Mitsuru Kitano

MOLECULAR ANALYSIS OF EXTRACELLULAR-SUPEROXIDE DISMUTASE GENE ASSOCIATED WITH HIGH LEVEL IN SERUM

SummaryExtracellular-superoxide dismutase (EC-SOD) is one of the SOD isozymes mainly distributed in the extracellular fluid. In the vascular system, it is located on the endothelial cell surface according to studies on the heparin binding capacity. By measurement of serum EC-SOD levels of Japanese in healthy persons (n=103) and hemodialysis patients (n=150), 7 healthy subjects and 24 hemodialysis patients were classified into group II associated with high EC-SOD levels. By molecular analysis of the EC-SOD coding region from the group II individuals in Sweden, a single nucleotide substitution of G to C generating an amino acid change of arginine to glycine has been identified in the region associated with the heparin affinity of the enzyme. The same mutation was detected in the Japanese as a homozygote in both alleles of 2 hemodialysis patients and as a heterozygote in one allele of all the healthy group II individuals and 17 hemodialysis patients. The amino acid substitution may result in the decrease of the heparin affinity which is favorable for the existence of EC-SOD in the serum.

Polymorphism of extracellular superoxide dismutase (EC-SOD) gene: relation to the mutation responsible for high EC-SOD level in serum.

SummaryExtracellular superoxide dismutase (EC-SOD) with amino acid substitution R213G generated by the nucleotide substitution 760C→G in the heparin binding domain is responsible for the high EC-SOD level in serum. We identified the two DNA polymorphic sites in the coding region of EC-SOD gene related to the 760C→G and determined the allele frequencies. The polymorphisms were A and G at nucleotide position (nt.) 241 and C and T at nt. 280 near the N-terminal. The haplotype frequencies in Japanese were 241A280C: 0.45, 241G280T: 0.37, and 241G280C: 0.18. The haplotype of 241A280T did not exist. The mutation 760C→G must occur on the allele having the haplotype of 241G280T.

A case of thymoma protruding into the superior vena cava through the thymic vein

We describe an unusual case of an invasive thymoma protruding into the superior vena cava and left brachiocephalic vein through the thymic veins in a 64-year-old patient. The tumor was resected with a bypass of the right brachiocephalic vein and right atrium. Although this type of growth form is rare for an invasive thymoma, this case suggests that in surgical procedures for thymomas, meticulous examination of the thymic veins is necessary to avoid leaving residual tumor.

The Relationship between Tension and Length of the Aortic Adventitia Resected from the Aortic Wall of Acute Aortic Dissection.

OBJECTIVE To our knowledge, no previous study has described the measurement of the tensile strength of the human aortic adventitia. In the present study, we examined the relationship between the tension and length of the aortic adventitia resected from the aortic wall of patients with acute aortic dissection. METHODS We obtained rectangular specimens from the aortic adventitia that was resected in patients with acute aortic dissection during surgery. The specimens were placed on a tension meter (Digital Force Gauge FGS-10, SHIMPO, Kyoto, Japan) within 15 min after resection and stretched until they were pulled apart, and the tension and length were recorded. RESULTS We obtained 18 specimens during surgery from 11 cases of acute aortic dissection. When the specimen was being pulled apart, the mean tension recorded was 10.2 ± 4.9 N/cm specimen width, whereas the mean elongated length recorded was 4.2 ± 1.1 mm/cm specimen length. DISCUSSION We determined that the aortic adventitia is elastic and expandable up to 140% of its original length. This indicates that dilation of the aorta to >4.2 cm in diameter may result in a rupture if the original aortic diameter prior to dissection was 3 cm. (English translation of J Jpn Coll Angiol 2013; 53: 77-81).

Two Cases of Infected Abdominal Aortic Aneurysm

感染性腹部大動脈瘤は腹部大動脈瘤全体の0.06～3.4%,感染性動脈瘤の18%を占める.われわれは,合併症を伴う腎動脈下の感染性腹部大動脈瘤を2例経験し,診断および治療上の問題点を検討した.症例1:75歳,男性.糖尿病,高血圧あり.全身倦怠感,発熱,腹膜刺激症状があり急性虫垂炎と診断されたが,虫垂に異常なく閉腹され,CTで腎動脈下の仮性大動脈瘤と診断された.後腹膜に多量の血腫があり,瘤の内部に悪臭のある膿様の液体が貯留していた.症例2:50歳,男性.高血圧,糖尿病,肝硬変,HCV抗体陽性で食道静脈瘤を合併していた.全身倦怠感,熱発,水様性下痢,血小板減少のため入院し,CTで腎動脈下の感染性動脈瘤と診断された.大動脈分岐部右側の黒色の仮性瘤の内部は,多量の血栓と黒色の液体が貯留していた.術前血液培養はそれぞれKlebsiella pneumoniae, Methicillin-susceptible Staphylococcus aureus (MSSA)が陽性であったが,瘤壁や周囲組織の培養は陰性であった.2例とも準緊急手術であったが,局所のデブリドマンと解剖学的血行再建で幸い良好な経過を示した.しかし,感染性腹部大動脈瘤に対して,局所感染状況を把握しつつ適切な手術時期を決定することは容易ではないと考えられた.