Quantitative Analysis of Magnetization Transfer by Phase Sensitive Method in Knee Disorder

Magnetization Transfer (MT) imaging generates contrast dependent on the phenomenon of magnetization exchange between free water proton and restricted proton in macromolecules. In biological materials in knee, MT or cross-relaxation is commonly modeled using two spin pools identified by their different T2 relaxation times. Two models for cross-relaxation emphasize the role of proton chemical exchange between protons of water and exchangeable protons on macromolecules, as well as through dipole-dipole interaction between the water and macromolecule protons. The most essential tool in medical image manipulation is the ability to adjust the contrast and intensity. Thus, it is desirable to adjust the contrast and intensity of an image interactively in the real time. The proton density (PD) and T2-weighted SE MR images allow the depiction of knee structures and can demonstrate defects and gross morphologic changes. The PD- and T2-weighted images also show the cartilage internal pathology due to the more intermediate signal of the knee joint in these sequences. Suppression of fat extends the dynamic range of tissue contrast, removes chemical shift artifacts, and decreases motion-related ghost artifacts. Like fat saturation, phase sensitive methods are also based on the difference in precession frequencies of water and fat. In this study, phase sensitive methods look at the phase difference that is accumulated in time as a result of Larmor frequency differences rather than using this difference directly. Although how MT work was given with clinical evidence that leads to quantitative model for MT in tissues, the mathematical formalism used to describe the MT effect applies to explaining to evaluate knee disorder, such as anterior cruciate ligament (ACL) tear and meniscal tear. Calculation of the effect of the effect of the MT saturation is given in the magnetization transfer ratio (MTR) which is a quantitative measure of the relative decrease in signal intensity due to the MT pulse.

Evaluation of a Apo-1/Fas promoter polymorphism in Korean stroke patients

Apoptosis has been implicated in the pathogenesis of neurodegenerative diseases such as stroke and Alzheimer's disease. Apo-1/Fas gene is one of the mediators of apoptosis in stroke. MvaI polymorphism is the first polymorphic marker identified in the Apo-1/Fas gene promoter, which was typed by PCR and followed by MvaI digestion and gel electrophoresis. DNA isolated from peripheral blood collected from 91 stroke patients and 103 healthy blood donors was used for genotypes of GG, GA and AA by sequence specific primer PCR. MvaI polymorphism was examined based on Fas gene promotor region by restriction fragment length polymorphism (RFLP). The Fas-GG genotype was the least frequent in patients with stroke and healthy controls (P = 0.57). In normal Korean controls the MvaI polymorphism GA, AA and GG were 48.6%, 34.9% and 16.5%. In stroke patients were 56.2%, 29.6% and 14.2% respectively. And the allelic frequencies of MvaI*2 (G) allele were less frequent than MvaI*1 (A) allele in patients with stroke and healthy controls (P = 0.76). In normal Korean controls MvaI*1 (A) and MvaI*2 (G) alleles were 59.2% and 40.8%. In stroke patients were 57.6% and 42.4%, respectively. Our results, pending confirmation in a larger study, indicate that the Fas genotype may not appear to be a risk factor for stroke in Korean stroke patients.

Evaluation of a Apo-1/Fas promoter polymorphism in Korean stroke patients

Apoptosis has been implicated in the pathogenesis of neurodegenerative diseases such as stroke and Alzheimer's disease. Apo-1/Fas gene is one of the mediators of apoptosis in stroke. MvaI polymorphism is the first polymorphic marker identified in the Apo-1/Fas gene promoter, which was typed by PCR and followed by MvaI digestion and gel electrophoresis. DNA isolated from peripheral blood collected from 91 stroke patients and 103 healthy blood donors was used for genotypes of GG, GA and AA by sequence specific primer PCR. MvaI polymorphism was examined based on Fas gene promotor region by restriction fragment length polymorphism (RFLP). The Fas-GG genotype was the least frequent in patients with stroke and healthy controls (P = 0.57). In normal Korean controls the MvaI polymorphism GA, AA and GG were 48.6%, 34.9% and 16.5%. In stroke patients were 56.2%, 29.6% and 14.2% respectively. And the allelic frequencies of MvaI*2 (G) allele were less frequent than MvaI*1 (A) allele in patients with stroke and healthy controls (P = 0.76). In normal Korean controls MvaI*1 (A) and MvaI*2 (G) alleles were 59.2% and 40.8%. In stroke patients were 57.6% and 42.4%, respectively. Our results, pending confirmation in a larger study, indicate that the Fas genotype may not appear to be a risk factor for stroke in Korean stroke patients.