Possible mechanisms of mitral regurgitation in dilated hearts: A study using transesophageal echocardiography

Hypothesis: This study was undertaken to clarify the mechanisms of mitral regurgitation (MR) in dilated hearts. Methods: in all, 68 patients with dilated heart and MR, including 26 patients with dilated cardiomyopathy (DCM), 24 with prior anterior myocardial infarction (A-MI), and 18 with prior posteroinferior myocardial infarction (I-MI), as well as 25 normal subjects were examined by transesophageal two-dimensional and color Doppler echocardiography. Results: The maximum area of the MR signal in the DCM group correlated positively with the anteroposterior diameter of the mitral annulus at late systole. Although the coaptation edge length of the anterior and posterior mitral leaflets appeared shorter in dilated hearts than in the hearts of controls, a significant difference did not exist. The length of the coaptation edge correlated negatively with the maximum area of the MR signal in all dilated hearts, and characteristic systolic displacement of the coaptation point of both mitral leaflets occurred. The MI groups demonstrated anterior and posterior displacement in the direction of the short axis of the left ventricle in the A-MI and I-MI groups, respectively. However, the DCM group demonstrated inferior displacement toward the long axis of the left ventricle; its magnitude correlated positively with the maximum area of the MR signal. Conclusion: A major cause of MR in dilated hearts is mitral malcoaptation due to displacement of the coaptation point of the mitral leaflets along the long or short axis of the left ventricle. This is caused by left ventricular enlargement and/or asynergy of the left ventricular wall, rather than by a decrease in mitral coaptation edge length due to mitral annular dilation.     

Familial Creutzfeldt-Jakob Disease with a codon 200 mutation presenting as thalamic syndrome: diagnosis by single photon emission computed tomography using (99m)Tc-ethyl cysteinate dimer

The clinical features of familial Creutzfeldt-Jakob disease with a codon 200 point mutation [fCJD (E200K)] are similar to those of sporadic CJD (sCJD). MRI diffusion-weighted imaging (MRI-DWI) has been reported to be useful for the early diagnosis of CJD. We describe a Japanese fCJD (E200K) case in which thalamic symptoms were the initial manifestations. On admission, electroencephalography (ECG) showed no periodic synchronous discharge (PSD), and MRI showed no abnormalities. However, single photon emission computed tomography (SPECT) using (99m)Tc-ethyl cysteinate dimer ((99m)Tc-ECD) revealed hypoperfusion in the right thalamus. We conclude that the thalamic form of CJD tends to show no high-intensity area (HIA) by MRI-DWI, and that SPECT may be more useful for visualizing the affected area responsible for the thalamic symptoms at an early stage.     

Strong Telomerase Activity of B Lymphocyte from Mesenteric Lymph Nodes of Patients with Inflammatory Bowel Disease

Telomerase acitivity can be induced in human B lymphocytes by in vitro stimulation of their antigen receptors. To determine whether telomerase activity is induced in vivo, we analyzed telomerase activity in B lymphocytes from the mesenteric lymph nodes of patients with inflammatory bowel disease (IBD), whose lymph nodes are well known to be strongly stimulated, and from those of noninflamed controls. Seven IBD patients and 4 noninflamed controls were enrolled. Telomerase activity was assayed by telomeric repeat amplification protocol with minor modifications. The mesenteric lymph nodes from patients with IBD had stronger telomerase activity than those from controls or peripheral mononuclear cells. Isolation of CD19⁺ B lymphocytes from these lymph nodes showed that this strong activity resides in this lymphocytes subpopulation. This study provides the evidence that telomerase activity is induced in human B lymphocytes in human inflammatory disease.     

Delayed esophageal perforation after laparoscopic fundoplication in a patient with diabetes mellitus: a case report

A 55-year-old man on hemodialysis for diabetic nephropathy suffered from vomiting and hematoemesis. He was diagnosed to have reflux esophagitis with Los Angeles classification grade D, which was accompanied by a shortened esophagus and stricture. His reflux esophagitis was proton pump inhibitor resistant. Therefore, we performed laparoscopic Toupet fundoplication. Delayed esophageal perforation occurred on the ninth day postoperatively, for which he had to be reoperated. To our knowledge, there is no previous report of delayed esophageal perforation after laparoscopic fundoplication. Esophageal perforation might have been caused by denudation or attenuation of the abdominal esophagus.     

Age-related changes in the electrophysiologic properties of the atrium in patients with no history of atrial fibrillation

Although atrial fibrillation is a common arrhythmia, especially in the elderly, little is known about age-related changes in the electrophysiologic properties of the atrium. The aim of this study was to analyze the effect of aging on atrial vulnerability to atrial fibrillation. An electrophysiologic study was performed in 45 patients with no history of atrial fibrillation, Wolff-Parkinson-White syndrome, structural heart disease, or conditions with potential effects on cardiac hemodynamic or electrophysiologic function (15 females; mean age, 52 +/- 18 years; range, 14 to 84 years). The following atrial excitability parameters were assessed: spontaneous or paced (A1) and extrastimulated (A2) atrial electrogram widths, percent maximum atrial fragmentation (A2/A1 x 100), effective refractory period, wavelength index (ERP/A2), and inducibility of atrial fibrillation. Atrial fibrillation was induced in 9 patients. Percent maximum atrial fragmentation was greater (176 +/- 36 vs 137 +/- 26%, P < 0.001) and wavelength index was shorter (2.4 +/- 0.4 vs 3.2 +/- 0.9, P < 0.01) in the patients with than without inducible atrial fibrillation. However, age was similar in patients with and without inducible atrial fibrillation (47 +/- 11 vs 53 +/- 19 years, P = 0.36). Percent maximum atrial fragmentation and effective refractory period directly correlated with age (r = 0.32, P < 0.05 and r = 0.45, P < 0.001, respectively). On the other hand, wavelength index (3.1 +/- 0.9) did not correlate with age (r = -0.05, P = 0.77). This study suggests that the mechanism triggering atrial fibrillation may be very well different between older and younger patients with atrial fibrillation, because younger patients have no marked substrate for atrial fibrillation.     

Formation of N7-methylguanine in nuclear DNA and cytoplasmic RNA in mice on continuous oral administration of dimethylnitrosamine-3H solution

Summary Radioactivity in liver nucleic acids increased to a plateau in one week, and decreased slightly after 3 weeks. Radioactivity of nucleic acids in the lungs and kidneys was less than that of liver nucleic acids for the first week, but then gradually increased to the same level as the latter. However, the amount of N⁷-methylguanine in nucleic acids was 2 to 4 times more in the liver than in the kidneys and lungs after 30 days. The maximal level of N⁷-methylguanine in DNA was found after 21 days, when approximately 0.1% of guanine residues in liver DNA were methylated. Maximum methylation of RNA was also observed after 21 days. Initially methylation of liver 4S RNA was more than that of ribosomal RNA, but later the extents of methylation to the cytoplasmic RNA species became similar.

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Die Bildung von N⁷-Methylguanin in der Kern-DNS und cytoplasmatischen RNS bei Mäusen während kontinuierlicher oraler Gabe einer Lösung von Dimethyl-nitrosamin-³H

Zusammenfassung Die Aktivität der Nucleinsäuren stieg in der Leber in einer Woche zu einem Plateau an und nahm nach 3 Wochen wieder leicht ab, in Lungen und Nieren war sie in der ersten Woche geringer als in der Leber, stieg aber später zur selben Höhe wie in der Leber. Die Menge von N⁷-Methylguanin in den Nucleinsäuren war jedoch nach 30 Tagen in der Leber 2-bis 4mal größer als in Nieren und Lunge. Der höchste Spiegel von N⁷-Methylguanin in DNS fand sich nach 21 Tagen, wenn etwa 0.1% der Guaninreste in der Leber DNS methyliert waren. Maximale Methylierung der RNS wurde ebenfalls nach 21 Tagen beobachtet. Die anfängliche Methylierung von 4S RNA¹ war größer als die der ribosomalen RNS; später wurde das Ausmaß der Methylierung ähnlich dem der cytoplasmatischen RNS.

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The Abbreviations used are DMN dimethylnitrosamine - EDTA ethylenediaminetetraacetic acid disodium - SSC 0.15 M NaCl-0.015 M sodium citrate This work was partly supported by a grant from the Ministry of Education of Japan.     

Association study of human MTH1 gene polymorphisms with type 1 diabetes mellitus

Reactive oxygen species are considered to play a role in the development of diabetes mellitus and its complications. Human MTH1 (mutT homologue 1) has 8-oxo-7,8-dihydrodeoxyguanosine triphosphatase activity, which repairs oxidized forms of dGTP. This enzyme is known to have a thermolabile Met83 variant. We examined whether Val83Met polymorphism of human MTH1 gene is associated with type 1 diabetes mellitus. We recruited 156 type 1 diabetic patients (59 males and 97 females). The polymorphism was analyzed by restriction fragment length polymorphism analysis with Nsi I. The Met/Met genotype at codon 83 was very rare in both control and patient groups. Val/Met genotype tended to be more frequent in the whole type 1 diabetic patients than in controls. When subjects were divided into subgroups according to gender, there were no differences in the genotype and allele frequencies between patients and controls in males. On the other hand, in female type 1 diabetic patients, the Val/Met genotype was more frequent than in female controls (corrected P = 0.102). The Met allele was significantly more frequent in female type 1 diabetic patients than in female controls (corrected P = 0.022). Our results suggested that the Met allele at codon 83 of MTH1 gene might be involved in the development of type 1 diabetes mellitus in the Japanese female population.     

A Case of Cardiac Amyloidosis Presenting with Mid- to Late Diastolic Retrograde Flow from the Left Atrium to the Pulmonary Vein: Transesophageal Pulsed Doppler Echocardiographic Observations

A patient of cardiac amyloidosis was found to have mid-to late diastolic retrograde flow from the left atrium (LA) to the pulmonary vein. Congo-red staining was positive for amyloid in the rectal tissue. M-mode and two-dimensional echocardiograms revealed symmetric hypertrophy and typical speckled pattern of the left ventricle (LV). The LV pressure curve showed a dip and plateau configuration during diastole, and end-diastolic pressure was 28 mmHg. In addition, the LV pressure was high at mid-diastole, surpassing the pulmonary capillary wedge pressure from mid-to late diastole. The transmitral flow velocity revealed "restrictive" pattern, and the pulmonary venous flow velocity showed retrograde flow from the LA to the pulmonary vein during mid-diastole and atrial systole. It is suggested that recording of the pulmonary venous flow velocity by transesophageal pulsed Doppler echocardiography is useful for understanding the mechanism of the development of pulmonary congestion or edema.