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N Ghanem

Publications and source records attributed to N Ghanem.

At least 37 records · Page 2Linked to original sources
PubMed2001

18F-DOPA positron emission tomography for tumour detection in patients with medullary thyroid carcinoma and elevated calcitonin levels.

In spite of the availability of numerous procedures, diagnostic imaging of tumour manifestations in patients with medullary thyroid carcinoma and elevated calcitonin levels is often difficult. In the present study, the new procedure of fluorine-18 dihydroxyphenylalanine positron emission tomography (18F-DOPA PET) was compared with the established functional and morphological imaging methods. After evaluation of the normal distribution of 18F-DOPA, 11 patients with medullary thyroid carcinoma were examined using 18F-DOPA PET. Results of 18F-fluorodeoxyglucose (18F-FDG) PET, somatostatin receptor scintigraphy (SRS) and morphological tomographic imaging (CT/MRI) were available for all patients. All individual procedures were evaluated without reference to prior information. Data assessment for each patient was based on cooperation between experienced radiologists and specialists in nuclear medicine, who considered all the available findings (histological results, imaging, follow-up studies). This cooperation served as the gold standard against which the results of the individual procedures were evaluated. A total of 27 tumours were studied [three primary tumours (PT)/local recurrence (LR), 16 lymph node metastases (LNM) and eight organ metastases (OM)]. 18F-DOPA PET produced 17 true-positive findings (2 PT/LR, 14 LNM, 1 OM), 18F-FDG PET 12 (2 PT/LR, 7 LNM, 3 OM), SRS 14 (2 PT/LR, 8 LNM, 4 OM) and morphological imaging 22 (3 PT/LR, 11 LNM, 8 OM). The following sensitivities were calculated with respect to total tumour manifestations: 18F-DOPA PET 63%, 18F-FDG PET 44%, SRS 52%, morphological imaging 81%. Thus, the morphological imaging procedures produce the best overall sensitivity, but the specificity for PT/LR (55%) and LNM (57%) was low. With respect to lymph node staging, the best results were obtained with 18F-DOPA PET. 18F-DOPA PET is a new functional imaging procedure for medullary thyroid carcinoma that seems to provide better results than SRS and 18F-FDG PET. Moreover, the data indicate that no single procedure provides adequate diagnostic certainty. Therefore, 18F-DOPA PET is a useful supplement to morphological diagnostic imaging, improving lymph node staging and enabling a more specific diagnosis of primary tumour and local recurrence.

Aged↗
PubMed2001

Breathhold unenhanced and gadolinium-enhanced magnetic resonance tomography and magnetic resonance cholangiography in hilar cholangiocarcinoma.

We assessed the imaging characteristics of hilar cholangiocarcinoma in magnetic resonance imaging (MRI) and magnetic resonance cholangiography (MRC). Breathhold MRI (T2-weighted turbo spin echo sequences, unenhanced T1-weighted gradient echo sequences, and gadolinium-enhanced fat-suppressed gradient echo sequences) and breathhold MRC (fat-suppressed two-dimensional projection images) performed in 12 patients with histologically confirmed hilar cholangiocarcinoma were retrospectively reviewed for morphological tumor characteristics and contrast enhancement patterns. MRC demonstrated a significant bile duct stenosis with intrahepatic bile duct dilatation in all cases except in one patient who received an endoprothesis prior to imaging. Hilar cholangiocarcinoma was diagnosed by MRC only in one patient and MRI and MRC in 11. Mass lesions were seen in nine patients and circumferential tumor growth in three, including the patient diagnosed by MRC only. The tumor appeared hypointense relative to liver parenchyma in 10 of 11 patients in unenhanced T1-weighted images. T2-weighted sequences showed isointense or only slightly hyperintense signal in 5 of 11 patients, 3 of whom demonstrated desmoplastic reactions by histology. The other 6 patients revealed strongly hyperintense signal intensities. Contrast enhancement was increased compared to liver in 5 of 11 patients and decreased in 6 of 11 patients. MRI with MRC seem to be a sensitive tools in the detection of hilar cholangiocarcinomas. The variable imaging characteristics are most probably related to the inhomogeneous histological appearance of this tumor entity.

Aged↗
PubMed2001

Comparative detectability of bone metastases and impact on therapy of magnetic resonance imaging and bone scintigraphy in patients with breast cancer.

OBJECTIVE: to evaluate the comparative impact of magnetic resonance imaging and bone scintigraphy in bone metastases of breast cancer. METHODS AND PATIENTS: in 81 patients with histologically proven breast cancer magnetic resonance imaging of the axial skeleton and whole-body bone scintigraphy had been performed. Images were retrospectively reviewed and compared for detection of metastases, extent of metastatic disease and therapeutic implications according to the patients' records. RESULTS: about 54/81 (67%) patients revealed bone metastases. In 7/54 (13%) patients with bone metastases, scintigraphy was false negative. In one patient a solitary sternal metastases was seen. In 26/53 [49%] patients with spinal metastases, magnetic resonance imaging showed more extensive disease. Local radiotherapy or surgery was indicated in ten patients with metastases not evident in bone scintigraphy, in 20 patients with positive results by both imaging modalities and in six patients with metastases of pelvis imaged by bone scintigraphy only. CONCLUSION: magnetic resonance imaging of the axial skeleton and pelvis appears superior for staging as only one patient had metastases merely outside the axial skeleton and local therapy was indicated even in spinal regions negative in bone scintigraphy.

Bone Neoplasms↗
PubMed2001

Whole-body 18F dopa PET for detection of gastrointestinal carcinoid tumors.

PURPOSE: To evaluate fluorine 18 (18F) dopa positron emission tomography (PET) in comparison with established imaging procedures in gastrointestinal carcinoid tumors. MATERIALS AND METHODS: After evaluation of the normal distribution of 18F dopa, 17 patients with histologically confirmed tumors were examined with 18F dopa PET. Results of 2-[fluorine 18]fluoro-2-deoxy-D-glucose (FDG) PET, somatostatin-receptor scintigraphy, and morphologic imaging (computed tomography and/or magnetic resonance imaging) were available for all patients. Results of the procedures were evaluated by two radiologists and two nuclear medicine specialists, whose consensus based on all available histologic, imaging, and follow-up findings was used as the reference standard. RESULTS: Ninety-two tumors were diagnosed: eight primary tumors, 47 lymph node metastases, and 37 organ metastases. 18F dopa PET led to 60 true-positive findings (seven primary tumors, 41 lymph node metastases, 12 organ metastases); FDG PET, 27 (two primary tumors, 14 lymph node metastases, 11 organ metastases); somatostatin-receptor scintigraphy, 52 (four primary tumors, 27 lymph node metastases, 21 organ metastases); and morphologic imaging, 67 (two primary tumors, 29 lymph node metastases, 36 organ metastases). This resulted in the following overall sensitivities: 18F dopa PET, 65% (60 of 92); FDG PET, 29% (27 of 92); somatostatin-receptor scintigraphy, 57% (52 of 92); morphologic procedures, 73% (67 of 92). Although the morphologic procedures were most sensitive for organ metastases, 18F dopa PET enabled best localization of primary tumors and lymph node staging. CONCLUSION: 18F dopa PET is a promising procedure and useful supplement to morphologic methods in diagnostic imaging of gastrointestinal carcinoid tumors.

Adult↗
PubMed1999

[Adhesive capsulitis of the shoulder].

Adhesive capsulitis is a painful stiff shoulder due to the thickening of the capsule and synovium. The main observed changes are hyperhaemia of the synovium and a capsular fibrosis similar to that of Dupuytren's disease. Stiffness involves mainly flexion, lateral rotation and abduction. In most cases, a spontaneous healing is observed within 12 to 30 months. When the capsulitis is disabling and pain still present, a joint distension followed by rehabilitation can be indicated. When the disability is important and mainly due to stiffness, a manipulation under anesthesia with or without arthroscopic release of soft tissues can be indicated.

Bursitis↗
PubMed1999

Comparison between a screen-film system and a selenium radiography system. An ROC study using simulated thoracic lesions.

RATIONALE AND OBJECTIVES: To evaluate the diagnostic image quality of the hard copies of a commercially available selenium detector-based computed radiography system compared to that of a conventional screen-film system. METHODS: Ten radiographs of an anthropomorphic chest phantom with simulated nodular and linear-reticular lesions were produced using either system. Each radiograph was subdivided into 15 fields containing zero lesions, one nodular lesion, one linear-reticular lesion, or both lesions. The total of 150 fields for each modality was reviewed by six radiologists, and receiver operating analysis was performed. RESULTS: The conventional screen-film system performed significantly better for nodular lesions, whereas no statistically significant difference was found between the detection rates of both systems for linear-reticular lesions. CONCLUSIONS: The better detection of nodules with the dedicated selenium detector can be explained by the higher dynamic range of the system. Detection of linear-reticular lesions was slightly but not significantly better with the screen-film system, but the detection rate of the selenium detector might be further improved with a different image processing technique.

Humans↗
PubMed1998

alpha-Thalassaemia due to a single codon deletion in the alpha1-globin gene. Computational structural analysis of the new alpha-chain variant. Mutations in brief no. 132. Online.

A new unstable alpha-globin chain associated with alpha-thalassemia phenotype has been found in a Spanish patient. Molecular analysis of the alpha-globin gene complex using PCR and non-radioactive single-strand conformation analysis, allowed to identify a new mutation in the second exon of the alpha-globin gene. Direct sequencing of the abnormal fragment revealed a 3 bp deletion, which led to the loss of a single codon corresponding to a Lys (K) residue at position 60 or 61 DK60 or DK61. Theoretical structural analysis, performed by computational methods, indicated that the loss of an amino acid residue at this position disturbed the contact region between the B and E-helices, affecting the overall stability of the molecule. Therefore, the DK60 and DK61 results in a structurally abnormal alpha-globin chain, not previously described, named Hb Clinic, which leads to the alpha-thalassemia phenotype in the heterozygote patient. No abnormal hemoglobin was detected by standard electrophoretic procedures, suggesting that this alpha-globin chain variant is so unstable that it may be catabolized immediately after its synthesis. This mutation was confirmed by PCR using an allele specific primer.

Codon↗
PubMed1997

Molecular analysis of the insulin receptor gene for prenatal diagnosis of leprechaunism in two families.

Leprechaunism is a rare autosomal recessive disorder characterized by marked intrauterine and postnatal growth retardation, severe insulin resistance, and altered glucose homeostasis. This syndrome is related to mutations in the insulin receptor (IR) gene that impair the transmission of the insulin signal by several mechanisms. There is no effective therapy and patients usually die within the first months of life. Here we report the prenatal diagnosis of leprechaunism in two unrelated families in which affected children were compound heterozygotes with two different deficient IR alleles. In family Par-1, the disease IR alleles carried a missense mutation located in exon 18 (Arg1092-->Trp) and exon 20 (Glu1179-->Lys). In family Als, a 3-basepair deletion causing the loss of Asn281 in exon 3 and a major deletion of exons 10-13 were present in the maternal and paternal mutant IR alleles, respectively. Prenatal diagnosis was made in each family by a specific approach combining denaturing gradient gel electrophoresis (DGGE) and Southern blotting. This methodology allowed us to correctly predict the genotype of the two fetuses at the IR locus.

Abnormalities, Multiple↗
PubMed1995

Factor VIII gene inversions in severe hemophilia A: results of an international consortium study.

Twenty-two molecular diagnostic laboratories from 14 countries participated in a consortium study to estimate the impact of Factor VIII gene inversions in severe hemophilia A. A total of 2,093 patients with severe hemophilia A were studied; of those, 740 (35%) had a type 1 (distal) factor VIII inversion, and 140 (7%) showed a type 2 (proximal) inversion. In 25 cases, the molecular analysis showed additional abnormal or polymorphic patterns. Ninety-eight percent of 532 mothers of patients with inversions were carriers of the abnormal factor VIII gene; when only mothers of nonfamilial cases were studied, 9 de novo inversions in maternal germ cells were observed among 225 cases (approximately 1 de novo maternal origin of the inversion in 25 mothers of sporadic cases). When the maternal grandparental origin was examined, the inversions occurred de novo in male germ cells in 69 cases and female germ cells in 1 case. The presence of factor VIII inversions is not a major predisposing factor for the development of factor VIII inhibitors; however, slightly more patients with severe hemophilia A and factor VIII inversions develop inhibitors (130 of 642 [20%]) than patients with severe hemophilia A without inversions (131 of 821 [16%]).

Blotting, Southern↗
PubMed1995

Frequent occurrence of the CFTR intron 8 (TG)n 5T allele in men with congenital bilateral absence of the vas deferens.

Isolated congenital bilateral absence of the vas deferens (CBAVD) is an autosomal recessive disorder which has recently been shown to be associated with cystic fibrosis (CF) mutations. As part of an effort to understanding the genetic basis of this disorder, we have analysed the entire coding sequence and all the intron/exon boundaries of the cystic fibrosis transmembrane conductance regulator (CFTR) gene from 45 azoospermic individuals with this phenotype. We were able to detect a CFTR gene defect in 86% of chromosomes from these subjects. In addition to identifying 9 novel CFTR gene mutations, we found that a surprisingly high proportion (84%) of men with CBAVD who are heterozygous for a CF mutation carry the intron 8 polypyrimidine 5T CFTR allele on one chromosome. We hypothesise that this tight and significant (p < 10(-6)) linkage reflects the very mild impact of this mutation on CFTR gene expression. Although genetic heterogeneity cannot be excluded, CBAVD patients in whom no CFTR mutation has been detected are likely to harbour additional unidentified mild mutations. These observations have implications for the genetic counselling of CBAVD patients and CF families, and couples undergoing in vitro fertilisation procedures.

Alleles↗
PubMed1995

Prenatal diagnosis of hemoglobinopathies.

Hemoglobinopathies are the most frequent and severe inherited diseases worldwide. Prenatal diagnosis is an effective way of controlling severe hemoglobin disorders for which effective treatments are not yet available everywhere. It is a multidisciplinary process requiring knowledge of the spectrum of molecular defects and involving laboratory investigations and genetic counseling. Hematological screening for these disorders is simple, rapid, and reliable. Carrier screening in populations at risk and genetic counseling are part of a number of European health programs, offering many couples at risk the chance of having a healthy child. This article describes the current molecular biology techniques for prenatal diagnosis of hemoglobinopathies.

Animals↗
PubMed1995

[Cystic fibrosis: the CFTR gene, its mutations, the genetic counseling].

Cystic fibrosis is the most frequent autosomic recessively inherited disease in the European population. The gene implicated in this disease was cloned in 1989 but the consequences of the biochemical defect in the cell have not been fully elucidated. To date, 500 mutations of this 230 kilobase gene have been identified. These molecular anomalies each have an effect on the encoded protein (CFTR) an ion channel which appears to play a role in regulator functions. Results of the gene cloning and research into the different mutations have led to the development of effective strategies for molecular diagnosis facilitating genetic counselling for families at risk and the identification of atypical forms of the disease.

Chromosome Mapping↗
PubMed1994

Identification of eight mutations and three sequence variations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene.

To determine cystic fibrosis (CF) defects in a sample of 224 non-delta F508 CF chromosomes, we used denaturing gradient gel multiplex analysis of CF transmembrane conductance regulator gene segments, a strategy based on blind exhaustive analysis rather than a search for known mutations. This process allowed us to detect 11 novel variations comprising two nonsense mutations (Q890X and W1204X), a splice defect (405 + 4 A-->G), a frameshift (3293delA), four presumed missense mutations (S912L, H949Y, L1065P, Q1071P), and three sequence polymorphisms (R31C or 223 C/T, 3471 T/C, and T1220I or 3791 C/T). We describe these variations, together with the associated phenotype when defects on both CF chromosomes were identified.

Base Sequence↗
PubMed1994

[Screening of hemoglobinopathies and molecular analysis of beta-thalassemia in Central Tunisia].

BACKGROUND: Previous investigations have permitted to locate 16 beta-thalassemic mutations in different samples of the Tunisian population. One of them (IVS I nt 2: T--G) had been found only in the central region of Tunisia. Our research was carried out in this part of the country to estimate the prevalence of this mutation and to establish a prenatal diagnosis using appropriate probes. POPULATION AND METHODS: One thousand one hundred and five blood samples taken from 1987 to 1990 from healthy blood donors and 346 samples taken from 1985 to 1992 from patients were analysed. Detection of hemoglobinopathies was carried out by means of specific hematological tests and different electrophoretic and chromatographic techniques. Mutations were detected by means of the usual techniques of molecular biology. RESULTS: Sickle cell anemia and beta-thalassemia were the most frequent in the samples studied. The molecular analysis carried out on eight patients native of the Essouassi-El-Djem region point out that all these patients carry the same point mutation (IVS I nt 2: T-G) detected for the first time in 1988 in a patient native of the same region. One of these patients, aged 43, who did not suffer from anemia and did not show the usual symptoms of beta O thalassemia, had one hemolytic attack at the age of 17. CONCLUSIONS: The high number of persons carrying Hb S and beta-thalassemia trait increase the risk of appearance of homozygous forms. The presence of the same mutation IVS I nt 2: (T-G) in all beta O-thalassemic patients from Essouassi-El Djem region may indicate that it may have its origin there. The heterogeneity of clinical phenotype of these patients shows the difficulty of establishing a unique strategy of prenatal diagnosis by DNA analysing which can be applied in all cases.

Anemia, Sickle Cell↗
PubMed1994

New data for AG haplotype frequencies in Caucasoid populations and selective neutrality of the AG polymorphism.

We present the results of AG antigen typings of three Caucasoid population samples: Lebanese, Tunisians, and Finns. AG haplotype frequencies estimated by maximum-likelihood methods are compared with the frequencies observed in 13 world populations previously tested for AG specificities by computing a genetic distance matrix used in a multivariate analysis. A high degree of polymorphism characterizes the three samples, with 10 haplotypes detected in the Lebanese and 11 haplotypes detected in the Tunisians and Finns; high heterozygosity levels are also present in the three populations. The genetic distance analysis shows that the three populations possess a genetic structure intermediate between those observed in sub-Saharan Africans and in Caucasoids from the Near East and India. This tight correspondence between AG differentiation and geography is confirmed by a highly significant correlation coefficient found between genetic and geographic distances computed worldwide, suggesting that an isolation by distance model of evolution applies to the AG system. The Ewens-Watterson test for selective neutrality on all world populations tested for AG specificities also supports the hypothesis that the AG system behaves like a neutral polymorphism. Overall, the AG differentiation pattern appears to be close to the patterns observed for other serological polymorphisms, such as RH, GM, and HLA, whose evolutionary mechanisms are also discussed.

Antigens, Differentiation↗
PubMed1993

A rapid, efficient, and sensitive assay for simultaneous detection of multiple cystic fibrosis mutations.

We describe the use of DGGE multiplex systems for rapid analysis of 15 exons of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, in which about half of the known CF molecular defects are clustered. We have previously determined the spectrum of mutations affecting the CFTR gene in the French population using a strategy based on denaturing gradient gel electrophoresis (DGGE) of amplified gene segments. Analysis of CF patients' DNA with five DGGE multiplex systems permitted us to characterize nearly 35% of non-delta F508 CF alleles and increased the CF allele detection rate to almost 82% in this population. This simple and rapid multiplex analysis strategy, which allows a significant proportion of the most frequent CF mutations in Caucasians to be detected, will be helpful in the implementation of genetic screening programs.

Alleles↗