Two cases of variant form angina pectoris associated with myocardial bridge--a possible relationship among coronary vasospasm, atherosclerosis and myocardial bridge.

Myocardial bridge (MB) is a congenital anomaly of the coronary artery and may occur in 5 to 12% of the human population. However, the mechanism of MB-induced myocardial ischemia is still speculative. We report 2 cases of variant form angina pectoris associated with MB in which myocardial ischemia seemed to be related to the interaction between coronary perfusion and MB. In case 1, electrocardiography during anginal attack at rest showed ST elevation in the inferior leads and MB was observed after percutaneous transluminal coronary angioplasty at the site of the right coronary artery lesion following successful dilatation. In case 2, MB of the left anterior descending coronary was located in the identical portion where coronary vasospasm was induced by intracoronary acetylcholine injection, although ischemia during the spontaneous anginal attack was limited to the inferior area of myocardium. These 2 cases suggest that MB can be, at least in some patients, one of the possible causes of the endothelial damage which seems to be related to coronary vasospasm; this was documented in both cases.     

Incidence of human parvovirus B19 DNA detection in blood donors

Summary. 1000 serum samples from blood donors were tested for human parvovirus B19 (B19) DNA by a nested PCR assay: six samples were positive for B19 DNA. The frequency was 1/167 (0-6%), considerably higher than previous surveys (0-004-0-03%). Five of the six samples were also positive for anti-B19 IgM, indicating an acute phase of infection. It is recommended to screen for B19 DNA in blood products to prevent transfusion mediated viral infection for those susceptible such as immunocompromised patients and pregnant women.     

Comparison of gastric peristalsis inhibition by scopolamine butylbromide and glucagon: evaluation by electrogastrography and analysis of heart rate variability

Background. Activation of glucagon receptors of the smooth muscle membrane suppresses gastric peristalsis. We evaluated autonomic nervous activity by two methods, electrogastrography (EGG) and analysis of heart rate variability, to compare the inhibiting effects of glucagon and scopolamine butylbromide on gastric peristalsis. Methods. Heart rate variability, EGG, and blood catecholamine levels were measured before and after administration of glucagon (G group), scopolamine butylbromide (SB group), or physiological saline (C group). Autonomic nervous function was evaluated using spectral analysis of heart rate variability, and low frequency (LF) and high frequency (HF) power; the LF/HF ratios were also determined. Results. After administration of scopolamine butylbromide, HF power, an index of parasympathetic nervous activity, decreased; and the LF/HF ratio, an index of sympathetic nervous activity, increased. In contrast, no significant change was observed in autonomic nervous activity after administration of glucagon. The peak power amplitudes of the EGG decreased significantly in the G and SB groups after intramuscular injection, but the difference between the groups was not significant. Furthermore, the dominant frequency increased significantly in the G and SB groups after injection. Serum catecholamine levels showed no significant changes after administration of scopolamine butylbromide or glucagon. Conclusions. Inhibition of gastric peristalsis by glucagon via glucagon receptors on smooth muscles did not influence autonomic nervous activity, unlike the results obtained after administration of scopolamine butylbromide. Therefore, glucagon may be safe for use with elderly patients and those with cardiopulmonary complications.     

Genetic and environmental effects on fasting and postchallenge plasma glucose and serum insulin values in Finnish twins

The aim of this study was to evaluate genetic and environmental effects on plasma glucose, insulin secretion, and resistance in Finnish twins. Altogether 151 randomly selected twin pairs were examined by the oral glucose tolerance test; 66 twin pairs were monozygotic and 85 like-sexed dizygotic. We estimated the intraclass correlation coefficients and variance components of genetic and environmental effects on waist circumference, plasma glucose, and serum insulin. For fasting insulin, the proportion of total variation accounted for by additive genetic effects (A) and nonshared environmental effects (E) were 43 and 57%, respectively. As to postchallenge insulin and waist circumference, A effects were stronger in female twins (51 and 70%, respectively) than male twins in whom no significant evidence for genetic variance was found. Of the variation in fasting glucose, A and E effects accounted for 45 and 55%, respectively. Of the variation in postchallenge glucose, E effects had a greater role (65%), compared with A effects (35%); A effects on pre- and postchallenge insulin levels were highly correlated (genetic correlation coefficient = 0.81). In conclusion, additive genetic effects are important for the insulin secretion, whereas nonshared environmental effects contribute strongly to peripheral insulin resistance.     

Diagnostic implications of elevated levels of smooth-muscle myosin heavy-chain protein in acute aortic dissection. The smooth muscle myosin heavy chain study

BACKGROUND: A rapid 30-minute assay of circulating smooth-muscle myosin heavy-chain protein has been developed as a biochemical diagnostic tool for aortic dissection. OBJECTIVE: To determine the sensitivity and specificity of this assay. DESIGN: Cross-sectional study. SETTING: 8 major cardiovascular centers in Japan. PATIENTS: 95 patients with acute aortic dissection, 48 patients with acute myocardial infarction, and 131 healthy volunteers. MEASUREMENTS: Levels of circulating smooth-muscle myosin heavy-chain protein. RESULTS: Patients with acute aortic dissection who presented within 3 hours after onset had elevated levels of circulating smooth-muscle myosin heavy-chain protein. In these patients, the assay had a sensitivity of 90.9%, a specificity of 98% compared with healthy volunteers, and a specificity of 83% compared with patients who had acute myocardial infarction; the clinical decision limit was 2.5 microgram/L. All patients with proximal lesions had elevated levels of smooth-muscle myosin heavy-chain protein, and only patients with distal lesions had decreased levels (<2.5 microgram/L). CONCLUSIONS: Levels of smooth-muscle myosin heavy-chain protein can be used to diagnose aortic dissection soon after symptom onset. The assay had the greatest diagnostic value in patients with proximal lesions.     

Absolute reliability of shoulder joint horizontal adductor muscle strength measurements using a handheld dynamometer

[Purpose] The aim of this study was to verify the absolute reliability of shoulder joint horizontal adductor muscle strength measurements using a handheld dynamometer (HHD). [Subjects and Methods] The subjects were 33 healthy college students. The measurements were made three times with the HHD fixed using a belt (BFHHD) or with the examiner’s hand (conventional method; HFHHD). The absolute reliability of measurements was verified using Bland-Altman analysis, both in the all subjects group and a group of subjects showing measurements less than a fixed limit of 30 kgf. [Results] In the <30 kgf group, a systematic bias was not observed, and BFHHD values were greater than HFHHD values. BFHHD values in the all subjects group showed a systematic bias; the 3rd measurement value was less than the maximum value obtained during the 1st and 2nd measurements. [Conclusion] For obtaining an acceptable value during clinical measurements of horizontal adductor muscle strength, single measurements obtained using an HFHHD in the case of a <30 kgf group and the maximum value of two measurements obtained using a BFHHD are reliable.Key words: Absolute reliability, Handheld dynamometer, Shoulder joint horizontal adduction strength