Publications by authors named "Walter H Johnson"

Mitral and tricuspid valves are essential for unidirectional blood flow in the heart. They are derived from similar cell sources, and yet congenital dysplasia affecting both valves is clinically rare, suggesting the presence of differential regulatory mechanisms underlying their development. Here, we specifically inactivated Dicer1 in the endocardium during cardiogenesis and found that Dicer1 deletion caused congenital mitral valve stenosis and regurgitation, whereas it had no impact on other valves.

View Article and Find Full Text PDF

Single ventricle (SV) cardiac lesions and tetralogy of Fallot (TOF) are both common forms of cyanotic congenital heart disease. With advances in perioperative care and longitudinal follow-up, survival of these patients has dramatically improved and the majority survive to adulthood. This study compares health-related quality of life (HRQoL) of adult SV and TOF patients to each other and the general population.

View Article and Find Full Text PDF

Biology and biochemistry students must learn to visualize and comprehend the complex three-dimensional (3D) structures of macromolecules such as proteins or DNA. However, most tools available for teaching biomolecular structures typically operate in two dimensions. Here, we present protocols and pedagogical approaches for using immersive augmented reality (AR) visors, specifically the Microsoft HoloLens, to reinforce learning with large scale 3D holographic structures.

View Article and Find Full Text PDF

The Adult Congenital and Pediatric Cardiology (ACPC) Section of the American College of Cardiology sought to develop quality indicators/metrics for ambulatory pediatric cardiology practice. The objective of this study was to report the creation of metrics for patients with Kawasaki disease. Over a period of 5 months, 12 pediatric cardiologists developed 24 quality metrics based on the most relevant statements, guidelines, and research studies pertaining to Kawasaki disease.

View Article and Find Full Text PDF

Introduction: Knowledge gaps exist in the life expectancy and functional outcome of patients with congenitally corrected transposition (ccTGA) presenting early in life, which is relevant in the evaluation of early anatomic repair.

Methods: In a single-center analysis, 91 patients with ccTGA were identified over 25 years, of which 31 presented with biventricular anatomy in the first year of life and formed the study cohort. End points for analysis included survival, moderate or worse tricuspid valve regurgitation, and systemic right ventricle (RV) dysfunction.

View Article and Find Full Text PDF

Postpartum uterine disease due to poor uterine involution continues to be a significant factor that contributes to poor reproductive efficiency in dairy cattle. Therapy that increases the frequency, duration and strength of uterine contractions in the postpartum period might enhance uterine involution, resulting in improved reproductive performance. The objective of this clinical trial was to study the effect of two uterine ecbolic therapies, oxytocin and prostaglandinF2α on uterine involution, postpartum endometritis, and reproductive performance.

View Article and Find Full Text PDF

Girls and women with Turner syndrome face a lifelong struggle with both congenital heart disease and acquired cardiovascular conditions. Bicuspid aortic valve is common, and many have left-sided heart obstructive disease of varying severity, from hypoplastic left-sided heart syndrome to minimal aortic stenosis or coarctation of the aorta. Significant enlargement of the thoracic aorta may progress to catastrophic aortic dissection and rupture.

View Article and Find Full Text PDF

Persistence of the oxytocin receptor (OTR) in the bovine uterus during the first 7 d after calving was investigated by means of immunohistochemical staining. Immunoreactive OTRs were present in different locations in the uterus on almost all days except day 2, when staining was seen only in the endothelium of blood vessels in the endometrium and myometrium. This finding supports the hypothesis that oxytocin may be ecbolic in cows through the 1st week post partum, but further studies are required to assess the receptor functionality during this period.

View Article and Find Full Text PDF

Background: The goal of this statement was to review the available literature on surveillance, screening, evaluation, and management strategies and put forward a scientific statement that would comprehensively review the literature and create recommendations to optimize neurodevelopmental outcome in the pediatric congenital heart disease (CHD) population.

Methods And Results: A writing group appointed by the American Heart Association and American Academy of Pediatrics reviewed the available literature addressing developmental disorder and disability and developmental delay in the CHD population, with specific attention given to surveillance, screening, evaluation, and management strategies. MEDLINE and Google Scholar database searches from 1966 to 2011 were performed for English-language articles cross-referencing CHD with pertinent search terms.

View Article and Find Full Text PDF

A novel technique of valve-sparing aortic root replacement was applied to 2 children younger than 3 years of age with Marfan syndrome and large aortic root aneurysms. Using elements of both the remodeling and reimplantation techniques, circumferential rings from a 20-mm to 22-mm polyester graft provide stabilization at the subannular and sinotubular levels, and bovine pericardial patches create pseudosinuses. Follow-up at 2 years in 1 patient and 7 months in a second patient revealed satisfactory valve function with stable aortic root size.

View Article and Find Full Text PDF

Background: The widespread use of anthracycline chemotherapy has contributed to improved outcomes in children with cancer. The most feared complication of the anthracyclines is cardiotoxicity. Routine echocardiographic monitoring typically is used before, during, and after treatment to minimize cardiotoxicity.

View Article and Find Full Text PDF

Purpose: To analyze serum cytokine levels in subjects with different stages of AMD and to study the expression of salient cytokines in postmortem eyes with AMD.

Methods: A suspension array system was used to analyze sera (n = 18 to 20/group) from control subjects and those with early AMD (AREDS stage 1), intermediate dry AMD (AREDS stage 3), advanced AMD with geographic atrophy (GA), or neovascular AMD (CNV). Postmortem eyes with AMD or control eyes were examined immunohistochemically for expression of IP-10 and eotaxin (n = 4 to 8/group).

View Article and Find Full Text PDF

Objective: In 1990, Fontan, Kirklin, and colleagues published equations for survival after the so-called "Perfect Fontan" operation. After 1988, we evolved a protocol using an internal or external polytetraflouroethylene tube of 16 to 19 millimetres diameter placed from the inferior caval vein to either the right or left pulmonary artery along with a bidirectional cava-pulmonary connection. The objective of this study was to test the hypothesis that a "perfect" outcome is routinely achievable in the current era when using a standardized surgical procedure.

View Article and Find Full Text PDF

Animal models have played an important part in establishing our knowledge base on reproduction, development, and the occurrence and impact of chromosome abnormalities. Translocations involving the X chromosome and an autosome are unique in that they elicit sex-dependent infertility, with male carriers rendered sterile by synaptic anomalies during meiosis, whereas female carriers conceive but repeatedly abort. Until now the limited access to relevant fetal oocytes has precluded direct study of meiotic events in female carriers.

View Article and Find Full Text PDF

This study compares cytobrush and lavage techniques for the assessment of endometrial cytology (EC) in clinically normal postpartum dairy cows. The EC samples were collected from Holstein cows (n = 35) during visit 1 (V1) at 20 to 33 d in milk (DIM) and 2 wk later during visit 2 (V2) at 34 to 47 DIM by using both techniques. A minimum of 100 cells were counted to determine the percentage of cells that were neutrophils (%PMN).

View Article and Find Full Text PDF

Background: Unexplained left ventricular hypertrophy often prompts the diagnosis of hypertrophic cardiomyopathy, a sarcomere-protein gene disorder. Because mutations in the gene for AMP-activated protein kinase gamma2 (PRKAG2) cause an accumulation of cardiac glycogen and left ventricular hypertrophy that mimics hypertrophic cardiomyopathy, we hypothesized that hypertrophic cardiomyopathy might also be clinically misdiagnosed in patients with other mutations in genes regulating glycogen metabolism.

Methods: Genetic analyses performed in 75 consecutive unrelated patients with hypertrophic cardiomyopathy detected 40 sarcomere-protein mutations.

View Article and Find Full Text PDF

Previous studies have identified mutations in five ion channel genes as a cause of long QT syndrome, a heterogeneous disorder characterized by prolongation of the QT interval, multiform ventricular tachycardia (torsades de pointes), seizures, syncope, and sudden death. However, in these studies, the average age of initial symptoms is in the third decade of life or later, and few reports have described the genetic causes of long QT syndrome presenting in the prenatal or neonatal period. We used a candidate gene approach to identify the genetic cause of long QT syndrome in an infant whose initial manifestations were detected in utero.

View Article and Find Full Text PDF

Pulmonary vasospasm and hypertension may occur after repair or palliation of congenital cardiac defects, and can be fatal in spite of conventional treatment. Nitric oxide has been shown to improve pulmonary hypertension unresponsive to conventional measures after a variety of repairs, but use has infrequently been reported after palliative systemic to pulmonary artery shunts. We report a case of pulmonary hypertension and life threatening desaturation after a modified Blalock-Taussig shunt that responded rapidly to inhaled nitric oxide.

View Article and Find Full Text PDF

The objective of this study was to investigate parenteral vitamin E for the prevention of peripartum disease in dairy cows. A randomized clinical trial was conducted in 21 commercial dairy herds. Cows (n = 1142) were randomly assigned to receive either a single subcutaneous injection of 3000 IU of vitamin E, or placebo, 1 wk before expected calving.

View Article and Find Full Text PDF

To obtain reliable thermodynamic data on substituted triazines, it is necessary to use a calorimeter that is capable of high precision with small quantities of sample and in which a homogeneous solution of the corrosive combustion products can be maintained. The enthalpies of combustion of six substituted triazines have been determined in a platinum-lined adiabatic rotating bomb calorimeter. These are the first determinations of enthalpies of combustion or formation to have been reported for these compounds.

View Article and Find Full Text PDF

The enthalpies of combustion and formation of 2,2'-dichlorethyl sulfìde (mustard gas) have been determined by combustion in an adiabatic rotating-bomb calorimeter. The bomb process has been corrected to: for which the following values were obtained: .

View Article and Find Full Text PDF

The enthalpy of combustion of thianthrene (diphenylene disulfide) has been determined in an oxygen-bomb calorimeter. The enthalpy of formation has been derived using data from the available literature. The results obtained are as follows: A comparison is given of the results of this investigation with those of previous investigators.

View Article and Find Full Text PDF

The enthalpy of combustion of cholesterol was measured in an adiabatic, rotating-bomb calorimeter capable of high precision with relatively small samples. The random error for the experimental measurements was 0.006 percent which may be compared with approximately 0.

View Article and Find Full Text PDF

The enthalpies of combustion of acetanilide and urea have been determined in an oxygen-bomb calorimeter. The following values and their estimated uncertainties were obtained. [Table: see text].

View Article and Find Full Text PDF

The enthalpies of combustion and formation of one sample of ortho- and two samples of parafluorobenzoic acids have been determined by combustion in an oxygen-bomb calorimeter. The data obtained by other investigators are discussed briefly. The values obtained and their estimated uncertainties are as follows: [Table: see text] where Δ° corresponds to the reaction: .

View Article and Find Full Text PDF

A PHP Error was encountered

Severity: Warning

Message: fopen(/var/lib/php/sessions/ci_session66o78o6d9uc9c3p46db962n7hi0np43l): Failed to open stream: No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 177

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once

A PHP Error was encountered

Severity: Warning

Message: session_start(): Failed to read session data: user (path: /var/lib/php/sessions)

Filename: Session/Session.php

Line Number: 137

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once