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  1. Article ; Online: The Swedish childhood tumor biobank: systematic collection and molecular characterization of all pediatric CNS and other solid tumors in Sweden.

    Díaz de Ståhl, Teresita / Shamikh, Alia / Mayrhofer, Markus / Juhos, Szilvester / Basmaci, Elisa / Prochazka, Gabriela / Garcia, Maxime / Somarajan, Praveen Raj / Zielinska-Chomej, Katarzyna / Illies, Christopher / Øra, Ingrid / Siesjö, Peter / Sandström, Per-Erik / Stenman, Jakob / Sabel, Magnus / Gustavsson, Bengt / Kogner, Per / Pfeifer, Susan / Ljungman, Gustaf /
    Sandgren, Johanna / Nistér, Monica

    Journal of translational medicine

    2023  Volume 21, Issue 1, Page(s) 342

    Abstract: The Swedish Childhood Tumor Biobank (BTB) is a nonprofit national infrastructure for collecting tissue samples and genomic data from pediatric patients diagnosed with central nervous system (CNS) and other solid tumors. The BTB is built on a ... ...

    Abstract The Swedish Childhood Tumor Biobank (BTB) is a nonprofit national infrastructure for collecting tissue samples and genomic data from pediatric patients diagnosed with central nervous system (CNS) and other solid tumors. The BTB is built on a multidisciplinary network established to provide the scientific community with standardized biospecimens and genomic data, thereby improving knowledge of the biology, treatment and outcome of childhood tumors. As of 2022, over 1100 fresh-frozen tumor samples are available for researchers. We present the workflow of the BTB from sample collection and processing to the generation of genomic data and services offered. To determine the research and clinical utility of the data, we performed bioinformatics analyses on next-generation sequencing (NGS) data obtained from a subset of 82 brain tumors and patient blood-derived DNA combined with methylation profiling to enhance the diagnostic accuracy and identified germline and somatic alterations with potential biological or clinical significance. The BTB procedures for collection, processing, sequencing, and bioinformatics deliver high-quality data. We observed that the findings could impact patient management by confirming or clarifying the diagnosis in 79 of the 82 tumors and detecting known or likely driver mutations in 68 of 79 patients. In addition to revealing known mutations in a broad spectrum of genes implicated in pediatric cancer, we discovered numerous alterations that may represent novel driver events and specific tumor entities. In summary, these examples reveal the power of NGS to identify a wide number of actionable gene alterations. Making the power of NGS available in healthcare is a challenging task requiring the integration of the work of clinical specialists and cancer biologists; this approach requires a dedicated infrastructure, as exemplified here by the BTB.
    MeSH term(s) Humans ; Child ; Sweden ; Biological Specimen Banks ; Brain Neoplasms ; Central Nervous System ; Genomics
    Language English
    Publishing date 2023-05-23
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2118570-0
    ISSN 1479-5876 ; 1479-5876
    ISSN (online) 1479-5876
    ISSN 1479-5876
    DOI 10.1186/s12967-023-04178-4
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Mechanisms of secondary brain injury.

    Siesjö, B K / Siesjö, P

    European journal of anaesthesiology

    1996  Volume 13, Issue 3, Page(s) 247–268

    Abstract: ... concentration (Ca2(i)), with subsequent calcium overload of mitochondria, (b) a sustained reduction ...

    Abstract The mechanisms which lead to secondary brain damage following transient ischaemia are incompletely defined. As discussed in this hypothesis article, the events which lead to such damage could encompass (a) a perturbed membrane handling of calcium, leading to a slow, gradual increase in the free cytosolic calcium concentration (Ca2(i)), with subsequent calcium overload of mitochondria, (b) a sustained reduction of protein synthesis which, in the long run, deprives cells of enzymes or trophic factors essential to their survival, or (c) the initiation of an inherent program for cell death. Results obtained in ischaemia of brief to intermediate duration demonstrate that the ultimate cell death is heralded by a reduction in the respiratory capacity of isolated mitochondria. However, the results fail to demonstrate whether or not such a reduction precedes deterioration of the bioenergetic state which then precipitates cell death. Cyclosporin A (CsA) has recently been shown to dramatically improve the delayed CA1 damage following transient forebrain ischaemia. Since CsA is known to block a deleterious permeability transition (PT) in mitochondria from several tissues in response to calcium accumulation and oxidative stress, the results on CsA effects in forebrain ischaemia support a mitochondrial origin for the delayed cell death. Furthermore, comparisons with the effects of CsA and alpha-phenyl-N-tert-butyl nitrone (PBN) in thymocytes and other cells undergoing programmed cell death suggest that delayed neuronal damage occurs by a sequence of events akin to those leading to apoptotic cell death. However, whether cell death is apoptotic or necrotic may depend on the severity of the insult (and its duration). We speculate that the initial ischaemic transient leads to gradual mitochondrial calcium overload, the latter triggering a PT, and apoptotic or necrotic cell death. Since similar results have been obtained in normoglycaemic animals subjected to ischaemia of intermediate duration, and in animals with preischaemic hyperglycaemia, it seems likely that both increased ischaemia duration and hyperglycaemia accelerate damage to mitochondria in the reperfusion period. Recent results obtained in transient focal ischaemia of 2 h duration demonstrate that the free radical spin trap PBN reduces infarct size, even when given 1 or 3 h after the start of reperfusion, thus providing a second window of therapeutic possibility. A major effect of the drug is exerted on the recovery of energy metabolism of the tissue since it reduces a secondary deterioration in the bioenergetic state, occurring after 2-4 h of reperfusion. At least in part, the spin trap may exert its effect by reducing microvascular dysfunction caused by oedema and to adhesion of polymorphonuclear (PMN) leucocytes, which give rise to an inflammatory response mediated by cytokines, lipid mediators, or free radicals. This contention is supported by the reduction in focal ischaemic damage by antibodies to adhesion molecules for PMNs. However, it has now been found that the secondary deterioration of the bioenergetic state of core and penumbral tissues are mirrored by corresponding changes in the respiratory functions of isolated mitochondria, suggesting that, also in this type of ischaemia, the mitochondria suffer secondary damage. It is conceivable that a significant fraction of malfunctioning mitochondria emanate from microvascular tissue, explaining why antibodies to adhesion molecules mitigate the ischaemic lesions.
    MeSH term(s) Animals ; Brain Injuries/etiology ; Brain Injuries/pathology ; Humans ; Ischemic Attack, Transient/complications ; Ischemic Attack, Transient/pathology ; Reperfusion Injury/pathology
    Language English
    Publishing date 1996-05
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, P.H.S. ; Review
    ZDB-ID 605770-6
    ISSN 1365-2346 ; 0265-0215
    ISSN (online) 1365-2346
    ISSN 0265-0215
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Natural history and surgical outcome of Rathke's cleft cysts-A study from the Swedish Pituitary Registry.

    Petersson, Maria / Berinder, Katarina / Eden Engström, Britt / Tsatsaris, Erika / Ekman, Bertil / Wahlberg, Jeanette / Burman, Pia / Borg, Henrik / Siesjö, Peter / Dahlqvist, Per / Åkerman, Anna-Karin / Ragnarsson, Oskar / Olsson, Martin / Förander, Petter / Bensing, Sophie / Höybye, Charlotte

    Clinical endocrinology

    2021  Volume 96, Issue 1, Page(s) 54–61

    Abstract: Objective: Rathke's cleft cysts are benign, embryological remnants in the pituitary gland. The majority of them are small and asymptomatic but a few may become large, and cause mass effects, pituitary hormone deficiencies and visual impairment. ... ...

    Abstract Objective: Rathke's cleft cysts are benign, embryological remnants in the pituitary gland. The majority of them are small and asymptomatic but a few may become large, and cause mass effects, pituitary hormone deficiencies and visual impairment. Recommendations for the follow-up of Rathke's cleft cysts vary since data on the natural history are sparse.
    Patients and design: Data at diagnosis and at 1, 5 and 10 years for patients with a Rathke's cleft cyst (434 at diagnosis, 317 females) were retrieved from the Swedish Pituitary Registry. Cysts ≤3 mm in diameter were excluded from the study.
    Measurements: Data included demographics, cyst size, pituitary function, visual defects and surgery.
    Results: The mean age at diagnosis was 45 years. In patients with cysts <10 mm in diameter (n = 204) 2.9% had pituitary hormone deficiencies and 2% had visual field impairments. Cyst size did not progress during the 5 years. Cysts with a diameter of ≥10 mm that were not operated (n = 174) decreased in size over the years (p < .01). Pituitary hormone deficiencies and visual impairments were more frequent (18% and 5.7%, respectively) but were stable over time. Transphenoidal surgery was performed in 56 patients of whom 51 underwent surgery before the 1-year follow-up. The mean cyst diameter at diagnosis was 18 mm (range: 9─30 mm), 36% had pituitary hormone deficiency, 45% had visual field defects and 20% had impaired visual acuity. One year after surgery 60% had no cyst remnants, 50% had a pituitary deficiency, 26% had visual field defects and 12% had impaired visual acuity. No major changes were observed after 5 years. Twelve of the operated patients had a follow-up at 10 years, in eight the cyst remnants or recurrences increased in size over time (p < .05).
    Conclusions: Rathke's cleft cysts with a size less than 10 mm rarely grow and our results indicate that radiological follow-up can be restricted to 5 years. In contrast, progression of postoperative remnants or recurrent cysts is more likely and require long-term follow-up.
    MeSH term(s) Central Nervous System Cysts/surgery ; Female ; Humans ; Neoplasm Recurrence, Local ; Pituitary Gland/surgery ; Pituitary Neoplasms/surgery ; Registries ; Sweden ; Treatment Outcome
    Language English
    Publishing date 2021-11-01
    Publishing country England
    Document type Journal Article
    ZDB-ID 121745-8
    ISSN 1365-2265 ; 0300-0664
    ISSN (online) 1365-2265
    ISSN 0300-0664
    DOI 10.1111/cen.14622
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  4. Article: Calcium-mediated processes in neuronal degeneration.

    Siesjö, B K

    Annals of the New York Academy of Sciences

    1994  Volume 747, Page(s) 140–161

    MeSH term(s) Animals ; Biological Transport ; Brain Ischemia/physiopathology ; Calcium/physiology ; Calcium Channels/physiology ; Cell Death ; Cellular Senescence ; Coma/physiopathology ; Free Radicals ; Glutamates/physiology ; Hydrogen-Ion Concentration ; Hypoglycemia/physiopathology ; Microtubules/metabolism ; Nerve Degeneration ; Phospholipids/metabolism ; Potassium/pharmacology ; Rats
    Chemical Substances Calcium Channels ; Free Radicals ; Glutamates ; Phospholipids ; Potassium (RWP5GA015D) ; Calcium (SY7Q814VUP)
    Language English
    Publishing date 1994-12-15
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, P.H.S. ; Review
    ZDB-ID 211003-9
    ISSN 1749-6632 ; 0077-8923
    ISSN (online) 1749-6632
    ISSN 0077-8923
    DOI 10.1111/j.1749-6632.1994.tb44406.x
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: Framtida behandling vid slaganfall. Hjärnskada vid slaganfall kan minskas med farmaka.

    Siesjö, B K

    Lakartidningen

    1993  Volume 90, Issue 36, Page(s) 2958, 2962–4

    Title translation Future treatment of stroke. Brain damage in stroke can be reduced by drugs.
    MeSH term(s) Brain Damage, Chronic/etiology ; Brain Damage, Chronic/prevention & control ; Cerebrovascular Circulation/drug effects ; Cerebrovascular Disorders/complications ; Cerebrovascular Disorders/drug therapy ; Cerebrovascular Disorders/physiopathology ; Forecasting ; Humans ; Ischemic Attack, Transient/complications ; Ischemic Attack, Transient/drug therapy ; Ischemic Attack, Transient/physiopathology
    Language Swedish
    Publishing date 1993-09-08
    Publishing country Sweden
    Document type Journal Article
    ZDB-ID 391010-6
    ISSN 1652-7518 ; 0023-7205
    ISSN (online) 1652-7518
    ISSN 0023-7205
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  6. Article: Basic mechanisms of traumatic brain damage.

    Siesjö, B K

    Annals of emergency medicine

    1993  Volume 22, Issue 6, Page(s) 959–969

    Abstract: Brain damage induced by blunt head trauma is multifactorial in that the initial injury both induces extensive depolarization and damages tissue through transient sheer forces that mechanically deform tissue components, especially axons and microvessels. ... ...

    Abstract Brain damage induced by blunt head trauma is multifactorial in that the initial injury both induces extensive depolarization and damages tissue through transient sheer forces that mechanically deform tissue components, especially axons and microvessels. Furthermore, although there is little evidence for initial energy depletion, subsequent tissue edema and microvascular perfusion shunting may result in areas of focal ischemia. This review suggests that these events lead to a final common pathway of neuronal death that involves loss of cellular calcium homeostasis, production of injurious free radicals, and tissue acidosis.
    MeSH term(s) Brain Injuries/physiopathology ; Brain Injuries/therapy ; Brain Ischemia/physiopathology ; Brain Ischemia/therapy ; Humans
    Language English
    Publishing date 1993-06
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 603080-4
    ISSN 1097-6760 ; 0196-0644
    ISSN (online) 1097-6760
    ISSN 0196-0644
    DOI 10.1016/s0196-0644(05)82736-2
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article: A new perspective on ischemic brain damage?

    Siesjö, B K

    Progress in brain research

    1993  Volume 96, Page(s) 1–9

    Abstract: The last 20-30 years of research has brought detailed information on the pathophysiology and the neurochemistry of anoxic/ischemic brain damage. On the basis of this information, important mediators of such damage have been identified, notably loss of ... ...

    Abstract The last 20-30 years of research has brought detailed information on the pathophysiology and the neurochemistry of anoxic/ischemic brain damage. On the basis of this information, important mediators of such damage have been identified, notably loss of calcium homeostasis, excessive acidosis and enhanced production of free radicals. At present, the tools of basic neuroscience are being employed to unravel the cellular and molecular mechanisms involved. The results suggest that the second and third messengers expressed as a result of a calcium transient may be instrumental in triggering cell damage. These encompass excessive activation of protein kinases and phosphatases, and expression of new genes. The new data emerging in this field herald the advent of new concepts which can explain the causes of ischemic/anoxic brain damage in molecular terms.
    MeSH term(s) Animals ; Brain/metabolism ; Brain/pathology ; Brain Ischemia/etiology ; Calcium/metabolism ; Energy Metabolism ; Free Radicals ; Humans
    Chemical Substances Free Radicals ; Calcium (SY7Q814VUP)
    Language English
    Publishing date 1993
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, P.H.S. ; Review
    ISSN 0079-6123
    ISSN 0079-6123
    DOI 10.1016/s0079-6123(08)63255-0
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article: The ionic basis of neurocytotoxic damage.

    Siesjö, B K

    Clinical neuropharmacology

    1992  Volume 15 Suppl 1 Pt A, Page(s) 128A–129A

    MeSH term(s) Brain Ischemia/physiopathology ; Calcium/metabolism ; Cell Death/drug effects ; Cell Death/physiology ; Cerebrovascular Disorders/physiopathology ; Energy Metabolism ; Homeostasis/physiology ; Humans ; Neurons/drug effects ; Neurons/metabolism
    Chemical Substances Calcium (SY7Q814VUP)
    Language English
    Publishing date 1992
    Publishing country United States
    Document type Journal Article
    ZDB-ID 199293-4
    ISSN 1537-162X ; 0362-5664
    ISSN (online) 1537-162X
    ISSN 0362-5664
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  9. Article: Pathophysiology and treatment of focal cerebral ischemia. Part I: Pathophysiology.

    Siesjö, B K

    Journal of neurosurgery

    1992  Volume 77, Issue 2, Page(s) 169–184

    Abstract: ... edema, K+/Ca++ transients, and inhibition of protein synthesis. Central to any discussion ...

    Abstract This article examines the pathophysiology of lesions caused by focal cerebral ischemia. Ischemia due to middle cerebral artery occlusion encompasses a densely ischemic focus and a less densely ischemic penumbral zone. Cells in the focus are usually doomed unless reperfusion is quickly instituted. In contrast, although the penumbra contains cells "at risk," these may remain viable for at least 4 to 8 hours. Cells in the penumbra may be salvaged by reperfusion or by drugs that prevent an extension of the infarction into the penumbral zone. Factors responsible for such an extension probably include acidosis, edema, K+/Ca++ transients, and inhibition of protein synthesis. Central to any discussion of the pathophysiology of ischemic lesions is energy depletion. This is because failure to maintain cellular adenosine triphosphate (ATP) levels leads to degradation of macromolecules of key importance to membrane and cytoskeletal integrity, to loss of ion homeostasis, involving cellular accumulation of Ca++, Na+, and Cl-, with osmotically obligated water, and to production of metabolic acids with a resulting decrease in intra- and extracellular pH. In all probability, loss of cellular calcium homeostasis plays an important role in the pathogenesis of ischemic cell damage. The resulting rise in the free cytosolic intracellular calcium concentration (Ca++) depends on both the loss of calcium pump function (due to ATP depletion), and the rise in membrane permeability to calcium. In ischemia, calcium influx occurs via multiple pathways. Some of the most important routes depend on activation of receptors by glutamate and associated excitatory amino acids released from depolarized presynaptic endings. However, ischemia also interfers with the intracellular sequestration and binding of calcium, thereby contributing to the rise in intracellular Ca++. A second key event in the ischemic tissue is activation of anaerobic glucolysis. The main reason for this activation is inhibition of mitochondrial metabolism by lack of oxygen; however, other factors probably contribute. For example, there is a complex interplay between loss of cellular calcium homeostasis and acidosis. On the one hand, a rise in intracellular Ca++ is apt to cause mitochondrial accumulation of calcium. This must interfere with ATP production and enhance anaerobic glucolysis. On the other hand, acidosis must interfere with calcium binding, thereby contributing to the rise in intracellular Ca++.
    MeSH term(s) Acidosis/metabolism ; Adenosine Triphosphate/metabolism ; Amino Acids/metabolism ; Brain Injuries/physiopathology ; Brain Ischemia/physiopathology ; Brain Ischemia/therapy ; Calcium/metabolism ; Cerebrovascular Circulation ; Energy Metabolism ; Humans ; Intracellular Fluid ; Ions ; Potassium/physiology ; Sodium/metabolism
    Chemical Substances Amino Acids ; Ions ; Adenosine Triphosphate (8L70Q75FXE) ; Sodium (9NEZ333N27) ; Potassium (RWP5GA015D) ; Calcium (SY7Q814VUP)
    Language English
    Publishing date 1992-08
    Publishing country United States
    Document type Journal Article ; Review
    ZDB-ID 3089-2
    ISSN 1933-0693 ; 0022-3085
    ISSN (online) 1933-0693
    ISSN 0022-3085
    DOI 10.3171/jns.1992.77.2.0169
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article: Pathophysiology and treatment of focal cerebral ischemia. Part II: Mechanisms of damage and treatment.

    Siesjö, B K

    Journal of neurosurgery

    1992  Volume 77, Issue 3, Page(s) 337–354

    Abstract: The mechanisms that give rise to ischemic brain damage have not been definitively determined, but considerable evidence exists that three major factors are involved: increases in the intercellular cytosolic calcium concentration (Ca++i), acidosis, and ... ...

    Abstract The mechanisms that give rise to ischemic brain damage have not been definitively determined, but considerable evidence exists that three major factors are involved: increases in the intercellular cytosolic calcium concentration (Ca++i), acidosis, and production of free radicals. A nonphysiological rise in Ca++i due to a disturbed pump/leak relationship for calcium is believed to cause cell damage by overactivation of lipases and proteases and possibly also of endonucleases, and by alterations of protein phosphorylation, which secondarily affects protein synthesis and genome expression. The severity of this disturbance depends on the density of ischemia. In complete or near-complete ischemia of the cardiac arrest type, pump activity has ceased and the calcium leak is enhanced by the massive release of excitatory amino acids. As a result, multiple calcium channels are opened. This is probably the scenario in the focus of an ischemic lesion due to middle cerebral artery occlusion. Such ischemic tissues can be salvaged only by recirculation, and any brain damage incurred is delayed, suggesting that the calcium transient gives rise to sustained changes in membrane function and metabolism. If the ischemia is less dense, as in the penumbral zone of a focal ischemic lesion, pump failure may be moderate and the leak may be only slightly or intermittently enhanced. These differences in the pump/leak relationship for calcium explain why calcium and glutamate antagonists may lack effect on the cardiac arrest type of ischemia, while decreasing infarct size in focal ischemia. The adverse effects of acidosis may be exerted by several mechanisms. When the ischemia is sustained, acidosis may promote edema formation by inducing Na+ and Cl- accumulation via coupled Na+/H+ and Cl-/HCO3- exchange; however, it may also prevent recovery of mitochondrial metabolism and resumption of H+ extrusion. If the ischemia is transient, pronounced intraischemic acidosis triggers delayed damage characterized by gross edema and seizures. Possibly, this is a result of free-radical formation. If the ischemia is moderate, as in the penumbral zone of a focal ischemic lesion, the effect of acidosis is controversial. In fact, enhanced glucolysis may then be beneficial. Although free radicals have long been assumed to be mediators of ischemic cell death, it is only recently that more substantial evidence of their participation has been produced. It now seems likely that one major target of free radicals is the microvasculature, and that free radicals and other mediators of inflammatory reactions (such as platelet-activating factor) aggravate the ischemic lesion by causing microvascular dysfunction and blood-brain barrier disruption.(ABSTRACT TRUNCATED AT 400 WORDS)
    MeSH term(s) Animals ; Humans ; Ischemic Attack, Transient/metabolism ; Ischemic Attack, Transient/therapy
    Language English
    Publishing date 1992-09
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, P.H.S. ; Review
    ZDB-ID 3089-2
    ISSN 1933-0693 ; 0022-3085
    ISSN (online) 1933-0693
    ISSN 0022-3085
    DOI 10.3171/jns.1992.77.3.0337
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