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M J Weston

Publications and source records attributed to M J Weston.

At least 19 recordsLinked to original sources
PubMed2005

Intra-operative Doppler flow measurement do not predict 'at-risk' status of infrainguinal bypass grafts.

AIMS: Patients undergoing infrainguinal arterial reconstruction using vein conduits, frequently undergo intra-operative Doppler flow measurements to determine technical adequacy. The aim of this study was to determine the proportion of vein grafts with normal intra-operative haemodynamic parameters that were subsequently discovered to be 'at risk' on post-operative duplex surveillance scanning. METHODS: We prospectively collected data on 82, primary infrainguinal vein bypass grafts. Post papaverine graft flow and peripheral resistance were measured using the Scimed Opdop intra-operative Doppler machine. All grafts were determined to be technically adequate on the basis of measured peripheral resistance units (mPRU) being < or =1. At 1 week, a post-operative duplex surveillance scan was performed. At risk status was determined and compared to the intra-operative Doppler flow measurement. Statistical analysis was performed using the Mann-Whitney U-test. RESULTS: The post-operative duplex scan demonstrated that 53 (65%) of the 82 vein bypass grafts were diagnosed as being 'not at risk'; and 29 (35%) were regarded as at risk. When the groups were compared, there was no significant difference in intra-operative haemodynamic parameters between those not at risk and those at risk (P=0.19, Mann-Whitney U-test). The 1 month primary patency rate was 79% with a secondary patency rate of 100%. CONCLUSION: Despite normal intra-operative Doppler flow measurements, 35% of vein grafts were regarded as being at risk at the 1 week post-operative duplex surveillance scan. No single value may be universally applicable for identifying at risk grafts intraoperatively. Indeed, graft failure appears to be a multifactorial process.

Aged↗
PubMed2004

Percutaneous nephrostomy insertion: outcome data from a prospective multi-operator study at a UK training centre.

AIM: To determine the success and complication rates of percutaneous nephrostomies (PCNs) performed at a UK training centre over a one-year period by different groups of operators. MATERIALS AND METHODS: During 2002, a total of 276 PCNs were performed in 190 patients by operators of varying experience. We employed two different techniques: (1) a "Seldinger" technique (ultrasound-guided puncture with a 19G sheathed needle followed by guide-wire insertion and track dilatation to accommodate 8-12F nephrostomy catheters), with or without fluoroscopic guidance, and (2) an ultrasound-guided "one-stab" technique using a 6F Bonanno catheter. Selection of technique was according to configuration of the collecting system and whether the procedure was performed out of hours. RESULTS: There were 218 procedures using the Seldinger technique and 62 using the one-stab technique. The Seldinger technique and one-stab technique were compared: primary technical success rate was 98 versus 93%, the major complication rate was 4.1 versus 3.2%, the minor complication rate was 5 versus 13%, and tube complications, such as drainage catheter dislodgement and blockage, were 29.5 versus 17.7%, respectively. The 30-day mortality was 4.3%, none of which were procedure related. CONCLUSION: Based on data from the USA, proposed targets for primary technical success rates are 88-99%, major complications 4-8%, and minor complications 3-15%, and the results were within these target ranges. The ultrasound-guided one-stab technique is a quick and safe procedure in selected cases, and we recommend this method for temporary urinary diversion in cases with moderate to severe degrees of pelvicalyceal system dilatation. These data may help to form a baseline for outcome targets in the UK.

Adolescent↗
PubMed2003

Lower moiety pelvic-ureteric junction obstruction (PUJO) of the duplex kidney presenting with pyonephrosis in adults.

The most common congenital abnormality of the urinary tract is a duplex kidney. Pelvic-ureteric junction obstruction (PUJO) is a rare association that can affect the lower moiety of incomplete duplex kidneys. We report two adult cases of PUJO of the lower moiety in a duplex kidney that both presented with pyonephrosis. This late presentation of lower moiety PUJO with pyonephrosis has not been described previously. We describe the imaging appearances of this rare association and highlight this important diagnostic consideration in lower moiety hydronephrosis of the adult patient.

Adolescent↗
PubMed2002

A family study and the natural history of prenatally detected unilateral multicystic dysplastic kidney.

PURPOSE: We document the inheritance pattern of multicystic dysplastic kidney in 3 affected families and screen first-degree relatives of a cohort of children with prenatally detected multicystic dysplastic kidney for renal anomalies. The study also afforded an opportunity to document the natural history of prenatally detected multicystic dysplastic kidney. MATERIALS AND METHODS: We identified 3 families during clinical treatment of children with prenatally detected multicystic dysplastic kidneys. Other members of these families were evaluated with renal ultrasonography. For the family screening study index cases were identified from a fetal uropathy database. A total of 94 first-degree relatives (52 parents, 35 full siblings and 7 half siblings) of 29 children with prenatally detected multicystic dysplastic kidneys were studied with urinary tract ultrasonography, blood pressure measurement, urinalysis and plasma biochemistry. RESULTS: Two families had affected sibling pairs, 1 of which also had a half sibling with vesicoureteral reflux. The third family included 3 individuals with multicystic dysplastic kidney and 1 with renal agenesis thought to have resulted from involution of multicystic dysplastic kidney. This family is consistent with autosomal dominant inheritance with variable expressivity and reduced penetrance. In the screening study ultrasonography did not demonstrate significant renal anomalies in any of the 94 first-degree relatives of the multicystic dysplastic kidney index cases. Followup assessment of prenatally detected multicystic dysplastic kidneys in index cases demonstrated total involution in 52% at a median age of 6.5 years with no multicystic dysplastic kidney related morbidity. CONCLUSIONS: Multicystic dysplastic kidney can be familial but is most commonly a sporadic anomaly. Formal screening of relatives is not recommended. Followup data on a cohort of children with prenatally detected multicystic dysplastic kidney add further support to conservative management.

Female↗
PubMed2001

Barentsz is essential for the posterior localization of oskar mRNA and colocalizes with it to the posterior pole.

The localization of Oskar at the posterior pole of the Drosophila oocyte induces the assembly of the pole plasm and therefore defines where the abdomen and germ cells form in the embryo. This localization is achieved by the targeting of oskar mRNA to the posterior and the localized activation of its translation. oskar mRNA seems likely to be actively transported along microtubules, since its localization requires both an intact microtubule cytoskeleton and the plus end-directed motor kinesin I, but nothing is known about how the RNA is coupled to the motor. Here, we describe barentsz, a novel gene required for the localization of oskar mRNA. In contrast to all other mutations that disrupt this process, barentsz-null mutants completely block the posterior localization of oskar mRNA without affecting bicoid and gurken mRNA localization, the organization of the microtubules, or subsequent steps in pole plasm assembly. Surprisingly, most mutant embryos still form an abdomen, indicating that oskar mRNA localization is partially redundant with the translational control. Barentsz protein colocalizes to the posterior with oskar mRNA, and this localization is oskar mRNA dependent. Thus, Barentsz is essential for the posterior localization of oskar mRNA and behaves as a specific component of the oskar RNA transport complex.

Animals↗
PubMed2001

Leading into the future: coaching and mentoring Generation X employees.

Managers who recognize that Generation X employees are looking for workplaces that allow them to develop their competencies as well as have a balance in their personal and professional lives, are more successful in attracting and retaining employees in this age group. Savvy managers understand that adapting to meet the needs of Generation X employees also assists the manager in transitioning into the Information Age and the workplace of the future.

Adult↗
PubMed2000

Early report: comparison of breath-hold MR excretory urography, Doppler ultrasound and isotope renography in evaluation of symptomatic hydronephrosis in pregnancy.

AIM: To compare assessment by MR excretory urography (MREU), Doppler ultrasound and isotope renography of women with symptomatic hydronephrosis in pregnancy and to define its cause. MATERIALS AND METHODS: Eleven women at 19-34 weeks of gestation were studied prospectively with gadolinium-enhanced breath-hold gradient echo MREU and transabdominal Doppler ultrasound compared with a 'gold standard' of isotope renography employing frusemide challenge. All studies were performed within 24 h, were reported independently in a blinded fashion and employed clearly defined criteria. Obstetric and infant outcomes were obtained. RESULTS: There were no adverse reactions to gadolinium administration in pregnancy and no adverse obstetric or infant outcomes. Three of the 11 women were unable to tolerate the complete MREU protocol. Ultrasound indices could not be used to predict ureteric obstruction as shown by isotope renography. MREU agreed with renographic findings in five of the six cases with obstruction and in two without obstruction. MREU directly demonstrated hydronephrosis to result from extrinsic compression of the ureter between the gravid uterus and iliopsoas muscle. CONCLUSION: MR excretory urography is a promising technique which affords equivalent functional and additional anatomical information to isotope renography. It is more accurate than Doppler ultrasound in the assessment of ureteric obstruction in pregnancy.Spencer, J. A. (2000). Clinical Radiology55, 446-453.

Contrast Media↗
PubMed1999

Duplex-derived evidence of reflux after varicose vein surgery: neoreflux or neovascularisation?

BACKGROUND: Recurrent varicose veins remain a problem in surgical practice despite improvements to the preoperative investigation of, and surgery for varicose veins. Neovascularisation accounts for some cases of recurrence within a few years of surgery, but other factors relating to disease progression must also play a part. We investigated whether new venous reflux (neoreflux) could occur in the early postoperative period (within 6 weeks) following successful varicose vein surgery. METHODS: Eighteen-month prospective observational study in the dedicated vascular surgery unit of a university teaching hospital. Forty-six patients, with primary saphenofemoral junction reflux, awaiting varicose vein surgery were chosen consecutively from the waiting list. All saphenofemoral surgery was performed in a standardised fashion. Assessments were performed prior to, at 6 weeks and at 1 year after surgery. Duplex ultrasound was used to identify and locate sites of reflux. RESULTS: Neoreflux was present at the 6-week postoperative scan in nine limbs after varicose vein surgery (19.6%), and resolved in 55.6% of patients within 1 year. Neovascularisation was noted in two limbs at the 1-year scan. CONCLUSION: New sites of reflux, which may resolve spontaneously, occur in the early postoperative period despite adequate varicose vein surgery. It is our hypothesis that this is a manifestation of the effect of altered venous haemodynamics in a system of susceptible veins.

Adult↗
PubMed1999

Neural networks in the diagnosis of malignant ovarian tumours.

OBJECTIVE: To assess the role of neural networks in predicting the likelihood of malignancy in women presenting with ovarian tumours. DESIGN: Retrospective case study. SETTING: University Department of Obstetrics and Gynaecology, St James's Hospital, Leeds. METHODS: Information from 217 cases with histologically proven benign, borderline or malignant tumours was extracted for study. Four variables (age, ultrasound findings with and without colour Doppler imaging and CA125) were entered in the neural network classifier. The neural network results were compared with logistic regression analysis. RESULTS: When used in the neural network the variables of age, CA125 and ultrasound score produced the best result with a sensitivity of 95% and a corresponding specificity of 78% in predicting malignancy. Logistic regression gave a sensitivity or 82% for a specificity of 51%. CONCLUSION: The neural network is a good method of combining diagnostic variables and may be a useful predictor of malignancy in women presenting with ovarian tumours. A comparison of the performance of the neural network with conventional diagnostic methods would be warranted prior to use in clinical practice.

Adolescent↗
PubMed1998

Bilateral massive ovarian edema: a case report.

Massive ovarian edema is an unusual cause of ovarian enlargement in young patients. Most cases are thought to result from venous and lymphatic obstruction, producing edema. We report the case of a 15-year-old girl with bilateral massive ovarian edema, findings on ultrasound imaging, and a review of the literature. The sonographic appearance is non-specific and can mimic neoplasia, and the definitive diagnosis requires histological examination. It is, however, an important condition to consider in a young patient with a complex ovarian mass in an appropriate clinical setting, as conservative treatment with ovarian preservation is often possible.

Adolescent↗
PubMed1998

Duplex scanning may be used selectively in patients with primary varicose veins.

Reflux was assessed using hand-held Doppler (HHD) and duplex scanning in 72 patients with primary, previously untreated varicose veins (108 limbs). The aims of the study were (i) to compare the accuracy of HHD assessment with duplex scanning, (ii) to assess the benefit of tourniquet testing and (iii) to identify patients who would benefit from a policy of selective duplex scanning. HHD accurately assesses the saphenofemoral junction (SFJ) and long saphenous vein (LSV) reflux. HHD assessment of the saphenopopliteal junction (SPJ) reflux has a low positive predictive value. A high negative predictive value reflects absent SPJ reflux assessed using HHD accurately. Tourniquet testing is not helpful. Selective duplex scanning of limbs with suspected SPJ reflux, no identifiable site of reflux or posterior thigh perforator reflux on HDD (39% of limbs), would result in the appropriate surgical procedure being performed in 102 (94%) limbs, excessive surgery in 5 (5%) limbs and inadequate surgery in only 1 (1%) limb. The use of selective criteria for duplex scanning would reduce the workload of the vascular laboratory without compromising patient care.

Adult↗
PubMed1997

The changing face of emphysematous cholecystitis.

Emphysematous cholecystitis is a variant of acute cholecystitis characterized by the presence of gas in the gall bladder lumen, wall or pericholecystic tissues in the absence of an abnormal communication between the biliary system and the gastrointestinal tract. In the past, the diagnosis has relied on the plain abdominal radiograph (AXR), since there are no clinical features to separate this condition from simple acute cholecystitis. The apparently high mortality and morbidity associated with emphysematous cholecystitis has previously emphasized the importance of emergency cholecystectomy. We have reviewed eight cases of emphysematous cholecystitis presenting to this hospital over the last 5 years. The diagnosis was made on AXR in only one of these cases. Ultrasound (US) scans were performed in all eight cases, of which five were positive and three negative, due to non-visualization of the gall bladder. In the three negative cases, the diagnosis was made on subsequent CT scans. On initial clinical examination, only one of the eight patients appeared systemically unwell and conservative management was employed in five of the patients. The remaining three patients underwent cholecystectomy within 3-5 days because of continuing signs or symptoms. It is concluded that the AXR is relatively insensitive in the diagnosis of emphysematous cholecystitis. As a result of the regular use of US in suspected hepatobiliary disease, emphysematous cholecystitis is being diagnosed with increased frequency, uncovering a broad spectrum of disease ranging from mild to severe. Previously, failure to separate milder cases from simple acute cholecystitis may have been responsible for reports of unremitting severity and progression requiring emergency cholecystectomy. Based on clinical assessment, conservative surgical management is possible in a significant proportion of patients.

Acute Disease↗
PubMed1997

The agreement between colour Doppler systems in measuring internal carotid artery peak systolic velocities.

The study was undertaken to determine if the internal carotid artery peak systolic velocities (ICA PSVs) measured by two colour Doppler imaging systems (Acuson 128 and Siemens Quantum) agree sufficiently for the two systems to be interchangeable in evaluating carotid artery disease. One operator obtained blinded measurements of ICA PSV in 63 prospective nonrandomized patients at risk of stroke. The operator examined 20 patients in the first cohort to assess the intraobserver variation, and 43 patients in the second cohort to assess the limits of agreement between the systems. In vitro comparisons of the systems were also undertaken, using both string and flow phantoms. Excluding one outlier, the intraobserver reproducibility coefficient for both machines was 0.48 m s-1. The limits of agreement (within which 95% of differences lie) between systems were -0.47 to 0.45 m s-1. This reduced to -0.39 to 0.33 m s-1 when the one outlier was excluded. This is within the intraobserver reproducibility range. In vitro data show little intersystem variation with phantom velocity. Intratransducer differences increase when the Doppler angle is increased using the string phantom; maximum differences: Acuson 0.30 m s-1 (42%) and Siemens 0.32 m s-1 (32%). These are within the in vivo reproducibility range. Intratransducer difference decreases when the Doppler angle is increased using the flow phantom, maximum differences: Acuson 0.05 m s-1 and Siemens 0.07 m s-1. The results show the systems agree sufficiently to be interchangeable in evaluating carotid artery disease; however, errors in maximum PSVs, caused by operator or system variation, may lead to errors in percent stenosis grading of the carotid arteries.

Adult↗
PubMed1997

Optimising a varicose vein service to reduce recurrence.

A prospective observational study of 63 legs in 49 patients was undertaken to evaluate the adequacy of primary varicose vein surgery performed by surgical trainees. Appropriate surgery was carried out by a surgical senior house officer (SHO) under direct consultant supervision. All patients underwent pre- and postoperative duplex scanning. The preoperative duplex scan demonstrated incompetence of the saphenofemoral junction (SFJ) or long saphenous vein (LSV) in 59 limbs, a mid-thigh perforator (MTP) in 11 limbs, and saphenopopliteal junction (SPJ) in 5 limbs. Surgery successfully abolished all sites of pre-existing reflux. The postoperative duplex scan revealed that 17 new sites of reflux, not identified preoperatively, had developed in 12 limbs. With a consultant-led service and accurate preoperative identification of sites of reflux, the surgical trainee can adequately perform varicose vein surgery. This would seem a reasonable approach to training and eliminating recurrence owing to inadequate surgery. The development of new sites of reflux within 6 months of varicose vein surgery may be owing to altered venous haemodynamics consequent upon this surgery.

Adult↗