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D Goldowitz

Publications and source records attributed to D Goldowitz.

At least 55 records · Page 3Linked to original sources
PubMed1992

Distribution of the blood-brain barrier in heterotopic brain transplants and its relationship to the lesions of EAE.

The blood-brain barrier (BBB) is recognized as a barrier to the trafficking of molecules and cellular elements into the central nervous system (CNS). Horseradish peroxidase (HRP) exclusion is used as a measure of BBB integrity. The BBB is altered and becomes permeable during the course of experimental allergic encephalomyelitis (EAE). Heterotopic brain transplantation into the anterior eye chamber is a technique for studying genetic influences and the role of individual cell types on the development of EAE. Prior to EAE induction, HRP is excluded from the central portion of the transplant, demonstrating an intact BBB. In contrast, HRP localization is found at the periphery of the transplant, suggesting an incomplete barrier. However, EAE lesions typically occur within the more central regions of the transplant, where the BBB is intact, and not at peripherally located "leaky" areas. This suggests that endothelial cells at intact BBB sites may direct trafficking of lymphocytes (gating) into the CNS during the development of EAE, rather than the passive entry of lymphocytes into the CNS through a leaky BBB.

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PubMed1991

Expression of prostaglandin G/H synthase (cyclooxygenase) during murine fetal thymic development.

Fetal thymic lobes in organ culture have been shown to have the capacity to metabolize [14C]arachidonic acid (AA) to prostaglandins (PGs), including 6-ketoPGF1 alpha, PGF2 alpha, PGE2, and PGA2. Inhibition of AA metabolism results in inhibition of growth and Thy 1 expression during thymic organ culture. We report herein that freshly-isolated fetal thymic lobes also have the capacity to metabolize [14C]AA to PGs and HETEs at Days 14 and 16 of prenatal murine development. RNA encoding phospholipase A2, which liberates arachidonic acid from membrane phospholipids, and cyclooxygenase (prostaglandin G/H synthase), the first enzyme involved in the conversion of AA to PGs, are expressed during thymic development. We have localized the cyclooxygenase protein to stromal cells in the fetal and adult thymus. Exogenous AA or an analogue of PGI2 (iloprost) stimulated growth of fetal thymocytes in organ culture. These findings, together with our studies of the morphology of thymic lobes cultured with inhibitors of arachidonate metabolism, support the hypothesis that PGs are required for thymocyte proliferation during thymic development.

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PubMed1991

Abnormalities in premigratory granule cells in the weaver cerebellum defined by monoclonal antibody OZ42.

The immunoreactivity in OZ42, a neural cell specific antibody that recognizes premigratory cerebellar granule cells, was examined in early postnatal wild-type and weaver mouse cerebella. We find that the OZ42-positive staining in the external granular layer (EGL) is first seen at postnatal day 1 in the most posterior and ventral aspect of midline cerebellum in the wild-type and heterozygous weaver mouse. By postnatal day 4 strong immunoreactivity is observed in the EGL of all cerebellar lobules. This staining is localized to a band of immunoreactive cells present at the interface of the EGL and the molecular layer (ML). In the homozygous weaver cerebellum, OZ42-positive staining is not seen until postnatal day 3. In the postnatal day 4 weaver cerebellum, immunoreactivity is considerably ligther than in littermate control cerebella, and found throughout the width of the EGL (i.e., not localized to the EGL-ML interface). This study demonstrates that the expression of a specific marker of granule cell development is abnormal in the granule cell population of the homozygous weaver mouse, a population of cells known to be intrinsically affected by the action of this mutant gene. In the light of previous studies, which have shown that the weaver phenotype is identifiable as early as the day of birth, and that the OZ42-antigen may be involved with the development process of axonal growth, it is reasonable to suggest that the weaver mutation results in an abnormality in the ability of granule cells to produce and/or stabilize axons.

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PubMed1990

Postnatal development of the wild-type and weaver cerebellum after embryonic administration of propylthiouracil (PTU).

In this study we used propylthiouracil (PTU), a thyroid hormone-inhibiting compound, to render +/+, wv/+, and wv/wv embryos hypothyroid in order to test if the appearance of external granule layer (EGL) cell death in the weaver cerebellum is affected by alteration of granule cell development. At birth, the number of EGL cells in the PTU-treated cerebellum was reduced, compared to control animals, by 50%. Also, the amount of cell death was reduced in the PTU-treated wv/wv cerebellum. As adults, no differences were seen between PTU-treated and untreated mutant or normal cerebella. If the hypothyroid treatment that results in a 50% decrease in EGL cell number is due to an extension of cell cycling time, then the expression of the weaver phenotype of cell death likely follows granule cell exit from the cell cycle.

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PubMed1990

NCAM gene expression during the development of cerebellum and dentate gyrus in the mouse.

The neural cell adhesion molecule (NCAM) is thought to be involved in several important events during CNS vertebrate development. This study provides additional information concerning the biochemical determination and anatomical localization of NCAM transcripts. Using S1 nuclease protection assays (S1-NPAs), NCAM transcripts in brain appear highest at birth, with NCAM messenger levels reduced some 20-fold by adulthood. By use of in situ hybridization, NCAM mRNA is demonstrated to be developmentally regulated in the cerebellum and hippocampus. The in situ hybridization findings, in addition to providing results to compare with past studies of NCAM immunolocalization, reveal that NCAM expression in dentate gyrus granule cells and cerebellar Purkinje cells is correlated with the final stages of axonal growth, e.g., synaptic stabilization. In situ hybridization demonstrates a developmental outside-to-inside gradient of NCAM transcripts in the dentate gyrus. Neurological mutant mice, reeler and stagger, provide evidence that NCAM expression is normal in the brain regions investigated, and does not correlate with the developmental perturbations present in these strains.

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PubMed1990

Purkinje cell loss is due to a direct action of the weaver gene in Purkinje cells: evidence from chimeric mice.

Within the cerebellum of the adult homozygous weaver mutant mouse there is an approximate 50% reduction in the number of vermal Purkinje cells. It is not known if this deficit is due to a primary action of the weaver gene or if the cell loss is due to a secondary effect of the weaver gene. We examined this question using chimeric mice, produced by fusing C57BL/6 homozygous or heterozygous weaver embryos (high beta-glucuronidase activity, Gusb) with C3HAw wild-type embryos (low beta-glucuronidase activity, Gush). Chimeric cerebella were stained for beta-glucuronidase activity and counts were made of the number of wv/- (Gusb) and +/+ (Gush) Purkinje cells. If the weaver gene acts intrinsically in the Purkinje cells, then the number of genetically wv/- and not +/+ Purkinje cells should be decreased. Alternatively, if the Purkinje cells are extrinsically affected by the weaver gene, then both wv/- and +/+ should be equally reduced. In this study, using comparative measures of chimerism and Purkinje cell numbers, only weaver Purkinje cells were reduced, while the +/+ Purkinje cells were unaffected in the chimera. These results indicate that the decrease in Purkinje cell number seen in the wv/wv and wv/+ cerebellum is a direct effect of the weaver gene. In concordance with previous work, the disorganization of the Purkinje cells in the cerebellum, however, results from an indirect effect of the weaver gene.

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PubMed1990

Olivocerebellar fiber maturation in normal and lurcher mutant mice: defective development in lurcher.

Olivocerebellar fiber maturation was examined in normal and lurcher mutant mice between postnatal day 5 (P5) and P15, using the anterograde transport of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) from the inferior olive. Immunocytochemistry for the Purkinje cell marker PEP-19 was used to demonstrate Purkinje cell development in the same material. In mutant and normal animals, a regional developmental variation is observed such that, when compared at a given age, cortex lining the vermal fissures appears developmentally advanced over cortex in the cerebellar hemispheres. In the primary fissure of the normal animals, the first recognizable Purkinje cell dendrites appear on P6, and the olivocerebellar fibers first enter the climbing stage of their development on P9. In lurcher animals Purkinje cell development proceeds on this schedule, but olivocerebellar fibers are never observed to enter the molecular layer. These afferents maintain dense perisomatic nests around Purkinje cells, even in P13-15 lurchers. Examination of P14 lurchers by transmission electron microscopy indicates that the olivocerebellar fibers form synapses on Purkinje cell somatic spines and that the basket cell axons fail to form their typical perisomal nests around Purkinje cells. In addition, parallel fibers can be observed to synapse on dendritic spines on the Purkinje cell primary dendrites. We interpret these results as indicating a recognition defect between olivocerebellar fibers and Purkinje cell dendrites. An analysis of this defect in lurcher may reveal how the normal transformation of olivocerebellar fibers, from perisomal to dendritic terminals, is achieved.

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PubMed1989

Purkinje cell reduction in the reeler mutant mouse: a quantitative immunohistochemical study.

We have used the immunohistochemical detection of the Purkinje cell marker cGMP-dependent protein kinase to identify Purkinje neurons in the cerebellum of the reeler mutant mouse. Our quantitative analysis of Purkinje cell number based on this marker indicates that reeler mice possess approximately 82,000 Purkinje cells, slightly less than half the number found in normal mice. Our analysis also shows that 5% of the Purkinje cells in reeler are located in a normal position (between molecular and granular layers), 10% are found in the granular layer, and the remainder form the deep cellular masses characteristic of the reeler cerebellum. The finding of a major Purkinje cell deficit in reeler was surprising in that most investigators consider this mutation to effect cell migration as opposed to cell number. Although we cannot determine whether the Purkinje cell loss in reeler is a primary or secondary gene effect, the possibility that the reeler gene has its effect on migration through a primary effect on neurogenesis or cell survival should be considered.

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PubMed1989

The mouse neurological mutant weaver maps within the region of chromosome 16 that is homologous to human chromosome 21.

Utilizing the backcross C57BL/6 wv/wv x (C57BL/6 wv/wv x MOLD/Rk), the mouse neurological mutation weaver (wv) was mapped less than 1 cM proximal to Ets-2 and Mx on mouse chromosome 16 (0.96 +/- 0.1% recombination). This region is known to include eight genes that are found on human chromosome 21 (HSA 21) and appears to be highly conserved between the two species. We therefore predict that the normal human homolog of wv will be located on HSA 21 and would be in dosage imbalance in individuals with Down syndrome.

Alleles↗
PubMed1989

The weaver granuloprival phenotype is due to intrinsic action of the mutant locus in granule cells: evidence from homozygous weaver chimeras.

The weaver mutation (wv) causes a near total loss of midline granule cells in the mouse cerebellum. The cellular site of mutant locus action leading to the granuloprival phenotype was examined with experimental intraspecific and interspecific homozygous weaver chimeras. It was found that the granule cells which survived and successfully migrated to the internal granular layer of the chimeric cerebellum were all of the wild-type (non-wv) genotype. Using interspecies chimeras, it was determined that the genotype of Purkinje cells and Bergmann glia cells was apparently irrelevant to the survival of granule cells. It is concluded that granule cell death is most likely due to the wv locus acting intrinsically to the weaver granule cells, and not to another cellular site of gene action.

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PubMed1989

Cell allocation in mammalian CNS formation: evidence from murine interspecies aggregation chimeras.

The central nervous system of murine intraspecies chimeras generally consists of an apparently random mixture of neurons derived from each of the parental genotypes. In this study, interspecies mouse chimeras were examined, and an analysis of the parental genotype donation to the chimeric CNS revealed large clusters of like-genotype neurons in small regions as well as in major subdivisions of the CNS. This coherent clustering of like-genotype neurons is proposed to be due to an autonomous developmental clock that is sufficiently mismatched between species to create preferential cell allotment in the chimeric brain.

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PubMed1989

Development and death of external granular layer cells in the weaver mouse cerebellum: a quantitative study.

Previous studies have identified the cerebellar granule cell as a primary site of gene action in the weaver mutant mouse. The temporal expression of the weaver mutant granule cell phenotype has not been fully investigated. To identify early postnatal expression of the weaver mutant phenotype, we quantitated 4 parameters of cerebellar development in postnatal day 0, 2, 4, 6, and 8 +/+, wv/+, and wv/wv mice: (1) cerebellar area, (2) cells in the external granule layer (EGL), (3) number of mitotic figures in the EGL, and (4) number of pyknotic figures in the EGL. Qualitative observations suggest a generalized retardation in the development of wv/wv and wv/+ EGL cells compared with the +/+ cells. Quantitatively, the earliest detectable mutant phenotype in wv/wv and wv/+ cerebella is the increased presence of cell death in the EGL, apparent at the day of birth. Degenerating cells in the EGL, the majority of which are found in the postmitotic zone of this layer, contain abnormally clumped heterochromatin, suggestive of "nuclear" cell death. Previous hypotheses concerning the mechanism of weaver gene action have suggested that granule cells die due to their inability to migrate from the EGL. The time course, mode, and spatial organization of cell death found in the present studies lead us to suggest that an earlier event in granule cell development, such as the exit of neuroblasts from the cell cycle or axonogenesis, is affected by the weaver gene.

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PubMed1988

Description of putative ribosomal RNAs with low abundance, developmental regulation, and the identifier sequence.

Three RNA species (5, 2, 0.15 kb) characterized by the repetitive identifier (ID) sequence, expressed constitutively, and at low abundance have been identified in rat L6 muscle cells by hybridization to cDNA pL6-411. Comigration of these three RNAs with 28, 18, and 5.8 S ribosomal RNAs (rRNAs) has suggested the possibility that pL6-411 RNAs are related to ribosomes or ribosome-like structures. Subsequent experiments showed that pL6-411-related RNAs could indeed be found in ribosome-like particles which were indistinguishable from ribosomes when separated on sucrose gradients under native (low salt, isolation of intact ribosomes) or denaturing conditions (detergent, high salt, isolation of ribosome subunits). Furthermore, we demonstrate that pL6-411-related RNAs are cytoplasmic in L6 cells, may be transcribed in nucleoli, and, based on their nucleotide sequence, have the potential of inter- and intramolecular hybridization. Expression of pL6-411 RNAs was also shown in adult as well as in fetal rat tissues after Day 14 of gestation. These above findings provide supportive evidence for the hypothesis that pL6-411 5- and 2-kb RNAs could exist in a subset of ribosomes. These ribosome-like pL6-411 particles nevertheless differ from ribosomes in that their associated RNAs have different nucleotide sequences, are of lower abundance, and are up-regulated later in development than rRNAs. We discuss our results in the context of a postulated ribosome subset containing RNAs other than rRNAs. These ribosome-like particles might be involved in the translational control of ID-positive mRNAs.

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PubMed1988

Evidence for the transneuronal regulation of cerebellin biosynthesis in developing Purkinje cells.

We have investigated the expression of a unique class of neuropeptides, the cerebellins, in normal and neurodevelopmentally mutant mice. Employing HPLC separation, gas-phase Edman sequencing, and immunocytochemistry, the normal Balb/c mouse cerebellum is shown to contain 2 Purkinje cell-specific neuropeptides, cerebellin and des-Ser1-cerebellin. In this strain of mouse the cerebellins appear during early postnatal development and their subsequent levels parallel the most dramatic period of cerebellar development: granule cell migration and parallel fiber formation, synaptogenesis, Purkinje cell dendritic maturation, and establishment of adult cytoarchitecture. In mutant mice (reeler, weaver, and staggerer), in which these early developmental events are markedly disrupted, Purkinje cells contain much lower levels of cerebellin and des-Ser1-cerebellin. In general there is a correlation between the formation and number of parallel fiber-Purkinje cell synapses and cerebellin levels. For example, the staggerer mutant, which totally lacks these synapses, is essentially devoid of cerebellin, whereas in reeler, cerebellin seems to be dependent upon the position of individual Purkinje cells and their ability to form contacts with granule cells. These results indicate that granule cells can modulate the level of cerebellin in Purkinje cells. A number of models to explain these data are discussed.

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PubMed1987

Heterotopic brain transplants in the study of experimental allergic encephalomyelitis.

A heterotopic transplant paradigm was developed for its potential usefulness in dissecting genetically determined immune and central nervous system (CNS) components in the induction of experimental allergic encephalomyelitis (EAE). EAE is a cell-mediated, organ-specific, autoimmune disease producing inflammatory demyelination in the CNS. Susceptibility to EAE is determined by multiple genes and reflects both immune competence and target tissue responses. Syngeneic fetal CNS was heterotopically transplanted into the anterior chamber of the eye or beneath the capsule of the kidney of adult SJL or (SJL X BALB/c)F1 mice. Transplants usually survived better in the eye than the kidney. Six to eight weeks after transplantation, some mice were immunized for EAE. Immunized mice developed clinical and pathological signs of EAE in 12 to 15 days. The placement of CNS tissue into the eye or kidney prior to immunization did not suppress induction of EAE. Transplants in either location, in immunized mice, manifested perivascular inflammation and demyelination similar to that seen in the host CNS. However, transplants in mice not immunized for EAE, but maintained an equal time period after transplantation, did not demonstrate these features. The ability to produce the specific pathologic lesions of EAE in CNS tissue transplanted outside the CNS allows the design of studies of the tissue localization of genetic restrictions to development of EAE.

Animals↗
PubMed1987

Cell partitioning and mixing in the formation of the CNS: analysis of the cortical somatosensory barrels in chimeric mice.

Development of structural units along clonal lines as demonstrated in some invertebrates is an elegantly simple way to proceed in the formation of tissues. The possibility of a related event occurring in mammalian neurogenesis, i.e. that discrete assemblies of cortical neurons may be presorted according to lineage during neuronal development, was examined in chimeric mice. These mice consist of cells of two genotypes. Genetically determined differences in beta-glucuronidase activity, detected by histochemical means, were used as the cell-marker to determine the genotypic origin of neurons. Individual 'barrels' of the mouse somatosensory cortex were examined, and each neuron classified as high (Gusb) or low (Gush) as to the expression of beta-glucuronidase activity. Neurons from the two genotypes were found to be distributed in the same proportion amongst all the barrels examined from a given animal. The distribution of like-genotype neurons in the barrels was similar to neighboring cortical areas. Furthermore, there was no evidence for unusual distributions of neurons from one genotype within a single barrel. Such evidence does not support the notion of a unique founder population of neurons for individual barrels (or groups of barrels), and supports the notion of extensive cell mixing and epi-genetic events in the determination of individual barrels in the mouse somatosensory cortex.

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PubMed1987

A highly abundant transcript in adult murine cerebellar granule cells contains repetitive sequences homologous to L1.

Cloned cDNA from adult mouse cerebellum composed of subsequences homologous to the L1Md consensus sequence (long interspersed repetitive element "LINE" family of the mouse) hybridizes specifically with large nuclear poly(A)+RNAs that are highly concentrated in the murine and rat cerebellum. These homogeneous L1-related transcripts were localized in the mouse CNS by in situ hybridization with 3H- and biotin-labeled DNA probes. They were found to hybridize to cerebellar granule cells specifically.

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