Prozone-like phenomenon found in chemiluminescent enzyme immunoassay using magnetic particles for measurement of serum anti-single stranded DNA antibody titers: Definition and management.

BACKGROUND: Serum anti-single stranded DNA antibody (anti-ssDNAab) is used as a marker for systemic lupus erythematosus. We found a 'prozone-like phenomenon,' which was different from an original prozone phenomenon, in chemiluminescent enzyme immunoassay using magnetic particles for the measurement of serum anti-ssDNAab titers. We investigated mechanisms of the prozone-like phenomenon and countermeasures to prevent it from being overlooked. METHODS: This study examined 679 samples from patients tested for anti-ssDNAab titer at our hospital. In addition, the BF photometry OD value 2 (OD2), an index of optical density, was monitored simultaneously. RESULTS: The undiluted samples with a prozone-like phenomenon showed extremely lower OD2. Those samples were able to be distinguished from other samples by setting OD2 criteria based on the 95% prediction interval. Significant differences (p < 0.05) were found in the titer ratios (ten-fold diluted against undiluted) between groups with >1.5 and other groups with <1.5 for the ratios of OD2. CONCLUSIONS: We proposed two valuable methods to find a prozone-like phenomenon: one by setting OD2 criteria based on the 95% prediction interval and the other by analyzing the ratios both in titers and OD2 between undiluted and 10-fold diluted samples.

[Haplotype Analysis of Coagulation Factor VII Gene in a Patient with Congenital Coagulation Factor VII Deficiency with Heterozygous p.Arg337Cys Mutation and o.Aro413Gin Polymorphism..]

Congenital coagulation factor VII (FVII) deficiency is a rare hemorrhagic disease with an autosomal reces- sive inheritance pattern. We analyzed coagulation factor VII gene (F7) of a patient with FVII deficiency and used expression studies to investigate the effect of a missense mutation on FVII secretion. The proband, a 69-year-old Japanese woman, had a history of postpartum bleeding and excessive bleeding after dental extrac- tion. She was found to have mildly increased PT-INR (1.17) before an ophthalmic operation. FVII activity and antigen were reduced (29.0% and 32.8%). Suspecting that the proband was FVII deficient, we analyzed F7 of the patient. Sequence analysis revealed that the patient was heterozygous for a point mutation (p.Arg337Cys) in the catalytic domain and polymorphisms: the decanucleotide insertion at the promoter re- gion, dimorphism (c.525C >T) in exon 5, and p.Arg413Gln in exon 8. Haplotype analysis clarified that p.Arg337Cys was located on the p.Arg413 allele (Ml allele). The other allele had the p.Arg413Gln polymor- phism(M2 allele) which is known to produce less FVII. Expression studies revealed that p.Arg337Cys causes impairment of FVII secretion. Insufficient secretion of FVII arising from both the p.Arg337Cys/M1 allele and the p.Arg337/M2 allele might lower the FVII level of this patient(<50%). The FVII level in a heterozygous FVII deficient patient might be influenced by F7 polymorphisms on the normal allele. There- fore, genetic analyses are important for the diagnosis of heterozygous FVII deficiency.

Exercise-ankle brachial pressure index with one-minute treadmill walking in patients on maintenance hemodialysis.

BACKGROUND: The ankle-brachial pressure index (ABI) is widely used as a standard screening method for arterial occlusive lesion above the knee. However, the sensitivity of ABI is low in hemodialysis (HD) patients. Exercise stress (Ex-ABI) may reduce the false negative results. PATIENTS AND METHODS: After measuring resting ABI and toe-brachial pressure index (TBI), ankle pressure and ABI immediately after walking (Post-AP, Post-ABI) were measured using one-minute treadmill walking in 52 lower limbs of 26 HD patients. The definition of peripheral arterial occlusive disease (PAD) required an ABI value of less than 0.90, TBI value of less than 0.60, and decrease of more than 15% of the Post-ABI value and 20 mmHg of Post-AP in Ex-ABI. Computed tomographic angiography (CTA) was performed in 32 lower limbs of 16 HD patients. PAD is defined as presence of stenosis of more than 75% in the case of lesions from an iliac artery to knee on CTA. RESULTS: The accuracy of Ex-ABI (Sensitivity, 85.7%; Specificity, 77.7%) was higher than those of ABI (Sensitivity, 42.9%; Specificity, 83.3%) or TBI (Sensitivity, 78.6%; Specificity, 61.1%). CONCLUSION: Ex-ABI with one-minute treadmill walking is the most useful tool for the screening of arterial occlusive lesions above the knee in maintenance HD patients.

[Current states and future aspects of graduate schools for adult graduate students: experiences of the master's course as a medical technologist].

The educational system for medical technologists (MTs) has gradually shifted from a three-year technical school system to a four-year university system. It is worthwhile for MTs to advance to a graduate school, in order to improve their routine-work skills, performances, and also to advance their own research as well as to learn how to direct younger MTs. Recently, MTs who advance to the graduate school as adult graduate students are increasing. In this article, the current states and future aspects of the graduate school of Iwate Medical University are reported. In our Department of Central Clinical Laboratory in Iwate Medical University Hospital, three of my colleagues have completed the master's course of the graduate school as adult graduate students, and three are currently attending the school. Nevertheless, none of them has advanced to the doctor's course yet. The primary reason why they do not advance is the heavy burden on any adult graduate students physically, mentally, and financially to study in the graduate school and carry out routine duties at the same time. Thus, in order to encourage MTs to go or to graduate school education, it is important to arrange systems which will enable MTs to advance to the graduate school as adult graduate students. I believe there are three key elements to make this possible. Firstly, prepare easier access to curriculums for MTs to study special fields and learn special skills. Secondly, arrange an increase in the salary scheme depending on the degree attained from the graduate school. Thirdly, provide financial support for graduate school expenses. In conclusion, it is expected that a large number of MTs will advance to the graduate school if these changes for a better educational environment are made.