 35%.

Proinsulin is converted to insulin and C-peptide in the pancreatic islet cells; the latter two polypeptides are then secreted in equimolar concentration. Thus, measurement of C-peptide may provide an alternative means of studying B-cell function in pregnant, insulin-treated, diabetic patients and in their newborn infants (IDM). Using this approach, B-cell function was studied in eight normal, ten juvenile onset and five gestational diabetic patients at the time of delivery. Normal maternal and cord CPR (C-peptide immunoreactivity levels, mean ± SEM, were 1.5 ± 0.3 and 0.9 ± 0.1 ng/ml, respectively. In six of ten juvenile onset diabetics, CPR levels were undetectable, while in four CPR was elevated. Five gestational diabetic women had elevated CPR levels. Cord CPR levels were significantly higher in all IDM than in the normal controls. A prompt rise in CPR was seen following intravenous glucose load in four IDM. Gel filtration of selected sera demonstrated both C-peptide and proinsulin, the latter protein being bound to circulating insulin antibodies which have crossed the placenta. Thus, active B-cell secretion composed of proinsulin, C-peptide and presumably insulin is present during insulin therapy in gestational, in some juvenile-onset-diabetic, pregnant women and in their offspring.

In some species of polygynous songbirds, males assist in feeding nestlings of their first (primary) female but ignore offspring of subsequent (secondary) mates. A number of adaptations important in minimizing the disadvantages of a secondary status in female Bobolinks ( Dolichonyx oryzivorus ) have been discovered. In Bobolinks, clutches of secondary females are significantly smaller than those of primary females, thereby adjusting brood size to correspond better with food delivery capabilities of secondary hens. Commencement of incubation with deposition of the penultimate egg allows additional brood size adjustment, for the resulting hatching asynchronism promotes efficient culling of the late-hatching chick in times of food shortage, without endangering the entire brood. Secondary females differ from primary pairs in food exploitation techniques by capitalizing on insects found close to the nest and by showing less discrimination in food selection. Such behavior permits compensation in the rate of food delivery trips to secondary nestlings so as to equal the tempo maintained by both members of the primary pair, yet results in quantitative disparities in food brought to primary and secondary nestlings. Flexibility in male feeding responses, resulting in partial male assistance at secondary nests in situations where secondary brood size is exceptionally large, is also important in helping to maximize the reproductive performance of birds engaging in this mating strategy.

Testicular feminization is an inherited disorder which is transmitted by some women to half their male offspring. The affected individuals are genetic males with end organ insensitivity to endogenous and exogenous androgens. As a consequence, they lack androgen-dependent differentiation and present clinically as phenotypic females with primary amenorrhea. Testicular feminization has also been described in the rat and the mouse. Studies on these rodents indicate that a major tissue abnormality in testicular feminization is decreased cytosol androgen receptor activity. Deficiency of this cytosol binder could account for the lowered nuclear binding of testosterone and dihydrotestosterone in these animals. If androgen uptake and binding in the nucleus is required to initiate RNA and DNA synthesis, the inability to concentrate androgens at the active site in the nucleus of the cell could account for the androgen insensitivity in testicular feminization. Since a detect in the androgen receptor was present in rodents with testicular feminization, a similar abnormality will probably be found in man.

Two lines of mice (A and Y) differing in age at mating were maintained with as similar ancestry as possible for nine and 13 generations, and were used for diallel matings to contemporaneously produce various genotypes of offspring (A, Y, F1, F2, and backcross). Body weights of offspring at birth, and at 12, 20 and 42 days of age were recorded, and data on actual and logarithmic scales were analysed Regression of the mean body weight for the respective genotype on the coded A-line gene effects was significant (P < 0. 05) only in 20-day weight on both actual and logarithmic scales. When the mean body weight was expressed in standard deviation unit, regression was significant (P < 0. 05) for 20-day and 42-day weight on actual scale. It was concluded that birth weight and 12-day weight were not genetically affected by accumulated parent age effects. The results inconclusive with respect to 20-day and 42-day weight were discussed.