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Biomedical subjects

F Cotton

Publications and source records attributed to F Cotton.

At least 19 recordsLinked to original sources
PubMed2003

Transpedicular screwing of the seventh cervical vertebra: anatomical considerations and surgical technique.

The purpose of this study was first to assess the feasibility of C7 transpedicular screwing with a morphological study and secondly to evaluate the safety of such a surgical technique when guided only by posterior landmarks. Eighteen C7 vertebrae, harvested from fresh human cadavers, were included in this study. First the morphometry of C7 pedicle was performed on computed tomography with multiplanar reconstructions. Results of this quantitative anatomy were compared with the literature data. Secondly 30 pedicle screws, whose placement was guided only by anatomical features on the posterior face of the dorsal arch, were inserted in 15 C7 vertebrae. A second computed tomographic examination was done after the surgical procedure to check the screw placement in both planes. The average pedicular width was 6+/-1.2 mm and the average height was 5.8+/-1.1 mm. The pedicle angulation in the transverse plane was 33.3 degrees +/-6.6 degrees, the pedicle angulation in the sagittal plane was 4.3 degrees +/-4.5 degrees downward with reference to the lower endplate of C7. The average distance from the entry point of transpedicular screwing to the anterior cortex of the vertebral body was 29+/-3 mm. Concerning the safety of transpedicular screwing, 63% of screws were found entirely inside the pedicle without any violation of the pedicle cortex. Most of pedicle violations were observed in the transverse plane. No grade II violation of the pedicle was observed. Dimensions of the C7 pedicle are amply compatible with transpedicular fixation using 3.5 mm screws. Such a surgical technique seems to be an interesting option when posterior fixation of C7 is required. Nevertheless morphological guidelines appeared not to be sufficient to ensure safe transpedicular screwing. Laminoforaminotomy is strongly recommended, although it has not been evaluated in this study.

Aged↗
PubMed2003

[The maxillary sinus: evolution and function in aging].

The maxillary sinus, or Highmore's antrum, is located in the maxillary bone. The maxillary, above the buccal cavity, below the orbital cavity and outside the nasal fossa, is going to take a part in the formation of the three cavities which surround it. Although voluminous, it is consists of a light bone. This distinctive feature is essentially due to the fact that the maxillary has a cavity. The maxillary sinus occupies the upper 2/3s of this maxillary bone. It is the largest of the facial structure's cavities. Its volume is very variable, depending on the individual, the condition of their edentulousness and their age. We find small, average or large sinuses. This sinus communicates with the corresponding nasal fossa by a canal. It opens at the level of the nasofrontalis duct by a meatic ostium, an ostium located at the top of the meatus nasi medius, i.e. under the floor of the sinus. This highly positioned drainage location easily explains the problems that sinus pathologies can come up against. The sinus is lined with a mucous membrane and we can point out that in the normal condition this mucous membrane adheres weakly to the bone. It is more or less thick as a function of the pathologies to which the sinus has been subjected, or even as a function of the geographical location where the individual lives. The imaging of this sinus as a function of age is not obvious due to the fact that it is invisible throughout embryonic and foetal development, and that it only becomes visible to X-rays relatively late, at about 6 years old. Its role is important at the level of the growth of the facial structure because it is always easier to have growth around cavities. It also has a mechanical role concerning the transmission of shockwaves during traumas. In old individuals, due to the condition of the edentulousness, the volume of the sinus is larger; in fact one can note the resorption of the alveolar bone. The maxillary sinus is a cavity which plays a very important role throughout an individual's existence because of the previously mentioned reasons, and which could be used during surgical reconstructions, by the partial filling of this space, to increase the quantity of usable bone (grafts...).

Adolescent↗
PubMed2003

The delayed perfusion sign at MRI.

PURPOSE: Effective collateral blood flow seem to be an important factor associated with a small infarct volume and a good clinical outcome. We aimed to assess leptomeningeal collateral blood flow on source perfusion-weighted images in patients with acute stroke. MATERIALS AND METHODS: 29 patients with proximal middle cerebral artery occlusion (MCA alone, n=17; MCA + internal carotid artery [ICA] occlusion, n=12) were evaluated with MRI at baseline before thrombolytic therapy, and at day 60. Clinical evaluation was performed at days 0 and 60 with the National Institutes of Health Stroke Scale (NIHSS) score, and at day 60 with the modified Rankin score. We assessed (on source images of the dynamic contrast-enhanced T2*-weighted perfusion [PWI] sequence) the presence of a hypointensity consistent with delayed contrast arrival within the global perfusion deficit (delayed perfusion sign). We analyzed the extent of the area demonstrating such delayed perfusion (DP area) on source images of the PWI sequence, and compared it with the global perfusion (GP) abnormality shown by time-to-peak maps. We calculated the Spearman rank correlation coefficient between the DP/GP ratio and: 1. age; 2. clinical scores; 3. site of occlusion [MCA alone versus ICA+MCA occlusion]; 4. DWI lesion size at day 0, and T2WI lesion size at day 60; 5. PWI-derived parameters (time-to-peak [TTP], relative cerebral blood volume [rCBV], relative cerebral blood flow [rCBF], and peak height). All tests were bilateral and a p value<0.05 was considered as significant. RESULTS: Delayed perfusion areas of various size were found within the global perfusion deficit in all patients. High DP/GP ratio values were significantly correlated with: 1. better clinical scores at day 0 and day 60 (all p<=0.04); 2. smaller lesions at day 0 DWI and at day 60 T2WI (all p<=0.004); 3. ICA patency (r=0.49, p=0.01); 4. lower TTP delays, and higher values of rCBV, rCBF, and peak height. CONCLUSION: These preliminary data suggest that a delayed contrast filling observed on native perfusion-weighted images may be a marker of leptomeningeal collateral blood flow, and may lead to better clinical and morphological outcomes in acute ischemic stroke.

Acute Disease↗
PubMed2002

Myelopathy and sciatica induced by an extradural S1 root haemangioblastoma.

Haemangioblastomas are vascular tumours which mainly involve the central nervous system and retina, often in the setting of von Hippel-Lindau disease. Haemangioblastomas occurring outside the central nervous system are uncommon. Wherever it is, recognising this tumour prior to surgery is desirable, as preoperative embolisation may be considered. We report the clinical, imaging and pathological features of a sporadic sacral root haemangioblastoma in a 58-year-old man with chronic sciatica and myelopathy. The diagnosis was questioned preoperatively because an enlarged sacral foramen, seen to be filled by a highly vascular, enhancing mass and dilated vessels. Myelopathy was attributed to the presumed high venous pressure resulting from increased flow in veins draining the vascular tumour. Microneurosurgical excision was performed after endovascular embolisation and led to persistent clinical improvement.

Cerebellar Neoplasms↗
PubMed2002

[The medical chemistry department].

The laboratory of clinical chemistry performs more than 300 different tests in biochemistry, hormone and tumor markers analysis, therapeutic drug monitoring and toxicology. For the most basic tests it has followed the trend of clinical chemistry towards automation and since 2001 the heart of the laboratory is a modular automated system (MODULAR) including a preanalytical platform, unique in Belgium. For more sophisticated tests, the most recent techniques have been implemented, in particular capillary electrophoresis and ICP-MS ("inductively coupled plasma-mass spectrometry). Since 1994, the laboratory has become a reference center in the field of erythrocyte hereditary diseases, combining screening, diagnosis and research. The other research themes are the physiopathology of first trimester pregnancy and the P2Y receptors of extracellular nucleotides.

Belgium↗
PubMed2001

Molecular characterization of the PK-LR gene in sixteen pyruvate kinase-deficient patients.

We studied the PK-LR gene in 16 unrelated patients with congenital haemolytic anaemia associated with erythrocyte pyruvate kinase deficiency. Fifteen different mutations were detected among the 28 mutated alleles identified: two deletions (del 1010G, del 1042--1044); one four nucleotide duplication (nt 1515--1518, GGTC); one splice site [IVS6(-2)t]; nine missense (991A, 1003A, 1151T, 1160G, 1181T, 1181A, 1456T, 1483A, 1529A); and two nonsense (721T, 1675T) mutations. Eight of them [del 1010G, del 1042--1044, dupl 1515--1518, IVS6(-2)t, 1003A, 1160G, 1181T, 1181A] were novel. The deletion 1042-1044 causes the loss of Lys 348. Deletion 1010G and duplication 1515-1518 determine a frameshift and the creation of a stop codon at nucleotides 1019 and 1554 respectively. Mutation IVS6(-2)t leads to an alteration of the 5' and 3' splice site consensus sequence; the cDNA analysis shows a 67-bp deletion in the first part of exon 11 (del 1437--1503). All the four new missense mutations involve highly conserved amino acids. The most frequent mutation in Italy would appear to be 1456T. Correlation was made between mutations, biochemical characteristics of the enzyme and clinical course of the disease.

Adult↗
PubMed2001

Could capillary zone electrophoresis of tryptic peptides be used for the characterization of hemoglobin variants?

The present article describes a simple and rapid new peptide mapping procedure that could be used to assist identification of rare hemoglobin variants in clinical laboratories. Four hemoglobin variants were taken as example, namely Hb D-Ouled Rabah, Hb Marseille, Hb G-Philadelphia, and Hb Ube-2, and isolated by electrophoresis at alkaline pH. The globin chains were aminoethylated and, after tryptic digestion, the peptides were separated by a capillary zone electrophoresis method. Highly reproducible migration times of the peptides were obtained with intra-assay and inter-assay coefficients of variation of less than 1 and 2%, respectively.

Amino Acid Sequence↗
PubMed2001

[Screening for hemoglobinopathies in medical practice: audit of gynecologists, pediatricians and generalists in Brussels].

The haemoglobin disorders are frequent genetic diseases in tropical regions and in the mediterranean basin. They include thalassaemia and sickle cell disease. Because of important migrations of populations after the Second World War many big cities are confronted with the disease in West Europe nowadays. In Brussels where a neonatal screening has been organised in the majority of the maternity's, 45% of newborns have at least one parent originating from a region at risk for an haemoglobin disorder. One neonate among 2.000 is diagnosed with a major haemoglobinopathy at the screening. This rate is important and it appeared essential to evaluate the knowledge and need for complementary information among the doctors confronted with the disease. A survey was done in January 1999 and a questionnaire was sent to all gynaecologists, paediatricians and general practitioners in Brussels. The main results were a general self-evaluation of poor knowledge and a great need for complementary information. This survey was important to obtain adequate support of official health authorities in term of screening, prevention and financial aid to information campaigns. A consensus is needed among the different doctors for the best care possible of sick patients.

Attitude of Health Personnel↗
PubMed2001

[Prevention of hemoglobinopathies in Brussels: a necessity?].

Haemoglobinopathies are the most frequent genetic diseases in the world. The estimated frequency of carriers in the world is of 200 millions while there is about 300.000 births per year of major forms of haemoglobinopathies. The neonatal screening of haemoglobinopathies performed at the Hospital Erasme on around 80% of births in Brussels since 1994 has demonstrated that the frequency of carriers of an abnormal haemoglobin is around 1.5% while more than 1/2.000 newborns has a major haemoglobinopathy. A strategy must be adopted to manage the haemoglobinopathies in Brussels.

Algorithms↗
PubMed2001

Analyzer transfer of a broad range high-sensitivity C-reactive protein immunoassay.

C-reactive protein (CRP) is measured in two main clinical situations: inflammation, where levels in the range of 5-300 mg/L are expected, and, more recently, assessment of the cardiovascular risk, where concentrations between 0.1 and 10 mg/L shoud be determined. Few commercially available methods display a measuring range covering both zones and laboratories are compelled to use two different assay protocols or even two different methods. The aim of the study was to adapt the Roche C-Reactive Protein (Latex) kit, initially developed for the Roche Cobas Integra analyzers, to the Hitachi Modular P800 analyzer in order to obtain on this instrument a broad range assay for CRP measurement. The method was successfully adapted and validated against a high-sensitivity and a traditional assay. The resulting method correlates well with the other two and displays a measuring range of 0.10-171 mg/L with an imprecision lower than 5.5%. This assay could be particularly practical in the routine clinical laboratory, being suitable for every use of CRP measurements.

C-Reactive Protein↗
PubMed2000

Capillary gel electrophoresis: separation of major erythrocyte membrane proteins.

A new separation method of human erythrocyte membrane proteins by sodium dodecyl sulfate capillary gel electrophoresis (SDS-CGE) is described. In this method, a replaceable gel matrix was used. Seven major erythrocyte membrane proteins, alpha-and beta-spectrin, ankyrin 2.1, band 3 (anion-exchanger), 4.1a and b, and 4.2 (pallidin), were separated and identified by SDS-CGE method. High reproducible migration times of these proteins (inter-assay coefficients of variation less than 2%), as well as quantification (inter-assay coefficients of variation less than 11%) were obtained. This new SDS-CGE method may provide important diagnostic evidence for hereditary spherocytosis. It can be a powerful diagnostic tool in place of SDS polyacrylamide gel electrophoresis for erythrocyte membrane protein analysis.

Electrophoresis, Capillary↗
PubMed2000

Measurement of soluble transferrin receptor by immunoturbidimetry and immunonephelometry.

OBJECTIVE: To evaluate and compare two new commercially available immunoturbidimetric and immunonephelometric assays for measuring soluble transferrin receptor (sTfR) in serum. To adapt the immunonephelometric assay to an automated chemistry analyzer. DESIGN AND METHODS: Total imprecisions and detection limits were calculated and compared. Fifty-six samples were used for methods comparison. The nephelometric assay was adapted to the Hitachi 911 analyzer. RESULTS: Both methods displayed acceptable imprecisions and detection limits. Their correlation was good but a proportional bias was observed. The adaptation of the nephelometric assay to the Hitachi 911 was successful. CONCLUSIONS: These two new immunoassays are analytically acceptable and more practicable than previously developed methods. The differences observed between both methods underscores the need for standardization. The nephelometric assay was easily adaptable to an automated chemistry analyzer.

Biomarkers↗
PubMed2000

[CT enteroclysis for detection of small bowel tumors].

PURPOSE: To assess the feasibility and the usefulness of CT enteroclysis (helical CT with enteroclysis) in detecting small bowel tumors. MATERIALS AND METHODS: Fifty patients were referred for suspicion of small bowel tumor. CT enteroclysis is performed by injecting a large volume of water using a pomp through a nasojejunal tube followed by a thin section helical acquisition. RESULTS: Forty-eight helical CT enteroclysis were performed in order to detect 25 small bowel tumors. Among them 22 were confirmed by histological study. The mean size of tumors was 23 mm. In 12 of 17 cases, diagnosis was missed or incomplete at conventional barium study. Enteroscopy was performed in 12 of 22 cases, with discordant result in one case and incomplete result in 3 cases. In 8 cases, including 5 carcinoid tumors, patients had surgery after CT enteroclysis only, enteroscopy would probably have not made the diagnosis because the lesions were far from the duodenojejunal junction and ileocaecal valve. CONCLUSION: Helical CT enteroclysis is a new method for detecting small bowel tumors, easy to perform, well tolerated. It seems to be more sensitive than conventional barium studies and less invasive than enteroscopy. Tumor characterization and staging can be performed using a single examination. It seems to be justified to perform CT enteroclysis to detect small bowel tumors or in the evaluation of patients with polyposis.

Adult↗
PubMed1999

Newborn screening for haemoglobinopathies: the Brussels experience.

OBJECTIVES: To determine the prevalence of haemoglobinopathies and the need for neonatal screening for haemoglobinopathies in Brussels. METHODS: Between December 1994 and June 1998 23,136 cord blood samples obtained in eight hospital nurseries of Brussels were systematically screened for haemoglobinopathies by isoelectric focusing. RESULTS: 45% of the newborns were from regions at risk for haemoglobinopathies. Sickle cell disease was diagnosed for 11 neonates (0.048%) and beta thalassaemia major for one neonate. Three hundred and fifty neonates (1.5%) were carriers for a haemoglobin variant, and Hb Bart's was found in 672 cases (2.9%). These prevalences are similar to those reported elsewhere in northern Europe. CONCLUSIONS: These results confirm the value of universal screening for haemoglobinopathies in Brussels.

Anemia, Sickle Cell↗
PubMed1999

Capillary zone electrophoresis: an additional technique for the identification of hemoglobin variants.

Two capillary zone electrophoresis kits (Hb A2 and Hb A1c) were tested for confirmation and identification of hemoglobin variants. The capillary zone electrophoresis experiments were performed at pH 4.7 (Hb A1c kit) and 8.7 (Hb A2 kit) in a 24 cm uncoated fused silica capillary tube (25 microm I.D.). Normal hemoglobins and common hemoglobin variants, including Hbs S, D-Punjab, C, E, O-Arab, and G-Philadelphia, were successfully separated by both methods within a few minutes. Both systems provided completely different elution profiles of normal and abnormal hemoglobin fractions tested and were complementary. The inter-assay coefficient of variations of the migration times of hemoglobin variants were less than 1.0 and 1.3% by the Hb A2 and Hb A1c, respectively. This permits a higher resolution of some hemoglobin variants in low concentrations, like Hb S in newborns, compared with conventional electrophoresis methods. The present capillary zone electrophoresis methods are sensitive, rapid, not labor intensive, and highly selective for the separation of hemoglobin variants. Combination of both methods with some conventional methods, such as isoelectrofocusing, allows identification of Hbs C, E, O-Arab, S, and D-Punjab, as well as their quantification. We have demonstrated that the conventional electrophoresis methods (electrophoresis at pH 6.5 in citrate agar gel and electrophoresis at pH 8.6 on cellulose acetate) can be advantageously replaced by the present capillary zone electrophoresis methods in a clinical laboratory practice for the detection and quantification of hemoglobin variants.

Electrophoresis, Capillary↗