Role of astrocytes in the pathomechanisms of hyperammonemia and related brain disorders: further insights into neuron-glia metabolic trafficking
Saved in:
| Main Author: | |
|---|---|
| Format: | Book |
| Language: | English |
| Published: |
Berlin
dissertation.de
2001
|
| Edition: | Als Ms. gedr. |
| Subjects: | |
| Online Access: | Inhaltsverzeichnis |
| Item Description: | Zugl.: Bremen, Univ., Diss., 2000 |
| Physical Description: | 278 S. Ill., graph. Darst. |
| ISBN: | 3898252566 |
Staff View
MARC
| LEADER | 00000nam a2200000 c 4500 | ||
|---|---|---|---|
| 001 | BV019638143 | ||
| 003 | DE-604 | ||
| 005 | 20050118 | ||
| 007 | t | ||
| 008 | 041220s2001 gw ad|| m||| 00||| eng d | ||
| 016 | 7 | |a 961365234 |2 DE-101 | |
| 020 | |a 3898252566 |c kart. : DM 77.26, EUR 39.50 |9 3-89825-256-6 | ||
| 035 | |a (OCoLC)50523795 | ||
| 035 | |a (DE-599)BVBBV019638143 | ||
| 040 | |a DE-604 |b ger |e rakddb | ||
| 041 | 0 | |a eng | |
| 044 | |a gw |c DE | ||
| 049 | |a DE-355 | ||
| 084 | |a 610 |2 sdnb | ||
| 100 | 1 | |a Zwingmann, Claudia |d 1967- |e Verfasser |0 (DE-588)122964381 |4 aut | |
| 245 | 1 | 0 | |a Role of astrocytes in the pathomechanisms of hyperammonemia and related brain disorders |b further insights into neuron-glia metabolic trafficking |c vorgelegt von Claudia Zwingmann |
| 250 | |a Als Ms. gedr. | ||
| 264 | 1 | |a Berlin |b dissertation.de |c 2001 | |
| 300 | |a 278 S. |b Ill., graph. Darst. | ||
| 336 | |b txt |2 rdacontent | ||
| 337 | |b n |2 rdamedia | ||
| 338 | |b nc |2 rdacarrier | ||
| 500 | |a Zugl.: Bremen, Univ., Diss., 2000 | ||
| 650 | 0 | 7 | |a Encephalopathia hepatica |0 (DE-588)4130645-4 |2 gnd |9 rswk-swf |
| 650 | 0 | 7 | |a Nervenzelle |0 (DE-588)4041649-5 |2 gnd |9 rswk-swf |
| 650 | 0 | 7 | |a Hyperammonämie |0 (DE-588)4130751-3 |2 gnd |9 rswk-swf |
| 650 | 0 | 7 | |a Pathomechanismus |0 (DE-588)4173544-4 |2 gnd |9 rswk-swf |
| 650 | 0 | 7 | |a Wechselwirkung |0 (DE-588)4064937-4 |2 gnd |9 rswk-swf |
| 650 | 0 | 7 | |a Astrozyt |0 (DE-588)4143257-5 |2 gnd |9 rswk-swf |
| 655 | 7 | |0 (DE-588)4113937-9 |a Hochschulschrift |2 gnd-content | |
| 689 | 0 | 0 | |a Encephalopathia hepatica |0 (DE-588)4130645-4 |D s |
| 689 | 0 | 1 | |a Hyperammonämie |0 (DE-588)4130751-3 |D s |
| 689 | 0 | 2 | |a Pathomechanismus |0 (DE-588)4173544-4 |D s |
| 689 | 0 | 3 | |a Astrozyt |0 (DE-588)4143257-5 |D s |
| 689 | 0 | 4 | |a Nervenzelle |0 (DE-588)4041649-5 |D s |
| 689 | 0 | 5 | |a Wechselwirkung |0 (DE-588)4064937-4 |D s |
| 689 | 0 | |5 DE-604 | |
| 856 | 4 | 2 | |m HBZ Datenaustausch |q application/pdf |u http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&local_base=BVB01&doc_number=012967082&sequence=000002&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA |3 Inhaltsverzeichnis |
| 999 | |a oai:aleph.bib-bvb.de:BVB01-012967082 | ||
Record in the Search Index
| _version_ | 1804133008918183936 |
|---|---|
| adam_text | Content
Acknowledgement
List of Abbreviations
Thesis outline
1 SUMMARY 19
1 ZUSAMMENFASSUNG 23
2 INTRODUCTION 27
2.1 General Introduction 27
2.2 Aim of the study 30
3 BACKGROUND 31
3.1 Nervous system and brain structure 31
3.1.1 Brain cells neurons and glia 31
3.1.1.1 Brain signalling by neurons 32
3.1.1.2 Neurotransmission 33
3.1.1.2.1 Glutamate as a neurotransmitter 34
3.1.1.2.2 Glutamate and excitotoxicity 34
3.1.1.3 Role of glia in brain function 35
3.1.1.3.1 Neurotransmitter uptake role of astrocytes 36
3.1.1.4 Glutamate compartmentation 37
3.1.1.4.1 The glutamine glutamate cyde 39
3.1.1.4 Brain energy metabolis role of astrocytes and
metabolic trafficking between astrocytes and neurons 42
3.1.1.6 Astrocytes in pathological conditions 44
3.2 Hepatic encephalopathy and ammonia toxicity 44
3.2.1 Overview 44
3.2.2 The neurotoxin (ammonia) hypothesis 45
3.2.2.1 Astrocytes as the primary target of ammonia toxicity 47
14 Content
3.2.2.2 Cerebral ammonia detoxification 49
3.2.2.3 Interactions with glutamale neurolransmission 50
3.2.2.4 Interactions with cerebral energy metabolism SO
4 RESULTS AND DISCUSSION si
4.1 Comparison of acute ammonia exposure on glial and neuronal
metabolism 51
4.1.1 Introduction SI
4.1.2 Biochemical pathways and energy metabolism in neuronal and glial
cells 52
4.1.2.1 Glutamine and glutamate 52
4.1.2.2 Other amino acids alanine and aspartate 54
4.1.2.3 Energy metabolism 55
4.1.3 Summary 56
4.2 Effect of acute ammonia exposure on filial cell volume and
osmolyte content 58
4.2.1 Introduction 58
4.2.2 Changes in glial cell volume 58
4.2.3 Inlracellular osmolytes 58
4.2.4 Time dependence of metabolic alterations 59
4.2.5 Effects of anisosmotic conditions on ammonia induced metabolic
alterations 60
4.2.6 Concluding remarks 61
4.3 Effect of acute ammonia exposure on glial lipid metabolism 61
4.3.1 Introduction 61
4.3.2 Results 62
4.3.3 Discussion 62
4.4 Summary of 4.1 4.3 63
4.5 Impact of exogenous alanine on glial metabolism and neuron glia
interaction 64
4.5.1 Introduction 64
4.5.2 Impact of exogenous alanine on osmoregulatory response and
energy state of glial cells 64
4.5.3 Impact of exogenous alanine on glial glucose metabolism: Substrate
selection and intracellular pyruvate compartmentation in astrocytes 66
4.5.3.1 Implications for neuron glia interactions 68
4.5.4 Metabolic fate of alanine in neurons, astrocytes, and eoeultures
of both 7°
4.5.4.1 Consumption of alanine and release of lactate 70
Content 15
4.5.4.2 Utilization of [3 l:lC]alanine via TCA cycle activity 71
4.5.4.3 Contribution of the anaplerotic pathway 72
4.5.4.4 Precursor product relationships between amino acids 72
4.5.4.5 Scrambling of label in the TCA cycle 72
4.5.4.6 Competition with other extracellular substrates
substrate selectivity and intracellular compartmentation in
neuron glia interaction 73
4.5.2.7 Concluding remarks 73
5 METHODS 75
5.1 Neural cells 75
5.1.1 Primary cultures 76
5.1.1.1 Introduction to experimental approach and 76
5.1.1.2 Preparation of astroglia rich cultures 76
5.1.1.3 Preparation of neuron cultures 78
5.1.1.4 Preparation of cocultures 80
5.1.1.5 Examination of culture purity 80
5.1.2 Clonal Cells 81
5.1.2.1 Gliomacells 81
5.1.2.2 Neuroblastoma cells 81
5.1.3 Work up of cultured brain cells 82
5.1.3.1 Introduction to experimental approach and methodology 82
5.1.3.2 Experimental incubation 82
5.1.3.3 Preparation of perchloric acid extracts 82
5.1.3.4 Combined acid and lipid extraction 83
5.1.3.5 Direct lipid extraction 84
5.1.3.6 Hydrolysis of cellular proteins 85
5.1.3.7 Preparation of cell homogenates 85
5.1.3.7.1 Subcellularfractionation 85
5.1.3.8 Basement membrane gel (BMG) threads 85
5.2 Biochemical analysis 86
5.2.1 Introduction to experimental approach 86
5.2.2 Enzymatic analysis 87
5.2.2.1 General 87
5.2.2.2 Principle of the method 87
5.2.2.3 Enzymatic metabolite determination 88
5.2.2.4 Determination of enzyme activities 89
5.2.3 Quantification of the protein content 90
5.2.4 Quantification of the DNA content 90
, Content
5.3 NMR spectroscopy 71
5.3.1 Introduction 71
5.3.2 Principle of the method 71
5.3.3 Multinuclear high resolution NMR spectroscopy 93
5.3.3.1 Sample preparation 93
5.3.3.2 Acquisition and processing parameter of NMR spectra 93
5.3.3.2.1 H NMR spectroscopy 93
5.3.3.2.2 C NMR spectroscopy 93
5.3.3.2.3 31P NMR spectroscopy 93
5.3.3.2.4 2H NMR spectroscopy 93
5.3.3.2.5 INEPT spectra 94
5.3.3.3 Analysis of H and P NMR spectra 95
5.3.3.4 C isotopomer analysis from C NMR spectra of cell
extracts 96
5.3.3.5 Quantitative analysis of C NMR spectra 98
5.3.3.6 Calculation of metabolic fluxes 101
5.3.3.7 I3C isotopomer analysis from BC NMR spectra of
lipid extracts Analysis of H and 3IP NMR spectra 101
5.3.4 NMR measurements of viable cells 103
5.3.4.1 Perfusion 103
5.3.4.2 Diffusion weighted H NMR spectroscopy 104
5.3.4.3 3IP NMR measurements of viable cells 104
5.4 Coupled HPLC H NMR(LC NMR) 104
5.4.1 Introduction 104
5.4.2 Principle of the LC NMR method 105
5.4.3 Solvents for LC NMR measurements 105
5.4.4 Solvent suppression 106
5.4.5 Analysis of lipid components in brain cells 107
i REFERENCES 109
Content 17
APPENDIX 121
1.1 Multinuclear NMR studies on NH^Cl induced metabolic alterations and
detoxification process in primary astrocytes and glioma cells 121
1.2 Effects of Ammonia Exposition on Glioma Cells: Changes in Cell
Volume and Organic Osmolytes studied by diffusion weighted and
high resolution NMR Spectroscopy 133
1.3 Effects of hyponairemia on metabolic alterations induced by acute hyper
ammonemia in glial cells: A nC NMR spectroscopic study of | l C|glucose
metabolism 143
1.4 Lipid Syntheses in Glia Cells during Hyperammonemia studied by NMR
Spectroscopy 159
1.5 Implication of hyperammonemic conditions on astrocytic lipid metabolism 165
1.6 A NMR study on the impact of exogenous alanine on osmoregulatory
response and energy state of primary aslrocytes and glioma cells 169
1.7 nC isotopomer analysis of glucose and alanine metabolism reveals cytosolic
pyruvate compartmentation as part of energy metabolism in astrocytes 179
1.8 A NMR spectroscopic study on the metabolic fate of [3 C]alanine in
astrocytes, neurons, and cocultures: Implications for glia neuron interactions
in neurotransmitter metabolism 197
1.9 Role of substrate selection and intracellular compartmentation for the
metabolic trafficking between astrocyles and neurons 221
2.1 Use of 96 well microtiter plates for enzymatic determination of
metabolites and en/yme activities related to glucose metabolism in
extracts and homogenates of cultured brain cells 225
2.2 Analysis of lipids in primary and clonal brain cells by coupled HPLC H NMR:
localization of sphingomyelin in glia 269
CURRICULUM VITAE 273
|
| any_adam_object | 1 |
| author | Zwingmann, Claudia 1967- |
| author_GND | (DE-588)122964381 |
| author_facet | Zwingmann, Claudia 1967- |
| author_role | aut |
| author_sort | Zwingmann, Claudia 1967- |
| author_variant | c z cz |
| building | Verbundindex |
| bvnumber | BV019638143 |
| ctrlnum | (OCoLC)50523795 (DE-599)BVBBV019638143 |
| discipline | Medizin |
| edition | Als Ms. gedr. |
| format | Book |
| fullrecord | <?xml version="1.0" encoding="UTF-8"?><collection xmlns="http://www.loc.gov/MARC21/slim"><record><leader>02103nam a2200493 c 4500</leader><controlfield tag="001">BV019638143</controlfield><controlfield tag="003">DE-604</controlfield><controlfield tag="005">20050118 </controlfield><controlfield tag="007">t</controlfield><controlfield tag="008">041220s2001 gw ad|| m||| 00||| eng d</controlfield><datafield tag="016" ind1="7" ind2=" "><subfield code="a">961365234</subfield><subfield code="2">DE-101</subfield></datafield><datafield tag="020" ind1=" " ind2=" "><subfield code="a">3898252566</subfield><subfield code="c">kart. : DM 77.26, EUR 39.50</subfield><subfield code="9">3-89825-256-6</subfield></datafield><datafield tag="035" ind1=" " ind2=" "><subfield code="a">(OCoLC)50523795</subfield></datafield><datafield tag="035" ind1=" " ind2=" "><subfield code="a">(DE-599)BVBBV019638143</subfield></datafield><datafield tag="040" ind1=" " ind2=" "><subfield code="a">DE-604</subfield><subfield code="b">ger</subfield><subfield code="e">rakddb</subfield></datafield><datafield tag="041" ind1="0" ind2=" "><subfield code="a">eng</subfield></datafield><datafield tag="044" ind1=" " ind2=" "><subfield code="a">gw</subfield><subfield code="c">DE</subfield></datafield><datafield tag="049" ind1=" " ind2=" "><subfield code="a">DE-355</subfield></datafield><datafield tag="084" ind1=" " ind2=" "><subfield code="a">610</subfield><subfield code="2">sdnb</subfield></datafield><datafield tag="100" ind1="1" ind2=" "><subfield code="a">Zwingmann, Claudia</subfield><subfield code="d">1967-</subfield><subfield code="e">Verfasser</subfield><subfield code="0">(DE-588)122964381</subfield><subfield code="4">aut</subfield></datafield><datafield tag="245" ind1="1" ind2="0"><subfield code="a">Role of astrocytes in the pathomechanisms of hyperammonemia and related brain disorders</subfield><subfield code="b">further insights into neuron-glia metabolic trafficking</subfield><subfield code="c">vorgelegt von Claudia Zwingmann</subfield></datafield><datafield tag="250" ind1=" " ind2=" "><subfield code="a">Als Ms. gedr.</subfield></datafield><datafield tag="264" ind1=" " ind2="1"><subfield code="a">Berlin</subfield><subfield code="b">dissertation.de</subfield><subfield code="c">2001</subfield></datafield><datafield tag="300" ind1=" " ind2=" "><subfield code="a">278 S.</subfield><subfield code="b">Ill., graph. Darst.</subfield></datafield><datafield tag="336" ind1=" " ind2=" "><subfield code="b">txt</subfield><subfield code="2">rdacontent</subfield></datafield><datafield tag="337" ind1=" " ind2=" "><subfield code="b">n</subfield><subfield code="2">rdamedia</subfield></datafield><datafield tag="338" ind1=" " ind2=" "><subfield code="b">nc</subfield><subfield code="2">rdacarrier</subfield></datafield><datafield tag="500" ind1=" " ind2=" "><subfield code="a">Zugl.: Bremen, Univ., Diss., 2000</subfield></datafield><datafield tag="650" ind1="0" ind2="7"><subfield code="a">Encephalopathia hepatica</subfield><subfield code="0">(DE-588)4130645-4</subfield><subfield code="2">gnd</subfield><subfield code="9">rswk-swf</subfield></datafield><datafield tag="650" ind1="0" ind2="7"><subfield code="a">Nervenzelle</subfield><subfield code="0">(DE-588)4041649-5</subfield><subfield code="2">gnd</subfield><subfield code="9">rswk-swf</subfield></datafield><datafield tag="650" ind1="0" ind2="7"><subfield code="a">Hyperammonämie</subfield><subfield code="0">(DE-588)4130751-3</subfield><subfield code="2">gnd</subfield><subfield code="9">rswk-swf</subfield></datafield><datafield tag="650" ind1="0" ind2="7"><subfield code="a">Pathomechanismus</subfield><subfield code="0">(DE-588)4173544-4</subfield><subfield code="2">gnd</subfield><subfield code="9">rswk-swf</subfield></datafield><datafield tag="650" ind1="0" ind2="7"><subfield code="a">Wechselwirkung</subfield><subfield code="0">(DE-588)4064937-4</subfield><subfield code="2">gnd</subfield><subfield code="9">rswk-swf</subfield></datafield><datafield tag="650" ind1="0" ind2="7"><subfield code="a">Astrozyt</subfield><subfield code="0">(DE-588)4143257-5</subfield><subfield code="2">gnd</subfield><subfield code="9">rswk-swf</subfield></datafield><datafield tag="655" ind1=" " ind2="7"><subfield code="0">(DE-588)4113937-9</subfield><subfield code="a">Hochschulschrift</subfield><subfield code="2">gnd-content</subfield></datafield><datafield tag="689" ind1="0" ind2="0"><subfield code="a">Encephalopathia hepatica</subfield><subfield code="0">(DE-588)4130645-4</subfield><subfield code="D">s</subfield></datafield><datafield tag="689" ind1="0" ind2="1"><subfield code="a">Hyperammonämie</subfield><subfield code="0">(DE-588)4130751-3</subfield><subfield code="D">s</subfield></datafield><datafield tag="689" ind1="0" ind2="2"><subfield code="a">Pathomechanismus</subfield><subfield code="0">(DE-588)4173544-4</subfield><subfield code="D">s</subfield></datafield><datafield tag="689" ind1="0" ind2="3"><subfield code="a">Astrozyt</subfield><subfield code="0">(DE-588)4143257-5</subfield><subfield code="D">s</subfield></datafield><datafield tag="689" ind1="0" ind2="4"><subfield code="a">Nervenzelle</subfield><subfield code="0">(DE-588)4041649-5</subfield><subfield code="D">s</subfield></datafield><datafield tag="689" ind1="0" ind2="5"><subfield code="a">Wechselwirkung</subfield><subfield code="0">(DE-588)4064937-4</subfield><subfield code="D">s</subfield></datafield><datafield tag="689" ind1="0" ind2=" "><subfield code="5">DE-604</subfield></datafield><datafield tag="856" ind1="4" ind2="2"><subfield code="m">HBZ Datenaustausch</subfield><subfield code="q">application/pdf</subfield><subfield code="u">http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&local_base=BVB01&doc_number=012967082&sequence=000002&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA</subfield><subfield code="3">Inhaltsverzeichnis</subfield></datafield><datafield tag="999" ind1=" " ind2=" "><subfield code="a">oai:aleph.bib-bvb.de:BVB01-012967082</subfield></datafield></record></collection> |
| genre | (DE-588)4113937-9 Hochschulschrift gnd-content |
| genre_facet | Hochschulschrift |
| id | DE-604.BV019638143 |
| illustrated | Illustrated |
| indexdate | 2024-07-09T20:01:53Z |
| institution | BVB |
| isbn | 3898252566 |
| language | English |
| oai_aleph_id | oai:aleph.bib-bvb.de:BVB01-012967082 |
| oclc_num | 50523795 |
| open_access_boolean | |
| owner | DE-355 DE-BY-UBR |
| owner_facet | DE-355 DE-BY-UBR |
| physical | 278 S. Ill., graph. Darst. |
| publishDate | 2001 |
| publishDateSearch | 2001 |
| publishDateSort | 2001 |
| publisher | dissertation.de |
| record_format | marc |
| spelling | Zwingmann, Claudia 1967- Verfasser (DE-588)122964381 aut Role of astrocytes in the pathomechanisms of hyperammonemia and related brain disorders further insights into neuron-glia metabolic trafficking vorgelegt von Claudia Zwingmann Als Ms. gedr. Berlin dissertation.de 2001 278 S. Ill., graph. Darst. txt rdacontent n rdamedia nc rdacarrier Zugl.: Bremen, Univ., Diss., 2000 Encephalopathia hepatica (DE-588)4130645-4 gnd rswk-swf Nervenzelle (DE-588)4041649-5 gnd rswk-swf Hyperammonämie (DE-588)4130751-3 gnd rswk-swf Pathomechanismus (DE-588)4173544-4 gnd rswk-swf Wechselwirkung (DE-588)4064937-4 gnd rswk-swf Astrozyt (DE-588)4143257-5 gnd rswk-swf (DE-588)4113937-9 Hochschulschrift gnd-content Encephalopathia hepatica (DE-588)4130645-4 s Hyperammonämie (DE-588)4130751-3 s Pathomechanismus (DE-588)4173544-4 s Astrozyt (DE-588)4143257-5 s Nervenzelle (DE-588)4041649-5 s Wechselwirkung (DE-588)4064937-4 s DE-604 HBZ Datenaustausch application/pdf http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&local_base=BVB01&doc_number=012967082&sequence=000002&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA Inhaltsverzeichnis |
| spellingShingle | Zwingmann, Claudia 1967- Role of astrocytes in the pathomechanisms of hyperammonemia and related brain disorders further insights into neuron-glia metabolic trafficking Encephalopathia hepatica (DE-588)4130645-4 gnd Nervenzelle (DE-588)4041649-5 gnd Hyperammonämie (DE-588)4130751-3 gnd Pathomechanismus (DE-588)4173544-4 gnd Wechselwirkung (DE-588)4064937-4 gnd Astrozyt (DE-588)4143257-5 gnd |
| subject_GND | (DE-588)4130645-4 (DE-588)4041649-5 (DE-588)4130751-3 (DE-588)4173544-4 (DE-588)4064937-4 (DE-588)4143257-5 (DE-588)4113937-9 |
| title | Role of astrocytes in the pathomechanisms of hyperammonemia and related brain disorders further insights into neuron-glia metabolic trafficking |
| title_auth | Role of astrocytes in the pathomechanisms of hyperammonemia and related brain disorders further insights into neuron-glia metabolic trafficking |
| title_exact_search | Role of astrocytes in the pathomechanisms of hyperammonemia and related brain disorders further insights into neuron-glia metabolic trafficking |
| title_full | Role of astrocytes in the pathomechanisms of hyperammonemia and related brain disorders further insights into neuron-glia metabolic trafficking vorgelegt von Claudia Zwingmann |
| title_fullStr | Role of astrocytes in the pathomechanisms of hyperammonemia and related brain disorders further insights into neuron-glia metabolic trafficking vorgelegt von Claudia Zwingmann |
| title_full_unstemmed | Role of astrocytes in the pathomechanisms of hyperammonemia and related brain disorders further insights into neuron-glia metabolic trafficking vorgelegt von Claudia Zwingmann |
| title_short | Role of astrocytes in the pathomechanisms of hyperammonemia and related brain disorders |
| title_sort | role of astrocytes in the pathomechanisms of hyperammonemia and related brain disorders further insights into neuron glia metabolic trafficking |
| title_sub | further insights into neuron-glia metabolic trafficking |
| topic | Encephalopathia hepatica (DE-588)4130645-4 gnd Nervenzelle (DE-588)4041649-5 gnd Hyperammonämie (DE-588)4130751-3 gnd Pathomechanismus (DE-588)4173544-4 gnd Wechselwirkung (DE-588)4064937-4 gnd Astrozyt (DE-588)4143257-5 gnd |
| topic_facet | Encephalopathia hepatica Nervenzelle Hyperammonämie Pathomechanismus Wechselwirkung Astrozyt Hochschulschrift |
| url | http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&local_base=BVB01&doc_number=012967082&sequence=000002&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA |
| work_keys_str_mv | AT zwingmannclaudia roleofastrocytesinthepathomechanismsofhyperammonemiaandrelatedbraindisordersfurtherinsightsintoneurongliametabolictrafficking |