Atlantoaxial instability in a patient with neck pain and rheumatoid arthritis

Context: The purpose of this report is to describe the clinical decision-making process for a patient with rheumatoid arthritis with neck pain with underlying atlantoaxial instability.Findings: The patient was evaluated for worsening upper neck pain that began insidiously 1 year prior. The patient denied numbness or tingling in her upper or lower extremities, dizziness or lightheadedness, difficulty maintaining balance with walking, or muscle weakness. Cervical spine range of motion was limited in all planes due to pain and apprehension. The patient’s neurological examination was unremarkable. Prior flexion and extension radiographs of the cervical spine were interpreted as unremarkable with alignment preserved in flexion and extension. However, upon further inspection, the cervical spine flexion radiograph was concerning for inadequate cervical motion, which may have limited the diagnostic utility of these radiographs. Additionally, a Sharp-Purser test was performed, which was positive for excessive motion. Flexion and extension radiographs of the cervical spine were then repeated ensuring the patient adequately flexed and extended during the imaging. Severe anterior subluxation of C1 relative to C2 with cervical flexion was noted, as C1 moved as much as 8–9 mm anterior to C2 with cervical flexion. Given the degree of atlantoaxial instability, the patient subsequently underwent successful posterior fusion from the occiput to C2.Conclusion/Clinical Relevance: This case report demonstrates the importance of properly screening for upper cervical spine instability in patients with rheumatoid arthritis and neck pain and understanding the importance of obtaining adequate and appropriate diagnostic imaging.     

常染色体嵌合变异的流行病学分布及其影响因素研究进展

人类体细胞突变的发生和积累,又称体细胞嵌合现象。其中,嵌合染色体变异（mCA）对基因组完整性的影响最为显著,被视为人类衰老的表型之一。随着全球人口老龄化进程的加速,了解mCA的人群流行病学分布及其影响因素,有助于探索人体衰老进程中“基因组失稳”及其相关生物学机制,为人类年龄相关疾病的一级预防提供科学依据。本文旨在汇总既往大规模人群研究结果,对外周血常染色体mCA的人群流行病学分布及其影响因素进行综述。     

Analysis of types of chromosomal aberrations following the combined action of chemical mutagens

Types of chromosomal aberrations in cultures of human lymphocytes exposed to the combined action of various concentrations of thiophosphamide and dipin, with different proportions of each, were studied. The mutagens acted on the G₀ stage. The range of concentrations used was from 3.17·10^–5 to 22.19·10^–5M. Equimolar concentrations of thiophosphamide inhibited more chromatid exchanges and fewer sister-strand (isolocus) unions than dipin, and it also induced a greater proportion of single breaks and a greater proportion of breaks in chromatid exchanges relative to the total number of chromosome breaks. Both the absolute and the relative frequencies of chromosomal aberrations depended on the concentration of the mutagens. A change in the ratio between thiophosphamide and dipin, if the total number of molecules of the two mutagens at the different concentration levels remained constant, gave rise to an effect whose level was between the effects of action of equimolar concentrations of the pure mutagens. This effect depended on the proportion of each mutagen in the combined treatment. It is concluded that the action of thiophosphamide and dipin is additive.Laboratory of Mutagenesis, Institute of Medical Genetics, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. V. Smol'yannikov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 1, pp. 79–81, January, 1978.     

New technique for posterior intra-articular arthrodesis using a single-block graft in cases of atlantoaxial instability

A new method of posterior C1-2 arthrodesis, derived from the W. V. Cone and G. Bertrand, technique (Montreal, 1970) is described with two modifications: (1) the exact measurements of the ideal graft are determined preoperatively, using CT and a sterilized pasteboard horseshoe-shaped model; (2) in the sitting postion, single occipital block graft was cut out microsurgically, using the preoperative model. After decortication of the graft, posterior arches of C1 and 2, and microsurgical excision of the cartilage of the C1-2 lateral joints, the graft was imbedded into the entire C1-2 space, fixed, and tightened using a braid of nylacap yarn. A case report of rotatory luxation and associated atlantoaxial instability in a 10-year-old girl illustrates the excellent functional results of this technique.Presented at the XVII Annual Meeting of the International Society for Pediatric Neurosurgery, Bombay 1989     

小鼠高低转移性肝癌微卫星不稳定性的研究

目的：了解小鼠高、低转移性肝癌细胞系Ｈｃａ／１６Ａ３－Ｆ（Ｆ）和Ｈｃａ／Ａ２－Ｐ（Ｐ）发生微卫星不稳定性（ＭＳＩ）情况,探讨它们与肝癌发生及转移之间的关系。方法：随机选择３号和１６号染色体上１５个多态微卫星标记,采用聚合酶链式反应－简单重复序列多态性（ＳＳＬＰ）和单链构象多态性（ＳＳＣＰ）方法对Ｆ和Ｐ细胞系进行分析。结果：Ｆ和Ｐ细胞系有信息的微卫星位点其等位基因与Ｃ３Ｈ相同,且存在多位点ＭＳＩ。结     

1p36 deletion syndrome: Review and mapping with further characterization of the phenotype,a new cohort of 86 patients

Chromosome 1p36 deletion syndrome (1p36DS) is one of the most common terminal deletion syndromes (incidence between 1/5000 and 1/10,000 live births in the American population), due to a heterozygous deletion of part of the short arm of chromosome 1. The 1p36DS is characterized by typical craniofacial features, developmental delay/intellectual disability, hypotonia, epilepsy, cardiomyopathy/congenital heart defect, brain abnormalities, hearing loss, eyes/vision problem, and short stature. The aim of our study was to (1) evaluate the incidence of the 1p36DS in the French population compared to 22q11.2 deletion syndrome and trisomy 21; (2) review the postnatal phenotype related to microarray data, compared to previously publish prenatal data. Thanks to a collaboration with the ACLF (Association des Cytogénéticiens de Langue Française), we have collected data of 86 patients constituting, to the best of our knowledge, the second-largest cohort of 1p36DS patients in the literature. We estimated an average of at least 10 cases per year in France. 1p36DS seems to be much less frequent than 22q11.2 deletion syndrome and trisomy 21. Patients presented mainly dysmorphism, microcephaly, developmental delay/intellectual disability, hypotonia, epilepsy, brain malformations, behavioral disorders, cardiomyopathy, or cardiovascular malformations and, pre and/or postnatal growth retardation. Cardiac abnormalities, brain malformations, and epilepsy were more frequent in distal deletions, whereas microcephaly was more common in proximal deletions. Mapping and genotype–phenotype correlation allowed us to identify four critical regions responsible for intellectual disability. This study highlights some phenotypic variability, according to the deletion position, and helps to refine the phenotype of 1p36DS, allowing improved management and follow-up of patients.     

A role for genomic instability in cellular radioresistance?

Summary Inherent cellular radioresistance plays a critical role in the failure of radiotherapy. Although the consequences of radioresistance are well known, the molecular, biological, and cellular bases of radioresistance remain a mystery. We propose that genomic instability, the increased rate of acquisition of alterations in the mammalian genome, can directly modulate cells' sensitivity to radiation. In particular, destabilization of chromosomes occurring as a consequence of genomic instability may result in enhanced plasticity of the genome. This increased plasticity of the genome allows cells to better adapt to changes in local environment(s) during tumor progression, or improve cell survival following exposure to DNA damage encountered during radiotherapy protocols, thereby contributing to radioresistant cell populations found in tumors both before and after radiotherapy.