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Status epilepticus in BRAF-related cardio-facio-cutaneous syndrome: Focus on neuroimaging clues to physiopathology. Epilepsia Open 2024; 9:258-267. [PMID: 37943120 PMCID: PMC10839340 DOI: 10.1002/epi4.12864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Accepted: 11/06/2023] [Indexed: 11/10/2023] Open
Abstract
OBJECTIVE Cardio-facio-cutaneous syndrome (CFC) is a genetic disorder due to variants affecting genes coding key proteins of the Ras/MAPK signaling pathway. Among the different features of CFC, neurological involvement, including cerebral malformations and epilepsy, represents a common and clinically relevant aspect. Status epilepticus (SE) is a recurrent feature, especially in a specific subgroup of CFC patients with developmental and epileptic encephalopathy (DEE) and history of severe pharmacoresistant epilepsy. Here we dissect the features of SE in CFC patients with a particular focus on longitudinal magnetic resonance imaging (MRI) findings to identify clinical-radiological patterns and discuss the underlying physiopathology. METHODS We retrospectively analyzed clinical, electroencephalogram (EEG), and MRI data collected in a single center from a cohort of 23 patients with CFC carrying pathogenic BRAF variants who experienced SE during a 5-year period. RESULTS Seven episodes of SE were documented in 5 CFC patients who underwent EEG and MRI at baseline. MRI was performed during SE/within 72 hours from SE termination in 5/7 events. Acute/early post-ictal MRI findings showed heterogenous abnormalities: restricted diffusion in 2/7, focal area of pcASL perfusion change in 2/7, focal cortical T2/FLAIR hyperintensity in 2/7. Follow-up images were available for 4/7 SE. No acute changes were detected in 2/7 (MRI performed 4 days after SE termination). SIGNIFICANCE Acute focal neuroimaging changes concomitant with ictal EEG focus were present in 5/7 episodes, though with different findings. The heterogeneous patterns suggest different contributing factors, possibly including the presence of focal cortical malformations and autoinflammation. When cytotoxic edema is revealed by MRI, it can be followed by permanent structural damage, as already observed in other genetic conditions. A better understanding of the physiopathology will provide access to targeted treatments allowing to prevent long-term adverse neurological outcome. PLAIN LANGUAGE SUMMARY Cardio-facio-cutaneous syndrome is a genetic disorder that often causes prolonged seizures known as status epilepticus. This study has a focus on electroclinical and neuroimaging patterns in patients with cardio-facio-cutaneous syndrome. During these status epilepticus episodes, we found different abnormal brain imaging patterns in patients, indicating various causes like brain malformations and inflammation. Understanding these patterns could help doctors find specific treatments, protecting cardio-facio-cutaneous syndrome patients from long-term brain damage.
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Short- vs long-term assessment of heart rate variability: Clinical significance in Dravet Syndrome. Epilepsy Behav 2023; 146:109357. [PMID: 37499580 DOI: 10.1016/j.yebeh.2023.109357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 07/06/2023] [Accepted: 07/07/2023] [Indexed: 07/29/2023]
Abstract
PURPOSE Heart rate variability (HRV) is a promising prognostic biomarker in Dravet Syndrome (DS), but different studies are not always comparable, limiting its clinical application. In fact, multiple HRV parameters, analyzed over different timescales and in different states are reported. The aim of this study was to assess which HRV parameter is more reproducible and clinically significant, analyzing differences between wake and sleep. METHOD Patients with DS, with available 24 h-ECG Holter-derived HRV, were screened to evaluate if they had EEG-derived ECG traces available within one month before/after the Holter. A 5-minute period in the awake and sleep state were analyzed and correlated with the 24 h-HRV. Several relevant clinical features such as age, a recent history of status epilepticus (SE), and frequent generalized tonic-clonic seizures (GTCS) were correlated to HRV parameters with multiple linear regression models. RESULTS Thirty-oneawake recordings and 22 sleep recordings were included. HF was the parameter with the highest correlation in awake (Rho 0.745, p < 0.001) and in sleep (Rho 0.727, p < 0.001). Age was a significant factor in simple models for most of the parameters except RMSSD. A recent history of SE was associated with a significant reduction of HRV, both in simple and multiple regressions for all parameters except for awake LF and for sleep RMSSD and PNN50. Frequent GTCS were associated with a significant decrease in sleep RMSSD, HF, and LF, also when correcting for the effect of age and history of SE. When compared pairwise, a significant increase in sleep was seen for HF (median + 24.45 ms2, IQR -7.51/+172.18 ms2, p = 0.036; increase in 15/22 patients). CONCLUSION A moderate degree of correlation between long- and short-term HRV was seen both in sleep and in awake, and a strong correlation for awake HF. HF, both in awake and sleep, was significantly associated with high seizure burden, including SE and frequent GTCS.
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Visual Function in Children with GNAO1-Related Encephalopathy. Genes (Basel) 2023; 14:genes14030544. [PMID: 36980817 PMCID: PMC10047968 DOI: 10.3390/genes14030544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 02/09/2023] [Accepted: 02/20/2023] [Indexed: 02/24/2023] Open
Abstract
Background: GNAO1-related encephalopathies include a broad spectrum of developmental disorders caused by de novo heterozygous mutations in the GNAO1 gene, encoding the G (o) subunit α of G-proteins. These conditions are characterized by epilepsy, movement disorders and developmental impairment, in combination or as isolated features. Objective: This study aimed at describing the profile of neurovisual competences in children with GNAO1 deficiency to better characterize the phenotype of the disease spectrum. Methods: Four male and three female patients with confirmed genetic diagnosis underwent neurological examination, visual function assessment, and neurovisual and ophthalmological evaluation. Present clinical history of epilepsy and movement disorders, and neuroimaging findings were also evaluated. Results: The assessment revealed two trends in visual development. Some aspects of visual function, such as discrimination and perception of distance, depth and volume, appeared to be impaired at all ages, with no sign of improvement. Other aspects, reliant on temporal lobe competences (ventral stream) and more related to object–face exploration, recognition and environmental control, appeared to be preserved and improved with age. Significance: Visual function is often impaired, with patterns of visual impairment affecting the ventral stream less.
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Pyridoxine supplementation in PACS2-related encephalopathy: A case report of possible precision therapy. Seizure 2023; 105:14-16. [PMID: 36645998 DOI: 10.1016/j.seizure.2023.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/31/2022] [Accepted: 01/02/2023] [Indexed: 01/05/2023] Open
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Cortical Visual Impairment in CDKL5 Deficiency Disorder. Front Neurol 2022; 12:805745. [PMID: 35153983 PMCID: PMC8825365 DOI: 10.3389/fneur.2021.805745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 12/10/2021] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND CDKL5 deficiency disorder (CDD) is a developmental encephalopathy caused by pathogenic variants in the gene cyclin-dependent kinase-like 5. Cerebral visual impairment (CVI) is frequent in patients with CDD. In addition to being recognized as a specific feature of the pathology, it has been suggested that visual impairment may correlate with neurodevelopmental outcome and epilepsy severity, but no systematic behavioral visual assessment has been performed. The aim of our study was to evaluate clinical and electrophysiological profile of CVI in patients with CDD, to correlate various aspects of visual function to neurodevelopmental and epileptic features. METHODS The study included all patients with CDD from the National Pathology Registry. All patients underwent neurological examination, a disease-specific functional assessment, structured clinical evaluation of visual functions, including pattern reversal visual evoked potential (VEP), and a detailed monitoring of epileptic features, including video-EEG. RESULTS All the 11 patients recorded in the CDKL5 national registry, 10 females and one male, age range of 1.5 to 24 years (mean 9, SD 7.7, median 6.5), were enrolled. Visual function is impaired in all patients; in particular, visual fields, visual acuity, contrast sensitivity, and stereopsis were consistently abnormal whereas other aspects, such as fixing and tracking, were relatively preserved. Pattern reversal VEP was abnormal in nearly 80% of our patients. No correlation was found among CVI severity, age, level of psychomotor development, EEG abnormalities, and pathology stages even if an overall less abnormal EEG pattern was more often associated with better visual results. CONCLUSION In conclusion, CVI can be considered as a major feature of CDD with a diffuse involvement in several behavioral and electrophysiological aspects. Larger cohorts will help to better clarify the possible prognostic role of EEG severity in predicting both visual and developmental abnormalities.
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Fighting autoinflammation in FIRES: The role of interleukins and early immunomodulation. Epilepsy Behav Rep 2022; 18:100531. [PMID: 35356746 PMCID: PMC8958320 DOI: 10.1016/j.ebr.2022.100531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 02/15/2022] [Accepted: 02/16/2022] [Indexed: 01/11/2023] Open
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Heart rate variability alterations in Dravet Syndrome: The role of status epilepticus and a possible association with mortality risk. Seizure 2021; 94:129-135. [PMID: 34896816 DOI: 10.1016/j.seizure.2021.11.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/02/2021] [Accepted: 11/26/2021] [Indexed: 11/15/2022] Open
Abstract
PURPOSE Preliminary data suggest that patients with Dravet Syndrome (DS) have a reduced heart rate variability (HRV). This seems particularly evident in patients who experienced sudden unexpected death in epilepsy (SUDEP). This study aims at confirming these findings in a larger cohort and at defining clinical, genetic or electroencephalographic predictors of HRV impairment in DS patients. METHODS DS patients followed at our Institution performed a 24h-ECG Holter to derive HRV parameters. We used as control population patients with epilepsy (PWEs) and healthy controls (HCs). In DS patients, we assessed the impact of different clinical, neurophysiological and genetic features on HRV alterations through multiple linear regression. After a mean follow-up of 7.4 ± 3.2 years since the HRV assessment, all DS patients were contacted to record death or life-threatening events. RESULTS 56 DS patients had a significantly reduced HRV compared to both HCs and PWEs. A recent history of status epilepticus (SE) was the only significant predictor of lower HRV in the multivariate analysis. At follow-up, only one patient died; her HRV was lower than that of all the controls and was in the low range for DS patients. CONCLUSION We describe for the first time an association between SE and HRV alterations in DS. Further studies on other SCN1A-related phenotypes and other epilepsies with frequent SE will help clarify this finding. Compared to the literature, our cohort showed better HRV and lower mortality. Although limited, this observation reinforces the role of HRV as a biomarker for mortality risk in DS.
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Epilepsy and BRAF Mutations: Phenotypes, Natural History and Genotype-Phenotype Correlations. Genes (Basel) 2021; 12:genes12091316. [PMID: 34573299 PMCID: PMC8470450 DOI: 10.3390/genes12091316] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 08/11/2021] [Accepted: 08/23/2021] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVE Cardiofaciocutaneous syndrome (CFCS) is a rare developmental disorder caused by upregulated signaling through the RAS-mitogen-activated protein kinase (MAPK) pathway, mostly resulting from de novo activating BRAF mutations. Children with CFCS are prone to epilepsy, which is a major life-threatening complication. The aim of our study was to define the natural history of epilepsy in this syndrome and exploring genotype-phenotype correlations. METHODS We performed an observational study, including 34 patients with molecularly confirmed diagnosis (11 males, mean age: 15.8 years). The mean follow-up period was 9.2 years. For all patients, we performed neurological examination, cognitive assessment when possible, neuroimaging, electrophysiological assessment and systematic assessment of epilepsy features. Correlation analyses were performed, taking into account gender, age of seizure onset, EEG features, degree of cognitive deficits, type of mutation, presence of non-epileptic paroxysmal events and neuroimaging features. RESULTS Epilepsy was documented in 64% of cases, a higher prevalence compared to previous reports. Patients were classified into three groups based on their electroclinical features, long-term outcome and response to therapy. A genotype-phenotype correlation linking the presence/severity of epilepsy to the nature of the structural/functional consequences of mutations was observed, providing a stratification based on genotype to improve the clinical management of these patients.
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Role of high-density EEG (hdEEG) in pre-surgical epilepsy evaluation in children: case report and review of the literature. Childs Nerv Syst 2021; 37:1429-1437. [PMID: 33604716 PMCID: PMC8084826 DOI: 10.1007/s00381-021-05069-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Accepted: 02/02/2021] [Indexed: 11/27/2022]
Abstract
INTRODUCTION Electrical source imaging (ESI) and especially hdEEG represent a noninvasive, low cost and accurate method of localizing epileptic zone (EZ). Such capability can greatly increase seizure freedom rate in surgically treated drug resistant epilepsy cases. Furthermore, ESI might be important in intracranial record planning. CASE REPORT We report the case of a 15 years old boy suffering from drug resistant epilepsy with a previous history of DNET removal. The patient suffered from heterogeneous seizure semiology characterized by anesthesia and loss of tone in the left arm, twisting of the jaw to the left and dysarthria accompanied by daze; lightheadedness sometimes associated with headache and dizziness and at a relatively short time distance negative myoclonus involving the left hand. Clinical evidence poorly match scalp and video EEG monitoring thus requiring hdEEG recording followed by SEEG to define surgical target. Surgery was also guided by ECoG and obtained seizure freedom. DISCUSSION ESI offers an excellent estimate of EZ, being hdEEG and intracranial recordings especially important in defining it. We analyzed our results together with the data from the literature showing how in children hdEEG might be even more crucial than in adults due to the heterogeneity in seizures phenomenology. The complexity of each case and the technical difficulties in dealing with children, stress even more the importance of a noninvasive tool for diagnosis. In fact, hdEEG not only guided in the presented case SEEG planning but may also in the future offer the possibility to replace it.
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Efficacy and safety of Fenfluramine hydrochloride for the treatment of seizures in Dravet syndrome: A real‐world study. Epilepsia 2020; 61:2405-2414. [DOI: 10.1111/epi.16690] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 08/18/2020] [Accepted: 08/19/2020] [Indexed: 02/06/2023]
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Early visual and neuro-development in preterm infants with and without retinopathy. Early Hum Dev 2020; 148:105134. [PMID: 32688300 DOI: 10.1016/j.earlhumdev.2020.105134] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/06/2020] [Accepted: 07/07/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND Retinopathy of prematurity (ROP) is often associated with visual impairment and multiple developmental disabilities. AIMS As most of the previous studies include infants with brain lesions, that can determine visual impairment per se, a cohort of low neurological risk preterm infants without ROP and with various degree of severity of ROP was assessed in order to establish visual and neurodevelopmental outcome. STUDY DESIGN Preterm infants born at <31 weeks gestation, without major brain lesions, underwent visual function assessment at 1 year corrected age and neurodevelopmental assessment at 2 years corrected age. SUBJECTS One hundred and five infants were included in the study: 42 infants did not develop ROP, 7 reached stage 1 in zone 2 ROP, 37 reached prethreshold (untreated) type 2 ROP. The remaining 19 infants were classified as type 1 ROP. OUTCOME MEASURES Visual function (including fixing, tracking, visual acuity, visual field, attention at distance and nystagmus) were assessed at 12 months corrected age and Griffiths Scales at 2 years corrected age. RESULTS The severity of ROP was strongly correlated (p < 0.001) with both visual function at 1 year and neurodevelopment at 2 years. Similarly, the presence of nystagmus was also strongly correlated with visual and neurodevelopmental sequelae. CONCLUSIONS Infants with no or milder retinopathy showed normal visual function at 1 year and neurodevelopment at 2 years. Infants who underwent treatment more frequently showed abnormal results on several aspects of visual function. Presence of nystagmus appeared to increase the risk for abnormal visual function and neurodevelopmental outcome.
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Sleep-potentiated epileptiform activity in early thalamic injuries: Study in a large series (60 cases). Epilepsy Res 2015; 109:90-9. [DOI: 10.1016/j.eplepsyres.2014.10.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 09/18/2014] [Accepted: 10/18/2014] [Indexed: 10/24/2022]
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Application of the sleep disturbance scale for children (SDSC) in preschool age. Eur J Paediatr Neurol 2013; 17:374-82. [PMID: 23352289 DOI: 10.1016/j.ejpn.2012.12.009] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 12/25/2012] [Accepted: 12/30/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND The Sleep Disturbance Scale for Children (SDSC) was originally validated on a sample of healthy children aged 6-16 years, investigating the occurrence of sleep disorders during the previous 6 months. AIMS The aim of this new study was to assess the psychometric properties of the SDSC in an Italian population of preschool children. METHODS The SDSC was distributed to the primary caregivers of children recruited via nurseries. Letters describing the study design and requesting the co-operation of the caregivers (parents) and co-signed by the investigators and by the head teacher were distributed with the questionnaire and collected by the teachers. Reliability analysis for evaluating internal consistency and item-total correlation coefficients, and factor analysis were performed. RESULTS During a 12-months study period, 601 questionnaires from healthy preschool age children (range 3-6 years) were collected. SDSC in preschool children showed a good level of internal consistency (Cronbach's alpha: 0.83) and six factors were derived from the factor analysis by using the principal component method of extraction and rotated with the varimax method: Parasomnias, Difficulty in initiating and maintaining sleep, Sleep disordered breathing, Disorders of excessive somnolence, Sleep hyperhydrosis and Non-restorative Sleep. CONCLUSIONS The statistical analysis, the internal consistency and the factor analysis support the use of SDSC as an evaluation tool even at preschool age. A different factorial structure from the original SDSC was found due to a different prevalence of the sleep disturbances in younger children, but with similar cut-off total SDSC score.
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Abstract
AIM The aim of this study was to assess the onset of forward parachute reaction (FPR) in infants with brain lesions and its correlation with age of walking. METHOD FPR was assessed at 6, 9, and 12 months in 140 infants with brain lesions (78 males, 62 females; mean gestational age 31 wks; SD 3.6 wks; mean birthweight 1450 g, SD 252 g). On cranial ultrasound 62 infants had mild and 78 had major abnormalities; 86 developed cerebral palsy. All were followed for 5 years, and the age at which each child achieved independent walking was recorded. Infants who had been born small for gestational age (weight <10th centile) were excluded, as were those who had major congenital malformations, severe postnatal infectious diseases, or metabolic or haematological complications. RESULTS A complete FPR was present in eight infants at 6 months, in 42 at 9 months, and in 71 at 12 months. At 12 months, 29 infants presented incomplete FPR and 40 presented absent FPR. Seventy-three infants were able to walk independently between the ages of 11 months and 60 months (67 with complete FPR and six with incomplete FPR at 12 mo). A complete FPR at 12 months was a good predictor of independent walking. The age at onset of complete FPR was also a good predictor of age of walking. INTERPRETATION The late acquisition of a complete FPR appears to be an early sign of a more general delayed maturation of functional abilities.
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Early visual assessment in preterm infants with and without brain lesions: correlation with visual and neurodevelopmental outcome at 12 months. Early Hum Dev 2011; 87:177-82. [PMID: 21237588 DOI: 10.1016/j.earlhumdev.2010.12.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 12/07/2010] [Accepted: 12/11/2010] [Indexed: 11/17/2022]
Abstract
BACKGROUND Several studies have reported the development of various aspects of visual function in infancy and early childhood in both preterm and term-born infants, but only a few studies have focused on the predictive power of neonatal visual findings in infants with brain lesions. AIMS To explore visual findings at term age, and at 3 and 12 months corrected age in preterm infants (gestational age <33 weeks) with and without brain lesions; to compare the assessment at term age and at 12 months; and to assess the relationship between visual findings and neurodevelopmental outcome at 12 months. STUDY DESIGN Cranial ultrasound scans (US) were classified in normal, mild or major abnormalities. One-hundred and forty-five infants were assessed with age specific tests for visual function at term age, and at 3 and 12 months. Neurodevelopmental assessment (Griffiths' Scales) was performed at 12 months. RESULTS A good correlation was found between early and late visual assessment and neurodevelopment outcome. Of the 121 infants with normal neonatal visual assessment, 119 were also normal at 12 months and 116 had normal developmental quotient. Of the 24 infants with abnormal neonatal visual assessment, 12 were also abnormal at 12 months. All the false positives had normalised by 3 months. Of the 35 infants with major US abnormalities, 20 had normal and 15 abnormal scores on the neonatal assessment. At 1 year 17 had normal and 18 abnormal scores. CONCLUSION A normal visual assessment at term age is a good predictor of normal visual and neurodevelopmental outcome at 12 months. An abnormal visual examination in the neonatal period was a less reliable prognostic indicator, infant should be reassessed at 3 months.
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Survival of Type A and B Spermatogonia in the Mouse Testis after Exposure to High Dose-rates of Electrons. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/rab.22.2.191.195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Relationships between cell killing, mutation induction and DNA damage in X-irradiated V79 cells: the influence of oxygen and DMSO. Int J Radiat Biol 1991; 60:467-82. [PMID: 1679087 DOI: 10.1080/09553009114552321] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The relationships between cell killing, mutation induction and DNA double (dsb) and single (ssb) strand breaks have been studied in V79 cells irradiated with X-rays under oxic and anoxic conditions in the presence and in the absence of dimethylsulphoxide (DMSO). Curvilinear relationships were found between all pairs of endpoints, except for dsb versus ssb. Statistical analysis of experimental data has shown that in the absence of DMSO there is evidence of good correlations between cell killing, mutation induction and dsb in oxic and anoxic conditions. However, when DMSO was present, no significant correlation was found. In the presence of oxygen DMSO always exerts a protective effect while in anoxia it is generally much less protective and induces a strong sensitization with respect to mutation induction. Possibly DMSO acts not only as a radical scavenger but also as an agent inducing chromatin relaxation and/or under anoxia, forming highly mutagenic short-term radicals. The present data suggest that lethal and mutational events are at least partially independent and not proportional to the initial number of DNA breaks. This may imply that either other kinds of lesions are involved in cell lethality and mutability, or dose-dependent repair mechanisms of dsb have to be considered.
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Model experiments to evaluate the protective role of thiols and other reductants against oxidative damage. Pharmacol Ther 1988; 39:155-6. [PMID: 3200887 DOI: 10.1016/0163-7258(88)90056-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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The oxygen effect in radiation inactivation of DNA and enzymes. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1986; 50:573-94. [PMID: 3531055 DOI: 10.1080/09553008614550981] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A survey is made of literature data dealing with the influence of oxygen on radiation effects in biologically active DNA and enzymes irradiated extracellularly. There is evidence that oxygen takes part in physico-chemical events, directly or indirectly produced by radiation in several ways: from scavenging reducing primary water radicals to reacting directly with macromolecular radical sites. There is evidence that radiation-induced secondary radicals, originating from a variety of low molecular weight biomolecules, can react with DNA and enzymes in their native state, and produce inactivation. By reaction with oxygen secondary radicals become peroxidized and in this form are generally more harmful to biological macromolecules. There are indications that thiol peroxy radicals can also act in the same way. Possible implications for the oxygen effect observed in vivo are discussed.
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Interactions of thiyl free radicals with oxygen: a pulse radiolysis study. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1986; 50:595-600. [PMID: 3489683 DOI: 10.1080/09553008614550991] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A pulse radiolysis study of glutathione in aqueous solution at pH 5.5 containing N2O/O2 mixtures at various ratios indicates that oxygen rapidly adds to the thiyl glutathione radical yielding a transient absorption, with a maximum at 540 nm, whose characteristics appear to be compatible with assignment to the GSOO. radical. The reaction (Formula: see text) appears to be an equilibrium whose kinetic constants have been estimated (kf = 2.0 X 10(9) dm3 mol-1, kb = 6.2 X 10(5) s-1). Evidence for electron transfer from ascorbate to the GSOO. radical has been obtained and the respective rate constant has been determined to be 1.75 +/- 0.15 X 10(8) dm3 mol-1 s-1.
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Radiation chemical and physical mechanisms of radiosensitization of single cell systems by iothalamate. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1986; 50:481-90. [PMID: 3528013 DOI: 10.1080/09553008614550891] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The radiosensitizing effect of iothalamate (ITA) has been investigated in bacterial and mammalian cells in order to obtain a better understanding of the physical and radiation chemical mechanisms of sensitization displayed by the drug. In order to distinguish between the two, Escherichia coli B/r cells were irradiated with 9 MeV electrons, which allow only the radiation chemical mechanism to operate, and V79 cells with 250 KVp X-rays, which instead make possible the occurrence of both mechanisms. It has been shown that: Maximum sensitization already occurs in bacteria with 10(-2) mol dm-3 ITA (enhancement ratio (ER) 11.2 in oxygen, 2.7 in nitrogen), while in mammalian cells a concentration higher by a factor of 10 is required (ER 2.2 both in air and nitrogen). ITA sensitization is inhibited when bacteria are irradiated in growth medium instead of buffer. Such inhibition does not occur with V79 cells. Cysteine and glycerol completely cancel the sensitizing effect of ITA on bacterial cells in both gas phases. Dimethylsulphoxide (DMSO) does the same in nitrogen, while in oxygen it only reduces ITA sensitization to about 50 per cent of the level observed in control conditions. With mammalian cells, all the three scavengers do not modify significantly the enhancement produced by ITA, either in air or in nitrogen. The experimental results are consistent with both postulated mechanisms of sensitization.
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Role of glutathione in affecting the radiosensitivity of molecular and cellular systems. RADIATION AND ENVIRONMENTAL BIOPHYSICS 1983; 22:215-223. [PMID: 6359235 DOI: 10.1007/bf01323711] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
It has previously been shown that radioinduced organic radicals can be repaired by hydrogen donation from glutathione (GSH) and this repair is in competition with oxygen (damage fixation). In this paper the influence of exogenous glutathione on the radiation response of the enzyme alcohol dehydrogenase (YADH), DNA in vitro, and E. coli B/r cells has been investigated. GSH is observed to protect YADH essentially by free radical scavenging mechanisms in both presence or absence of oxygen. The same mechanism seems operate in the radioprotection afforded by GSH to DNA in vitro. E. coli B/r cells are protected at higher extent by GSH than its oxidized form (GSSG); the possibility that GSH penetrate into bacterial cells more easily that GSSG can explain their different behaviour. None of the three systems studied has provided definitive support for the occurrence of the hydrogen donation reaction in the radioprotective mechanisms of GSH versus biomolecules and bacterial cells.
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Pulse radiolytic study of hydrogen transfer from glutathione to organic radicals. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1982; 41:595-602. [PMID: 6981616 DOI: 10.1080/09553008214550691] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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24
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Biological Responses to Various Neutron Energies from 1 to 600 MeV: I. Testes Weight Loss in Mice. Radiat Res 1980. [DOI: 10.2307/3575483] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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25
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Biological responses to various neutron energies from 1 to 600 MeV. I. Testes weight loss in mice. Radiat Res 1980; 84:444-52. [PMID: 7454988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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26
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The induction of beta-galactosidase and tryptophanase in X-irradiated E. coli B and B/r. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1977; 32:595-601. [PMID: 338524 DOI: 10.1080/09553007714551391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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28
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Radiolysis of glutathione in oxygen-containing solutions of pH7. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1977; 32:195-202. [PMID: 302250 DOI: 10.1080/09553007714550891] [Citation(s) in RCA: 72] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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29
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Iodinated radiological contrast media as radiosensitizers. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1977; 31:1-10. [PMID: 14900 DOI: 10.1080/09553007714550011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This paper describes the radiosensitizing effects of diatrizoic (DA) and iothalamic (ITA) acids and of iodipamide (IP) on the survival of E coli B/r irradiated with X-rays and with high-intensity electron pulses. All compounds at concentrations between 10 and 50 mM display a strong sensitizing effect in the presence of oxygen (DMF between 0-1 and 0-3) and are much less effective in nitrogen. In N2O the degree of sensitization is intermediate between oxygen and nitrogen. The situation is the same at pH 7 or 5-6. Solutions of DA, ITA and IP irradiated at pH lower than 6 become highly toxic to bacteria added after irradiation, for several hours after X-irradiation or several minutes after pulsed irradiation. The maximum toxic effect occurs with 2 krad of X-ray and with 6-8 krad of electrons. Oxygen must be present in order to observe the bactericidal activity. This is not affected by scavenging hydrated electrons with nitrate, but is completely cancelled by scavenging OH radicals with formate. It is also cancelled by adding thiosulphate to the irradiated solutions immediately before the bacteria. In the presence of nutrient broth, the radiosensitizing effect is absent after irradiation with pulsed electrons; whereas after X-irradiation it is reduced when the concentration of sensitizers is 50 mM. The experimental data appear to be compatible with a mechanism operated by short and long-lived transients resulting from the radiolysis of iodinated contrast media.
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Proceedings: Radiation chemistry of glutathione and its possible role in affecting radio-sensitivity of biological systems. Br J Cancer 1975; 32:766. [PMID: 1220799 PMCID: PMC2025005 DOI: 10.1038/bjc.1975.339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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31
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The Influence of Agents That Enhance Lethal Effects of Radiation on the Damage to Bacterial Membranes by X Rays and Ultraviolet Light. Radiat Res 1975. [DOI: 10.2307/3574249] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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32
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Influence of agents that enhance lethal effects of radiation on the damage to bacterial membranes by x rays and ultraviolet light. Radiat Res 1975; 64:593-601. [PMID: 1105654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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33
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Primary and secondary radicals in the radiation-induced inactivation of yeast alcoholdehydrogenase. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1974; 26:311-9. [PMID: 4611933 DOI: 10.1080/09553007414551291] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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34
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Letter: Indane-trione influence on radiation damage to bacterial DNA and on its repair. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1974; 26:297-303. [PMID: 4609940 DOI: 10.1080/09553007414551271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Reactions of radiation-induced I-, I2- and I3- with alcohol dehydrogenase and aldolase. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1973; 24:243-55. [PMID: 4542985 DOI: 10.1080/09553007314551091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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36
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DNA repair and degradation in x-irradiated E. coli B-r cells after treatment with ultra-violet light and N-ethylameimide. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1973; 24:99-105. [PMID: 4580661 DOI: 10.1080/09553007314550871] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Survival of type A and B spermatogonia in the mouse testis after exposure to high dose-rates of electrons. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1972; 22:191-5. [PMID: 4538223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Survival of Type A and B Spermatogonia in the Mouse Testis after Exposure to High Dose-rates of Electrons. Int J Radiat Biol 1972. [DOI: 10.1080/713853262] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Extraction and Partial Purification of Blood Group
Substances A, B and H from Erythrocyte Stroma. Vox Sang 1972. [DOI: 10.1159/000464498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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An estimation of the RBE of stopped pions from observations of spermatogonia survival in mice. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1971; 19:537-46. [PMID: 5315437 DOI: 10.1080/09553007114550721] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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42
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The influence of selenourea and of colloidal selenium on the survival of E. coli B-r after x-irradiation. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1971; 20:61-8. [PMID: 4936810 DOI: 10.1080/09553007114550871] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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43
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Survival of mouse type-B spermatognoia for the study of the biological effectiveness of very high-energy neutrons. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1969; 15:185-9. [PMID: 5305670 DOI: 10.1080/09553006914550291] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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44
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Modification by iodine compounds of the inactivation yield of enzymes irradiated in vitro with x-rays and ultra-violet-light. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1969; 16:267-76. [PMID: 5308016 DOI: 10.1080/09553006914551271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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45
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Radiation sensitizers in ultra-violet irradiation of cellular systems. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1969; 16:393-6. [PMID: 4905877 DOI: 10.1080/09553006914551421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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46
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Blood Group Activity A in Phenol Extracts from A
Human Erythrocyte Stroma. Vox Sang 1969. [DOI: 10.1159/000465800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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The inactivation of alcohol dehydrogenase by x-rays and the dose-modifying effect of some added substances. Radiat Res 1967; 32:671-84. [PMID: 6066584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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49
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On the mechanism of radiosensitization by iodine compounds at the molecular level. EXPERIENTIA 1967; 23:630-1. [PMID: 6051682 DOI: 10.1007/bf02144164] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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50
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[Influence of physical and chemical factors on radio-sensitization in vitro of rabbit erythrocytes]. MINERVA RADIOLOGICA 1967; 12:56-61. [PMID: 5628140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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