The proband was a Noonan syndrome child who had a prolonged activated partial thromboplastin time and low level activities in factors V, VII, VIII, IX, XII, high molecular weight kininogen and plasma prekallikrein. The protein C in plasma of the proband and his healthy father was characterized by normal antigen and amidolytic activity levels but low anticoagulant activity. This suggested that they are type II protein C deficient (Protein C Sakaiminato). DNA sequence analyses of all coding regions in the protein C gene derived from them revealed a substitution from G to A at position 10365 in exon IX (Plutzky J, et al. 1986). This mutation abolished a Sfc I restriction site by changing the nucleotide sequence CTACAG to CTACAA. Thus, in heterozygotes of this mutation, the proband and his father, Sfc I cleavage of PCR-amplified DNA fragments including the mutation site yielded both an undigested 620bp fragment from the mutant allele and the digested 437bp and 183bp fragments from normal allele. This mutation was predicted to cause the substitution of Ser250 (AGC) to Asn (AAC). This region was considered as an exosite which is responsible for the binding of activated protein C to macromolecular substrates such as factors Va and VIIIa. Therefore, this mutation would result in the defect of the substrate recognition mechanism of activated protein C. Furthermore, the Ser250 Asn substitution was predicted to cause the loss of one consensus sequence for glycosylation (Asn248-Tyr-Ser). The influence of a sugar chain delation at Asn248 on the maturation process, catalytic properties or stability of protein C should be studied further in detail.

View full abstract

Plasma IL-6 and D-dimer levels were studied by enzyme immunoassay in 25 patients with ischemic heart disease (IHD) and 29 normal controls. The severity of coronary arterial disease was evaluated by coronary artery angiography. IL-6 (6.0±8.7pg/ml) and D-dimer (186±163ng/ml) concentrations were significantly higher in patients with IHD than in nomal controls with p values of 0.0005 and 0.02, respectively. Plasma D-dimer level was higher in 9 patients with high IL-6 concentration (≥4pg/ml) than in 15 patients with normal IL-6 concentration (<4pg/ml). It was also higher in 16 patients (231±183ng/ml) with positive angiographic findings than in 8 patients (98±51ng/ml) with negative findings (p=0.012). Patients (9/17) with high IL-6 concentration had a positive coronary angiography more frequently than those with normal IL-6 concentration (0/8, χ2=4.60, p=0.022). These findings suggest that plasma IL-6 levels are closely related to the severity of coronary atherosclerosis.

View full abstract

Congenital factor XIII (FXIII) deficiency is a rare autosomal recessive bleeding disorder. To date 33 patients with FXIII deficiency have been reported in Japan. we examined the genetic defects in two unrelated Japanese families in which three patients had been diagnosed as congenital FXIII A subunit deficiency. Exons I-XV of the gene encoding the FXIII A subunit were individually amplified by polymerase chain reaction (PCR) and the PCR products were directly sequenced by the dideoxy termination method. The sequence analysis revealed a substitution from G to A at position 1468 in exon XI resulting in Gly461Arg in Family A, and a substitution from C to T at position 2068 in exon XIV resulting in Arg661stop in Family B. One patient of Family A was homozygote of the Gly461Arg mutation and his daughter and grandchild were heterozygote. Since this mutation did not generate or lose any restriction endonuclease recognition sites, we designed a mutagenic primer (F13E11Mut) that serves to generate a new EcoN restriction site in the amplified DNA from affected individuals, when 100 normal alleles were amplified by PCR using the F13E11Mut primer and digested by EcoN, the G to A mutation was not found in any of the normal alleles, and no other mutation was found in the remaining region of the gene encoding the FXIII A subunit. This suggests that Gly461Arg would cause a FXIII A subunit deficiency in Family A. Two patients in Family B were homozygote of the mutation Arg661stop and three other members of this family were heterozygote. This mutation has previously been reported by Mikkola et al. They observed this mutation in six of eight Finnish families and one Swedish family with congenital FXIII deficiency. Since the mutation is due to CpG dinucleotide change to TpG, a hot spot mutation site, the Arg661stop is considered to be a common cause of FXIII A subunit deficiency.

View full abstract

We retrospectively studied the correlative recurrences of deep vein thrombosis (DVT) and thrombophilia in 258 patients with DVT. Subjects were followed for 4 to 115 months (mean 34 months). Recurrences were seen in 12 of 258 patients. The presence of thrombophilia in DVT was observed in 8 of 98 patients (3 with antithrombin III deficiency, 3 with protein C deficiency, 1 with protein S deficiency, 1 with antiphospholipid syndrome), and recurrent DVT with thrombophilia was seen in 5 of 12 patients with recurrent DVT. Recurrence of DVT occured from 1 to 36 months after halting warfarin therapy. In conclusion, long term warfarin therapy is necessary for the prevention of recurrent DVT with thrombophilia.

View full abstract