Determinants of fasting and post-methionine homocysteine levels in families predisposed to hyperhomocysteinemia and premature vascular disease.

Elevated plasma total homocysteine (tHcy) levels, either measured in the fasting state or after oral methionine loading, are associated with an increased risk of atherothrombotic disease. Fasting and post-methionine hyperhomocysteinemia (HHC) overlap to a limited extent; both can occur as familial traits. We investigated determinants of fasting, postmethionine and delta (ie, post-methionine minus fasting levels) tHcy levels in 510 subjects of 192 HHC-prone families including 161 patients with clinical vascular disease and 349 without vascular disease. We focused on tHcy levels in relation to levels of vitamin B12, B6 and folate and the methylenetetrahydrofolate reductase (MTHFR) C677T mutation. Multivariate linear analyses adjusted for the presence of vascular disease showed that fasting tHcy was significantly related to folate and vitamin B12, and the presence of the MTHFR TT genotype and the T allele, and to age, smoking habits, and serum levels of creatinine. Both post-methionine and delta tHcy levels were related to serum folate levels, and the presence of the MTHFR TT genotype and the T allele, and to postmenopausal status, and body mass index. An interaction was found between MTHFR TT genotype and serum folate levels for both fasting and post-methionine tHcy, ie, for a given decrease in serum folate, homocysteine levels increased more in subjects with the TT genotype than in those with the CC genotype. Fasting, post-methionine and delta tHcy were higher in patients with vascular disease than in their healthy siblings, but these levels were less dependent on serum folate levels (P<0.05), whereas the effect of MTHFR genotype was stronger (P=0.01). This study found evidence that post-methionine and delta tHcy levels are not only influenced by factors affecting homocysteine transsulfuration but also by factors that affect remethylation. The explained variances of fasting, post-methionine and delta tHcy were 49%, 62%, and 78%, respectively. We also found evidence, in patients with premature vascular disease but not in their healthy siblings, for a factor that increases tHcy levels but weakens the normal inverse relation between folate and tHcy and amplifies the effect of the MTHFR genotype.     

蛋白维护与皮肤衰老

氧化蛋白聚集是细胞衰老的标志,也是导致细胞出现衰老的主要原因之一.引起氧化蛋白聚集的主要原因是持续性的蛋白氧化损伤及细胞对受损氧化蛋白清除能力的下降~([1]).细胞内氧化蛋白的清除机制通常依赖于蛋白酶体系统对氧化蛋白的降解;此外,蛋白内部还有一些其他修复机制修复受损的氧化蛋白,如蛋氨酸残基的氧化可通过蛋氨酸硫氧化物还原酶(Msrs)系统逆转.     

5q35 duplication syndrome: Narrowing the critical region on the distal side and further evidence of intrafamilial variability and expression

The key features of patients with a microduplication 5q35.2q35.3 (including the NSD1 gene) are short stature, microcephaly, mild developmental delay, behavioral problems, digital anomalies and congenital anomalies of internal organs. This core phenotype can be viewed as the reversed phenotype of Sotos syndrome, which is caused by a microdeletion in the same chromosomal region or a pathogenic variant in the NSD1 gene, and includes tall stature and macrocephaly, developmental delay, and epilepsy. Here, we report on a patient and his mother, both with a 5q35.2q35.3 duplication, adding a fifth family to the recently published overview of 39 patients of Quintero-Rivera et al. Our patient had several congenital anomalies, intrauterine growth restriction with a persisting short stature, while his mother was only mildly affected with decreased growth parameters. In addition, he had hemophagogocytic lymphohistiocytosis (HLH) triggered by Haemophilus influenzae and was recently diagnosed with Ewing sarcoma. Our cases carry the smallest duplication published (ca 332 kb, arr[hg19] 5q35.2q35.3(176493106-176824785)x3) further narrowing the distal side of the critical region of the 5q35.2q35.3 duplication. Besides broadening the clinical phenotypic spectrum, our report indicates that the 5q35.2q35.3 microduplication also shows a large intra-familial variability and expression.     

The emergence,spread and vanishing of a French SARS-CoV-2 variant exemplifies the fate of RNA virus epidemics and obeys the Mistigri rule

The nature and dynamics of mutations associated with the emergence, spread, and vanishing of SARS-CoV-2 variants causing successive waves are complex. We determined the kinetics of the most common French variant (“Marseille-4”) for 10 months since its onset in July 2020. Here, we analyzed and classified into subvariants and lineages 7453 genomes obtained by next-generation sequencing. We identified two subvariants, Marseille-4A, which contains 22 different lineages of at least 50 genomes, and Marseille-4B. Their average lifetime was 4.1 ± 1.4 months, during which 4.1 ± 2.6 mutations accumulated. Growth rate was 0.079 ± 0.045, varying from 0.010 to 0.173. Most of the lineages exhibited a bell-shaped distribution. Several beneficial mutations at unpredicted sites initiated a new outbreak, while the accumulation of other mutations resulted in more viral heterogenicity, increased diversity and vanishing of the lineages. Marseille-4B emerged when the other Marseille-4 lineages vanished. Its ORF8 gene was knocked out by a stop codon, as reported in SARS-CoV-2 of mink and in the Alpha variant. This subvariant was associated with increased hospitalization and death rates, suggesting that ORF8 is a nonvirulence gene. We speculate that the observed heterogenicity of a lineage may predict the end of the outbreak.     

T Cell Receptor Expression And Activation Of Synovial Lymphocyte Subsets In Patients With Rheumatoid Arthritis

Two-color flow cytometry analysis of peripheral blood and synovial lymphocytes from rheumatoid arthritis patients was performed using monoclonal antibodies directed against T cell subsets, T cell activation markers, and T cell receptors. The results showed an abnormally high percentage (>15%) of CD3⁺, CD4⁻, and CD8⁻ T cells expressing a specific receptor containing a γ chain. Phenotypic analysis of lymphocytes infiltrating both knee joints of individual rheumatoid arthritis patients revealed very similar subset distribution and activation levels, despite strong differences in the clinical status between the 2 sites.