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S Nour

Publications and source records attributed to S Nour.

At least 19 recordsLinked to original sources
PubMed2004

Radium-228 determination of natural waters via concentration on manganese dioxide and separation using Diphonix ion exchange resin.

The objective of this work was to establish a new procedure for 228Ra determination of natural waters via preconcentration of radium on MnO2 and separation of its daughter, 228Ac, using Diphonix ion exchange resin. Following removal of potential interferences via passage through an initial Diphonix Resin column, the first daughter of 228Ra, 228Ac, is isolated by chromatographic separation via a second Diphonix column. A holding time of > 30 h for 228Ac ingrowth in between the two column separations ensures secular equilibrium. Barium-133 is used as a yield tracer. Actinium-228 is eluted from the second Diphonix Resin with 5 ml 1M 1-Hydroxyethane-1,1-diphosphonic acid (HEDPA) and quantified by addition of scintillation cocktail and LSC counting. Radium (and 133Ba) from the load and rinse solutions from the 2nd Diphonix column may be prepared for alpha spectrometry (for determination of 223Ra, 224Ra, and 226Ra) by BaSO4 microprecipitation and filtration. Decontamination tests indicate that U, Th, and Ra series nuclides do not interfere with these measurements, although high contents of 90Sr (90Y) require additional treatment for accurate measurement of 228Ra. Addition of stable Sr as a "hold back" carrier during the initial MnO2 preconcentration step was shown to remove most 90Sr interference.

Chromatography, Ion Exchange↗
PubMed2004

Pyloric stenosis: unusual presentations and rare assoclations.

Pyloric stenosis is a common paediatric surgical condition with a well-recognised pattern of clinical features. Diagnosis is usually straightforward and a Ramstedt pyloromyotomy is curative. We present three patients who developed pyloric stenosis incidentally during the management of other primary surgical conditions. Issues of diagnostic difficulty following presentation of pyloric stenosis in the post-operative period (all three patients), its rare syndromic associations (one patient) and its management in this unusual situation are discussed. An awareness of the unusual presentations of pyloric stenosis during treatment for other primary surgical conditions can help in earlier diagnosis and treatment.

Congenital Abnormalities↗
PubMed2003

Preconcentration of radium isotopes from natural waters using MnO2 Resin.

We have characterized "MnO2 Resin," a new resin developed by the PG Research Foundation, for radium adsorption over wide ranges of pH, reaction times and salt concentrations. We show that the sorption of 133Ba (used as a proxy for Ra) is highly dependent on pH with the most useful range from pH 4 to 8. The surface layers of the Mn oxides apparently become more positively charged under acidic conditions (below pH 4), which prevents diffusion of positively charged alkaline earth species (e.g. Ba2+, Ra2+) into the sorption sites. Adsorption at higher pH is thought to be inhibited because of carbonate complexation. We found that the sorption characteristics for radium onto MnO2 Resin are especially favorable for low-salinity waters but the sorption is still very satisfactory for highly salted solutions (KD=2.8x10(4) in both cases) but with slower kinetics. For analytical purposes, both column and pump experiments showed high recoveries with no measurable discrimination between Ra and Ba regardless of flow rates in fresh water. Seawater tests showed that recoveries of Ra and Ba are lower than fresh water at elevated flow rates with Ra adsorption higher than Ba at flow rates above 10 ml/min.

Barium Radioisotopes↗
PubMed2003

Management of superficial neck abscesses.

OBJECTIVE: To evaluate clinical features, management options and outcomes in children with neck abscesses, with a view to correlating this data with the different causative micro-organisms, specifically mycobacteria. PATIENTS AND METHODS: A retrospective chart review of fifty-one consecutive children who were admitted with suspected superficial neck abscesses to the Unit between January 1994 and June 1999 was performed. RESULTS: The causative organisms were identified in 21 cases--bacteria in 13 patients, atypical mycobacteria in 6 cases, and mycobacterium tuberculosis in 2 instances. Children with atypical mycobacterial infection had a significantly longer duration of symptoms at the time of admission (mean = 87 days) versus those with bacterial infection (mean = 6 days). Ultrasonography was performed in 20 patients in this series, and was seen to be of value in demonstrating a collection in situations where there was doubt on clinical basis alone. The outcome was seen to be complicated in all children with mycobacterial infections--either atypical or tuberculous. CONCLUSIONS: Neck abscesses are commonly encountered in paediatric practice. In most instances the diagnosis and treatment is straightforward, with an uncomplicated outcome. However, it is important to bear in mind that there exists a subset of abscesses caused by atypical mycobacteria, with greater risk of complications and recurrence, that needs special attention at the time of diagnosis, intervention and follow-up.

Abscess↗
PubMed2000

Cerebral activation during micturition in normal men.

Specific cerebral lesions have shown the crucial role of the brain in the control of micturition. The precise identification of the anatomical cerebral structures involved in micturition can contribute to a better understanding of the control of micturition and the development of therapeutic models. Various neuropathological and animal studies have referred to the medulla oblongata, pons, limbic system, superior frontal lobe and premotor cortical regions as areas implicated in micturition control. The aim of this study was to investigate whether the activity of these areas during micturition can be confirmed by PET in normal men. The distribution of the regional cerebral blood flow after bolus injection of (15)O water was used as an indirect measure of cerebral activation. PET scans were performed during the following three conditions: (i) at rest with the bladder empty; (ii) during simulated micturition after instillation of isotonic saline into the urinary bladder; and (iii) the withholding of urine (saline). Normal micturition using this model was achieved in eight out of 12 right-handed normal subjects. The changes in bladder contraction, bladder pressure and intra-abdominal pressure were monitored on-line during the whole scanning session by a cystometry device. The images were analysed using statistical parametric mapping at a significance threshold of P < 0.05 with correction for multiple independent comparisons. Micturition versus rest was associated with bilateral activation of areas close to the postcentral gyrus, inferior frontal gyrus, globus pallidus, cortex cerebelli, vermis and midbrain. On the left side, activation of the middle frontal gyrus, superior frontal gyrus, superior precentral gyrus, thalamus and the caudal part of the anterior cingulate gyrus was seen, while on the right side we found activation in the supramarginal gyrus, mesencephalon and insula. When the threshold value was lowered to P < 0.001 (Z > 3.09) without correction for multiple comparisons, we found additional activation in the medial pontine tegmentum, mesencephalon, right thalamus, right middle frontal gyrus and left insula. When urine- withholding was compared with rest, the left insula showed a tendency to activate. We conclude from this study, in which urinary bladder contraction was verified cystometrically, that the onset and maintenance of micturition in normal men is associated with a vast network of cortical and subcortical regions, confirming observations from clinical and animal studies.

Adult↗
PubMed2000

Quantitation of regional cerebral blood flow corrected for partial volume effect using O-15 water and PET: II. Normal values and gray matter blood flow response to visual activation.

One of the most limiting factors for the accurate quantification of physiologic parameters with positron emission tomography (PET) is the partial volume effect (PVE). To assess the magnitude of this contribution to the measurement of regional cerebral blood flow (rCBF), the authors have formulated four kinetic models each including a parameter defining the perfusable tissue fraction (PTF). The four kinetic models used were 2 one-tissue compartment models with (Model A) and without (Model B) a vascular term and 2 two-tissue compartment models with fixed (Model C) or variable (Model D) white matter flow. Furthermore, rCBF based on the autoradiographic method was measured. The goals of the study were to determine the following in normal humans: (1) the optimal model, (2) the optimal length of fit, (3) the model parameters and their reproducibility, and (4) the effects of data acquisition (2D or 3D). Furthermore, the authors wanted to measure the activation response in the occipital gray matter compartment, and in doing so test the stability of the PTF, during perturbations of rCBF induced by visual stimulation. Eight dynamic PET scans were acquired per subject (n = 8), each for a duration of 6 minutes after IV bolus injection of H2(15)O. Four of these scans were performed using 2D and four using 3D acquisition. Visual stimulation was presented in four scans, and four scans were during rest. Model C was found optimal based on Akaike's Information Criteria (AIC) and had the smallest coefficient of variance after a 6-minute length of fit. Using this model the average PVE corrected rCBF during rest in gray matter was 1.07 mL x min(-1) x g(-1) (0.11 SD), with an average coefficient of variance of 6%. Acquisition mode did not affect the estimated parameters, with the exception of a significant increase in the white matter rCBF using the autoradiographic method (2D: 0.17 mL x min(-1) x g(-1) (0.02 SD); 3D: 0.21 mL x min(-1) x g(-1) (0.02 SD)). At a 6-minute fit the average gray matter CBF using Models C and D were increased by 100% to 150% compared with Models A and B and the autoradiographic method. There were no significant changes in the perfusable tissue fraction by the activation induced rCBF increases. The largest activation response was found using Model C (median = 39.1%). The current study clearly demonstrates the importance of PVE correction in the quantitation of rCBF in normal humans. The potential use of this method is to cost-effectively deliver PVE corrected measures of rCBF and tissue volumes without reference to imaging modalities other than PET.

Adult↗
PubMed1998

Gastrostomy complications in infants and children.

Thirty children have had percutaneous endoscopic gastrostomy (PEG) inserted for feeding purposes. During a follow-up period of 5-45 months (mean 24 months), complications were recorded in 13 patients. Some patients had more than one complication. Complications included colocutaneous fistula, gastro-oesophageal reflux, wound infection, granulation tissue formation, tube leakage, tube blockage and bleeding. The authors present a retrospective review of the results and discuss the management of these complications.

Adolescent↗
PubMed1996

Antibiotic prophylaxis for infantile pyloromyotomy.

A retrospective study of 50 patients with infantile hypertrophic pyloric stenosis (IHPS) showed wound infection in six patients. In an attempt to assess the value of antibiotic prophylaxis in infantile pyloromyotomy 150 patients with infantile hypertrophic pyloric stenosis were entered in a prospective randomized controlled study. The infants were allocated to receive a dose of Cefuroxime (30 mg/kg) at induction of anaesthesia or no antibiotic. Eight infants developed wound infection, five in the control group and three in the antibiotic prophylaxis group. Although the difference between the two groups was not statistically significant there was an overall reduction of wound infection (6.5%) compared with pre-trial figures (12%). In order to study the bacterial flora in the umbilicus in these infants, culture swabs were taken from the umbilicus on admission, immediately prior to surgery and from the wound prior to skin closure. It was shown that the umbilicus was not the source of infection.

Antibiotic Prophylaxis↗
PubMed1996

Colostomy complications in infants and children.

This study analyses the morbidity and mortality of colostomy formation and closure over a 17-year period during which 138 consecutive infants and children had a colostomy formed as the initial management of Hirschsprung's disease or anorectal malformation. Complications after colostomy formation were encountered in 38 (27.5%) patients and included colostomy prolapse, stenosis, retraction, dysfunction, skin excoriation and parastomal hernia. The complication rate with transverse colostomies was higher than with other types. Colostomy closure was associated with complications in nine patients (6.5%), the most serious of which was adhesive small bowel obstruction (5). The mortality was less than 1%, but significant morbidity still exists. Refinements in surgical technique may help reduce the incidence of complications, but stoma prolapse, particularly with transverse colostomies, remains a major challenge.

Anal Canal↗
PubMed1995

A gene for autosomal dominant sacral agenesis maps to the holoprosencephaly region at 7q36.

Sacral agenesis is a rare disorder of uncertain incidence that has been reported in diverse populations. Although usually sporadic and most commonly associated with maternal diabetes, there is a hereditary form which may occur in isolation or with a presacral mass (anterior meningocele and/or presacral teratoma) and anorectal abnormalities, which constitute the Currarino triad (MIM 176450). The radiological hallmark of hereditary sacral agenesis is a hemi-sacrum (sickle-shaped sacrum) with intact first sacral vertebra. Bowel obstruction is the usual neonatal presentation, but, unlike other neural tube defects, adult presentation is not uncommon. The major pathology is confined to the pelvic cavity and may present as a space-occupying lesion or meningitis due to ascending infection. All recurrences in families have been compatible with autosomal dominant inheritance except for those associated with the isomerism gene at Xq24-q27.1 (ref. 3). Several associated cytogenetic defects have been reported, including 7q deletions. Previous studies failed to detect linkage to HLA markers, but we now present evidence for a location on 7q36. The same region also contains a gene for holoprosencephaly, an early malformation of the extreme rostral end of the neural tube.

Abnormalities, Multiple↗
PubMed1995

Mitrofanoff stoma--an iceberg of problems?

The advent of a self-catheterisable continent abdominal wall urinary stoma has provided an enormous improvement in the quality of life for many patients. Successful results of surgery have been presented from many centres. However, these reports concentrate on the technical aspect of patient care. In this paper we review the work of the outreach nursing sister in supporting thirty patients operated upon during a four-year period, and their families.

Adaptation, Psychological↗
PubMed1995

Applied potential tomography in the measurement of gastric emptying in infants.

The aim of this study was to investigate the feasibility of using applied potential tomography (APT), a noninvasive and nonradioactive method, to measure the rate of gastric emptying in preterm babies and infants < 3 months old. APT, a form of electrical impedance tomography, creates tomographic images of tissue resistivity to a small electrical current and has been used to study gastric emptying in adults. The rate of gastric emptying of 53 preterm infants and 29 term infants was measured. The test feed was either milk (formula milk or expressed breast milk) or Dioralyte (a commercial rehydration solution). When a nasogastric tube was present, the results obtained by APT were validated by comparing the volume of feed estimated to be present with the volume that could be aspirated. All infants completed the investigation without any problems. APT demonstrated a slower rate of emptying of milk feeds than Dioralyte and showed that milk and Dioralyte feeds in preterm babies emptied at a similar rate to feeds in term infants. In validation studies, gastric emptying has been observed in 44 of 47 studies, and this finding was confirmed by aspiration of the nasogastric tube. Applied potential tomography is a safe, noninvasive method for measuring gastric emptying in small infants.

Bottle Feeding↗
PubMed1995

Intra-abdominal extravasation complicating parenteral nutrition in infants.

Two infants receiving total parenteral nutrition via a central venous catheter positioned in the inferior vena cava developed an acute abdomen secondary to extravasation of the infusate. The presence of an associated abdominal mass necessitated a laparotomy in one patient. Both infants recovered completely after the catheter had been removed.

Abdomen, Acute↗
PubMed1994

Long-term faecal continence in infants born with anorectal malformations.

In a retrospective study of 92 patients admitted between 1975 and 1986 with anorectal malformations, we reviewed the faecal continence according to the level of their anomaly using a scoring system taken from Pescatori et al. The results of the different operative procedures were compared. Forty-seven of the 50 patients in the low anomaly group had complete faecal continence. Two died from associated anomalies and one infant had incomplete continence. This child had an associated neural tube defect. Of eight patients in the intermediate group, three had good results while two were incontinent: three patients died from associated anomalies. There were 34 patients with high anomalies, 27 of whom showed a wide range of faecal control from complete continence to different degrees of incontinence. Seven infants died from septicaemia and/or associated anomalies. The anatomical level of the lesion and the presence or absence of any associated neurological defect were the main determinants of outcome. The sex of the child and the operative procedure employed to correct the anomaly appeared to be less important.

Anal Canal↗