Establishment and Magnetocardiographic Changes of Pressure Overload Left Ventricular Hypertrophy and Its Regression in Rats

BACKGROUND AND OBJECTIVES: Regression of left ventricular hypertrophy (LVH) is important because development of myocardial ischemia, heart failure or arrhythmias may be reduced. However, an animal model for LVH regression is not well established and there are no useful parameters to predict LVH regression. Magnetocardiogram (MCG), magnetic signal generated from the heart, has recently been investigated for the detection of electrical current changes of the heart. This study was undertaken to establish rat models of LVH-regression and to assess MCG changes during LVH induction and regression. MATERIALS AND METHODS: Rat models of pressure overload LVH were established by transverse aortic constriction (TAC) and LVH regression was generated by untying 2 weeks after TAC. Hemodynamic, echocardiographic and biochemical evaluation were performed in order to confirm this model. Magnetic fields were recorded with a SQUID gradiometer before and after TAC, and also recorded at 1, 3, 7, and 14 days after untying, respectively. RESULTS: Rat models of LVH-regression were established successfully by TAC and untying. The pressure gradient across TAC disappeared within 10 minutes after untying. LV weight, LV weight/body weight ratio, LV mass and expression level of atrial natriuretic factor were significantly increased following TAC and decreased to baseline value after pressure unloading. Deeper S waves and strain patterns were observed after LVH induction and gradually returned to basal levels over the 2 weeks after untying. CONCLUSION: MCG changes in the rat models of LVH-regression indicate that MCG can be a helpful modality for the diagnosis and evaluation of LVH as well as follow-up after treatment of LVH.

Sequential changes of magnetocardiogram in rat models of experimental myocardial infarction / 대한내과학회지

BACKGROUND: Magnetocardiogram (MCG), which records the changes of magnetic fields generated by the heart's electrical activity, theoritically can provide unique data for clinical application. To date, MCG has been investigated only at a single time point after myocardial infarction (MI) with severe left ventricular dysfunction in rats. The purpose of the present study was to investigate sequential changes of MCG after MI and to evaluate effects of infarct size on MCG. METHODS: Acute MI were induced by the permanent ligation of left coronary artery in 22 rats. Magnetic fields were recorded just above a rat with Nb Superconducting Quantum Interference Device (SQUID) gradiometer inside a magnetically shielded room. MCG was measured before and immediately after surgery and it was subsequently recorded at the time points of 1, 4 and 6 hours postoperatively. MCG was also measured at 1, 3, 7 and 21 days after surgery. RESULTS: Elevation of ST segment and appearance of pathological Q wave on the MCG were evident immediately after the ligation of coronary artery and persisted to 6 hours after MI. On MCG, ST segment was depressed and T wave was inverted from 1 day after MI. In rats with small- and moderate-sized MI (infarct size or = 30%). CONCLUSION: Evolutional changes of MCG were well-recognized up to 21 days after MI. Furthermore, the infarct size can be expressed by the extent of Q wave and ST segment depression on MCG. Taken together, these data indicate that MCG is a helpful modality for the diagnosis, evaluation of infarct size and follow up after MI.

A Gastric Intramural Pancreatic Pseudocyst: An Unuaual Presentation as a Gastric Intramural Tumor / 대한소화기내시경학회지

We report a case of pancreatic pseudocyst presenting as an intramural gastric tumor on upper gastrointestinal examination, endoscopic ultrasound and computed tomography of the abdomen. Pancreatic pseudocysts in the stomach wall is rare and the most of them presented as a cystic mass, but this case was presented as a gastric mural solid tumor. Exploration revealed an about 4 4 2 cm sized round mass at the midbody of great curvature of stomach, it was in the muscle layer, and removed by surgical operation. The correct diagnosis of this case was established postoperately on the pathologic examination revealed pancreatic pseudocyst.

MTHFR gene polymorphism as a risk factor for diabetic nephropathy and macrovascular disease in NIDDM patient / 대한내과학회지

BACKGROUND: Diabetic nephropathy develops in 20-30% of patients with non-insulin dependent diabetes mellitus (NIDDM). Poor glycemic control, hypertension and duration of diabetes are known as risk factors for the development of diabetic nephropathy and there is high prevalence of diabetic nephropathy in the patients who have familial history of diabetic nephropathy, so it has been assumed that genetic factor is associated with the background of its occurences. Recently it has been observed that a cytosine to thymidine substitution of the methylenetetrahydrofolate reductase (MTHFR) gene at nucleotide 677 (C677T) was related to diabetic nephropathy in patients with NIDDM and MTHFR gene polymorphism was also known to predispose to vascular disease. This study was performed to investigate whether MTHFR gene polymorphism is associated with the development of diabetic nephropathy and macrovascular disease in NIDDM patients. METHODS: The study population consisted of 243 NIDDM patients (duration> OR = 10 years). Nephropathy was defined by 24 hour urinary protein excretion of more than 500 mg. The MTHFR gene fragment was extracted using the polymerase chain reaction. The presence of the mutation was identified by HinfI digestion, which cuts at the mutation site, followed by 2.5% metaphore agarose electrophoresis and ethidium bromide staining. Statistical differences in genotype distribution and allele frequencies among the groups were assessed by the chi-square test. RESULTS: There was no difference in clinical characteristics except the prevalence of hypertension and diabetic retinopathy between nephropathy group and non-nephropathy group. The data do not show any difference of genotype distribution or allele frequencies between patients with or without diabetic nephropathy and macrovascular disease CONCLUSION: With the above results, it is assumed that there are no significant relationships among MTHFR gene polymorphism, diabetic nephropathy, and macrovascular disease.

Two Cases of Gitelman's Syndrome Diagnosed by Renal Clearance Study / 대한신장학회잡지

We have experienced two patients who had hypokalemic metabolic alkalosis as well as hypomagnesemia and hypocalciuria with elevated plasma renin activity. We have performed renal clearance study after water loading, administration of furosemide and thiazide in two patients and two normal controls. Maximal free water clearance per 100 mL glomerular filtration rate(CH2O) and distal fractional chloride reabsorption[CH2O/(CH2O+CCl)] in our patients were reduced than the controls. Chloride clearance(CCl) was increased after furosemide administration but not after thiazide administration. Distal fractional chloride reabsorption[CH2O/(CH2O+CCl)] was dramatically decreased by furosemide administration in our patients, whereas thiazide had little effect on it. Fractional excretion of sodium, chloride, magnesium, calcium was increased by furosemide administration, whereas thiazide administration had little effect on this parameters. These findings suggested the presence of a defect in the distal convoluted tubule rather than in the thick ascending loop of Henle. Herein, we report two cases of Gitelman's syndrome diagnosed by renal clearace study after water loading, administration of furosemide and thiazide.