Migratory Neural Crest Cells Phagocytose Dead Cells in the Developing Nervous System

During neural tube closure and spinal cord development, many cells die in both the central and peripheral nervous systems (CNS and PNS, respectively). However, myeloid-derived professional phagocytes have not yet colonized the trunk region during early neurogenesis. How apoptotic cells are removed from this region during these stages remains largely unknown. Using live imaging in zebrafish, we demonstrate that neural crest cells (NCCs) respond rapidly to dying cells and phagocytose cellular debris around the neural tube. Additionally, NCCs have the ability to enter the CNS through motor exit point transition zones and clear debris in the spinal cord. Surprisingly, NCCs phagocytosis mechanistically resembles macrophage phagocytosis and their recruitment toward cellular debris is mediated by interleukin-1β. Taken together, our results reveal a role for NCCs in phagocytosis of debris in the developing nervous system before the presence of professional phagocytes.

Motor nerve transection and time-lapse imaging of glial cell behaviors in live zebrafish

The nervous system is often described as a hard-wired component of the body even though it is a considerably fluid organ system that reacts to external stimuli in a consistent, stereotyped manner, while maintaining incredible flexibility and plasticity. Unlike the central nervous system (CNS), the peripheral nervous system (PNS) is capable of significant repair, but we have only just begun to understand the cellular and molecular mechanisms that govern this phenomenon. Using zebrafish as a model system, we have the unprecedented opportunity to couple regenerative studies with in vivo imaging and genetic manipulation. Peripheral nerves are composed of axons surrounded by layers of glia and connective tissue. Axons are ensheathed by myelinating or non-myelinating Schwann cells, which are in turn wrapped into a fascicle by a cellular sheath called the perineurium. Following an injury, adult peripheral nerves have the remarkable capacity to remove damaged axonal debris and re-innervate targets. To investigate the roles of all peripheral glia in PNS regeneration, we describe here an axon transection assay that uses a commercially available nitrogen-pumped dye laser to axotomize motor nerves in live transgenic zebrafish. We further describe the methods to couple these experiments to time-lapse imaging of injured and control nerves. This experimental paradigm can be used to not only assess the role that glia play in nerve regeneration, but can also be the platform for elucidating the molecular mechanisms that govern nervous system repair.

Composite primary neuronal high-content screening assay for Huntington's disease incorporating non-cell-autonomous interactions

Huntington's disease (HD) is a fatal neurodegenerative disease characterized by progressive cognitive, behavioral, and motor deficits and caused by expansion of a polyglutamine repeat in the Huntingtin protein (Htt). Despite its monogenic nature, HD pathogenesis includes obligatory non-cell-autonomous pathways involving both the cortex and the striatum, and therefore effective recapitulation of relevant HD disease pathways in cell lines and primary neuronal monocultures is intrinsically limited. To address this, the authors developed an automated high-content imaging screen in high-density primary cultures of cortical and striatal neurons together with supporting glial cells. Cortical and striatal neurons are transfected separately with different fluorescent protein markers such that image-based high-content analysis can be used to assay these neuronal populations separately but still supporting their intercellular interactions, including abundant synaptic interconnectivity. This assay was reduced to practice using transfection of a mutant N-terminal Htt domain and validated via a screen of ~400 selected small molecules. Both expected as well as novel candidate targets for HD emerged from this screen; of particular interest were target classes with close relative proximity to clinical testing. These findings suggest that composite primary cultures incorporating increased levels of biological complexity can be used for high-content imaging and "high-context" screening to represent molecular targets that otherwise may be operant only in the complex tissue environment found in vivo during disease pathogenesis.

An international parentage and identification panel for the domestic cat (Felis catus)

Seventeen commercial and research laboratories participated in two comparison tests under the auspices of the International Society for Animal Genetics to develop an internationally tested, microsatellite-based parentage and identification panel for the domestic cat (Felis catus). Genetic marker selection was based on the polymorphism information content and allele ranges from seven random-bred populations (n = 261) from the USA, Europe and Brazil and eight breeds (n = 200) from the USA. Nineteen microsatellite markers were included in the comparison test and genotyped across the samples. Based on robustness and efficiency, nine autosomal microsatellite markers were ultimately selected as a single multiplex ‘core’ panel for cat identification and parentage testing. Most markers contained dinucleotide repeats. In addition to the autosomal markers, the panel included two gender-specific markers, amelogenin and zinc-finger XY, which produced genotypes for both the X and Y chromosomes. This international cat parentage and identification panel has a power of exclusion comparable to panels used in other species, ranging from 90.08% to 99.79% across breeds and 99.47% to 99.87% in random-bred cat populations.

Information sharing in semen donation: the views of donors

The authors report on a comparative questionnaire study of semen donors at two London clinics offering donor insemination (DI). Results presented here include donors' attitudes towards the storage of identifying information on the UK Human Fertilisation and Embryology Authority's central register, the importance of anonymity when donating, feelings about being traced by DI offspring, and views on the release of identifying donor information to mature offspring. Donors from the two clinics were found to differ on some, although not all, of the above points; in particular, donors from one clinic offered more support for the eventual release of identifying information to DI offspring. The discussion brings in the results of other studies and highlights the complexity of the anonymity question. The authors conclude that some donors may be willing to move towards greater openness of information under controlled conditions using the existing central register and a "veto" system.

Donor insemination: the gifting and selling of semen

The authors examine the implications for individuals and society of how semen is provided for use in donor insemination treatment. In particular, they focus on whether 'donors' make a gift of their semen or are paid. The role of health professionals in shaping the nature and meaning of semen provision is also explored. The currently predominant practice of buying semen is compared with other reproductive and biomedical exchanges: oocyte and embryo donation, surrogacy, and blood, organ and fetal tissue donation. The authors suggest that the commercialisation of semen determines and reflects the type of men frequently recruited to provide semen. This in turn influences the meaning that donors themselves, recipients, offspring, health professionals and society at large attribute to the provision of semen.

Semen donor recruitment: a study of donors in two clinics

We report on a comparative study of semen donors at two London (UK) clinics which have different recruitment and payment policies. Results presented here include data on the demographic characteristics, motivations, means of recruitment and attitudes towards payments of the donors, as well as their disclosure to others about the donation. Donors from the two clinics were found to differ on the above points. Comparisons with other studies are made and implications for donors recruitment are discussed.

Localization of Carbohydrate and DNA in Cyst-Like Structures from a Human Intestinal Spirochaete

This study examined the cyst-like structures found in human intestinal spirochaetes by transmission electron microscopy and by histochemical and immunocytochemical analysis. A human intestinal spirochaete which morphologically resembled other intestinal spirochaetes was grown anaerobically on blood agar plates and in Tryptone Soya broth (Oxoid) and harvested by centrifugation after 8 days growth. Specimens were either conventionally fixed for transmission electron microscopy or fixed in 0.5% glutaraldehyde in 0.1M sodium cacodylate buffer and embedded in LR White resin for immunocytochemistry. En bloc histochemical investigation using a periodic acid-thiosemicarbazide-silver proteinate technique was undertaken for the localization of carbohydrate. A post-embedding immunogold labelling technique was used on ultrathin sections to label DNA. Results from the histochemical study demonstrated a reaction product which was confined to the cytoplasm of mature spirochaetes and in the central bodies within the cysts. Immunogold labelling demonstrated the presence of DNA in both the mature protoplasmic cylinders and in the central bodies. The results of the present study indicate that spirochaetal cysts are highly organized structures, which contain both DNA and carbohydrate. These findings are compatible with the view that these structures have a functional role rather than representing degenerative artifacts.

Telling donor insemination offspring about their conception: the nature of couples' decision-making

The issue of openness and secrecy in the use of donor gametes is the subject of considerable disagreement and debate, not only for social scientists and health professionals, but also for the recipients of donor gametes. This paper has its origins in a study of 58 couples who had a child/children as a result of donor insemination (DI) at the Dunedin Infertility Clinic. Respondents completed questionnaires and took part in an interview during which they were asked whether they intended to tell their offspring about their DI conception. The nature of agreement/disagreement between partners on this issue, the dynamics operating between couples that may affect decision-making, and the views of couples in a time-frame perspective are the focus of this paper. Transcripts from some of the interviews are presented to illustrate the points made and commentary and discussion is provided.

Effects of rolipram and CI-930 on IL-2 mRNA transcription in human Jurkat cells

Interleukin-2 (IL-2) is a major mediator of immunologic responses involved in many chronic inflammatory diseases. We have investigated the effects of rolipram, a PDE-IV inhibitor, and CI-930, a PDE-III inhibitor, on IL-2 gene expression in the Jurkat human T cell line. The immunosuppressant cyclosporin A (CsA) was included as a positive control. Jurkat cells were stimulated with 1 microgram/ml phytohemagglutinin (PHA) and 50 ng/ml phorbol 12-myristate, 13-acetate (PMA) for 6 h, and mRNA was analyzed using reverse transcription and polymerase chain reaction (RT/PCR). IL-2 transcription was greatly inhibited by 1 microM CsA, whereas neither 10 microM rolipram nor 10 microM CI-930 had any effect on steady-state levels of IL-2 mRNA. Therefore, PDE inhibitors do not affect synthesis of IL-2 mRNA in this model of activated T cells. This is of interest given that these agents inhibit the proliferation of primary T cells. For murine splenocytes stimulated by 2.5 micrograms/ml concanavalin A (Con A), rolipram had an IC50 of 0.09 microM and CI-930 an IC50 of 4.4 microM. These concentrations are below those at which IL-2 mRNA synthesis was shown to be unaffected. Therefore, the mechanism by which inhibitors of PDE-III and PDE-IV affect T cell proliferation is not likely to involve suppression of IL-2 mRNA transcription.

A case of monthly unipolar psychotic depression with suicide attempt by self-burning: selective response to bupropion treatment

A second case of monthly, unipolar, psychotic depression is presented, involving a 26-year-old woman whose illness had a postpartum onset, recurred premenstrually for 33 consecutive months, and involved a suicide attempt by self-burning. Whereas various antidepressant, antipsychotic, and hormonal treatments were ineffective, bupropion (together with low-dose trifluoperazine) induced an immediate and complete remission that was maintained at a 16-month evaluation.

The preferential effects of chloroquine on the IgM and IgG subclass responses to TI and TD antigens in BALB/cAn mice

This study has determined the effects of chloroquine on the IgM and the IgG subclass responses of BALB/cAn mice to both thymus-independent (TI) and thymus-dependent (TD) antigens, and has found that in antigen-unprimed BALB/cAn mice chloroquine adversely affects antibody responses to both TI and TD antigens. However, in antigen-primed mice the immune responses to TD antigens were unaffected by chloroquine. The IgGl subclass response, but not necessarily other IgG subclass or IgM responses to TI and TD antigens, was adversely affected by chloroquine in unprimed mice only. Thus, in unprimed, but not in antigen-primed, BALB/cAn mice, chloroquine preferentially decreased the IgGl subclass responses to both TI and TD antigens.

BALB/cAn B cells and T cells have distinct susceptibilities to cytotoxic effects of snake venom

Previous studies have analyzed abilities of snake venoms to preferentially kill certain animal cells. Some studies have examined selective cytotoxic effects of snake venoms on B and T lymphocytes, but few studies have determined abilities of snake venoms to interact with B and T cells at distinct stages of cellular development. Thus, this study has analyzed susceptibilities of immature and mature BALB/cAn splenic B cells and T cells to cytotoxic effects of crude venoms of snakes belonging to the families of Crotalidae, Elapidae, and Viperidae. Both mitogen-stimulated and unstimulated BALB/cAn Ig- splenic T cells are sensitive to cytotoxic effects of snake venoms whereas mitogen-stimulated but not unstimulated Ig+ splenic B lymphocytes are sensitive to snake venoms. We also find that BALB/cAn myelomas but not B cell lymphomas are sensitive to cytotoxic effects of snake venoms. In addition, plaque forming cells making IgG1 subclass in BALB/cAn mitogen-stimulated spleens and in myelomas are preferentially killed by venom of pit viper Bothrops asper. Thus, the cytotoxic effects of crude snake venoms can distinguish BALB/cAn PFC making IgG1 subclass from other B and T cells.

Prolonged expiratory apnoea (cyanotic 'breath-holding') in association with a medullary tumour

From the age of four months to his sudden, unexpected death at 2 years 11 months, a child had severe cyanotic episodes attributed to cyanotic 'breath-holding' (prolonged expiratory apnoea). At postmortem he was found to have a previously undiagnosed gangliocytoma of the medulla, which had invaded the floor of the fourth ventricle and variably affected the 7th to 12th cranial-nerve nuclei.

Interstitial deletion of chromosome 7 detected in three unrelated patients

Chromosome studies were carried out on three patients for the following reasons: (1) growth retardation and mental subnormality in a boy; (2) marked developmental delay in a female infant; (3) routine check on a man whose wife had a stillborn with congenital anomalies. An interstitial deletion at 7q11::7q21 was observed in all three cases.

Teratoma of testis

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Infantile Hypoglycaemia due to Inherited Deficiency of Glycogen Synthetase in Liver

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