Complex circular subsidence structures in tephra deposited on large blocks of ice: Varða tuff cone, Öræfajökull, Iceland.

Several broadly circular structures up to 16 m in diameter, into which higher strata have sagged and locally collapsed, are present in a tephra outcrop on southwest Öræfajökull, southern Iceland. The tephra was sourced in a nearby basaltic tuff cone at Varða. The structures have not previously been described in tuff cones, and they probably formed by the melting out of large buried blocks of ice emplaced during a preceding jökulhlaup that may have been triggered by a subglacial eruption within the Öræfajökull ice cap. They are named ice-melt subsidence structures, and they are analogous to kettle holes that are commonly found in proglacial sandurs and some lahars sourced in ice-clad volcanoes. The internal structure is better exposed in the Varða examples because of an absence of fluvial infilling and reworking, and erosion of the outcrop to reveal the deeper geometry. The ice-melt subsidence structures at Varða are a proxy for buried ice. They are the only known evidence for a subglacial eruption and associated jökulhlaup that created the ice blocks. The recognition of such structures elsewhere will be useful in reconstructing more complete regional volcanic histories as well as for identifying ice-proximal settings during palaeoenvironmental investigations.

Technetium-99m-DMSA studies in pediatric urinary infection.

UNLABELLED: Urinary tract infection (UTI) is a common condition in children and may lead to renal scarring with a risk of later hypertension and renal insufficiency. We made a cross-sectional study of the 99mTc-DMSA findings in 496 children referred for following symptomatic UTI to a Department of Nuclear Medicine and we categorized the results, to provide a framework for further study. METHOD: A standard 99mTc-DMSA protocol was used to study 496 children (157 males, 339 females) aged from birth to 14 yr. Findings were classified according to the image appearance and relative function of each kidney. These were related to age, sex, history and timing of UTI and the results on micturating cysto-urethrography (MCU). RESULTS: Images were normal, with function within limits (45%-50% in one kidney), in approximately half the boys and girls studied. The other images were classified as equivocal in 68 children, abnormal unilaterally in 105 and bilaterally in 76, and they were subdivided according to the image appearance. No image changes could be identified that were specifically associated with acute UTI. Diffuse change alone was uncommon. A high proportion of abnormal images was found in infant boys, older girls with recurrent UTI and those children with vesico-ureteric reflux (VUR). Of the bilateral abnormal images, 98% were seen in children with VUR. CONCLUSION: Our findings suggest that infective renal change may be superimposed on underlying congenital lesions (perhaps detectable antenatally) or may be acquired following UTI in the presence of reflux and are thus potentially preventable. This study also suggests that VUR is almost certain to have occurred in a child who has bilateral abnormal 99mTc-DMSA images following UTI and is also commonly present in those with definite unilateral defects.

U-series disequilibria in a groundwater flow route as an indicator of uranium migration processes.

U-series data relating to groundwater, fracture coatings and the adjoining rock matrix in a groundwater flow system at the Palmottu natural analogue site was examined. The aim was to obtain an experimental reference for migration modelling in a transport section defined within the flow system. The U-series reference obtained turned out to be a very useful tool for fine tuning the flow route and for migration mechanism considerations. The U-series data are well in line with other interpretations of the migration system.

[Radiologic findings in the kidney of children with severe reflux. Five-year comparative study of conservative and surgical treatment]. / Radiologische Nierenbefunde bei Kindern mit schwerem Reflux. Fünfjahresvergleichsstudie konservativer und chirurgischer Behandlung.

The renal findings revealed by intravenous urography (IVU) in 306 children (73 boys, 233 girls) are reported. The children were seen at eight European centres and enrolled in an international study comparing medical and surgical management of children with urinary tract infection and severe vesico-ureteric reflux who were followed for 5 years. In all, 155 children were randomly allocated to medical and 151 to surgical treatment. The protocol and the investigative techniques were standardized, and randomization, data collection and analysis were performed centrally in Essen, Federal Republic of Germany. At entry 149 (49%) had established renal scarring (79 medical, 70 surgical). Presence of normal kidneys (105), areas of thinned parenchyma (52) and grade of reflux were also evenly distributed. IVU was repeated at 6, 18 and 54 months, and serial urine culture, 99mtechnetium-dimer-captosuccinic acid scans and plasma creatinine estimations were performed. Follow-up was complete in 272 children (89%). In 174 children (57%: 90 medical, 84 surgical) there was renal growth without morphological change. New renal scars developed in 19 children treated medically and 20 treated surgically; 12 (5 medical, 7 surgical) developed in previously normal kidneys. Six followed postoperative obstruction. No significant difference in outcome was found between medical and surgical management in terms of the development of new renal lesions or the progression of established renal scars.

Retrospective study of children with renal scarring associated with reflux and urinary infection.

OBJECTIVE: To review the histories of children with bilateral renal scarring and severe vesicoureteric reflux to determine whether an improvement in early management might reduce the risk of scarring. DESIGN: Retrospective study of medical records and discussion with parents. SETTING: Outpatient departments of two teaching hospitals. PATIENTS: 52 children aged 1-12 years participating in a randomised comparison of medical and surgical management. All had a history of symptomatic urinary tract infection. Two thirds presented with fever and two with hypertension or renal failure. In only one out of 32 children examined by antenatal ultrasonography was an abnormality suspected. RESULTS: There was delay in diagnosis or appropriate imaging or effective treatment of urinary infection in 50 of the 52 children. In 41 there was delay in diagnosis; there was delay in treating a confirmed infection in 45; no antibacterial prophylaxis was prescribed before imaging in 28; and investigation of the urinary tract was delayed in 33. The severity of scarring was significantly related to delay in diagnosis (chi 2 for trend 7.43, P = 0.01). Four children of mothers known to have reflux nephropathy were not investigated until they developed urinary tract infection. CONCLUSIONS: Efforts to reduce the incidence and severity of renal scarring should be directed towards rapid diagnosis and effective early management of urinary tract infection in infancy and childhood. Siblings and offspring of known patients with severe reflux nephropathy should be investigated for reflux.

Outpatient waiting times: indicators of hospital performance?

We monitored outpatient waiting times at UK military hospitals over an 18-month period (September 1996-March 1998). The highest mean waiting times for Consultant appointment were in urology (19 weeks) and orthopaedics (18 weeks). The lowest mean waiting times were in psychiatry (3 weeks), ENT surgery (5 weeks) and rheumatology (6 weeks). Waiting times for surgical specialties were around 50% higher than for medical specialties. The inter-hospital variability in waiting times was 260%. Military waiting list initiatives were introduced in 4 key specialties, but the majority of these initiatives only had a temporary impact in reducing outpatient waiting times. Waiting times reflect the accessibility of a hospital's services, and are a crude but easily measured indicator of one aspect of patient care. With a military population base, outpatient waiting times should be reduced to the lowest practicable level. The keys to achieving a long-term reduction in waiting times are proper staffing levels and the efficient management of clinics.

The safety and efficacy of bariatric surgery for obese, wheelchair bound patients.

INTRODUCTION: The aim of this study was to evaluate outcomes of bariatric surgery performed in order to improve mobility in patients with severe mobility limitations. METHODS: Patients with severe mobility impairment (wheelchair bound) who underwent laparoscopic Roux-en-Y gastric bypass (LRYGB) or laparoscopic adjustable gastric banding (LAGB) surgery to improve their mobility were included in this study. Patients were identified between July 2009 and October 2011 using an electronic prospective bariatric database. Mobility was assessed by questionnaire during clinic follow-up appointments. RESULTS: Fifteen patients (11 female, 4 male) with a mean age of 48 years (range: 26-71 years) and a mean body mass index of 46 kg/m(2) (range: 33-54 kg/m(2)) were included. Seven patients (47%) underwent LAGB and eight (53%) LRYGB. The aetiologies of mobility impairment included advanced osteoarthritis (n=6), spinal conditions (n=4), severe bilateral leg oedema and ulceration (n=2), advanced rheumatoid arthritis (n=2) and traumatic paraplegia (n=1). The mean length of hospital stay was 3.8 days. There was no mortality. One patient was lost to follow-up. Of the remaining 14 patients, the mean excess weight loss percentage at a mean of 18.5 months postoperatively was 48% (68% for LRYGB, 20 months; 29% for LAGB, 17 months). Ten patients reported improved mobility. Reduced pain, improved independence and ability to transfer were most commonly cited. Four patients reported no improvement in mobility (three LAGB patients, one LRYGB patient). CONCLUSIONS: Bariatric surgery can safely improve mobility and quality of life in obese patients with severe mobility impairment. Our paper supports the idea that severe mobility impairment should be considered an indication for bariatric surgery in selected patients. LRYGB demonstrated better weight loss and mobility improvement than LAGB. Larger studies are required to establish robust selection criteria for surgery in this group.

Comparison of weight loss achieved after laparoscopic adjustable gastric banding between Afro-Caribbean, Caucasian and South Asian adult female patients in a London bariatric centre.

INTRODUCTION: It has been shown that following laparoscopic adjustable gastric banding (LAGB) procedures, Afro-Caribbeans achieve poorer weight loss compared with Caucasians. The reasons for this are multifactorial. However, studies have been based on mainly female patients from the US and none to date have been from the UK. Furthermore, South Asians have not previously been compared. The aim of this study was to compare excess weight loss percentage (%EWL) outcomes up to five years following LAGB in Afro-Caribbean, Caucasian and South Asian females in a London-based teaching hospital. METHODS: An analysis was carried out of prospectively collected data of female patients aged ≥16 years of Afro-Caribbean, Caucasian or South Asian origin who underwent LAGB between October 2000 and December 2011. Data included demographics, co-morbidities and anthropometrics. RESULTS: Overall, 596 females underwent LAGB; 316 Caucasians (53.0%), 64 Afro-Caribbeans (10.8%) and 27 South Asians (4.5%) formed the majority of those who disclosed ethnicities. Age and initial body mass index (BMI) were comparable between Afro-Caribbeans and Caucasians (mean BMI: 47.3kg/m²[standard deviation [SD]: 7.5kg/m², range: 37.0-78.3kg/m²] vs 45.8kg/m²[SD: 7.1kg/m², range: 24.7-79.8kg/m²], p=0.225). A non-significant trend suggested less %EWL in Afro-Caribbeans than in Caucasians at 6 months, and at 1, 2, 3, 4 and 5 years (21.4% vs 24.4%, p=0.26; 27.4% vs 31.3%, p=0.27; 33.0% vs 36.8%, p=0.15; 39.0% vs 45.8%, p=0.14; 34.2% vs 45.3%, p=0.16; 37.1% vs 47.6%, p=0.67). South Asians and Caucasians had a similar age and preoperative BMI (mean BMI: 43.6kg/m² [range: 32.5-59.1kg/m²] vs 45.8kg/m² [range: 24.7-79.8kg/m²], p=0.08). The %EWL was greatest at three and four years among South Asians although numbers were small (n=4 and n=3 respectively). CONCLUSIONS: A non-significant trend suggests poorer weight loss outcomes in Afro-Caribbeans compared with Caucasians in our cohort. Discussion of realistic weight loss outcomes as well as enhanced follow-up and dietary modifications are required for Afro-Caribbean patients. Low numbers prevent definitive conclusions regarding South Asians. Multicentre studies across England are required to better define any differences between ethnicities.

Commentary: management of children with severe vesicoureteral reflux.

The main findings of the IRSC after 5 years of observation are summarized. Of the 434 children entered 128 were from centers in America and 306 from Europe. They were randomly allocated and stratified to a medical or surgical regimen. Of the children 50% had scarred kidneys at entry evenly distributed between the groups. After 5 years of observation there was no difference in outcome between the 2 treatment groups in terms of renal size and growth, the development of new radiological renal scars or areas of parenchymal thinning, or of progression of established scarring. In Europe infection recurred in equal numbers of children but pyelonephritic symptoms were more common in the medical group. Nevertheless, new scars developed in 19 of 155 children treated medically and 20 of 151 children treated surgically, including 5 and 7, respectively, with previously normal kidneys. Factors influencing the choice of treatment include patient age, availability of expert surgical care and experienced medical supervision, parental choice and compliance. Followup studies indicate that renal scarring rather than persistence of reflux determines the prognosis and, therefore, emphasis should be placed on the prevention of scarring.

The intravenous urogram in the detection and evaluation of renal damage following urinary tract infection.

Intravenous urography (IVU) still provides the most comprehensive structural assessment of the urinary tract. In particular, the radiological renal appearances approximate closely to the morphology of the renal scarring of reflux nephropathy or chronic atrophic pyelonephritis. It also provides reproducible renal measurements for follow-up assessment of renal growth and scarring. It is now less often used for first-line investigation of the acute urinary tract infection (UTI) because the swelling accompanying acute renal involvement is less easily recognised than the areas of defective function demonstrated on 99mtechnetium-dimercaptosuccinic acid (DMSA) studies. Also IVU contributes a higher radiation dose when calculated for full IVU (dependent on the number of films exposed) and there is a slight risk of side effects from injected contrast media, reduced by using non-ionic compounds. Because of its value in confirming such a serious diagnosis as renal scarring, suspected on ultrasonography or DMSA scintigraphy, modification of the technique of IVU with adequate preparation and the use of a reduced number of films, or single films localised to the renal areas, should be considered. Expertise in the interpretation of IVU must also be maintained because of the ancillary information regarding bowel and bladder function, the spine and evidence of stones, pertinent to the management of children with UTI and renal scarring. IVU and DMSA study remain complementary investigations.

Pitfalls in the investigation of children with urinary tract infection.

The histories and imaging results are presented in 10 children in whom errors had been made in the interpretation of early investigations. Ultrasonography may not detect either vesicoureteric reflux (VUR) or renal scars or inflammation. The reduced nephrogram or renal swelling following a first attack of acute pyelonephritis may not be recognised without renal measurement on an intravenous urogram. Renal scarring may be diagnosed incorrectly on the basis of functional defects of isotope uptake on a technetium 99m-dimercaptosuccinic acid study. In the absence of VUR, the micturating cystogram will not visualise the kidneys.

Urinary tract infection: a comparison of four methods of investigation.

The optimal regimen for investigating children with urinary tract infection (UTI) remains uncertain. Ultrasonography, contrast micturating cystourethrography (MCU), intravenous urography (IVU), and technetium-99m dimercaptosuccinic acid (DMSA) studies were performed in 58 children with UTI under 14 years of age attending two teaching hospitals and the results compared. All four investigations were normal in 12 children. In 36 with vesicoureteric reflux (VUR) on MCU, dilatation was reported on ultrasonography in eight children. Radiological renal scarring was seen in 20 children; it was suspected on ultrasonography in nine, with dilatation alone in four, and a normal report in seven. Duplex kidneys identified on IVU were unrecognised on ultrasonography or DMSA studies; ultrasonography showed no change corresponding to presumed acute defects on DMSA studies that later resolved. Disparities were observed at all ages. This study suggests that ultrasonography is unreliable in detecting VUR, renal scarring, or inflammatory change and, alone, is inadequate for investigating UTI in children.

Study of childhood urinary tract infection in general practice.

A study of bacteriuria was conducted among 426 of the 436 children under the age of 13 in a general practice in north-west London. Three girls and one boy were found to have asymptomatic bacteriuria, and a further girl with bacteriuria presented with abdominal pain and fever. The calculated incidence of urinary tract infection was 1.4% per annum. Most of the childhood urinary infections in this practice occurred before the age of 5 years, and the incidence of significant bacteriuria in this age group was 4.9% per annum. Five other children (four girls and one boy) in the practice were known to have had proved urinary tract infection. Of the total of eight children known to have had significant bacteriuria and investigated radiologically, three girls and two boys had radiological abnormalities in the urinary tract.Pyuria and proteinuria did not prove to be useful in the prediction of asymptomatic bacteriuria. Urinary tract infection with renal tract abnormality was found in this practice to be at least five times as common as diabetes in childhood.

Normal somatic growth in children receiving low-dose prophylactic co-trimoxazole.

Co-trimoxazole is an effective antibacterial agent for the prophylaxis of urinary tract infection. Because experimental evidence raises the possibility that high-dose cotrimoxazole might interfere with normal somatic growth, the longitudinal growth and growth velocities were analysed in 114 girls receiving long-term, low-dose prophylactic cotrimoxazole. They were aged 2-12 years at the start of prophylaxis which was given in a daily dose of approximately 10 mg sulphamethoxazole (SMX) and 2 mg trimethoprim (TMP)/kg body weight for at least 6 months and for up to 6 years. There was no significant variation from normal in height or weight attained or in growth velocity overall in 114 girls, 51 of whom had vesico-ureteric reflux (VUR). No difference was found in growth velocity when periods of 6 months on or off prophylactic therapy were compared in 53 girls. Growth did not vary between cohorts of girls receiving co-trimoxazole prophylaxis for 2, 3 or 4 years and growth proceeded normally in the 51 girls with VU reflux. We have not found evidence that long-term, low-dose cotrimoxazole prophylaxis has any adverse effect upon somatic growth in girls with a previous urinary infection with or without vesico-ureteric reflux and who are otherwise healthy.

Prophylactic co-trimoxazole and trimethoprim in the management of urinary tract infection in children.

In a prospective study of low-dose antibacterial prophylaxis of childhood urinary tract infection (UTI), co-trimoxazole and trimethoprim (TMP) have been compared for efficacy in preventing UTI, for their effect on the rectal flora and for secular selection of TMP-resistant organisms. Between 1979 and 1986, 334 children who had proven infection of an unobstructed urinary tract complied in a regimen of low-dose prophylaxis together with measures to eliminate residual urine for at least 6 months. Of these children, 167 had vesico-ureteric reflux and 27 had renal scarring. There was no difference between the two drugs in compliance, which was very good, or in the occurrence of side-effects, which were minimal. Recurrence rates of further infection were 1 per 22 child years for the 226 children receiving cotrimoxazole and 1 per 18 child years for the 108 receiving TMP. All but one of these urinary pathogens were resistant to TMP and reinfection of the urinary tract generally occurred following lapses in attention to complete bladder emptying. Neither a secular increase in recurrent infections during this period, nor a significant change in the proportions of TMP-resistant faecal coliform organisms, was observed. TMP and co-trimoxazole appeared to be equally effective prophylactic agents.

99mTc dimercaptosuccinic acid (DMSA) scan in patients with established radiological renal scarring.

The findings on 99mTc dimercaptosuccinic acid (DMSA) scans were examined in 54 patients aged 3 to 33 years in whom renal scarring had been diagnosed radiologically in childhood after urinary tract infection. There was no recent history of infection. Vesicoureteric reflux had been present in 48 patients and had stopped in 23 at the time of the DMSA scan. In six of the 72 radiologically scarred kidneys, the DMSA scan appeared normal but scarring would have been overlooked in only two of the 54 patients. DMSA scan changes are non-specific and underestimated individual scars in 21 kidneys. The intravenous urogram and the DMSA scan showed good correlation but should be regarded as complementary investigations in these patients, giving morphological and functional information, respectively. On DMSA scans the timing of any preceding urinary tract infection must be considered in order to differentiate diffuse potentially reversible defects in isotope uptake after urinary tract infection from those due to permanent renal scarring.

Disappearance of vesicoureteric reflux during long-term prophylaxis of urinary tract infection in children.

Seventy-five children aged 3 weeks to 12 years and found on investigation of symptomatic urinary infection to have vesicoureteric reflux were managed conservatively with continuous low-dose prophylaxis. Serial cystographic and renal growth studies were performed during seven to 15 years' follow-up. Reflux disappeared spontaneously in 53 children (71%) and from 79% of the affected ureters. This occurred at any age and not only in infancy or at puberty. The initial severity or reflux was the most important factor affecting the outcome. Reflux disappeared from 85% of ureters of normal calibre but from only 41% of dilated ureters. Gross reflux associated with existing severe renal scarring was least likely to disappear. Nevertheless, reflux stopped in 12 of the 19 initially scarred renal units (63%). Reflux was as likely to disappear in children who had a recurrence of urinary infection as in those who had no further infection. Renal growth appeared to be normal in 93% of kidneys and fresh or extending scarring was seen in only two children. Management programmes for children with vesicoureteric reflux should take into account the self-limiting nature of three-quarters of the reflux found on investigating uncomplicated urinary tract infection.