Electrocardiographic changes in cases of duchenne muscular dystrophy

BackgroundDuchene muscular dystrophy is an x-linked recessive progressive muscular disease. It presents in first year of life and is fatal by second decade mostly because of respiratory involvement and in 10% case because of cardiac failure. The cardiac involvement usually occurs after 10 years age. The incidence of cardiac involvement increases with increasing age affecting all patients by age of 18 years.Duchene muscular dystrophy(DMD) usually leads to dilated cardiomyopathy (DCM), congestive cardiac failure, arrhythmias, & sudden cardiac death. DMD may be associated with various ECG changes like sinus tachycardia, reduction of circadian index, decreased heart rate variability, short PR interval, right ventricular hypertrophy, S-T segment depression and prolonged QTc. Rarely it might be associated with Wolf Parkinson White syndrome(WPW syndrome). WPW syndrome is characterized by short PR interval, delta wave, and wide QRS complex and is a surface evidence of accessory pathway. It might be associated with supraventricular tachycardia and sudden cardiac death from ventricular tachycardia.AimTo study ECG findings in cases of Duchenne muscular dystrophy. Materials and methodsThe study was conducted at Pediatric cardiology department, Prince Salman Heart Centre Riyadh. All patients diagnosed as Duchenne muscular dystrophy were included in the study. The diagnostic criteria were clinical, biochemical and confirmed by PCR. All patients underwent 12 lead ECG and long lead II in recumbent posture and 24h holter monitoring and echocardiogram. The 24h holter was applied to all patients. The were given a diary to record any symptoms like palpitation, syncope, chest pain or dyspnea during 24 holter monitoring. The holters were reviewed for heart rate and presence of any ectopics or arrhythmias. The electrocardiogram of all patients were reviewed and following parameters were noted ; characteristics heart rate, R waves, waves, R–S ratio, PR interval, delata wave, Q waves, QT interval, T wave, ST segment. The aforementioned ECG parameters were studied and measured manually and compared with published standard age matched normal values. The abnormal were findings were defined if were away from minimal or maximal limits for that age.ResultsA total of 20 patients were studied. All were male. The mean age of patients was 10 years. The mean weight of patients was 34.5kg. Majority of patients (75%) were where wheelchair bound and 25% were ambulatory. The ECG abnormalities were noted in 80% of patients. Sinus tachycardia was present in 60% of patients. Tall R waves were present in 45% of patients with RS ratio more than 1 in lead V1 as well as deep S waves in leads V5 and V6.Short PR interval was noted in 3(15%) of patients. One patient had was diagnosed as WPW syndrome and had short PR interval, delta wave and wide QRS complex. 24h holter monitoring was normal in all patients.DiscussionThe most frequent electrocardiographic findings described in cases of Duchenne muscular dystrophy are sinus tachycardia and tall R waves in right precordial leads as seen in our study. Similar findings are also observed in female carriers of Duchenne muscular dystrophy gene. The presence of sinus tachycardia may suggest cardiac dysfunction or autonomic dysregulation in these cases. Other interesting finding in our cases was short PR interval in 3 cases(15%) and presence of WPW syndrome features in one patient. We planned further study in these patients to correlate clinical, biochemical, echo and ECG findings

Optimization of thermal design and geometrical parameters of a flat tube-fin adsorbent bed for automobile air-conditioning

Adsorbent bed design and performance strongly affect the overall performance of adsorption systems. In the present study, an analytical model was developed to determine the optimum geometrical and thermal parameters of a flat tube-fin adsorbent bed to reach the maximum system performance. This types of heat exchangers offer substantial reduced in weight, cost, volume and thermal conductivity, which can make them a good choice for adsorbent beds in automobile applications. Results showed that the overall thermal conductance of the bed and the maximum practical specific cooling capacity increased when reducing in flat tube thickness and fin pitch as well as by increasing in fin thickness and water channel wall thickness. The specific thermal conductance increased by 2.5% when reducing the channel pitch from its design value to a minimum permissible (0.004 m). From thermal parameters that have been studied, the adsorbent thermal conductivity is the most sensitive parameter to the specific thermal conductance in beds. The system performance also significantly enhanced by reducing the mass of the metal bed and the heat transfer fluids as well as the desorption heat of the selecting working pair. (C) 2016 Elsevier Ltd. All rights reserved.This work has been partially supported by the Thermally Operated Mobile Air Conditioning Systems (TOPMACS).Verde Trindade, M.; Harby Mohamed Abd Alaal, K.; Corberán, JM. (2017). Optimization of thermal design and geometrical parameters of a flat tube-fin adsorbent bed for automobile air-conditioning. Applied Thermal Engineering. 111:489-502. https://doi.org/10.1016/j.applthermaleng.2016.09.099S48950211

Clinical, biochemical, cellular and molecular characterization of mitochondrial DNA depletion syndrome due to novel mutations in the MPV17 gene

Mitochondrial DNA (mtDNA) depletion syndromes (MDS) are severe autosomal recessive disorders associated with decreased mtDNA copy number in clinically affected tissues. The hepatocerebral form (mtDNA depletion in liver and brain) has been associated with mutations in the POLG, PEO1 (Twinkle), DGUOK and MPV17 genes, the latter encoding a mitochondrial inner membrane protein of unknown function. The aims of this study were to clarify further the clinical, biochemical, cellular and molecular genetic features associated with MDS due to MPV17 gene mutations. We identified 12 pathogenic mutations in the MPV17 gene, of which 11 are novel, in 17 patients from 12 families. All patients manifested liver disease. Poor feeding, hypoglycaemia, raised serum lactate, hypotonia and faltering growth were common presenting features. mtDNA depletion in liver was demonstrated in all seven cases where liver tissue was available. Mosaic mtDNA depletion was found in primary fibroblasts by PicoGreen staining. These results confirm that MPV17 mutations are an important cause of hepatocerebral mtDNA depletion syndrome, and provide the first demonstration of mosaic mtDNA depletion in human MPV17 mutant fibroblast cultures. We found that a severe clinical phenotype was associated with profound tissue-specific mtDNA depletion in liver, and, in some cases, mosaic mtDNA depletion in fibroblasts

Expanding the genetic heterogeneity of intellectual disability

Intellectual disability (ID) is a common morbid condition with a wide range of etiologies. The list of monogenic forms of ID has increased rapidly in recent years thanks to the implementation of genomic sequencing techniques. In this study, we describe the phenotypic and genetic findings of 68 families (105 patients) all with novel ID-related variants. In addition to established ID genes, including ones for which we describe unusual mutational mechanism, some of these variants represent the first confirmatory disease-gene links following previous reports (TRAK1, GTF3C3, SPTBN4 and NKX6-2), some of which were based on single families. Furthermore, we describe novel variants in 14 genes that we propose as novel candidates (ANKHD1, ASTN2, ATP13A1, FMO4, MADD, MFSD11, NCKAP1, NFASC, PCDHGA10, PPP1R21, SLC12A2, SLK, STK32C and ZFAT). We highlight MADD and PCDHGA10 as particularly compelling candidates in which we identified biallelic likely deleterious variants in two independent ID families each. We also highlight NCKAP1 as another compelling candidate in a large family with autosomal dominant mild intellectual disability that fully segregates with a heterozygous truncating variant. The candidacy of NCKAP1 is further supported by its biological function, and our demonstration of relevant expression in human brain. Our study expands the locus and allelic heterogeneity of ID and demonstrates the power of positional mapping to reveal unusual mutational mechanisms

The Impact of Board Characteristics on Earnings Management: UK Evidence

This thesis uses mainly the agency theory to investigate the impact of board characteristics on its effectiveness in performing the monitoring function. It consists of three empirical studies. The first study explores the impact of board characteristics; particularly independence, CEO duality, activity and size; on earnings management for a sample of FTSE 350 UK listed companies. The sample for the first study comprises 168 non-financial listed firms during the period 2010-2014. Findings show that hiring independent directors on the board mitigates earnings management, both AEM and REM. Increasing the size of the board mitigates one technique of earnings management, REM, but its effectiveness in mitigating REM rests on several factors. Moreover, CEO duality is negatively associated with REM. Finally, no significant association is found between earnings management and other board characteristics. The second study investigates the diversity of the board of directors, specifically professional background and social diversity, and its impact on the board effectiveness in performing its monitoring function. Using the same sample investigated in the first study, results indicate that board professional background diversity might have negative impacts on the board effectiveness in mitigating REM, while board social diversity is insignificantly related to earnings management. The third study focuses on the impact of diversifying the board on its effectiveness in mitigating earnings management in family businesses for a sample of FTSE All Share UK listed companies. Based on data of 32 UK family-controlled firms listed during the period 2010-2017, findings show that board professional background diversity is positively associated with earnings management, while board gender diversity is insignificantly related to earnings management. Findings for the family businesses sample still emphasize the negative implications that board diversity might have in relation to performing the monitoring function. The findings of this thesis are beneficial to regulators and policy makers as they highlight the negative implications of board diversity and ways to overcome those implications in both family and non-family settings

Water Demand Management in Jordan

Jordan is located in the Middle East in the eastern Mediterranean. It has a surface area of approximately 90,000 km2 and its population reaches 6.3 million. Jordan is one of the fourth driest countries in the World and water demand exceeds Jordan's available water resources.Annual per capita water availability has declined from 3600m3/year in 1946 to 145 m3/year today. It is estimated that the population will continue to grow from about 5.87 million in 2008 to over 7.80 million by 2022. Total projected water demand will be 1673 million cubic meters by 2022.Fifteen years of complete records for water consumption was studied to see the supply and demand variation with time. It had been noticed that water demand management will address the actual needs for water. This management program will ensure further reduction in water use, reduce water loses through the distribution supply net, prevent pollution and waste water disposal in nature, efficient use of available water resources, prudent future planning for new water re-sources and finally imposing real cost for water supply that would be acceptable. In addition to the above, public awareness program is to be put in action. Such a program should be used in schools as well as the media. The public are to be aware of the problem and how they can assist to overcome the water shortage crisis.Validerad; 2014; 20131204 (nadhir)</p

Hepatocerebral form of mitochondrial DNA depletion syndrome due to mutation in MPV17 gene

Mitochondrial DNA depletion syndromes (MDSs) are autosomal recessive diseases characterized by a severe decrease in mitochondrial DNA content leading to dysfunction of the affected organ. Autosomal recessive mutations in MPV17 have been identified in the hepatocerebral form of MDS. We describe the clinical features, biochemical and molecular results of a Saudi infant with a new mutation of MPV17 and compared the features to those of previously reported cases. We stress the importance of such rare cases particularly in countries with high consanguineous marriage rate

Water Supply Network Losses in Jordan

Water supply network losses are an international problem especially in countries suffering from water scarcitylike Jordan. Jordan is one of the poorest countries in its water resources and it is estimated to be below the waterpoverty line. Jordan is located in the Middle East and has a surface area of approximately 90,000 km2. Its populationis around 6.3 million and it is estimated that the population will be 7.8 million in 2022. The gap betweenwater supply and demand is widening due to development and a relatively high population growth rate. In addition,global climate change is expected to intensify the water shortage problem in Jordan. Thirteen years of completerecords obtained from the Ministry of Water and Irrigation were analyzed. According to these records,water losses in Jordan reach about 50%. In view of the evaluation of the data and the case study conducted inthis research, it is believed that Jordan can overcome the water shortage problem by adopting a water demandmanagement strategy. In this context, efforts should be focused on reducing water losses. If this is achieved, itwill save huge quantities of water and revenue.Godkänd; 2014; 20140214 (nadhir)</p