Search Results - (Author, Cooperation:M. M. Herman)

2011-10-28

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Aging/*genetics ; Autopsy ; Continental Population Groups/genetics ; Fetus/metabolism ; *Gene Expression Profiling ; Gene Expression Regulation, Developmental/*genetics ; Genome, Human/genetics ; Humans ; Polymorphism, Single Nucleotide/genetics ; Prefrontal Cortex/embryology/*growth & development/*metabolism ; Time Factors ; Transcriptome/*genetics

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract— Non-histone chromosomal proteins (NHCP) from mouse brain at different stages of development and from adult liver and kidney of strain related mice were analyzed by SDS-polyacrylamide gel electrophoresis and were compared with the mouse teratoma, OTT-6050. The fetal, neonatal and adult brains were qualitatively similar in their NHCP profiles but had quantitative differences. The NHCP composition of the adult brain was clearly distinct from that of the liver and kidney and was dissimilar from that of the teratoma.

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1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

—The branched-chain amino and ketoacids [i.e. l-leucine, l-isoleucine, l-valine, alpha-ketoisocaproic acid (AKICA), alpha-keto-beta-methylvaleric acid (AKBMVA) and alpha-ketoisovaleric acid (AKIVA)] were administered to mouse strain l fibroblasts in tissue culture in an attempt to study the effects of increased levels of the compounds in an in vitro system. All of these compounds are found to be elevated in the blood of patients with Maple Syrup Urine Disease (MSUD).With AKICA, l-leucine, AKIVA and AKBMVA, there was a decreased growth rate at concentrations of 10 to 30 times the levels found in Maple Syrup Urine Disease. Combined administration of the above six compounds at the maximum blood levels noted in MSUD produced a significantly decreased growth rate. Electron microscopic studies revealed numerous annulate lamellae in cells treated with AKICA and in those treated with a combination of all six MSUD compounds. AKICA-treated cells contained elevated concentrations per cell of free fatty acids, triglycerides, sterols and some classes of phospholipids. Isotope labelling experiments were performed using [U-14C] AKICA and [3H]isoleucine, which were added to l-cell suspension cultures containing various levels of unlabelled AKICA. Labelled AKICA and isoleucine were both taken up by the cells. The net uptake of isoleucine was inhibited by AKICA in concentrations found in MSUD. Folch-Lees extraction of cells treated with labelled AKICA revealed increased 14C counts only in the lower lipid phase.The growth inhibition and annulate lamellae observed with AKICA treatment may be due to an arrest of the cells in phase G1 of the cell growth cycle, possibly due to decreased isoleucine uptake. It is proposed that a similarly-mediated arrest in the proliferation of oligodendroglial cells during the critical period of myelination gliosis might account for the myelination abnormalities reported in MSUD.

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1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract— The effects of altered osmolarity on respiration and fine structure were compared in isolated rat cerebral versus liver mitochondria.Polarographic study of cerebral mitochondria in hypo-osmolar media showed inhibition of State 3 (ADP-dependent) respiration which was not reversed by dinitrophenol. In hyperosmolar media, State 3 respiration was transiently inhibited and State 4 (ADP-independent) respiration increased with the NAD-linked substrate pair, glutamate and malate. With succinate as substrate, respiration was not affected by moderate hyperosmolarity. In the most hyperosmolar medium, State 3 respiration was inhibited with both substrates.In contrast to the results with cerebral mitochondria, State 4 respiration was increased in hypo-osmolar media and State 3 respiration was persistently inhibited in hyperosmolar media in liver mitochondria with both substrates.In both cerebral and liver mitochondria, cytochrome c oxidase (EC 1.9.3.1.) activity was mildly inhibited in hypo-osmolar media and increased in hyperosmolar media.Electron microscopy showed that liver mitochondria were swollen in hypo-osmolar media and condensed in hyperosmolar media. Cerebral mitochondria showed mild rarefaction in hypo-osmolar media and, in hyperosmolar media, more than half the mitochondria showed either no or minimal changes in fine structure.Our results suggest that there are differences in metabolic control and structure between mitochondria from different cell types, which may be important in the cellular metabolic response to pathologic changes in water or osmolarity.

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1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1460-9568

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Signalling through tyrosine kinase receptor B (trkB) influences neuronal survival, differentiation and synaptogenesis. trkB exists in a full-length form (trkBTK+), which contains a catalytic tyrosine kinase (TK) domain, and a truncated form (trkBTK–), which lacks this domain. In the rodent brain, expression of trkBTK+ decreases and trkBTK– increases during postnatal life. We hypothesized that both forms of trkB receptor mRNA would be present in the human neocortex and that the developmental profile of trkB gene expression in human may be distinct from that in rodent. We detected both trkBTK+ and trkBTK– mRNA in RNA extracted from multiple human brain regions by Northern blot. Using in situ hybridization, we found trkBTK+ mRNA in all cortical layers, with highest expression in layer IV and intermediate-to-high expression in layers III and V of the human dorsolateral prefrontal cortex. trkBTK+ mRNA was present in neurons with both pyramidal and nonpyramidal shapes in the dorsolateral prefrontal cortex. trkBTK+ mRNA levels were significantly increased in layer III in young adults as compared with infants and the elderly. In the elderly, trkBTK+ mRNA levels were reduced markedly in all cortical layers. Unlike the mRNA encoding the full-length form of trkB, trkBTK– mRNA was distributed homogeneously across the grey matter, and trkBTK– mRNA levels increased only slightly during postnatal life. The results suggest that neurons in the human dorsolateral prefrontal cortex are responsive to neurotrophins throughout postnatal life and that this responsiveness may be modulated during the human lifespan.

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1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] C-6 cells and mouse strain L-929 fibroblasts, both obtained from the American Type Culture Collection, were maintained at 36-37 C in several systems. Monolayer cultures were grown in Roux bottles in a medium consisting of minimal essential medium?Spinner solution (Grand Island Biological Co., Grand ...

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1399-3054

Blackwell Publishing Journal Backfiles 1879-2005

Biology

We studied the sequence of several metabolic reactions, representative for oxidative damage and protection, in primary leaves of Phaseolus vulgaris (cv. Limburgse vroege) as a function of root assimilation of a toxic sublethal Cu concentration (630 μM). A transient increase of products of membrane peroxidation was observed in the primary leaves during the period of Cu uptake. This rise was mainly due to the oxidizing properties of copper itself and not to a stimulation of the lipoxygenase (EC 1.13.11.12) activity. In our experimental conditions, membrane lipid peroxidation and K+-leakage were not directly related; during at least three days after Cu application to the roots, when products of lipid peroxidation were already detected in the leaf, permeability of the cytoplasmic membrane for K+ was improved. However, Cu stimulated the capacity of catalase (EC 1.11.1.6) and ascorbate peroxidase (EC 1.11.1.11). These enzymes protect the tissue against oxidative stress since at least the hydrogen peroxide content was significantly reduced. Superoxide dismutase (EC 1.15.1.1) was not involved in this defense mechanism.

Electronic Resource

1432-2307

Lead encephalopathy ; Mitochondria ; Respiration ; Elemental microanalysis

Springer Online Journal Archives 1860-2000

Medicine

Summary The toxic effects of inorganic lead feedings on the immature brain were studied in the rat pup. Beginning when litters were two weeks old, PbCO3 was fed to nursing mothers and then to pups directly after weaning. Results in lead-fed pups were compared to age-matched controls and to lead-fed young adult males (60 days old). Anaemia and growth failure developed in both pups and adults. In the second week, more than half the pups developed an encephalopathy, with haemorrhage and oedema predominately in the cerebellum and lead-containing densities in the cerebellar molecular layer. The latter were confirmed by X-ray microanalysis. No lead-fed adults showed signs of an encephalopathy. Cerebellar mitochondria from lead-fed pups, studied polarographically, showed a very early loss of respiratory control and a subsequent inhibition of phosphorylation-coupled respiration with NAD-linked substrates but not with succinate. Compared to the pup cerebellum, these changes were much less marked in immature cerebral mitochondria and were not found in adult cerebral or cerebellar mitochondria. Cerebral and cerebellar homogenates from immature and mature lead-fed animals showed large increases in lead content measured by atomic absorption spectrophotometry. Immature cerebellar mitochondrial lead contents were increased to the same extent as in the homogenates. Mitochondria from immature cerebrum and from both regions in the mature brain showed less immediate and smaller increases in lead content. In conclusion, altered mitochondrial respiration occurs early in regional and age-dependent association with lead encephalopathy in the rat pup. The development of lead encephalopathy also is associated with increased mitochondrial lead concentrations.

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1432-0533

Astroblastoma ; Electron microscopy ; Immunohistochemistry ; Organ culture ; Tanycytes

Springer Online Journal Archives 1860-2000

Medicine

Summary Two examples of cerebral astroblastoma have been studied by electron microscopy and immunohistochemistry, one of them having been maintained in vitro in an organ-culture matrix system for 8 months and the explants studied by light and electron microscopy at different time intervals. The fine structural characteristics were those of a glial cell type with features intermediary between those of astrocytes and ependymocytes. They recapitulated the structure of the tanycyte, a glial precursor cell which is normally found scattered along the ependymal lining of the embryonal and neonatal mammalian brain, but is distinct from epithelial ependymocytes. The possible origin of some astroblastomas from such a cell would account for a number of characteristics in this enigmatic type of glioma.

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1432-0533

Immunohistochemistry ; Medulloepithelioma ; Cytoskeletal proteins

Springer Online Journal Archives 1860-2000

Medicine

Summary Four examples of human cerebral medulloepithelioma were studied immunohistochemically with a panel of antibodies and antisera to neuronal and glial proteins. The tumors, in addition to primitive medullary epithelium, contained areas of neuroblastic, ganglionic, astrocytic, ependymoblastic and ependymal differentiation, and, in one tumor, areas resembling polar spongioblastoma. Tumor cells throughout the primitive medullary epithelium displayed focal immunocreactivity for vimentin, glial fibrillary acidic (GFA) protein and for the neuron-associated class III β-tubulin isotype. Neuroblasts showed immunoreactivity for the class III β-tubulin isotype, microtubule-associated protein 2 and neuron-specific enolase. Immunoreactivity for neurofilament epitopes and synaptophysin was detected in areas of ganglionic differentiation and coincided with the demonstration of neurofibrils in Bielschowsky's silver impregnations. Vimentin was the only marker detected in ependymoblastic and ependymal rosettes or in areas of polar spongioblastoma, as well as in mesenchymal, cells. The results indicate that, even in very primitive neoplastic neuroepithelium, immunocytochemical evidence of early commitment of some of the cells to a neuronal or glial lineage can be demonstrated. The neuron-associated class III β-tubulin isotype appears to be one of the earliest markers indicative of neuronal differentiation in normal and neoplastic primitive neuroepithelium.

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1432-0533

Glioblastomas ; Organ culture method ; Autoradiography ; Kinetics ; Growth fraction

Springer Online Journal Archives 1860-2000

Medicine

Summary Five human glioblastomas maintained in an organ culture system were studied by autoradiography to determine, after 8 days in vitro, the growth fraction (GF) of the explants, their total cell cycle time (T C) and cell cycle phase durations (T S,T G1,T G2 andT M), and their potential doubling time (T pot) after pulse-labeling with [3H] TdR for 1 h. These parameters were derived from computer analysis of fraction of labeled mitoses (FLM) curves. The results fell into two groups. In two tumors, the cultures had a GF of 0.25 and 0.23. From the FLM curves were derived aT C of 89 and 83 h, aT S of 16.5 and 9.5 h, and aT G1 of 60 and 61 h.T M was estimated at 0.9 and 0.6 h, andT G2 12h. TheT pot was 12 days. These values approximate those reported for glioblastomas and other human malignancies in vivo. The explants of three other glioblastomas gave different FLM curves: the derivedT S were increased to 36 and 55 h, estimatedT M ranged from 2.4 to 4.5 h, andT G2 ranged from 11 to 20 h.T C andT G1 could not be estimated. In two tumors the GF was reduced to 0.12 and 0.11, with aT pot of respectively 52 and 39 days. These values are comparable to those reported for astrocytomas of intermediate malignancy. In the third tumor, the GF was only 0.014. The reduction in GF and the lengthening of cell cycle components in this group of explants are similar to the kinetic changes reported in some in vivo tumors and three-dimensional in vitro systems that have reached a plateau stage of growth. They are probably related to the greater opportunities for cell-to-cell contacts and the resulting increased differentiation favored by the organ culture technique.

Electronic Resource

1432-0533

Neural cell surface antigens ; Neural differentiation ; Mouse teratoma ; Radioimmune assay ; Immunoperoxidase

Springer Online Journal Archives 1860-2000

Medicine

Summary A rabbit antiserum against mouse neonatal brain cell surface membranes labeled by immunoperoxidase (PAP) the cells of the central and peripheral nervous systems of adult and neonatal mice and their processes, as well as the differentiating neuroepithelial cells of three OTT-6050 mouse teratoma-derived tumors. Indirect immunofluorescence on living 14-day-old monolayer cultures of neonatal mouse brain demonstrated reaction of the immune serum with external surface membrane antigens of neuroblasts and of primitive and mature glial cells. Radioimmune assays (RIA) showed almost complete loss of antiserum binding to neonatal mouse brain plasma membranes after absorption with adult or neonatal mouse brain membranes, and no loss of binding after absorption by liver, spleen, kidney, and heart membranes. Cross-reactivity of the immune serum to several non-neural cell types was demonstrated by immunoperoxidase on sperm and sperm-precursors, on moderate numbers of epithelial cells in the medulla of adult mouse thymus, and, in the neonate, on a range of mesenchymal cells. This cross-reactivity was reflected in the RIA by a moderate reduction of immune serum binding to neonatal mouse brain plasma membranes after absorption with testis pellets and with thymus membranes. PAP staining showed loss of crossreactivity after testis or thymus absorption, without climination of neural cell recognition. Absorption with adult or neonatal mouse brain eliminated cross-reactivity. In the teratoma-derived tumors, absorption of the antiserum with testis or thymus eliminated or markedly reduced the PAP staining of primitive neuroepithelial cells, and only moderately reduced, but did not remove, that of neural cells in the mature neuropil. Among the proteins of neonatal mouse brain plasma membranes separated by polyacrylamide gel electrophoresis, there were six distinct bands indicating major proteins ranging from 26,000–54,000 daltons. Autoradiography of the antigen-antibody complexes with125I protein A on the same gels demonstrated three discrete bands of activity at 10,000–12,000, 76,000, and 97,000 daltons, and one greater than 130,000 daltons, suggesting that the immune serum recognizes only minor protein components of the mouse brain plasma membranes. The application of the PAP method to the recognition of neural cell surface antigens considerably enhances the potential of this antiserum as a tool for the early identification of primitive neural cells in the experimental mouse teratoma.

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1432-0533

S-Antigen ; Monoclonal antibody ; Pineal gland ; Pineocytoma ; Pineoblastoma

Springer Online Journal Archives 1860-2000

Medicine

Summary Using a four-step immunoperoxidase (PAP) method and the monoclonal antibody MAbA9-C6 (MAbA9-C6), which defines an epitope of the retinal S-antigen (S-Ag), we investigated the S-Ag immunoreactivity in human fetal, newborn, infantile and adult pineal glands and in 13 human pineal parenchymal tumors. S-Ag immunoreactivity was demonstrated in a few cells in one of the four fetal and in both infantile glands. Eight of nine adult pineal glands contained isolated MAbA9-C6-positive cells. In two of seven pineocytomas showing neuronal or gangliogliomatous differentiation a few scattered cells displayed S-Ag positivity; two of four pineoblastomas contained small groups of strongly immunoreactive neoplastic cells; two malignant pineocytomas did not demonstrate any S-Ag immunoreactivity. Our results indicate that isolated cells in human pineal gland retain some of the cytochemical characteristics of photoreceptor cells recognized by the MAbA9-C6, and that S-Ag immunoreactivity may be occasionally expressed in pineal parenchymal tumors.

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1432-0533

Neuroepithelial differentiation ; Microcomplement fixation ; Indirect immunofluorescence

Springer Online Journal Archives 1860-2000

Medicine

Summary Mouse neonatal brain cell fractions enriched for surface membranes were used as immunogens to produce a heterologous immune serum. Following absorption to remove non-neural anti-mouse activity, this serum demonstrated by microcomplement fixation an anti-brain activity that was completely removed by absorption with neonatal mouse brain or with solid tumors of the mouse transplantable teratoma OTT-6050. Indirect immunofluorescence applied to living monolayer cultures of differentiating teratoma embryoid bodies showed the absorbed serum's reaction with neural cell surfaces only. In material studied with frozen sections, the absorbed serum recognized antigenic sites in all examined areas of both neonatal and adult mouse brain, and only within neuroepithelial cell populations of solid transplants of the teratoma.

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1432-119X

Springer Online Journal Archives 1860-2000

Biology

Medicine

Summary Laminin immunoreactivity is thought to be masked in formalin-fixed sections since proteolytic treatment is required to unmask it. We analyzed this masking with frozen and formalin-fixed human autopsy brains obtained at various postmortem periods. In unfixed, frozen sections, intense immunoreactivity was invariably detected in vascular walls of entire sections. When such sections were postfixed in formalin, immunoreactivity was not diminished even after prolonged fixation. In vibratome sections of brain fixed in formalin in situ, immunoreactivity varied with postmortem delay: in most cases, immunoreactivity was weak and restricted to superficial cortical layers. However, the extent of immunoreactivity increased with postmortem delay. Two cases fixed after prolonged postmortem periods revealed moderate immunoreactivity throughout the sections. We also investigated rat brains processed without postmortem delay. In unfixed frozen sections, immunoreactivity again was observed throughout the sections, independent of the length of any postfixation. In vibratome sections of fixed rat brain, immunoreactivity was restricted to the cutting margins of the brain blocks and around a trauma-induced cortical lesion, regardless of how long the blocks had been kept in fixative. Our data suggest that postmortem proteolysis accomplishes similar unmasking of laminin antigen as digestion on paraffin sections and that such unmasking can also be effected by proteolysis induced by damaging tissue during cryostat sectioning of fresh tissue.

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1435-1463

Autoradiography ; neurotensin ; schizophrenia

Springer Online Journal Archives 1860-2000

Medicine

Summary Neurotensin, an endogenous peptide and putative neurotransmitter, exhibits a wide range of interactions with dopaminergic neurons and displays some actions akin to neuroleptics. Moreover, neurotensin receptors are abundant in specific layers of the entorhinal cortex where cytoarchitectural abnormalites have been reported in schizophrenia. We therefore examined the entorhinal cortex from postmortem specimens of five control patients and six schizophrenic patients for alterations in neurotensin receptor quantitation and distribution using receptor autoradiography. Specific125I-neurotensin binding was concentrated in layer II cell clusters, with a 40% reduction in binding in the schizophrenic group (p〈0.05). Moderate binding was observed in both cohorts in deep layers V/VI, with negligible binding in the hippocampus. There was no statistical difference in quantitative neurotensin binding in other lamina of the entorhinal cortex of schizophrenics compared with controls. The characteristic laminar pattern of binding did not differ between cohorts. The reduction in neurotensin binding in schizophrenics is consistent with an increasing number of reports of structural abnormalities in the medial temporal lobe of schizophrenics in general and the entorhinal cortex in particular. Further studies are required to examine the evidence for neuroanatomic and neurochemical pathology in the entorhinal cortex.

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1573-7233

embryonal tumors ; central nervous system ; growth factors ; indoleamines ; receptors

Springer Online Journal Archives 1860-2000

Medicine

Summary While the embryonal central neuroepithelial tumors present complex conceptual and clinical problems, advances in cell type identification by special neurohistological, immunohisto- and immunocytochemical techniques have permitted discrimination of distinct cytomorphogenetic entities. These are based in part on their resemblance to the normal phases of neurocytogenesis. Four of these tumors, medulloepithelioma, desmoplastic infantile ganglioglioma, pineoblastoma and medulloblastoma, are designated as multipotential in light of their capacity to undergo divergent differentiation. Cytomorphogenetic, clinical and experimental data implicate fetal neural cell targets for transformation and raise the possibility that aberrant developmental regulatory mechanisms may contribute to the biologic behavior of these tumors. Growth factors and some neuroregulatory neurotransmitters (such as serotonin) are known to act as modulators of normal neuromorphogenesis. They could play a regulatory role in central neuroepithelial tumors on the hypothesis that the aberrant behavior of the embryonal neoplasms could either be modified by fuctional receptor responses or result from abnormal receptor responses to these substances. Future challenges include 1) the definition of new cytomorphogenetic entities and subgroups of the currently defined forms of embryonal CNS tumors based on the presence of specific growth factors and neuroregulatory neurotransmitters, or their receptors, 2) the characterization of neoplastic receptor responses mediating any modulatory role of the presently known growth factors or neuroregulatory neurotransmitters on the growth and maturation potential of the embryonal central neuroepithelial tumors and 3) the further definition of developmental, stage-specific modulators that might be operative in these tumors.

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