Improvement of oligonucleotide separation using a repetto high-performance liquid chromatography recycling approach.

A new approach for the improvement of separation of oligonucleotides by recycling ion-pairing chromatography is described. In the so-called repetto process, segments of separated compounds are sequentially returned to the inlet for multiple passages through the column without a need to pass a pump and with the possibility of detecting the level of separation between individual passages. Unlike in the recently described twin-column recycle approach in which eluents are repeatedly transferred between two separation columns, with the repetto method a single column is sufficient, and the detector is not exposed to high back pressure. The repetto principle was used for the separation of synthetic oligonucleotides, resulting in a multi-fold improvement in single nt resolution of long (> 50 nt) synthetic oligonucleotide fragments with high gas chromatography (guanine-cytosine) content > 40% and their separation from impurities of the original synthesis.

Risk of delayed diagnosis in young patients with left ventricular non-compaction - a potential benefit of magnetic resonance imaging.

BACKGROUND: Left ventricular non-compaction (LVNC) is a rare form of cardiomyopathy resulting from a disorder of endomyocardial morphogenesis associated with significantly increased risk of cardiovascular morbidity and premature mortality. Despite the widespread use of echocardiography, LVNC is commonly overlooked, often due to lack of knowledge about this disorder. METHODS AND RESULTS: A complex diagnostic process and follow-up was analysed in 24 patients diagnosed with LVNC between March 2002 and February 2016 (16 boys, 8 girls; age at presentation 9 days - 18 years; follow-up 2-7 years). 17 patients were initially overlooked and followed-up for different diagnoses. After retrospective evaluation by a senior specialist in paediatric cardiology, LVNC was identified in 3 patients initially diagnosed with dilated cardiomyopathy, 11 patients followed-up with various forms of arrhythmias, and 3 patients with congenital heart disease. The diagnosis of LVNC was confirmed using magnetic resonance imaging in all patients. The classical triad of complications - heart failure, ventricular arrhythmias and systemic embolic events - was not confirmed in this study, electrocardiographic findings were abnormal in 87.5% of patients. Isolated non-compaction of the left ventricular myocardium was a dominant form of non-compaction. CONCLUSIONS: The high variability of morphological findings and clinical manifestations of LVNC results in frequent overlooking of this disorder. Therefore, it is important to make the specialists more familiar with this condition and its pathology. Magnetic resonance imaging represents a conducive method to make correct diagnosis of LVNC under several specific conditions, particularly in case of non-conclusive echocardiographic finding.

Importance of cardiovascular examination in patients with multiple lentigines: two cases of LEOPARD syndrome with hypertrophic cardiomyopathy.

Introduction LEOPARD syndrome is a rare genetic disorder characterised by lentigines, electrocardiographic conduction abnormalities, ocular hypertelorism, pulmonary stenosis, abnormal genitalia, retardation of growth and sensorineural deafness. Clinical manifestations are often mild, which may result in difficult and late diagnosis. Cardiac involvement may have a significant impact on the prognosis, however, appearance of severe abnormalities such as hypertrophic cardiomyopathy usually precedes the occurrence of multiple lentigines and may be asymptomatic. Case presentation We report two cases of LEOPARD syndrome with hypertrophic cardiomyopathy in a 10-year-old girl and an 18-year-old boy. In both cases, multiple lentigines, ocular hypertelorism and growth retardation were present. The first patient was followed up at the paediatric cardiology clinic due to the risk of progression of septal hypertrophy and pressure gradient across the left ventricular outflow tract, the second patient underwent surgery for a moderate obstruction of the left ventricular outflow tract with uncomplicated post-operative follow-up. Conclusion In both presented patients, hypertrophic cardiomyopathy was clinically silent and the murmur over the precordium was the sole cardiac abnormality revealed during routine visit. A detailed cardiologic examination should be considered in the patients with suspicion of LEOPARD syndrome since the ventricular hypertrophy is thought to precede the occurrence of lentigines and progress over time.

High performance liquid chromatography column efficiency enhancement by zero dead volume recycling and practical approach using park and recycle arrangement.

A new instrumental approach to recycling HPLC is described. The concept is based on fast reintroduction of incremental peak sections back onto the separation column. The re-circulation is performed within a closed loop containing only the column and two synchronized switching valves. By having HPLC pump out of the cycle, the method minimizes peak broadening due to dead volume. As a result the efficiency is dramatically increased allowing for the most demanding analytical applications. In addition, a parking loop is employed for temporary storage of analytes from the middle section of the separated mixture prior to their recycling.

Endothelial function in children with white-coat hypertension.

Several studies have demonstrated endothelial dysfunction in patients with essential hypertension. However, the presence of endothelial dysfunction in children with white-coat hypertension has not been studied. We evaluated the endothelial function in children with white-coat hypertension and essential hypertension using a novel method based on the assessment of flow-mediated dilation (FMD). Study involved 106 children: 30 white-coat hypertensives (age 16.3 ± 1.3 years, mean ± SD), 30 essential hypertensives (age 16.4 ± 1.3 years), and 46 healthy controls (age 16.2 ± 1.4 years). Ultrasound scans of the right brachial artery were performed using Prosound F75 Aloka system during protocol: baseline (1 min), forearm ischemia (5 min), and post-occlusion phase (3 min). FMD (%) was expressed as a change of the arterial diameter from baseline to maximum post-occlusion value and the values < 5% were considered as deficient FMD. We found significantly lower FMD in both essential and white-coat hypertension compared to control group (p < 0.05 for both) with no significant difference between the hypertensive groups. Deficient FMD was found in both hypertensive groups, but not in the control group. The occurence of deficient FMD was significantly higher in both essential and white-coat hypertensives compared to controls (p < 0.01 for both) with no significant difference between the hypertensive groups. Our findings of endothelial dysfunction indicated by impaired FMD in pediatric patients with white-coat hypertension could help to elucidate the mechanisms of the increased cardiovascular risk that could be similar as found in essential hypertension; therefore, white-coat hypertension should not be considered a benign phenomenon.

Neonatal Marfan syndrome: Report of two cases.

Marfan syndrome is rarely diagnosed in the neonatal period because of variable expression and age-dependent appearance of clinical signs. The prognosis is usually poor due to high probability of congestive heart failure, mitral and tricuspid regurgitations with suboptimal response to medical therapy and difficulties in surgical management. The authors have studied two cases of Marfan syndrome in the newborn period. Two cases of neonatal Marfan syndrome, one male and one female, were diagnosed by characteristic physical appearance. Both infants had significant cardiovascular abnormalities diagnosed by ultrasonography. Genetic DNA analysis in the second case confirmed the mutations in the fibrillin-1 gene located on chromosome 15q21 which is responsible for the development of Marfan syndrome. The boy died at six weeks of age with signs of rapidly progressive left ventricular failure associated with pneumonia. The second infant was having only mild signs of congestive heart failure and has been treated with beta blockers. At the age of 4 years her symptoms of congestive heart failure had worsened due to progression of mitral and tricuspid insufficiency and development of significant cardiomegaly. Mitral and tricuspid valvuloplasy had to be done at that time. Early diagnosis of Marfan syndrome in the newborn period can allow treatment in the early stages of cardiovascular abnormalities and may improve the prognosis. It also helps to explain to the family the serious health problem of their child.

Myocardial scarring after repair of anomalous origin of the left coronary artery from pulmonary artery.

OBJECTIVES: Prognosis of patients with anomalous origin of the left coronary artery from pulmonary artery has dramatically improved as a result of both, early diagnosis and improvements in surgical techniques. Post surgical complications are rare and most patients show quick improvement of the left ventricular performance after repair with complete functional recovery within one year after surgery. Exercise-induced electrocardiographic changes have been found in patients postoperatively and scars and perfusion deficits of the left ventricle may not be detected by standard echocardiographic evaluation. METHODS: Authors present 6 cases of anomalous origin of the left coronary artery from pulmonary artery observed at Martin Univesity Hospital and Pediatric Cardiology Clinic over the last eight-year period. In order to assess the presence of myocardial injury, cardiovascular magnetic resonance imaging with late gadolinium enhancement technique was performed in all 6 cases one year after surgical correction. RESULTS: One patient died 1.5 year after surgical treatment. One year after surgery, the heart size and myocardial functions returned to normal in all patients. Cardiovascular magnetic resonance imaging demonstrated subendocardial late gadolinium enhancement in varios segments of the left ventricle, representing myocardial fibrosis in all patients one year after surgical correction. CONCLUSION: Because of the presence of scarr tissue, the long term prognosis of these patients remains unclear. The damaged tissue may have arrhythmogenic potential, therefore close follow-up, excercise testing and avoidance of high-level sport activities may be needed.

White coat hypertension in pediatrics.

The article summarizes current information on blood pressure changes in children during clinic visit. White coat as a general dressing of physicians and health care personnel has been widely accepted at the end of the 19th century. Two problems can be associated with the use of white coat: white coat phenomenon and white coat hypertension. Children often attribute pain and other unpleasant experience to the white coat and refuse afterwards cooperation with examinations. Definition of white coat hypertension in the literature is not uniform. It has been defined as elevated blood pressure in the hospital or clinic with normal blood pressure at home measured during the day by ambulatory blood pressure monitoring system. White coat effect is defined as temporary increase in blood pressure before and during visit in the clinic, regardless what the average daily ambulatory blood pressure values are. Clinical importance of white coat hypertension is mainly because of higher risk for cardiovascular accidents that are dependent on end organ damage (heart, vessels, kidney). Current data do not allow any clear recommendations for the treatment. Pharmacological therapy is usually started in the presence of hypertrophic left ventricle, changes in intimal/medial wall thickness of carotic arteries, microalbuminuria and other cardiovascular risk factors. Nonpharmacological therapy is less controversial and certainly more appropriate. Patients have to change their life style, need to eliminate as much cardiovascular risk factors as possible and sustain a regular blood pressure monitoring.

A very rare case of late diagnosis of cor triatriatum sinistrum.

We presented a 73-year-old patient with a history of hospitalizations for heart failure as well as treatment for arterial hypertension and permanent atrial fibrillation and who was found to have cor triatriatum sinistrum in combination with bicuspid aortic valve. Patient refused surgical correction, but his condition improved on conservative therapy for heart failure and atrial fibrillation.

Prenatal diagnosis of cardiac rhabdomyoma associated with tuberous sclerosis: report of 3 cases.

Cardiac rhabdomyoma is the most common cardiac tumor in fetal life, accounting for 60-86% of primary fetal cardiac tumors. It is primarily benign, originating form myocardial muscles and consisting of immature myocytes. About 50-60% of these tumors are associated with tuberous sclerosis. In this report, we present the clinical course and discuss the importance of prenatal diagnosis of cardiac tumors and their follow-up after birth.

Congenital contractural arachnodactyly (Beals-Hecht syndrome): a rare connective tissue disorder.

Congenital contractural arachnodactyly (CCA) or Beals-Hecht syndrome (BHS) presents a very rare connective tissue disorder characterized by narrow body habitus, crumpled ears, arachnodactyly, contractures, and scoliosis. In our case report, the physical examination revealed typical physical findings to determine the physical diagnosis of BHS in contrast to negative finding on DNA analysis. From clinical point-of-view, it is important to include a complex clinical approach in making the diagnosis.

Congenital complete and partial absence of the left pericardium.

Congenital absence of pericardium is a rare malformation. We report 2 young patients with a diagnosis of congenital absence of the pericardium. The posteroanterior view of the chest X-ray showed displacement of the left cardiac border into the left hemithorax. Unusual acoustical windows and abnormal cardiac and septal motion during echocardiography suggested the diagnosis of congenital absence of pericardium. Magnetic resonance imaging definitive confirmed diagnosis of congenital absence of pericardium.

Neurofibromatosis associated with hypertrophic cardiomyopathy.

We present a case of an 18-year-old boy with neurofibromatosis type 1 and hypertrophic cardiomyopathy with systolic anteward movement of the anterior leaflet of the mitral valve. Gradient in the left ventricular outflow was 85 mm Hg secondary to subvalvular aortic stenosis with left ventricular diastolic dysfunction. The possibility of a coincidence, or a causal relationship of these 2 conditions is mentioned.

Natural course following pediatric tracheostomy.

OBJECTIVE: To describe the hospital course of pediatric posttracheostomy patients, their underlying diagnosis, and their demographic characteristics. DESIGN: Retrospective, descriptive record review. SETTINGS: Academic tertiary Pediatric Critical Care Unit. METHODS AND RESULTS: One hundred and forty-one patients 1 month to 20 years old identified and included in the study. The length of in-hospital stay ranged from 14 to 280 days. The most common indications for tracheostomy were ventilation of chronic lung disease (CLD), subglottic stenosis, or combination at 44.7% of the cases followed by neurological cases 26.2%. Patients requiring prolonged stay were more likely to have pulmonary hypertension (odds ratio [OR] = 5.43), gastrointestinal reflux (OR = 2.09), prior episodes of failure to thrive (OR = 4.17), feeding failure requiring feeding tube (OR = 3.32), and tracheitis (OR = 4.17). The chances for home ventilation requirement increased with long preoperative in-hospital ventilation time and high ventilator respiratory rate on the day of tracheostomy as 0.98 days for each preoperative day and 0.94 days for each set ventilator breath (set respiratory rate per minute). The survival rate was 98.9% for the first 30 days and 78% afterward. CONCLUSION: Chronic lung disease, subglottic stenosis, and combinations are the most common causes for tracheostomy at present followed for tracheostomy due to neurological problems. Children requiring tracheostomy have lengthy hospital stay. Establishing an accurate diagnosis helps predict the length of hospitalization and the need for home ventilation; however, in less clear cases, the length of stay can be predicted from the presence of pulmonary hypertension, reflux, and failure to thrive. The mortality rate is low at the postoperative period and increases depending upon the underline reason for tracheostomy referral.

Children with respiratory distress treated with high-flow nasal cannula.

UNLABELLED: High-flow nasal cannula (HFNC) therapy is a treatment for respiratory distress in neonates and children. In the present study, we assessed its effectiveness, comfort, and possible mechanism of action. METHODS: We reviewed records of 46 patients treated with HFNC and estimated the modified COMFORT score (7 to 35 units), the respiratory clinical scale (0 to 12 units), and the oxygen saturation level. Data were collected at time 0 (before the use of high-flow), time 2 (60 to 90 min post-application), and at time 3 (8 to 12 hours post-application). Furthermore, we measured the nasopharyngeal pressure while on continuous positive air pressure (CPAP) as well as the differences in ''lung expansion'' demonstrated by the prestudy and post-study chest x-ray. RESULTS: There were significant improvements in the modified COMFORT score (F(1,45) = 40.03, P < .05), respiratory clinical scale (F(1.69,76.15) = 121.19, P < .05), and oxygen saturation (F(2,90) = 101.54, P < .05). Application of HFNC therapy created a significant average positive expiratory pressure of 4.0 +/- 1.99 (SE) cm H(2)O. X-rays taken after initiation of HFNC showed either improved aeration of the lungs or no changes in 40 of 46 patients. Mechanical ventilation was needed in 5 of 46 patients. CONCLUSION: Our study indicates that high-flow nasal cannula improves the respiratory scale score, the oxygen saturation, and the patient's COMFORT scale. Its mechanism of action is application of mild positive airway pressure and lung volume recruitment.

Lactic acidosis in children with acute exacerbation of severe asthma.

This is a retrospective case series reporting lactic acidosis in four pediatric patients with acute severe asthma treated with nebulized beta2-agonists in a pediatric intensive care unit of a tertiary care teaching facility. During treatment with beta2-agonists, these patients developed lactic acidosis with a peak concentration of 5.2 to 13 mmol/l. Lactic acidosis improved within 24 h after discontinuation or decrease in the dosage of beta2-agonists. We conclude that the intensive use of beta2-agonists for acute severe asthma in children may be the primary and significant cause of lactic acidosis.

Atrial fibrillation associated with alcohol ingestion in adolescence: holiday heart in pediatrics.

An alcohol-naive 16-year-old male is presented with alcohol-induced atrial fibrillation. Past medical history, review of systems, and presentation were all otherwise benign. Atrial fibrillation occurred early in the intoxication at an alcohol level slightly higher than the legal limit for intoxication (153 mg/dL). His complete cardiac evaluation was otherwise normal. The atrial fibrillation was not treated aggressively and resolved as the alcohol level quickly fell to zero, consistent with his "nonalcoholic" metabolism. Complete follow-up found the adolescent with no evidence of cardiac or other disease.