Biomedical subjects

K A Roth

Publications and source records attributed to K A Roth.

At least 55 records · Page 3Linked to original sources

PubMed1997

Clear cell neoplasms and pseudoneoplastic lesions of the central nervous system.

Mass lesions of the central nervous system (CNS) that may assume a clear cell appearance are diverse in nature. Primary conditions in this category include oligodendroglioma, hemangioblastoma, germinoma (seminoma), clear cell and chordoid meningioma, pleomorphic xanthoastrocytoma, and lipid-rich glioblastoma. These proliferations usually can be identified by attention to clinical presentation, topographic location, radiographic details, and histological nuances. Occasionally, however, electron microscopy or immunohistological analysis may be necessary. A recommended panel of reagents for the evaluation of clear cell primary CNS lesions include antibodies to glial fibrillary acidic proteins, S-100 protein, epithelial membrane antigen, vimentin, keratins, placental-like alkaline phosphatase, and synaptophysin. This article reviews the salient clinicopathologic attributes of such proliferations, elaborates a practical approach to their diagnosis, and discusses important differential diagnostic considerations. The latter include malformative lesions, infarcts, inflammatory conditions, and secondary lymphomas, carcinomas, and melanomas.

Alkaline Phosphatase↗

PubMed1996

The neostriatal mosaic: basis for the changing distribution of neurokinin-1 receptor immunoreactivity during development.

The pattern of neurokinin-1 receptor-like immunoreactivity (NK-1Rir) was mapped in perinatal and adult mouse striatum by using a new polyclonal antiserum. NK-1Rir was detected in the differentiating regions of the ganglionic eminences on embryonic day 12.5 (E12.5). NK-1Rir structures were enriched in the striatal patch compartment between E16.5 and approximately postnatal day 3 (P3); distributed more uniformly, within portions of both the patch and matrix compartments on P7; and enriched in the matrix compartment in the adult. Analysis of the phenotype of NK-1Rir cells on P2, P7, and in the adult suggested that cholinergic cells accounted for the majority of NK-1Rir cells early postnatally, with increasing contributions from somatostatinergic cells later postnatally. In the adult, approximately half of NK-1Rir cells were cholinergic and half were somatostatinergic. The transient enrichment of NK-1R-bearing cells and processes in the patch compartment which contains cells that express substance P (SP), a putative ligand for the NK-1R, may be a consequence of compartment formation or may be functionally important for compartment development.

Amino Acid Sequence↗

PubMed1996

Cholera toxin binds to differentiating neurons in the developing murine basal ganglia.

Cell-surface expression of gangliosides in the developing mammalian central nervous system is temporally-regulated in a cell-type and regionally specific fashion. Gangliosides may be involved in cell-cell and cell-matrix interactions, and can act synergystically with several growth factors or growth factor receptors. Thus, a role for gangliosides in the regulation of neuronal stem cell proliferation and differentiation has been suggested. We have previously shown that cholera toxin B subunit (CTB), which binds to the ganglioside GM1, binds heterogeneously to dissociated neuroepithelial cells from the developing mouse telencephalon. We stained fixed sections of the ganglionic eminences (GE) of fetal mouse brains and found that CTB labels regions which contain differentiating neurons, but does not stain the rapidly dividing neuroepithelial cells in the ventricular zone. We dissociated cells from the GE on day 14 of gestation (E14), labeled the cells with CTB-FITC, and separated them by flow cytometry. We found the highest level of CTB binding in postmitotic cells which had begun to express markers of neuronal differentiation. When CTB-sorted cells were placed into short-term (48 h) cell culture, high CTB binding continued to correlate with fewer numbers of proliferating cells and larger numbers of differentiating neurons. CTB binding and fluorescence activated cell sorting appear to be useful for separating populations of differentiating neurons from immature, proliferating cells. These studies further lead us to suggest that GM1 plays a role in the differentiation of neurons in the basal ganglia.

Animals↗

PubMed1996

Apoptosis of bcl-x-deficient telencephalic cells in vitro.

bcl-x is a member of the bcl-2 gene family, which is expressed at high levels in the embryonic brain. The targeted disruption of bcl-x results in massive cell death of immature neurons in the developing mouse brain (Motoyama et al., 1995). bcl-x-deficient mice die around embryonic day 13 (E13), probably secondary to their inability to produce mature red blood cells. To determine whether the death of immature neurons in the bcl-x-deficient brain is cell autonomous, we examined primary telencephalic cell cultures from E12.5 homozygous mutant (bcl-x-/-), heterozygous mutant (bcl-x+/-), and wild-type (bcl-x+/+) mice. bcl-x-/- telencephalic cells cultured in 0.5 or 2.0% fetal calf serum (FCS)-containing medium for 48 hr showed increased apoptosis, defined by abnormal bisbenzamide staining and terminal-deoxytransferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL), and decreased numbers of microtubule-associated protein-2-immunoreactive neurons compared with bcl-x+/- and bcl-x+/+ cultures. Cycloheximide treatment of bcl-x-/- telencephalic cell cultures failed to prevent the increased cell death observed in low FCS-containing medium, suggesting a protein synthesis-independent apoptosis. There were no significant differences among bcl-x-/-, bcl-x+/-, and bcl-x+/+ telencephalic cells grown for 48 hr in 5% FCS-containing medium or in a chemically defined serum-free medium (ITS). bcl-x-/- neurons generated in ITS showed increased susceptibility to subsequent serum deprivation. These results indicate that bcl-x is important for both neuron maturation and survival.

Animals↗

PubMed1996

Neuronal argyrophilia and phosphorylated neurofilament accumulation secondary to deafferentation.

This work tests the hypothesis that deafferentation caused by experimental brain lesions leads to the appearance of perikaryal argyrophilia and the accumulation of phosphorylated cytoskeletal proteins which are potential precursors for neurofibrillary tangle formation. Destructive lesions of the ventral tegmental area, the septum of the medial forebrain and the entorhinal cortex, when combined with systemic administration of a D-1 dopamine receptor antagonist, produced transsynaptic changes in neurons of the hippocampal formation in the midbrain. Abnormally phosphorylated neurofilament protein was demonstrated immunohistochemically in the cytoplasm of mesencephalic pyramidal neurons, particularly in the red nucleus. These same neurons also developed cytoplasmic argyrophilia in Bielschowsky histologic preparations. Although distinct neurofibrillary tangles were not produced with this paradigm, both the protein immunoreactivity and argyrophilia were arranged in cytoplasmic linear arrays. The structural changes induced in this experimental model may be an important preliminary stage for neurofibrillary tangle formation.

Animals↗

PubMed1996

Double immunofluorescent staining using two unconjugated primary antisera raised in the same species.

Monoclonal antibodies (MAbs) capable of recognizing developmental stage-specific neuronal epitopes are becoming increasingly available. Because most of these MAbs are raised in a single species (mouse), simultaneous immunofluorescent detection of multiple epitopes has been difficult. We have taken advantage of the high sensitivity of tyramide signal amplification to develop a protocol that permits simultaneous detection of two antibodies raised in the same species. One primary antibody was applied at a concentration below the detection limit of fluorescently labeled secondary antibodies, yet sufficient for detection with the tyramide system. This first primary antibody was then effectively neglected during application of a second primary antibody that was detected by conventional fluorescently labeled secondary antibodies. Specifically, dual labeling for nestin and MAP2 was used to distinguish neuronal stem cells and precursor cells from immature postmitotic neurons, and synapsin I and GAP43 immunostaining was used to distinguish neurons with established synaptic connections from developing neurons. We have used this technique for staining both tissue sections and cultured cells from the embryonic mouse brain. This technique should be widely applicable and offers a simple procedure for simultaneously detecting two antigens when antibodies from only a single species are available.

Animals↗

PubMed1995

Developmentally-regulated lectin binding in the embryonic mouse telencephalon.

Cell-surface carbohydrate epitopes are important determinants in cell-cell and cell-matrix interactions, and oligosaccharide groups are structural components of many growth factor receptors and cell adhesion molecules. These epitopes may participate in the regulation of stem cell proliferation and differentiation during central nervous system development. To further understand these cellular phenomena, it is important to define the changes in neuroepithelial cell-surface carbohydrate expression during development. We used a panel of fluorescein-conjugated lectins to label live, freshly dissociated cells from the embryonic day 11 to 18 (E11 to E18) mouse telencephalon. The intensity and heterogeneity of lectin labeling was assessed by flow cytometry. The lectins that we examined exhibited widely varying levels of labeling intensity. Lectins with the highest degree of binding included cholera toxin B subunit (CTB), which binds primarily to the gangliosides GM1 and GD1b, phaseolus vulgaris erythroagglutinating lectin (PHA-E), which binds to a variety of cell adhesion molecules, and wheat germ agglutinin (WGA). Many lectins showed increasing labeling intensity and cellular heterogeneity as development progressed. To determine if the observed cellular heterogeneity in lectin binding reflected biological differences in neuroepithelial cell subpopulations, cells from the E14 telencephalon were separated into two populations based on their intensity of CTB labeling using a fluorescence activated cell sorter. The population of weakly CTB labeled cells contained more than four times as many cells in S-phase of the cell cycle than the population of intensely CTB labeled cells. These observations suggest that lectin cytochemistry and flow cytometry can be useful in identifying specific cell subpopulations of neuroepithelial precursor cells during development, allowing their isolation and characterization in vitro.

Animals↗

PubMed1995

Massive cell death of immature hematopoietic cells and neurons in Bcl-x-deficient mice.

bcl-x is a member of the bcl-2 gene family, which may regulate programmed cell death. Mice were generated that lacked Bcl-x. The Bcl-x-deficient mice died around embryonic day 13. Extensive apoptotic cell death was evident in postmitotic immature neurons of the developing brain, spinal cord, and dorsal root ganglia. Hematopoietic cells in the liver were also apoptotic. Analyses of bcl-x double-knockout chimeric mice showed that the maturation of Bcl-x-deficient lymphocytes was diminished. The life-span of immature lymphocytes, but not mature lymphocytes, was shortened. Thus, Bcl-x functions to support the viability of immature cells during the development of the nervous and hematopoietic systems.

Animals↗

PubMed1995

Simultaneous detection of TDT-mediated dUTP-biotin nick end-labeling (TUNEL)-positive cells and multiple immunohistochemical markers in single tissue sections.

We have modified the terminal deoxynucleotidyl transferase (TDT)-mediated dUTP-biotin nick end-labeling (TUNEL) method to permit the immunogold-silver intensification detection of apoptotic cells in tissue sections. Such sections can subsequently be processed for multi-labeling fluorescence microscopy, thus permitting the simultaneous detection of silver-positive apoptotic cells and three additional fluorescent signals. In this report, we combined TUNEL labeling with the fluorescent detection of bromodeoxyuridine-positive proliferating cells, growth-associated protein-43 (GAP-43) immunoreactive neurons and bisbenzimide-positive pyknotic cells in the embryonic mouse nervous system. This combination of stains allowed the simultaneous detection of proliferative, differentiated and apoptotic cells in the developing nervous system.

Animals↗

PubMed1994

Expression of wild-type and mutant simian virus 40 large tumor antigens in villus-associated enterocytes of transgenic mice.

The four principal gut epithelial cell lineages undergo continuous and rapid renewal during a geographically well-organized migration along the crypt-to-villus axis. The molecules that regulate their proliferation and differentiation programs are largely unknown. The large tumor antigen (TAg) of wild-type (wt) simian virus 40 (SV40) and its mutant derivatives represent tools for describing the contributions of regulators of the cell cycle to the proliferative state of each lineage. Expression of SV40 TAgwt in postmitotic, villus-associated enterocytes of transgenic mice causes them to reenter the cell cycle without an apparent effect on their state of differentiation. When human KRAS with a Val-12 substitution ([Val12]KRAS) is coexpressed with SV40 TAgwt in villus enterocytes of bitransgenic animals, the two oncoproteins cooperate to produce dedifferentiation (dysplasia). SV40 mutant d11137 expresses a TAg that is unable to complex with p53 but retains N-terminal transforming functions, including the ability to complex pRB, p107, and p300. When SV40 TAgd11137 is expressed in villus enterocytes, they reenter into the cell cycle. However, coexpression of SV40 TAgd11137 and [Val12]KRAS does not produce dysplastic changes. Thus, the N-terminal 121 residues of TAg are sufficient to perturb the proliferative state of the enterocyte but not to produce detectable changes in the state of differentiation when coexpressed with [Val12]KRAS.

Animals↗

PubMed1994

Neurotrophin-4 selectively promotes survival of striatal neurons in organotypic slice culture.

The neurotrophins (NGF, BDNF, NT-3, and NT-4) provide trophic support to subpopulations of neurons in the central and peripheral nervous systems. We examined organotypic slices of neonatal mouse striatum maintained in medium supplemented with neurotrophins or with CNTF to determine which of these factors influence the survivability of striatal neurons. Neuron counts at the end of the culture period revealed that NT-4 was the only factor that had a significant effect on neuronal survival, suggesting that NT-4 is a trophic factor for striatal neurons in organotypic slices.

Animals↗

PubMed1994

Immunohistochemical studies indicate multiple enteroendocrine cell differentiation pathways in the mouse proximal small intestine.

The enteroendocrine cell system of the mammalian gastrointestinal tract is comprised of at least 16 different subpopulations. Each subpopulation shows a characteristic distribution along both the crypt-villus and cephalo-caudal axes. In both the small intestine and colon of adult mice, multilabel immunohistochemistry has demonstrated that two or more neuroendocrine products can be coexpressed in various combinations in single cells along the crypt-villus axis, suggesting that enteroendocrine phenotypes may be actively regulated. Using bromodeoxyuridine (BrdU) incorporation and multilabel immunohistochemistry, we have previously demonstrated an enteroendocrine cell differentiation pathway consisting of two subpopulations of cells in the mouse proximal small intestine--one involving the sequential expression of substance P, serotonin, and secretin in cells migrating out of the crypts into the villi, and a second involving the expression of substance P and serotonin in cells which remain in the crypts. In this report, we use double label immunohistochemistry and BrdU incorporation to define the temporal and spatial interrelationships between gastrin, cholecystokinin (CCK), glucagon-like peptide-1 (GLP-1), and gastric inhibitory peptide (GIP) immunoreactive cells in the mouse proximal small intestine. The expression of these products was compared with that of substance P, serotonin, and secretin. Minimal overlap of expression was found in cells immunoreactive for substance P or serotonin with gastrin, CCK, GLP-1, or GIP; however, secretin was found colocalized in villus-associated gastrin, CCK, and GLP-1 containing cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Adaptation of enteroendocrine cells in response to jejunal-ileal transposition in the rat.

BACKGROUND/AIMS: Enteroendocrine cell subpopulations are uniquely distributed along the crypt-villus and cephalocaudal axes of the small intestine. These regional differences in enteroendocrine cell expression, which are maintained in spite of rapid turnover of the epithelium, serve as descriptive markers of physiological differences along the length of the bowel. This study aimed to determine the influence of luminal contents on the maintenance of regional differentiation patterns of enteroendocrine and enterocytic phenotypes. METHODS: Sections of jejunum and ileum were surgically transposed in rats, leaving the innervation and blood supply to the transposed segments intact. The animals were killed 1, 4, and 8 weeks after surgery. Enteroendocrine cell subpopulations and enterocytic cell markers were studied immunohistochemically. RESULTS: No change in regional expression patterns was seen in response to the altered luminal environment by any of the enterocytic markers and four of the five enteroendocrine cell subpopulation markers. Eight weeks after surgery, the number of gastrin-expressing enteroendocrine cells increased in ileal segments transplanted proximally. CONCLUSIONS: Although luminal signals can affect intestinal stem cells to alter their proliferation rates, the luminal environment has only limited effects on the regional-specific expression of enteroendocrine or enterocytic products.

Adaptation, Physiological↗

PubMed1994

Transganglionic neuropeptide Y response to sciatic nerve injury in young and aged rats.

Gracile neuroaxonal dystrophy (NAD) is a hallmark of the aging human and rodent sensory nervous systems which may represent an abnormal transganglionic response to peripheral axonal injury. To examine the structural plasticity of central dorsal root ganglia (DRG)-derived axons in the gracile nucleus, we evaluated the response of the lumbar DRG and their central projections to sciatic nerve injury in young and old rats. In uninjured rats neither the DRG nor its central projections contained histochemical immunoreactivity for neuropeptide Y (NPY). However, within 1 week of sciatic nerve crush or transection injury, NPY immunoreactivity appeared in the lumbar DRG and its central projections, reaching an apparent maximum in number and intensity of processes at 28 days. Neuropeptide Y immunoreactivity was more intense and sustained in response to transection compared to crush injury, results supported by NPY radioimmunoassay. Neuropeptide Y-immunoreactive processes in the gracile nuclei of axotomized young animals consisted of delicate axons or slightly enlarged profiles that may represent regenerative elements. Lumbar dorsal rhizotomy performed simultaneously with sciatic nerve transection prevented the transganglionic NPY response. Dystrophic axons in the gracile nucleus of non-lesioned aged animals were not NPY-immunoreactive; however, after sciatic nerve transection, NPY immunoreactivity developed in both delicate axons and markedly swollen dystrophic elements, a finding confirmed by ultrastructural immunolocalization. These results establish that despite the presence of NAD in DRG projections to aged gracile nuclei these elements remain capable of a plastic NPY response to peripheral nerve injury.

Aging↗

PubMed1994

Lectins are sensitive tools for defining the differentiation programs of mouse gut epithelial cell lineages.

We have used histochemical methods to survey the cellular patterns of binding of a panel of 45 lectins with well-defined carbohydrate specificities to sections prepared from various regions of the gastric-to-colonic axis of fetal, neonatal, and adult FVB/N mouse gut. The results suggest that lectins can be used as remarkably sensitive tools to describe the differentiation programs of gastric and intestinal epithelial cell lineages as a function of their position along the cephalocaudal axis of the gut and as a function of developmental stage. Studies of intestinal isografts and transgenic mice that express Simian virus-40 T antigen in enterocytes suggest that many of these cell lineage-specific and spatial patterns of glycoconjugate production can be established and maintained in the absence of exposure to luminal contents and in the presence of specific proliferative abnormalities. This lectin panel should be useful for operationally defining subpopulations of the principal gut epithelial cell lineages in normal strains of mice, for describing variations in gut epithelial cell differentiation programs in mutant and transgenic mice, and for recovering specific epithelial cell lineages or subpopulations.

Aging↗

PubMed1994

Infantile meningioma.

Childhood meningiomas are unusual, and meningiomas in patients less than 1 year of age are exceedingly rare. We report a case of a meningioma with malignant histologic features in a 6-month-old child who has had an excellent postoperative course. The pathologic features in relation to prognosis, as well as the magnetic resonance imaging characteristics of the case are presented. The literature is reviewed and implications for therapeutic management are discussed.

Brain↗

PubMed1993

Attachment of Helicobacter pylori to human gastric epithelium mediated by blood group antigens.

Helicobacter pylori is associated with development of gastritis, gastric ulcers, and adenocarcinomas in humans. The Lewis(b) (Le(b)) blood group antigen mediates H. pylori attachment to human gastric mucosa. Soluble glycoproteins presenting the Leb antigen or antibodies to the Leb antigen inhibited bacterial binding. Gastric tissue lacking Leb expression did not bind H. pylori. Bacteria did not bind to Leb antigen substituted with a terminal GalNAc alpha 1-3 residue (blood group A determinant), suggesting that the availability of H. pylori receptors might be reduced in individuals of blood group A and B phenotypes, as compared with blood group O individuals.

Antibodies, Monoclonal↗

PubMed1993

Use of transgenic mice to map cis-acting elements in the liver fatty acid-binding protein gene (Fabpl) that regulate its cell lineage-specific, differentiation-dependent, and spatial patterns of expression in the gut epithelium and in the liver acinus.

Axial pattern formation is sustained in the mammalian gut epithelium despite rapid and continuous renewal of its four principal cell lineages. The mouse and rat liver fatty acid-binding protein (L-FABP) genes (Fabpl) represent an excellent model for understanding the mechanisms that determine differentiation-dependent, cell lineage-specific, and distinct regional patterns of expression along the crypt-to-villus and duodenal-to-ileal axes of the gut, as well as within the liver acinus. We have used transgenic mice to map cis-acting elements in rat Fabpl that control these patterns of gene expression. Seven transgenes were analyzed, representing sequential deletions of the 5'-nontranscribed domain of Fabpl linked to the human growth hormone (hGH) gene beginning at its nucleotide +3 (L-FABP/hGH+3). Several pedigrees of mice containing each one of the L-FABP/hGH+3 transgenes were examined at the end of their 8th and 20th weeks of postnatal life using immunocytochemical and RNA hybridization analyses. A remarkably compact sequence spanning nucleotides -132 to +21 of Fabpl is sufficient to establish and maintain a distribution of reporter mRNA and protein in villus-associated enterocytes located along the duodenal-to-ileal axis of the gut that resembles the pattern of expression of the endogenous Fabpl gene. L-FABP-132 to +21/hGH+3 is also expressed in surface and pit mucous cells of gastric units and in enterocytes located in the colonic homologs of small intestinal villi, the surface epithelial cuffs. This pattern of transgene expression in the stomach and colon recapitulates that of the intact endogenous donor rat Fabpl but not that of mouse Fabpl, which is silent in these proximal and distal segments of the gastrointestinal tract. Analysis of mice containing L-FABP-4000 to +21/hGH+3, L-FABP-1600 to +21/hGH+3, L-FABP-596 to +21/hGH+3, L-FABP-246 to +21/hGH+3, and L-FABP-186 to +21/hGH+3 indicate that Fabpl's cephalocaudal gradient is influenced by cis-acting suppressors of cecal and colonic expression located between nucleotides -4000 and -1600 and by cis-acting activators of cecal and colonic expression located between nucleotides -597 and -351. L-FABP-132 to +21/hGH+3 is precociously activated in proliferating and nonproliferating epithelial cells located in intestinal crypts. The suppressor(s) of L-FABP accumulation in crypt epithelial cell populations are not represented between nucleotides -4000 and +21, indicating that different cis-acting sequences regulate regional and differentiation-dependent patterns of Fabpl expression.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗