The Indirect Fluorescent Antibody Test (IFAT) for the Detection of Nosema Cuniculi Antibodies in the Blue Fox (Alopex Lagopus)

During recent years nosematosis has been a major problem in the breeding of blue fox in the Scandinavian countries, causing heavy losses among growing pups (Nordstoga 1972, Nordstoga et al. 1974). The lack of reliable methods for diagnosing the infection in live foxes has so far made epizootiologic studies of the disease very difficult. However, reports on the IFAT in rabbits with nosematosis (Cox et al. 1972, Chalupsky et al. 1971, 1973, 1974), encouraged the search for a method of detecting Nosema antibodies in fox sera.     

Evidence for recombination between N- and B-tropic murine leukemia viruses.

After co-infection of Sc-1 cells with N- and B-tropic murine leukemia viruses that differ in their XC plaque morphology, Hopkins et al. (1976) obtained viruses, designated XLP-N, that appeared to be recombinants, since they possess the N-tropism of one parent and the XC plaque morphology of the other (the B-tropic virus) parent. Here we present evidence, based on antigenicity and electrophoretic mobility, that some clonal isolates of XLP-N have inherited gp70 gene of their B-tropic virus parent. In addition to providing evidence that XLP-N viruses are recombinants, the fact that an N-tropic virus may apparently possess a gp70 derived from a B-tropic virus provides evidence, which is in agreement with the findings of others (Huang et al., 1973; Krontiris et al., 1973) that the N- or B-tropism of murine leukemia virus does not reside in gp70.     

Correlations of developmental end points observed after 2,4,5-trichlorophenoxyacetic acid exposure in mice.

A large-scale developmental toxicology study of 2,4,5-trichlorophenoxyacetic acid was conducted in four inbred strains and one outbred strain of mice. The most significant developmental effects observed were reduced fetal weight and increased incidences of cleft palate (malformation) and prenatal death (deaths/resorptions). The correlation coefficients among the proportion of deaths/resorptions, proportion of malformations, average fetal weights, and number of viable fetuses were investigated, with each variable measured on a per-litter basis. Generally, the correlation coefficients between average fetal weight and number of viable fetuses were negative for the control and low-dose groups in the C57BL/6, C3H/He, and BALB/c strains. Overall, the correlation coefficients between proportion of malformations and number of viable fetuses were not significant. The correlation coefficients between proportion of malformations and average fetal weight were negative for all but one case. The correlations were weak in the control and low-dose groups, in which the malformation rates were very low, and were strong in the high-dose groups. The correlation coefficients between proportion of deaths/resorptions and proportion of malformations were generally positive at the high doses; some negative correlations were observed in control and low-dose groups. The correlation coefficients between proportion of deaths/resorptions and average fetal weight were negative for the A/JAX and CD-1 strains. In summary, the strongest relationship observed was the negative correlation between fetal weight and malformation.     

Antenatal screening for cystic fibrosis: a trial of the couple model.

OBJECTIVE--To assess the delivery and acceptability of antenatal couple screening for cystic fibrosis. Carrier status was notified only when both members of a partnership had cystic fibrosis alleles and therefore a one in four risk of having an affected child. DESIGN--Mouthwash samples were tested when both partners participated. Results were returned only to positive couples. SETTING--Two large maternity hospitals in Edinburgh. SUBJECTS--Screening was offered to all couples who booked at one of the two hospitals. MAIN OUTCOME MEASURES--(a) The take up of screening, carriers and carrier couples identified, take up of prenatal diagnosis, and numbers of affected fetuses detected; (b) questionnaire measures of patient satisfaction and stress. RESULTS--Screening was offered to 8536 couples. 714 (8.4%) were regarded as ineligible, usually because of late booking or absence of a partner. 1900 (24.3%) of the remainder declined screening. Among the 5922 screened couples, four tested positive--that is, both partners were cystic fibrosis heterozygotes. All four elected to have prenatal diagnosis. There were three terminations of pregnancy because of an affected fetus, one couple having two successive pregnancies with affected fetuses. The participation rate was 76% for eligible couples (5922/7822) and 69% for all couples (5922/8536). Only 89 screened couples (1.5%) requested information on individual carrier status. No anxiety was detected among a cohort of the screened population, and 99% of questioned participants expressed satisfaction with the concept of couple screening. CONCLUSIONS--Antenatal couple screening is a satisfactory and acceptable way of screening for cystic fibrosis and has been adopted as routine in the two trial hospitals.     

PROTEINS AND GLYCOPROTEINS IN MYELIN PURIFIED FROM THE DEVELOPING BOVINE AND HUMAN CENTRAL NERVOUS SYSTEMS

Myclin was purified from bovine and human midbrain at various stages of prenatal and postnatal development. Basic protein and proteolipid proteins were the major individual proteins at all stages. The specific activity of 2′3′-cyclic nucleotide 3′-phosphohydrolase remained constant in the bovine myclin during development but decreased slightly in human myelin. A high molecular weight glycoprotein with electrophoretic mobility similar to that previously reported in rodent myelin (QUARLES et al., 1973) was present in both bovine and human myelin at all stages of development. The intensity of staining of this glycoprotein with periodic acid-Schiff reagents per mg total myelin protein was less in mature bovine and human myelin than in rat myelin.     

Congenital malformations in rats with the semilethal mutation fused pulmonary lobes

It has been demonstrated that an autosomal recessive gene, fused pulmonary lobes (fpl), causes fusion of the right pulmonary lobes with several associated malformations and a high incidence of death in homozygous newborns (Aoyama et al. Teratology 1988; 37:159-166). The aim of the present study was to investigate whether the deaths of fpl/fpl newborns were caused by functional abnormalities of the malformed lung or other associated malformations. Day-20 fpl/fpl and fpl/+ fetuses were weighed and examined for gross abnormalities. The lungs of selected fetuses were further examined for histological abnormalities. A wide variety of associated external, visceral, and skeletal anomalies as well as relatively lower body weights than those of phenotypically normal fpl/+ littermates were observed in the fpl/fpl fetuses. The associated anomalies consisted of hematomas and/or subcutaneous hemorrhages in the head, truncus and limbs, eyelid anomalies, CNS defects, lobation anomalies of the liver, hypoplasia of the spleen, partial absence of the skull bones, and dorsi- or ventriflexion of the phalanges of the limbs. Among them, CNS defects and partial absence of the skull bones were considered to be possible causes of newborn deaths. However, the incidence of these malformations was approximately 10% and was lower than the neonatal mortality, which had been estimated to be approximately 50% in the previous study (Aoyama et al. Teratology 1988; 37:159-166). The lungs of fpl/fpl fetuses consistently had hypoplasia of the intermediate lobe and fusion of the right pulmonary lobes. No histological changes suggesting postnatal respiratory insufficiency were found in the lungs of day-20 fpl/fpl fetuses, and the cause of newborn death remains unclear.     

Effect of delayed enucleation on the developmental potential of nuclear-transferred oocytes receiving adult and fetal fibroblast cells

To enhance the probability of reprogramming somatic cell nuclei, fibroblast cells from an adult male rabbit and a 12-day-old fetus were fused with oocytes at the second metaphase. The chromosomes of recipient oocytes were then removed by treatment with demecolcine for 1 or 2 h after fusion. Demecolcine treatment of fused oocytes induced membrane protrusions that contained all the maternal chromosomes, thus making it possible to remove the chromosomes. The potential of nuclear-transferred oocytes to develop into blastocysts was high (48% and 59%) and the average cell number of the blastocysts was large (149 and 159) 96 h after in vitro culture. The proportions of nuclear-transferred oocytes enucleated 1 h after fusion and implanted after transfer to pseudopregnant recipients were relatively high (2.8% and 4.9%) compared with our previous reports (1.7%: Yin et al., 2000; 0.6% and 1.0%: Yin et al., 2002a) where donor cells were fused with previously enucleated oocytes. Of 34 adult somatic cell implantation sites, 6 had fetuses on day 12 or 14 of pregnancy, but none of the fetuses had a heart beat or developed to term. None of the nuclear-transferred oocytes whose chromosomes were removed 2 h after demecolcine treatment implanted after transfer to recipients. The possible reasons why the high-quality nuclear-transferred oocytes did not develop to term are discussed.     

Gender performance in a cultivated cohort of the cycad Zamia integrifolia (Zamiaceae)

A progeny of the native Florida cycad Zamia integrifolia grown from seeds planted in 1986 was monitored until 1995 to record mortality and the nature and time of expression of primary and secondary sex characters. In addition to gender-specific cone morphologies, males and females differed in secondary sex characters such as age at first cone production, frequency of cone production, mean cone numbers in second and later coning episodes, and, in older plants, mean leaf and branch numbers. Gender differences expressed themselves at different stages in the life history: their nature and extent varied during the years following sexual maturation. By 1995, 46% of the plants in the progeny had died, most of them before producing cones. Prior to 1988 the mean leaf number of plants that died did not differ from that of survivors, but the mean leaf number of plants dying between 1988 and 1989 was 0.4 times that of the survivors during that period, suggesting reduced vigor prior to death. Mean age at first cone production was 5.8 yr for males and 6.6 yr for females. Mean dry masses of individual male cones increased between the first and second coning episodes, but not between the second and third coning episodes. Mean dry masses of the entire cone crop of individual males increased through the third coning episode due to an increase in mean cone number per episode, but mean cone number was unchanged between the third and fourth coning episodes. Mean dry mass of unpollinated female cones did not change between the first and second coning episodes; mean cone numbers did not change between the first and third coning episodes. After the first coning episode, males produced higher mean cone numbers than females. By 1995, the mean dry mass of an individual male's cone crop was greater than that of a female. Coning frequency of males was 1.7 times greater than that of unpollinated females, suggesting a gender difference in the genetic control of coning frequency. Coning frequency of females pollinated 1 or 2 yr previously was reduced compared with that of unpollinated females. Cone production did not affect subsequent leaf production by either gender. Mean leaf numbers increased in some years and not in others. Mean leaf numbers of males and females did not differ prior to cone production. After cone production mean leaf numbers of males were greater than of females. Mean age of males producing first branches was 6.3 yr, with a mean of 2.5 first branches per plant. Mean age of females producing first branches was 7.7 yr, with a mean of 2.5 first branches per plant. By 1995 the mean branch number of males was 5.7 per plant and of females was 2.7 per plant. Between 1993 and 1995 the mean branch number of males and females increased incrementally, but mean leaf numbers did not change. In early years of branching, leaf number increased with branch number; higher mean leaf numbers of males of an age class thus reflected their earlier branching. Males produced first cones earlier than females. Since branch production was associated with cone production, higher branch numbers of males in an age class reflected their earlier first cone production. In 1995 the sex ratio of known males and females in the progeny was 1:1, with a few individuals not having produced cones by that year.     

Valuing Stillbirths

Estimates of the burden of disease assess the mortality and morbidity that affect a population by producing summary measures of health such as quality‐adjusted life years (QALYs) and disability‐adjusted life years (DALYs). These measures typically do not include stillbirths (fetal deaths occurring during the later stages of pregnancy or during labor) among the negative health outcomes they count. Priority‐setting decisions that rely on these measures are therefore likely to place little value on preventing the more than three million stillbirths that occur annually worldwide. In contrast, neonatal deaths, which occur in comparable numbers, have a substantial impact on burden of disease estimates and are commonly seen as a pressing health concern. In this article we argue in favor of incorporating unintended fetal deaths that occur late in pregnancy into estimates of the burden of disease. Our argument is based on the similarity between late‐term fetuses and newborn infants and the assumption that protecting newborns is important. We respond to four objections to counting stillbirths: (1) that fetuses are not yet part of the population and so their deaths should not be included in measures of population health; (2) that valuing the prevention of stillbirths will undermine women's reproductive rights; (3) that including stillbirths implies that miscarriages (fetal deaths early in pregnancy) should also be included; and (4) that birth itself is in fact ethically significant. We conclude that our proposal is ethically preferable to current practice and, if adopted, is likely to lead to improved decisions about health spending.     

Down syndrome: interaction between culture, demography, and biology in determining the prevalence of a genetic trait

The incidence of Down syndrome (DS) at conception is highly dependent upon the maternal age distribution and age-specific pregnancy rates. Live-birth prevalence of DS reflects these factors and fetal deaths. Since the introduction of prenatal diagnosis in the early 1970s, the role of fetal deaths in the equation has increased. Between 1920 and the early 1980s, DS live-birth prevalence decreased in many populations due to declining fertility rates, particularly among older women. In the late-1970s the trend reversed, as the median age of populations and birth rates among older women steadily increased. This paper illustrates these interactions using data we have analyzed for New York State (NYS) and comparative data obtained from the literature. Between 1983 and 1997 DS live-birth prevalence in NYS remained stable at about 9.9 per 10,000 live births. The number of prenatal tests performed increased by 158%, and the number of DS fetuses detected prenatally more than quadrupled. Fertility rates of women aged 35-49 continued to increase. The proportion of DS cases born to these older mothers increased from 23% in 1985 to 43% in 1997. We estimated that without prenatal diagnosis, DS live-birth prevalence would have been 17.0 per 10,000 live births by 1995. Cultural factors influence demographic trends, birthing technologies, physician practices, and women's decision-making regarding prenatal screening and diagnosis for DS.     

Mutagen-induced fetal anomalies and death following treatment of females within hours after mating

In an earlier study (Generoso et al., 1987), it was observed that the mutagen, ethylene oxide (EtO), produced remarkable increases in the incidence of developmental abnormalities and death of fetuses when early zygotic stages were exposed. This is a major finding in experimental induction of embryopathy, implicating genetic damage to the zygotes as the likely cause. In the subsequent study reported here, 3 other mutagens--ethyl methanesulfonate (EMS), ethyl nitrosourea (ENU), and triethylene melamine (TEM), were studied for embryopathic effects following exposure of dictyate oocytes, prefertilization oviducal eggs and sperm, early pronuclear zygotes, zygotes undergoing pronuclear DNA synthesis, and two-cell embryos. All 4 mutagens produced developmental abnormalities among living fetuses following exposure of early pronuclear zygotes (the only stage studied for this endpoint in this report). With respect to stage specificity and gestational timing of death of conceptuses, EMS and EtO on one hand and ENU and TEM on the other, are very similar to one another. EMS, like EtO, produced a high incidence of midgestation and late fetal deaths only in prefertilization oviducal eggs and sperm and in early pronuclear eggs. In contrast, ENU and TEM produced high losses of conceptuses in all postmating stages studied but death occurred primarily prior to or around the time of implantation. Thus, the frequency of induction and the expression of embryopathy, which ranged from early embryonic preimplantation and late fetal deaths to subtle fetal anomalies, are dependent upon the stage exposed and the mutagen used.     

Lack of dominant lethality in mice following 1-bromopropane treatment

1-Bromopropane (1-BP) is widely used in spray adhesives, precision cleaner, and degreaser. This study was conducted to investigate the potential of 1-BP to induce dominant lethality in mice. 1-BP was orally administered to males at doses of 300 and 600 mg/kg for 10 days before mating. Cyclophosphamide was used as a positive control (PC), which was administered intraperitoneally to males at 40 mg/kg for 5 days. The vehicle control (VC) group received corn oil only. Thereafter, males were mated with untreated females during six sequential mating periods of a week each. Males were sacrificed at the end of mating and so were the pregnant females on days 15-17 of gestation. Clinical signs, gross findings, mating index, gestation index, the numbers of corpora lutea, implantations, live fetuses, resorptions and dead fetuses, pre- and post-implantation losses, and dominant lethal mutation rate were examined. There were no treatment-related changes in clinical signs, gross findings, mating index, gestation index, number of corpora lutea and implantations, pre-implantation loss, live fetuses, resorptions, dead fetuses, post-implantation loss at any 1-BP doses tested. In the PC group, there were no treatment-related changes in mating index, gestation index, number of corpora lutea, and dead fetuses. However, a decrease in the number of implantations and an increase in pre-implantation loss were observed during the first 2 weeks as compared to those of the VC group. No treatment-related changes were observed in the third to sixth weeks. Increases in resorptions, fetal deaths and post-implantation loss, and a decrease in the number of live fetuses were observed in the first 3 weeks of the PC group compared to those of the VC group. However, no treatment-related changes were observed during the forth to sixth weeks. An increase in dominant lethal mutation rate was observed in 1-3 weeks of mating of the PC group, but there was no significant difference in 1-6 weeks of mating of the 1-BP treatment groups. In conclusion, 1-BP did not induce dominant lethality in mice. These results are in agreement with the report of Saito-Suzuki et al., demonstrating that no dominant lethality of 1-BP was observed in Sprague-Dawley rats.     

On travelling wave solutions in a model for the Belousov-Zhabotinskii reaction.

DNA fragments partially digested by a 3′- or 5′-specific nuclease to produce single chain ends of opposite polarity will form a ring if the ends contain complementary sequences and are allowed to anneal. The frequency of rings can then be used as an assay to determine where and how identical repetitious sequences are arranged in the DNA. Thomas et al. (1973b) showed that all eucaryote chromosomes studied contain similar if not identical repetitious sequences clustered into regions called g-regions. To account for the observed ring frequency under different experimental conditions Thomas, Zimm &; Dancis (1973c) derived equations for two possible models of g-region organization. In the pure tandem model, the repetitious sequences are contiguous and occupy the entire g-region. In the intermittent repetition model, the repetitious sequences are simple copolymers and are irregularly arranged among non-repetitious sequences which are heterogenous in length. In the present paper, the results of Thomas et al. (1973c) are extended to cover the fractional tandem model. In this model, adjacent repetitious sequences are separated by non-repetitious sequences of uniform length. In addition, the equations for both the pure tandem and intermittent repetition models are shown to be special cases of the fractional tandem model but not vice versa.The capabilities and limitations of an analysis of ring formation are demonstrated using data from Drosophila. Although it is not possible to rule out any of the three models, the analysis can limit the ranges of the parameters describing each of the models that are consistent with the data. Previous conclusions that the data could only be explained by a pure tandem model which lacks any intervening unique sequences (Bick, Huang &; Thomas, 1973; Thomas et al., 1973b), are shown to be incorrect, in part because the equations for the fractional tandem model had not then been derived. Thus ring theory equations can be used to show the presence of clusters of similar if not identical sequences from ring-forming experiments, but they may not be able to determine the exact spacing and arrangement of these sequences within the clusters.     

Genetic regulation of antibody heterogeneity: Its possible significance in human allergy

Conclusion Finally, in a broader context, part of the fascination of this subject is its relevance to the questions of how responses in the different Ig classes and subclasses are orchestrated, and why such a diversity of Ig classes exists at all. These questions are of great theoretical interest in themselves, and are also highly relevant to those immunological diseases that are characterized by production of auto-or isoantibodies of very restricted subclass (e.g., Karpatkinet al. 1973, Morellet al. 1973) or clonality (e.g., Goldberg and Fudenberg 1971, Harboe 1971, Kunkelet al. 1973). They are also questions that the IgE system—since it is so sophisticated and well-Defined—highlights in a particularly telling way.     

Influence of low-intensity ultrasonic irradiation on prenatal development of two inbred mouse strains.

Effects of low-intensity ultrasonic irradiation on prenatal development of DHS and A/HeMk mice were studied. On day 8 of gestation (VP day = 0) pregnant females were exposed to ultrasonic waves with a frequency of 2.25 MHz and power of 40 mW/cm2 for 5 h. A low frequency of severe cranial and facial anomalies occurred that was attributable to the irradiation in both strains. The difference in frequency of malformed fetuses was marked between irradiated and untreated control A/HeMk mice, but not DHS mice. Fetal growth inhibition and death were also produced in both strains, although the possible effect of binding the pregnant mice for irradiation cannot be discounted.     

Factors governing the adaptation of cells in area-17 of the cat visual cortex

Neurons in area 17 of the cat visual cortex adapt when stimulated by drifting patterns of optimal orientation, spatial frequency and temporal frequency (Ohzawa et al. 1982; Albrecht et al. 1984; Ohzawa et al. 1985). A component of this adaptation has been attributed to a contrast gain-control mechanism, rather than to neural fatigue, and results in enhanced differential sensitivity around the adapting contrast level (Ohzawa et al. 1982; Albrecht et al. 1984; Ohzawa et al. 1985). Experiments described here suggest that neural response rate, the directional selectivity of the cell, and the temporal frequency of the stimulus, are the principal determinants of adaptation, irrespective of other stimulus parameters such as contrast, velocity, or spatial frequency. The present results can nevertheless accommodate the results of previous studies of adaptation, and additionally provide scope for the resolution of apparent contradictions between results from psychophysical and neurophysiological studies of adaptation.     

Reproduction in captive common marmosets (Callithrix jacchus)

Though sexual maturation may begin at around one year of age, first successful reproduction of the common marmoset (Callithrix jacchus) is likely to be later, and it is generally recommended that animals not be mated before 1.5 years of age. The average gestation period is estimated to be 143 to 144 days. A crown-rump length measurement taken by use of ultrasonography during the linear, rapid, prenatal growth phase (between approx. days 60 and 95) can be compared against standard growth curves to estimate delivery date to within 3 to 4 days, on average. Marmosets produce more young per delivery than does any other anthropoid primate, and have more variation in litter size. Many long-established colonies report that triplets are the most common litter size, and there is documented association between higher maternal body weight and higher ovulation numbers. Higher litter sizes generally do not generate higher numbers of viable young. Marmosets are unusual among primates in having a postpartum ovulation that typically results in conception and successful delivery; reported median inter-birth intervals range from 154 to 162 days. However, pregnancy losses are quite common; one study of a large breeding colony indicated 50 percent loss between conception and term delivery. The average life span for breeding females is around six years; the range of reported average lifetime number of litters for a breeding pair is 3.45 to 4.0. Our purpose is to provide an overview of reproduction in the common marmoset, including basic reproductive life history, lactation and weaning, social housing requirements, and common problems encountered in the captive breeding of this species. A brief comparison between marmoset and tamarin reproduction also will be provided.     

Transplantation phenomena in hydra: Cooperation of position-dependent and structure-dependent factors determines the transplantation result

Hydra transplantation phenomena were examined using lateral grafting (Browne, 1909; Wolpert et al., 1974) and axial grafting (Shostak, 1972, Shostak, 1973, Shostak, 1974; Hicklin et al., 1973) procedures. When a small piece of tissue excised from one hydra is transplanted to another by the former procedure, the transplanted tissue forms a small protrusion on the body column of the host animal, whereas such a protrusion is not produced by the latter procedure. It was found that transplantation experiments carried out by the two procedures gave significantly different results. The frequency of head formation by the transplanted tissue on the host was significantly higher by the lateral than by the axial grafting procedure. This suggests that the small protrusion introduced onto the smooth cylindrical structure of the host body column by the former, but not by the latter, procedure plays an important role in determining the fate of the transplant. It is suggested that the cooperation of two factors determines the transplantation result. One is the positional factor described and discussed by previous workers (e.g., Wolpert et al., 1974; Sugiyama, 1982; MacWilliams, 1983, MacWilliams, 1983; Takano and Sugiyama, 1983) and the other is the structural factor revealed in this study. The underlying mechanisms responsible for the latter factor are discussed.     

Mason-Pfizer virus RNA genome: relationship to the RNA of morphologically similar isolates and other oncornaviruses.

The 60-70S RNA of Mason-Pfizer virus (MPV) was iodinated in vitro and used in both direct and competitive molecular hybridization studies. MPV proviral sequences are present at a frequency of approximately one to two copies per haploid genome in the DNA of experimentally infected human cells. By nucleic acid competition hybridization, MPV RNA was found to be indistinguishable from the RNA of a virus (X381) isolated from a rhesus mammary gland and from RNA isolated from the cytoplasm of AO cells (Parks et al., 1973) and HeLa cells (Gelderblom et al., 1974), both previously reported to produce MPV-related particles. No homology was observed, however, between MPV RNA and the RNA, or the DNA, from two clones of HeLa cells obtained from the American Type Culture Collection. Hybridization of MPV 60-70S RNA to the DNA of normal tissues of humans and to the DNA of 11 other species revealed that MPV is not an endogenous virus of any of these species. Competition hybridization revealed no detectable sequence homology between the RNA of MPV and the RNAs of simian sarcoma virus, murine mammary tumor virus, murine leukemia virus, BUdR-induced guinea pig virus, or avian myeloblastosis virus. These nucleic acid studies substantiate previous ultrastructural and immunological findings that MPV and morphologically similar isolates constitute a distinct group of oncornavirus.