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Biomedical subjects

H Omran

Publications and source records attributed to H Omran.

At least 19 recordsLinked to original sources
PubMed2006

Atrial fibrillation - patients at high risk for cerebral embolism.

OBJECTIVE: Patients with atrial fibrillation (AF) have a risk of cerebral embolism. Echocardiographic parameters elevate this risk significantly. However, there is little knowledge about the long-term fate and the rate of clinically silent cerebral embolism under continued oral anticoagulation. The aims of our study were to assess prognosis of patients with AF and determine a high risk group with an increased risk of cerebral embolism under oral anticoagulation. METHODS: Consecutive patients with persistent or permanent AF and left atrial (LA) thrombi, dense spontaneous echo contrast (SEC) and/or reduced LA appendage peak emptying velocities (LAAv) were included in the study (N = 128). Patients with AF and without echocardiographic risk factors (N = 114) served as controls. All patients were examined with transesophageal echocardiography, cranial magnetic resonance imaging and clinically during a period of three years. RESULTS: During the three-year follow-up period 6 (5%) of the high risk patients had cerebral embolism with neurological deficits. 4 (3%) patients died due to embolic events and 17 (13%) patients had silent embolism as documented on MRI. In the control group 8 (7%) patients had embolic events (n = 1 clinically apparent and n = 7 silent embolism) documented on MRI, one was clinically apparent. Study patients with an event had more commonly previous thromboembolism (p < 0.0001). CONCLUSIONS: Patients with peristent or permanent AF and LA thrombi, dense SEC or reduced LAAv have an explicitly increased risk of cerebral embolism (21%) despite oral anticoagulation. Previous thromboembolic event is another important predictor for an event.

Atrial Fibrillation↗
PubMed2005

[Long-term fate of left atrial thrombi and incidence of cerebral embolism under continuous anticoagulation therapy].

PURPOSE: Patients (pts.) with atrial fibrillation (AF) and atrial thrombi are known to have an increased risk for cerebral embolism. However, little is known about the clinical course of atrial thrombi and the incidence of cerebral embolism in those patients during anticoagulation therapy. The high sensitivity of MR imaging (MRI) including diffusion-weighted imaging (DWI) suggests that this technique could provide an improved estimate of cerebral embolism associated with the presence of left atrial thrombi. The aims of this prospective study were to evaluate 1) the prevalence of clinically silent and apparent cerebral embolism in pts. with newly diagnosed AF and atrial thrombi using MRI/DWI, 2) the long-term fate of atrial thrombi under continues anticoagulation therapy and 3) the incidence of cerebral embolism during a follow-up period of 12 months with continuous anticoagulation therapy. MATERIALS AND METHODS: The study group consisted of 32 pts. with 1) newly diagnosed AF and evidence of left atrial (LA) thrombi detected by TEE and 2) a new start of anticoagulation therapy [International Normalized Ratio (INR) 2.0 - 3.0]. 19 pts. with 1) newly diagnosed AF and no evidence of atrial thrombi and 2) an equivalent anticoagulation regimen served as the control group. In both groups a) MRI/DWI studies of the brain (weeks 0, 4, 8, 12, 20, 28, 36, 44, and 52), b) transesophageal echocardiographic studies (TEE) for assessment of LA-Thrombi (weeks 0 and 52) and c) clinical neurological assessments (weeks 0, 20 and 52) were performed. RESULTS: In the study group (AF and LA-Thrombi) 11 out of 32 pts. (34 %) displayed signs of acute (n = 8) or chronic (n = 3) cerebral embolism in the initial MRI studies. In 4 out of 32 pts. (13 %), MRI/DWI depicted new or additional cerebral emboli (n = 12) during the follow-up period despite continuous anticoagulation therapy. 2 (n = 2/4; 50 %) of these patients had clinically apparent neurological deficits. In the control group 1 out of 19 pts. (5 %) showed evidence of chronic cerebral embolism as assessed by MRI/DWI at the beginning of the study (week 0). No embolic cerebral lesions were detected during the 12-month follow-up. Within 12 months only 63 % (n = 20/32) of LA thrombi in the study group resolved completely under anticoagulation. CONCLUSION: 1. The incidence of clinically inapparent cerebral emboli in pts. with newly diagnosed AF and atrial thrombi is much higher than the incidence of clinically apparent emboli and has been underestimated in the past. 2. New cerebral embolism may occur even with continued effective anticoagulation therapy in 13 % of pts. 3. Only 63 % of atrial thrombi resolve completely within 12 months under anticoagulation therapy.

Aged↗
PubMed2005

Congenital myopathy with arrest of myogenesis prior to formation of myotubes.

We report a novel type of congenital myopathy, which is characterized by an early arrest of muscle formation prior to formation of myotubes. A female infant born prematurely at 32 weeks of gestational age died after six weeks of continuous ventilatory support. Various muscle specimens including quadriceps, deltoid, pectoral, neck, psoas, tongue, and diaphragm musculature were studied. Light and electron microscopy revealed well-demarcated fascicular structures interspersed with undifferentiated, mononuclear myogenic cells. Multinucleated myotubes and muscle fibres were not detectable, pointing towards a defect prior to the generation of myotubes during myogenesis. Immunohistochemistry identified the absence of dystrophin, N-CAM, MyoD and myogenin expression in these myogenic cells, compatible with a block of the complex transcriptional network necessary for correct embryonic muscle formation at an early stage of muscle development. These myopathological findings were absent in cardiac muscle, indicating that the defect exclusively affects skeletal muscle formation.

Female↗
PubMed2005

Possible genotype-phenotype correlations in children with mild clinical course of Canavan disease.

Canavan disease is characterised as a rare, neurodegenerative disease that usually causes death in early childhood. It is an autosomal recessive disorder due to an aspartoacylase (ASPA) deficiency. The causative gene has been mapped to chromosome 17 pter-p13. Here we describe three affected children from two Greek families with an unusually mild course of Canavan disease. All children presented with muscular hypotonia and macrocephaly. Diagnosis was based on elevated N-acetylaspartate in urine, reduced aspartoacylase activity in fibroblasts, and marked white matter changes on cerebral imaging. All three affected individuals exhibited continuous psychomotor development without any regression. Genetic analyses revealed compound heterozygous mutations (Y288 C; F295 S) in two individuals. The Y288 C variant was previously described in a child with macrocephaly, mild developmental delay, increased signal intensity in the basal ganglia, partial cortical blindness and retinitis pigmentosa, and slightly elevated N-acetylaspartate in the urine. Demonstration of the same variant in two unusually mildly affected Canavan disease patients and absence of this variant in 154 control chromosomes suggest a possible pathogenic role in mild Canavan disease. In the third individual, two homozygous sequence variants were identified, which comprise the known G274R mutation and a novel K213E variant.

Adolescent↗
PubMed2003

[Biventricular thrombi dissolution and antibody development with lepirudin therapy].

HISTORY AND ADMISSION FINDINGS: A 50-year-old patient presented with clinical symptoms of heart failure with orthopnoe and edema (NYHA IV). INVESTIGATIONS: Echocardiography revealed a dilated left ventricle with severely reduced left ventricular function and biventricular floating thrombi, due to dilatative cardiomyopathy. TREATMENT AND COURSE: With a heart failure medication clinical symptoms reduced and body weight decreased > 10 kg in 3 weeks. Due to the high-risk constellation, anticoagulation was performed with lepirudin and the biventricular thrombi were dissolved within 17 days. At this point in time, the patient suffered from petechial bleedings, hemoptysis and gross hematuria. Despite breaking anticoagulation and substitution of PPSB with not measurable fibrinogen, subarachnoid hemorrhage occurred leading to exitus letalis. CONCLUSION: Lepirudin is a highly effective anticoagulant, that can induce severe hemorrhagic side effects in individual cases. The present case report demonstrates an immunological reaction as a rare cause with activation of prothrombin and formation of fibrin.

Antibody Formation↗
PubMed2003

Classical infantile spinal muscular atrophy with SMN deficiency causes sensory neuronopathy.

OBJECTIVE: Classic infantile spinal muscular atrophy (SMA) is believed to be a purely motor disorder, affecting neurons of the spinal anterior horn and nuclei of the lower cranial nerves. Other organ malformations or peripheral nerve involvement have been regarded as exclusion criteria for infantile SMA. Whether SMN protein deficiency can also lead to loss of sensory neurons has not been systematically addressed. METHODS: The authors evaluated the sural nerve biopsies of 19 patients with infantile SMA of varying severity. The diagnosis of SMA was confirmed by the presence of a homozygous deletion of the SMN1 gene in all patients. RESULTS: In seven unrelated infants with SMA type I, axonal degeneration of the sural nerve was noted. Five patients showed abnormal sensory conduction, thus prompting sural nerve biopsy. Sural nerves showed different degrees of axonal loss: fiber density ranged from 3.482 to 22.076/mm2 and was markedly reduced in four patients. There was no evidence of primary demyelination: the ratio of total myelinated fiber thickness to axon diameter (g-ratio) was normal in the patients examined. In seven patients with SMA II and five patients with SMA III, no sural nerve alterations were seen, and conduction velocity was normal. In addition to SMN1 gene deletions, homozygous NAIP gene deletions were detected in six out of seven infants with peripheral neuropathy, whereas there was no evidence of a large deletion including the multicopy markers C212 and Ag1-CA in two out of three families tested. CONCLUSIONS: In this series of patients with SMA I through III who underwent sural nerve biopsy, there was significant sensory nerve pathology in severely affected patients with SMA type I, whereas there were no sensory nerve alterations clinically or morphologically in patients with milder SMA type II or III.

Axons↗
PubMed2003

[Syncope with cardiac arrest in a 30-year-old woman].

HISTORY AND ADMISSION FINDINGS: A 30-year-old woman presented with a cardiac arrest, which spontaneously converted into a regular sinus rhythm. The patient had no prior history of cardiovascular diseases. On admission, the cardiovascular clinical examination of this young female was regular. INVESTIGATIONS: On admission, discrete inferior repolarisation changes were documented which were slightly progressive during the next day. Electrophysiologic examination of the heart was regular, angiography showed a coronary fistula and an atypical descense of the circumflex artery from the right coronary artery. DIAGNOSIS: Right coronary artery fistula to the right ventricle. Atypical descense of the circumflex artery from the right coronary artery. TREATMENT AND COURSE: During hospitalisation no arrhythmias or pauses were revealed. The patient underwent cardiac pacemaker implantation. We plan a transcatheter closure of the fistula. CONCLUSIONS: Coronary fistulas are a rare cause of cardiac arrhythmias. Angiography performed at an early stage is therefore crucial in the initial assessment of a young adult presenting with cardiac arrest and subsequent changes in the ECG, as a small proportion may have coronary vascular abnormalities. The occlusion of the fistula by transcatheter or cardiac surgery is appropriate, especially as the risks of the interventions are limited.

Adult↗
PubMed2003

Identification of a novel LAMP2 mutation responsible for X-chromosomal dominant Danon disease.

Danon disease (DD) is a rare lysosomal glycogen storage disease with normal acid maltase activity, which is characterised clinically by cardiomyopathy and myopathy, and a variable degree of mental retardation. The causative gene, LAMP2, has been mapped to chromosome Xq24-q25. LAMP2 encodes a lysosome-associated membrane glycoprotein. We identified a novel LAMP2 mutation of the exon 8 splice acceptor site (IVS7-1G --> A) in an affected male and female, which predicts abnormal splicing. Both affected individuals presented solely with hypertrophic cardiomyopathy. Muscle weakness and mental impairment were absent. Diagnosis of Danon disease was established by muscle biopsy, when the male index patient developed transient severe muscle weakness following heart transplantation. Typical biopsy findings were also found in a heart muscle specimen. Demonstration of the LAMP2 mutation in affected male and female siblings is compatible with X-linked dominant inheritance. Danon disease should be actively looked for in cardiomyopathy patients.

Adult↗
PubMed2003

Atrial fibrillation: relation between clinical risk factors and transoesophageal echocardiographic risk factors for thromboembolism.

OBJECTIVE: To correlate clinical risk factors for thromboembolism with transoesophageal echocardiography (TOE) markers of a thrombogenic milieu. DESIGN: Clinical risk factors for thromboembolism and TOE markers of a thrombogenic milieu were assessed in consecutive patients with non-rheumatic atrial fibrillation. The following TOE parameters were assessed: presence of spontaneous echo contrast, thrombi, and left atrial appendage blood flow velocities. A history of hypertension, diabetes mellitus, or thromboembolic events, patient age > 65 years, and chronic heart failure were considered to be clinical risk factors for thromboembolism. SETTING: Tertiary cardiac care centre. PATIENTS: 301 consecutive patients with non-rheumatic atrial fibrillation scheduled for TOE. RESULTS: 255 patients presented with clinical risk factors. 158 patients had reduced left atrial blood flow velocities, dense spontaneous echo contrast, or both. Logistic regression analysis showed that a reduced left ventricular ejection fraction and age > 65 years were the only independent predictors of a thrombogenic milieu (both p < 0.0001). The probability of having a thrombogenic milieu increased with the number of clinical risk factors present (p < 0.0001). 17.4% of the patients without clinical risk factors had a thrombogenic milieu whereas 41.2% of the patients presenting one or more clinical risk factors had none. CONCLUSION: There is a close relation between clinical risk factors and TOE markers of a thrombogenic milieu. In addition, TOE examination allows for the identification of patients with a thrombogenic milieu without clinical risk factors.

Aged↗
PubMed2002

[Cardiac resynchronization therapy by biventricular pacing. How many patients with left ventricular dysfunction are eligible?].

BACKGROUND AND OBJECTIVE: Cardiac resynchronization therapy by multisite biventricular pacing presents an additive therapeutic option in the treatment of severe congestive heart failure. The objective of the study was to evaluate how many patients with left ventricular dysfunction may potentially benefit from this therapy. METHODS: A total of 975 patients were screened for the prevalence of left ventricular dysfunction. Patients with a left ventricular ejection fraction (LVEF) <45 % were included into the investigation. Potential benefit of biventricular pacing was presumed in the presence of: LVEF < 35 %, severe heart failure (NHYA class III or IV), intrinsic left bundle branch block pattern with QRS interval > 150 ms and the absence of atrial fibrillation in the last 3 months before study inclusion. RESULTS: In 203 patients (168 male, 35 female, mean age: 64 +/- 11) an LVEF <45 % was found. A total of 12 of these patients (6 %) or 12 of 113 patients (11 %) with an LVEF <35 % were identified as appropiate candidates for biventricular resynchronization therapy. CONCLUSIONS: Cardiac biventricular pacing currently serves as a therapeutic option for a relatively small subgroup of patients with left ventricular dysfunction. Focusing on estimations that the incidence of heart failure in Germany amounts to more than 100.000 cases per year our results suggest that after all more than 6.000 patients per year may potentially benefit from electric resynchronization therapy. This number may increase substantially if prospective studies can prove that patients with heart failure and atrial fibrillation or left ventricular conduction delay due to univentricular pacing also benefit from cardiac resynchronization therapy.

Aged↗
PubMed2002

Local intra-arterial thrombolysis in the carotid territory: does recanalization depend on the thromboembolus type?

Little is known about whether recanalization of carotid territory occlusions by local intra-arterial thrombolysis (LIT) depends on the type of the occluding thromboembolus. We retrospectively analysed the records of 62 patients with thromboembolic occlusions of the intracranial internal carotid artery (ICA) bifurcation or the middle cerebral artery who were undergoing LIT with urokinase within 6 h of symptom onset. We determined the influence of thromboembolus type (according to the TOAST criteria), thromboembolus location, leptomeningeal collaterals, time interval from onset of symptoms to onset of thrombolysis, and patient's age on recanalization. The thromboembolus type was atherosclerotic in six patients, cardioembolic in 29, of other determined etiology in four, and of undetermined etiology in 23 patients. Thirty-three (53%) thromboembolic occlusions were recanalized. The thromboembolus location but not the TOAST stroke type nor other parameters affected recanalization. In the TOAST group of patients with cardioembolic occlusions recanalization occurred significantly less frequently when transoesophageal echocardiography showed cardiac thrombus. The present study underlines the thromboembolus location as being the most important parameter affecting recanalization. The fact that thromboembolic occlusions originating from cardiac thrombi had a lower likelihood of being resolved by thrombolysis indicates the thromboembolus type as another parameter affecting recanalization.

Carotid Artery Thrombosis↗
PubMed2002

[Submillimeter 3D coronary MR angiography with real-time navigator correction in 107 patients with suspected coronary artery disease].

PURPOSE: To evaluate the clinical value of high-resolution coronary MR angiography (coronary MRA) in a large group of patients with suspected coronary artery disease. METHODS AND MATERIAL: 107 patients with suspected coronary artery disease underwent free-breathing coronary MRA (Intera, 1.5 T, Philips Medical Systems). To compensate for artefacts due to respiratory motion, a right hemidiaphragmatic navigator with real time-time slice correction was used. An ECG-gated, fat-suppressed, 3D segmented-k-space gradient echo sequence (in plane resolution 0.70 x 0.79 mm(2)) was used. Cardiac catheterization with selective coronary angiography was performed in all patients. Visualization of the coronary arteries (CA) was qualitatively assessed using a four-point grading scale. RESULTS: Image quality of grade 1 was achieved in 24 %, grade 2 in 48 %, grade 3 in 24 % and grade in in 4 % of patients. Based on an evaluation of the coronary MRAs of all patients (n = 107) sensitivity and specificity for the detection of stenoses > 60 % in the proximal and middle main coronary arteries were 74 % and 63 %, respectively. In coronary MRAs with good quality [grade 1 and 2, n = 77/107 (72 %)] sensitivity and specificity for the detection of coronary stenoses were 88 % and 91 %, respectively. CONCLUSION: Submillimeter 3D coronary MRA with real-time navigator correction allows high quality imaging of the proximal and middle main coronary arteries with good sensitivity and specificity for detection of stenoses > 50 % in selected patients. However, in about 28 % of patients image quality is severely impaired.

Adult↗
PubMed2002

[Stress cine MRI for detection of coronary artery disease].

Stress testing is the cornerstone in the diagnosis of patients with suspected coronary artery disease (CAD). Stress echocardiography has become a well-established modality for the detection of ischemia-induced wall motion abnormalities. However, display and reliable interpretation of stress echocardiography studies are user-dependent, the test reproducibility is low, and 10 to 15 % of patients yield suboptimal or non-diagnostic images. Due to its high spatial and contrast resolution, MRI is known to permit an accurate determination of left ventricular function and wall thickness at rest. Early stress MRI studies provided promising results with respect to the detection of CAD. However, the clinical impact was limited due to long imaging time and problematic patient monitoring in the MRI environment. Recent technical improvements - namely ultrafast MR image acquisition - led to a significant reduction of imaging time and improved patient safety. Stress can be induced by physical exercise or pharmacologically by administration of a beta1-agonist (dobutamine) or vasodilatator (dipyridamole and adenosine). The best developed and most promising stress MRI technique is a high-dose dobutamine/atropine stress protocol (10, 20, 30, 40 microgram/kg/min; optionally 0.25-mg fractions of atropine up to maximal dose 1 mg). Severe complications (myocardial infarction, ventricular fibrillation and sustained tachycardia, cardiogenic shock) may be expected in 0.25 % of patients. Currently, data of three high-dose dobutamine stress MRI studies are available, revealing a good sensitivity (83 - 87 %) and specificity (83 - 86 %) in the assessment of CAD. The direct comparison between echocardiography and MRI for the detection of stress-induced wall motion abnormalities yielded better results for dobutamine-MRI in terms of sensitivity (86.2 % vs. 74.3 %; p < 0.05) and specificity (85.7 % vs. 69.8 % p < 0.05) as compared to dobutamine stress echocardiography. The superior results of MRI can mainly be explained by the better image quality with sharp delineation of the endocardial and epicardial borders. Currently, stress MRI is already a realistic clinical alternative for the non-invasive assessment of CAD in patients with impaired image quality in echocardiography.

Adenosine↗
PubMed2002

Candidate gene analysis of KIAA0678 encoding a DnaJ-like protein for adolescent nephronophthisis and Senior-Løken syndrome type 3.

Nephronophthisis (NPH), an autosomal recessive cystic kidney disease, causes progressive renal failure. The gene for adolescent nephronophthisis (NPHP3) has been mapped to chromosome 3q21-->q22. Senior-Løken syndrome (SLS) describes the association of NPH and Leber congenital amaurosis. Recently a locus for Senior-Løken syndrome (SLSN3) has been localized on chromosome 3q21-->q22 containing the whole critical NPHP3 region. Within the critical NPHP3/SLSN3 region we identified the gene KIAA0678 encoding a DnaJ-like protein. KIAA0678 was considered a good functional candidate gene for NPH3 and SLS3, because molecular cha- perones are involved in the etiology of renal and retinal diseases. Analysis of the genomic structure of KIAA0678 identified 25 exons. For mutational analysis all exons and intron-exon boundaries were amplified and directly sequenced. Affected individuals of two NPH3 families and one SLS family with haplotypes indicative for homozygosity by descent for the NPHP3/SLSN3 locus were studied. No mutation in KIAA0678 was detected. We conclude, KIAA0678 most likely is not responsible for NPH and SLS in the patients studied.

Adolescent↗
PubMed2002

Identification of the human ortholog of the t-complex-encoded protein TCTE3 and evaluation as a candidate gene for primary ciliary dyskinesia.

Primary ciliary dyskinesia (PCD) is a heterogeneous autosomal recessive disease that is caused by impaired ciliary and flagellar functions. About 50% of PCD patients show situs inversus, denoted as Kartagener syndrome. In most cases, axonemal defects in cilia and sperm tails can be demonstrated by electron microscopy, i.e. PCD patients often lack inner and/or outer dynein arms in their sperm tails and cilia, supporting the hypothesis that mutations in dynein genes may cause PCD. In order to identify novel PCD genes we have isolated the human ortholog of the murine TCTE3 gene. The human TCTE3 gene encodes a dynein light chain and shares high similarity to dynein light chains of other species. The TCTE3 gene is expressed in tissues containing cilia or flagella, it is composed of four exons and located on chromosome 6q25-->q27. To elucidate the role of TCTE3 as a candidate gene for PCD a mutational analysis of thirty-six PCD patients was performed. We detected five polymorphisms in the coding sequence and in the 5' UTR of the TCTE3 gene. In one patient a heterozygous nucleotide exchange was identified resulting in an arginine to isoleucine substitution at the amino acid level. However, this exchange was also detected in one control DNA. Our results indicate that mutations in the TCTE3 gene are not a main cause of primary ciliary dyskinesia.

Amino Acid Sequence↗
PubMed2001

The impact of emission power on the destruction of echo contrast agents and on the origin of tissue harmonic signals using power pulse-inversion imaging.

The purpose of this study was to determine the impact of emission power on ultrasound (US)-induced destruction of echocontrast microbubbles during real-time power pulse inversion imaging (PPI) in myocardial contrast echocardiography (MCE) and to evaluate the magnitude of noncontrast PPI signals arising from myocardial tissue at variable emission power to define the cut-off emission power for optimal MCE using low power technologies. In vitro studies were performed in a flow phantom using Optison, Definity and AFO 150. PPI signal intensity during real-time imaging at 27 Hz was compared with intermittent imaging at 0.1 Hz to evaluate bubble destruction at variable emission power (MI: 0.09 to 1.3). In healthy volunteers, PPI signal intensities during constant infusion of Optison(R) was studied in real-time PPI 22 HZ and during intermittent imaging triggered end-systolic frames every, every 3rd and every 5th cardiac cycle. In addition, the impact of emission power on nonlinear PPI signals from myocardial structures was studied. In vitro, there was a 40% decrease of real-time PPI signal intensity for Optison and AFO 150 at lowest emission power (0.09), whereas no signal loss was observed for Definity. Increase of emission power resulted in a faster decay for Optison(R) and AFO 150 as compared to Definity. In vivo, real-time PPI during continuous infusion of Optison(R) resulted in a 40% decrease of myocardial signal intensity as compared to intermittent imaging every 5th cardiac cycle, even at lowest possible emission power (mechanical index = 0.09). There was a strong positive relationship between MI and noncontrast myocardial PPI signals in all myocardial segments. PPI signal intensity was found to be lower than 1 dB only for extremely low emission power (MI < 0.2). Destruction of microbubbles during real-time imaging by use of PPI at low emission power varies considerably for different echo contrast agents. However, bubble destruction and the onset of tissue harmonic signals focus the use of real-time perfusion imaging to very low emission power.

Adult↗