Joseph J. Billadello

Expression of creative kinase M and B mRNAs in treadmill trained rat skeletal muscle

Gastrocnemius muscle from treadmill trained rats was analyzed for creatine kinase (CK) isoenzyme activities by agarose electrophoresis and M and B CK mRNA levels by Northern blot analysis. Total CK activity in exercise-trained (143 (SD 15) U/g) and control (154 (SD 16) U/g) muscles did not differ. CK-MB increased 220% in exercised-trained muscle compared to controls. CK-B subunit mRNA increased 40%, while CK-M subunit mRNA decreased 42% in exercised-trained muscle compared to control. Thus, gene expression of CK isoenzymes appears to be partially controlled at the level of transcription following exercise training.

Potential attenuation of fibrinolysis by growth factors released from platelets and their pharmacologic implications

Increased concentrations of the fast-acting tissue-type plasminogen activator (t-PA) inhibitor attenuate the fibrinolytic activity of pharmacologically administered activators of the fibrinolytic system such as t-PA. Accordingly, it was hypothesized that augmentation of synthesis and elaboration of inhibitor from the liver, leading to increased concentrations of inhibitor in plasma, or from endothelial cells in the vicinity of thrombi undergoing lysis, leading to increased concentrations locally, may contribute to failure of pharmacologically induced thrombolysis or to early reocclusion. Because platelets are rich in transforming growth factor beta and epidermal growth factor-like activity, it was thought that release of growth factors from platelets activated in vivo could mediate increases of the inhibitor in plasma by stimulating its formation in the liver and its local release from endothelial cells in the vicinity of thrombi. If so, fibrinolysis might be rendered more effective by concomitant prevention of platelet growth factor release. Transforming growth factor beta, a major constituent of platelets, increased concentrations of the t-PA inhibitor messenger ribonucleic acid (mRNA) in human hepatoma cells in a specific and dose-dependent manner. A peak effect was seen with 5 ng/ml and a 10-fold increase in 6 hours. Release of inhibitor protein into conditioned media increased as well. Induction of the inhibitor mRNA increase was elicited by exposure as brief as 30 minutes. Cycloheximide, an inhibitor of protein synthesis, was not inhibitory. The mechanisms responsible differed from those seen with epidermal growth factor, shown previously in the laboratory to increase inhibitor mRNA. In addition, the 2 factors were synergistic. Platelet lysates elicited effects simulating those of the purified growth factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of expression of M, B, and mitochondrial creatine kinase mRNAs in the left ventricle after pressure overload in rats.

Pressure overload of the left ventricle induces synthesis of creatine kinase isoenzymes. To determine whether this response is associated with an altered pattern of creatine kinase gene expression, we induced arterial hypertension in rats by suprarenal aortic banding. After 4 days, left ventricular myocardium from hypertensive (n = 7) and normotensive, sham-operated (n = 5) rats was analyzed for isoenzyme activities by chromatography; M and B creatine kinase subunit protein by Western blot; and M, B, and mitochondrial creatine kinase mRNA by Northern blot. Although total creatine kinase activity increased in hypertensive (1,096 +/- 214 IU/g left ventricle) compared with normotensive rats (648 +/- 81 IU/g left ventricle, p less than 0.01), the relative proportions of the cytoplasmic and mitochondrial isoenzymes did not change. The mass of M and B subunits increased 1.9- and 2.7-fold, respectively, in hypertensive compared with control rats. Similarly, the mRNA for M and B subunits as well as mitochondrial creatine kinase increased 2.6-, 1.6-, and 1.8-fold, respectively, in hypertensive rats compared with control rats. Thus, increased energy requirements in acute pressure overload are met by generalized induction of creatine kinase mRNA and subunit protein and not by an isoenzyme switch.

Determination of intact-tissue glycerophosphorylcholine levels by quantitative 31P nuclear magnetic resonance spectroscopy and correlation with spectrophotometric quantification

A method for the dynamic quantification of glycerophosphorylcholine (GPC) levels in intact tissue by 31P nuclear magnetic resonance spectroscopy was developed and verified by a spectrophotometric technique. Intact tissue nuclear magnetic resonance areas were quantified utilizing an external standard and were corrected for magnetization saturation. Interactive computerized spectral fitting through Lorentzian lineshape analysis and subsequent integration with normalization to the external standard was utilized for the absolute quantification of GPC concentration. Hemodynamically and metabolically uncompromised Langendorff perfused rabbit hearts contained 1.70 +/- 0.23 mumol GPC/g wet wt. This value was not statistically significantly different from the value of 1.45 +/- 0.23 mumol GPC/g wet wt determined by an analytical technique employing glycerophosphoryl-[Me-3H]choline as an internal standard with spectrophotometric quantification. Both methods were accurate with a standard error of 11 and 10%, respectively. The recovery of internal standards utilizing the spectrophotometric technique was 95 +/- 8%. The application of these methods should facilitate the quantification of changes in tissue levels of glycerophosphorylcholine noted in several disease states.

Role of protein binding in renal elimination of leptin

objective Leptin, a hormone produced by fat which signals to the brain the extent of fat stores, is known to be eliminated from circulation primarily by the kidney. The hormone circulates in both free and protein‐bound forms, but there is little information concerning the inter‐relationship of these forms of leptin, or which form is influenced by physiological processes such as renal elimination. We studied total, free and bound concentrations of leptin in ambulatory adults undergoing catheterization for diagnosis/management of congenital cardiac disease.

Contraceptive Use and Unintended Pregnancy in Women With Congenital Heart Disease.

OBJECTIVE: To identify patterns of contraceptive use and pregnancy in an academic adult congenital cardiology practice. METHODS: In this cross-sectional study, from October 2013 through March 2014, 100 women with congenital heart disease aged 18–45 years were recruited from an academic congenital heart disease clinic and administered a survey regarding pregnancy history, contraception use, and understanding of pregnancy-related and contraceptive-related risk. The primary outcome was current use of long-acting reversible contraception, including intrauterine devices or subdermal implants. RESULTS: Of 83 sexually active women, 63 (75.9%, 95% confidence interval [CI] 65.3–85.1) reported currently using any contraceptive method, including 30 of 83 (36.1%, 95% CI 25.9–47.4) using tier I methods (typical-use failure rates of less than 1% per year) and 20 of 83 (24.1%, 95% CI 15.4–34.7) using tier II methods (typical-use failure rates of 6–12% per year). Nine of 83 (10.8%, 95% CI 5.1–19.6) reported currently using long-acting reversible contraception. Sixty-four of 141 total pregnancies (45.4%, 95% CI 31.9–58.9) were self-reported by participants as “unexpected” rather than “planned.” Only one (1.6%, 95% CI 0–4.6) of the 64 unintended pregnancies occurred when the woman was using a tier I method of contraception at the time of conception. CONCLUSION: Most women with congenital heart disease of childbearing age are sexually active. The high incidence of unintended pregnancy in this group may be related to underuse of highly effective methods of contraception. Specific counseling on tier I methods may reduce unintended pregnancies in women with congenital heart disease. LEVEL OF EVIDENCE: III

Usefulness of Medical Therapy for Pulmonary Hypertension and Delayed Atrial Septal Defect Closure

A subset of adult patients with an open atrial septal defect (ASD) have pulmonary arterial hypertension (PAH). We sought to identify predictors of response to PAH-specific medical therapy in this group. Invasive hemodynamic and clinical parameters from 12 patients with an open ASD and PAH (pulmonary vascular resistance [PVR], 8.8 ± 1.2 Wood units; mean pulmonary artery pressure, 55 ± 6 mm Hg; Qp:Qs ratio, 1.1 ± 0.1; and 6-minute walk test distance of 1,046 ± 116 feet) were analyzed. Responders (n = 5) underwent successful ASD closure at 1.3 ± 0.3 years after initiation of medical therapy and were characterized by >30% reduction in PVR (7.2 ± 1.5 to 4.6 ± 0.9 Wood units) versus <20% in nonresponders (n = 7; 9.9 ± 1.7 to 8.2 ± 1.5 Wood units, p <0.03), increased 6-minute walk test distance (1,087 ± 174 vs 1,405 ± 109 feet, p = 0.05), and higher Qp:Qs ratio after therapy (1.9 ± 0.2 vs 1.1 ± 0.2, p <0.02). Body mass index was a significant clinical predictor of response (23.3 ± 1.9 vs 30.0 ± 2.1 kg/m(2), p <0.05) and the change in arterial saturation with exercise correlated inversely with change in PVR (r = -0.739, p <0.01). In conclusion, medical therapy led to a significant improvement in hemodynamic and clinical parameters in a subset of patients with an open ASD and PAH, who were able to safely undergo delayed ASD closure.

Inferior type sinus venosus atrial septal defect: MR findings.

Atrial septal defects can occur at various levels of the interatrial septum. Sinus venosus atrial septal defect (SVASD) results from abnormal resorption of the embryologic sinus venosus, and may be of the superior or inferior type. In this paper, we describe a 46-year-old man with inferior-type SVASD who presented with arrhythmias and dyspnea. Cardiac magnetic resonance and cardiac catheterization were useful in evaluating the anatomic/functional characteristics of inferior-type SVASD and distinguishing it from unroofed coronary sinus.

Segmental analysis of congenital heart disease: putting the "puzzle" together with computed tomography.

Advances in surgical and medical treatment for congenital heart disease have resulted in greater life expectancy. As a result, there has been an increase in the utilization of cross-sectional imaging for diagnosis and management of complex congenital heart disease. This manuscript describes a morphological and sequential segmental approach to deciphering the code of complex congenital heart defects in cross-sectional imaging, mostly computed tomography. This manuscript will review approaches to differentiate types of transposition, the anatomic relationships of cardiac structures, and the application of these relationships in the description of complex congenital heart disease.

Images in cardiovascular medicine. Prinzmetal angina in an adolescent: adjunctive role of tissue synchronization imaging.

A previously asymptomatic 17-year-old male athlete presented with acute onset of left-sided chest pain that awakened him from sleep. The pain was described as “crushing,” radiated to the left arm and jaw, and associated with diaphoresis. He was evaluated in the emergency department of our hospital and was found to have an abnormal ECG with ST-segment elevation in the anterolateral leads (Figure 1A). Initial troponin I and creatine kinase-MB (CK-MB) were elevated, 5.7 ng/mL (0 …