Thyroglobulin inhibition of thyrotropin binding to thyroid plasma membrane.

The effect of thyroglobulin (TG) on binding of TSH to thyroid plasma membranes was studied in vitro. Human and bovine thyroid plasma membranes have specific binding sites for bovine [125I]TSH. The binding of [125I]TSH is inhibited by the addition of purified TG (100 ng/microgram/ml). The inhibitory mechanism appears to be noncompetitive when subjected to Lineweaver-Burk analysis. Incubation of TG with TSH did not show an interaction, as assessed by sucrose gradient centrifugation. Plasma membranes prepared from human thyroid tissue have specific binding sites for human TG, as shown by [125I]TG binding assay. The TG binding was not affected by adding low concentrations of unlabeled bovine TSH. In the presence of very high concentrations of TSH, TG binding was increased. Hemoglobin, beta-lactoglobin, and ovalbumin did not have an inhibitory effect on [125I]TSH and [125I] TG binding to membrane preparations. Both [125I]TSH and [125I]TG binding were inhibited by 10 mM neuraminic acid. These results suggested that 1) TG released from thyroid gland may have a regulatory effect on TSH binding to its specific receptor, and 2) there are specific binding sites for TG on the thyroid plasma membrane.     

Left ventricular retraining and anatomic correction in teenage patient with congenitally corrected transposition of the great arteries.

Left ventricular (LV) retraining followed by anatomical repair would be a superior alternative in patients with congenitally corrected transposition (ccTGA) having a deconditioned morphologically left ventricle (MLV); however, LV retraining in older children is a challenging task. A retraining process of the MLV in a teenage patient with ccTGA is reported here. Cardiac catheterization at 7 years of age revealed low pressure of the MLV (33/4 mm Hg) and a LV to right ventricular pressure ratio (LVp/RVp ratio) of 0.32. The first pulmonary artery banding (PAB) was performed at 10 years of age. Although the LVp/RVp ratio reached 0.68, there was no evidence of adequate LV hypertrophy. The second PAB was performed 2 years after the initial PAB, resulting in an increase in the LVp/RVp ratio to 0.93 and an adequate LV hypertrophy. The double switch procedure was successfully performed at 13 years of age. Although the ejection fraction of the MLV mildly decreased, the patient has been doing well during a follow-up period of 4 years. The MLV in the teenage patient with ccTGA was successfully trained using a retraining strategy and has sustained systemic circulation after anatomical repair.     

Early and Long-Term Outcomes in Japanese Patients Aged 80 Years or Older Undergoing Conventional Aortic Valve Replacement

In this study, we investigated the early and long-term results of conventional aortic valve replacement (AVR) in very old patients.Methods: Seventy-five patients with aortic stenosis underwent conventional AVR for patients aged 80 years.We examined early death and major adverse cardiovascular and cerebrovascular event (MACCE).Results: The operative mortality was 0% for isolated AVR and 19.2% for concomitant surgery. The postoperative survival rate and MACCE free-rate were no significant differences between the isolated AVR and the concomitant surgery. Univariate analysis confirmed that cardiac dysfunction, severe chronic kidney disease (CKD), hemodialysis, + coronary artery bypass grafting, and norepinephrine use were risk factor of early death. Univariate analysis confirmed that severe CKD, BNP >1000 pg/ml, aortic cross clamping time (ACCT) >180 min, and non-use carperitide and multivariate analysis confirmed that ACCT >180 min, and non-use carperitide were risk factor of MACCE.Conclusions: This study showed that the results of conventional AVR in very old patients were not satisfactory. However, the results obtained with isolated AVR were favorable with no operative deaths. The present study demonstrated that preoperative cardiac function, preoperative renal function, and operative factors have an important impact on early mortality and MACCE.