Ultrasonography for suspected deep vein thrombosis: how useful is single-point augmentation?

AIMS: To assess the role of single-point augmentation of spectral Doppler flow in the diagnosis of acute deep vein thrombosis (DVT). Secondary objectives included identifying the augmentation response in non-DVT diagnoses. METHODS: Patients attending the ultrasound departments of two hospitals for investigation of suspected acute DVT during an 8-month period were recruited to the study group. Spectral Doppler assessment of the superficial femoral vein was recorded during Valsalva and calf compression manoeuvres in the asymptomatic and symptomatic legs. The Doppler waveforms from the symptomatic limb were characterized as "normal" or "abnormal" by the operator. Standard compression ultrasonography of the symptomatic leg was then performed with the presence of DVT or an alternative diagnosis documented. RESULTS: One hundred and sixty-seven patients underwent ultrasound examinations using the study methodology. Nine patients were subsequently excluded due to bilateral DVT or inability to tolerate calf compression. The mean age of the remaining 158 patients was 65.4 years with 28 DVTs identified (18% of patients). Calf compression elicited a normal response in 118/130 of non-DVT examinations (specificity 91%) and an abnormal response in 18/28 DVT examinations (sensitivity 64%). Diminished or absent augmentation was identified in alternative diagnoses that included haematoma and Baker's cyst. CONCLUSIONS: This study demonstrates that single-point augmentation has a low sensitivity in suspected lower-limb DVT, and that the majority of undetected DVTs are isolated to the calf veins. An abnormal augmentation response is a poor predictor of lower-limb DVT as alternative diagnoses can produce diminished or reduced augmentation. Therefore, single-point augmentation does not add to the standard compression ultrasound examination for suspected DVT and should not be routinely performed.

Does antenatal pelvic dilation predict renal scarring?

Moderate antenatal renal pelvic dilation (5-15 mm) may suggest vesicoureteric reflux, but it is not known to predict renal scarring. Dimercaptosuccinic acid scans on such children aged over 4 years showed a scarring rate (0/133 boys, 1/56 girls) similar to our local population. Investigation and treatment of moderate dilation may not be required.

delta-opioid receptor mobilization of intracellular calcium in SH-SY5Y cells: lack of evidence for delta-receptor subtypes.

delta-opioid receptor agonists mobilize intracellular Ca2+([Ca2+]i) in SH-SY5Y cells when applied in the presence of muscarinic agonists. The putative delta 1 receptor agonist [D-Pen2,D-Pen5]-enkephalin (DPDPE) elevated [Ca2+]i with an EC50 of 11 nM and the putative delta 2 agonist deltorphin II elevated [Ca2+]i, with an EC50 of 14 nM. The maximal elevations of [Ca2+]i caused by both agonists were not different, nor were maximally effective concentrations of DPDPE (1 microM) and deltorphin II (1 microM) applied together more effective than either agonist applied alone. The elevations of [Ca2+]i caused by DPDPE (1 microM) and deltorphin II (1 microM), in the presence of carbachol, desensitized rapidly with continued opioid exposure and the cross-desensitization between PDPDE and deltorphin II was complete. The putative delta 1 selective antagonist 7-benzylidenenaltrexone (BNTX) and the putative delta 2 selective antagonist naltriben both reduced the elevations of [Ca2+]i caused by DPDPE (30 nM) and deltorphin II (10 nM), by greater than 50% at concentrations of less than 10 nM. In SH-SY5Y cells delta-receptor mediated elevation of [Ca2+]i is mediated by a population of receptors, which does not discriminate between agonists and antagonists purportedly selective for delta 1 or delta 2 receptors.

Characterisation and partial purification of the GABA(B) receptor from the rat cerebellum using the novel antagonist [3H]CGP 62349.

The novel GABA(B) receptor antagonist [3H]CGP 62349 binds rat cerebellar synaptosomal membranes with high affinity at a single population of sites (K(d) = 0.9 nM, B(max) = 760 fmol/mg protein). Solubilisation with 1% Triton X-100/0.5 M NaCl/10% glycerol resulted in a marked increase in [3H]CGP 62349 binding (K(d) = 0.5 nM, B(max) = 1285 fmol/mg protein). Competition of [3HCGP 35348 = CGP 36742. The GABA(A) ligand isoguvacine did not displace [3H]CGP 62349 binding. Partial purification of [3H]CGP 62349 binding sites was obtained by sucrose density centrifugation and a predominant protein in the peak binding fraction was recognised by an anti-GABA(B) receptor antibody and had a molecular weight similar to the recombinant expressed GABA(B)R1a. These results demonstrate that [3H]CGP 62349 provides a useful additional tool for further characterisation of the pharmacology and biochemistry of the native GABA(B) receptor.

Survey of general practitioners' opinions on the role of radiology in patients with low back pain.

Ninety general practitioners responded to a questionnaire about the role of radiology in patients with low back pain. Their clinical indications for requesting radiographs were mostly in agreement with the opinions of radiologists, but nearly 80% requested investigations for their own or patients' reassurance. Understanding of the terms used by radiologists was good, although 25% thought that acute disc prolapse could be demonstrated on plain films. Previous training in radiology did not seem to influence knowledge. When general practitioners understood radiological terms they had clear therapeutic and specialist referral preferences. Poorly understood terms and those with which they were familiar but unclear about the implications for management were also identified.

Computerized planimetry in the objective assessment of the antispasmodic effect of Zamifenacin in double contrast barium enemas.

A prospective, randomized, double-blind study was undertaken to evaluate Zamifenacin 30 mg (Pfizer Ltd), a novel, orally-administered, gut-specific muscarinic receptor antagonist, as an adjuvant to the double contrast barium enema examination (DCBE). Zamifenacin was compared with placebo in terms of side-effects and colonic tone. Analysis of colonic tone was carried out by two independent observers, using a subjective grading system and also by an objective method using computerized planimetry. Interobserver variability was also assessed. Zamifenacin is safe and well tolerated but at the prescribed dose is an ineffective antispasmodic for DCBE. Subjective assessment of colonic tone was shown to be of limited value whilst the objective analysis using computerized planimetry was reliable and highly reproducible.

Computed tomography evaluation of renal parenchymal volume in patients with chronic pyelonephritis and its relationship to glomerular filtration rate.

The measurement of renal parenchymal volume using a calibrated computed tomography image processing method has been evaluated clinically on a cohort of patients with chronic pyelonephritis. Comparison of renal volume with function as assessed by 99Tcm DTPA renography demonstrated a simple linear relationship in patients who were normotensive and aproteinuric. The implications of this result on the interpretation of prognostic factors determining declining renal function in chronic pyelonephritis are discussed.

How reliable are ultrasound measurements of renal length in adults?

Ultrasound assessment of patients with renal impairment commonly includes measurement of bipolar renal length. Reduction in length is considered to indicate chronic renal disease and is a factor in deciding whether to proceed to renal biopsy. To date, no published data are available on interobserver and intraobserver variation in sonographic renal length measurement in adults. Bilateral renal lengths were measured in 20 adult subjects, with no history of renal disease, by three experienced operators, on two separate occasions. Limits of agreement for replicate measurements by each ultrasonographer and for replicate measurements by each pair of ultrasonographers were determined. Values of repeatability (a measure of intraobserver variation) and reproducibility (a measure of interobserver variation) were calculated for all renal length measurements, and for right and left renal lengths separately. Results indicate that replicate renal length measurements differ by less than 1.85 cm in 95% of cases, and the magnitude of variations is similar when measurements are made by either single or different ultrasonographers, and are similar for right and left renal length measurements. This suggests that sonographic bipolar renal length measurements in normal adult kidneys are reasonably reliable. In diseased kidneys, however, in which identification of renal poles is difficult, interobserver and intraobserver variation may be much greater.

Evaluation of "Gastromiro" for bowel opacification during computed tomography: comparison with diatrizoate and barium sulphate.

A new oral formulation of iopamidol, "Gastromiro", was evaluated as a bowel contrast agent during abdominal computed tomography (CT). Comparison was made with the well established agents sodium/meglumine diatrizoate ("Urografin 370") and dilute barium sulphate ("E-Z CAT") in a randomized, blind study of 150 consecutive patients undergoing abdominal and/or pelvic CT. Parameters assessed included quality of bowel opacification, artefact generation, contrast-medium palatibility, side effects and cost. No significant difference was found between the three contrast media in stomach- or small-bowel opacification. E-Z CAT was superior at opacifying the caecum/ascending colon. No compelling reason to choose a particular agent was found in the other assessed parameters, but cost is a significant factor.

Toxaphene congeners in the Canadian Great Lakes basin: temporal and spatial food web dynamics.

Samples of a top predator fish species, lake trout (Salvelinus namaycush) and predominant forage species including smelt (Osmerus mordax), alewife (Alosa pseudoharengus), slimy sculpin (Cottus cognatus), deepwater sculpin (Myoxocephalus quadricornis) and lake herring (Coregonus artedii) were, collected from throughout 4 of the 5 Great Lakes (Superior, Huron, Erie and Ontario) (Fig. 1). Lake trout were also collected from three isolated lake systems (Lakes Nipigon, Simcoe and Opeongo), all located within the basin. All the samples were analysed for body burdens of total toxaphene and 22 toxaphene congeners. In addition, from each of the Great Lakes sites samples of major invertebrate dietary items, which included Mysis relicta, Diporeia hoyi and plankton, were similarly analysed. Whole lake trout samples, archived at -80 degrees C, were reanalysed to determine historical trends of toxaphene congeners plus carbon and nitrogen stable isotope signatures. The Lake Superior food web consistently had the highest levels of total toxaphene of all the Great Lakes monitored. The primary source of toxaphene to Lake Superior has been identified as atmospheric transport and deposition from sites in the southern US, Mexico and Central America (Hoff, R.M., Strachan, W.M.J., Sweet, C.W., Chan, C.H., Shackelton, M., Bidleman, T.F., Brice, K.A., Burnison, D.A., Cussion, S., Gatz, D.F., Harlin, K., Schroeder, W.H., 1996. Atmospheric deposition of toxic chemicals to the Great Lakes: A review of data through 1994. Atmospheric Environ. 30, 3505-3527). Of the offsystem lakes surveyed. Lake Nipigon, situated due north of Lake Superior and with a Lake Basin area of about 6% of Lake Superior (Hendendorf, C.E., 1982. J. Great Lakes Res. 8(3), 379-412) had total toxaphene levels in lake trout equivalent to about 50% of those found in lake trout from Lake Superior. Temporal trend toxaphene congener analysis was conducted on archived whole fish samples collected over the period 1980 through to the 1990's. Initially a nonachlorobornane congener (Parlar #50) was predominant, with congeners #40, #62 and #21 being the next most prominent in the 1980 samples. Samples from the 1990's showed a significant decline in the presence of lower chlorinated congeners #40 and #21. Analysis of total toxaphene in food webs, indicated elevated levels in lower trophic level species such as Diporeia and Cottus sp. which have a benthic association. The stable isotope temporal trend 13C signature identified a significant shift in the lake trout diet over the period 1993 to 1996.

The Great Lakes Fisheries Specimen Bank: a Canadian perspective in environmental specimen banking.

Since 1977 the Canadian Department of Fisheries and Oceans (DFO) has maintained a specimen bank for retrospective chemical analyses. The Great Lakes Fisheries Specimen Bank (GLFSB) is a complementary activity to the department's ongoing Great Lakes Contaminants Surveillance Program that has annually, since 1977, monitored levels of metals and organochlorines in aquatic biota throughout the Canadian Great Lakes. Past activities have focused on defining the effects of long-term frozen storage on the integrity of organochlorine residues in archived biological tissues. Archived samples have been reanalyzed for total PCBs, PCB congeners including co-planar PCBs, dioxin and furan isomers, and 22 toxaphene congeners. More recently, archived samples of predatory fish have been analyzed for stable isotopes of nitrogen (delta 15N) and carbon (delta 13C), as indicators of historical changes in food web dynamics. A catalogue or user-guide has recently been completed describing all information associated with samples stored in the GLFSB.

The direct measurement of glomerular filtration rate from the continuous monitoring of DTPA clearance.

A method of measuring glomerular filtration rate is proposed, intended for use during gamma camera renography and involving the continuous monitoring of DTPA activity in blood, a single blood sample, and a urine collection. Data obtained from experiments using a CsI scintillation detector are presented and used to demonstrate the validity of the method. In a comparison with a direct measurement of renal clearance of DTPA the proposed method showed an average overestimate of 13% compared to an overestimate of 30% for an uncorrected single-compartment model calculation of filtration rate. Some limited data using a gamma camera to monitor the DTPA activity in blood are also presented.

New renal scarring in children who at age 3 and 4 years had had normal scans with dimercaptosuccinic acid: follow up study.

OBJECTIVE: To determine up to what age children remain at risk of developing a new renal scar from a urinary tract infection. DESIGN: Follow up study. Families of children who had normal ultrasound scans and scanning with dimercaptosuccinic acid (DMSA) after referral with a urinary tract infection when aged 3 (209) or 4 (220) were invited to bring the children for repeat scans 2-11 years later. A history of infections since the original scan was obtained for children not having a repeat scan. SETTING: Teaching hospital. SUBJECTS: Children from three health districts in whom a normal scan had been obtained at age 3-4 years in 1985-1992 because of a urinary tract infection. MAIN OUTCOME MEASURE: Frequency of new renal scars in each age group. RESULTS: In each group, about 97% of children either had repeat scanning (over 80%) or were confidently believed by their general practitioner or parent not to have had another urinary infection. The rate of further infections since the original scan was similar in the 3 and 4 year old groups (48/176 (27%)) and 55/179 (31%)). Few children in either group known to have had further urinary infections did not have repeat scanning (3/209 (1.4%) and 4/220 (1.8%)). In the 3 year old group, 2.4% (5/209) had one or more new kidney scars at repeat scanning (one sided 95% confidence interval up to 5.0%), whereas none of the 4 year olds did (one sided 95% confidence interval up to 1.4%). The children who developed scars were all aged under 3.4 years when scanned originally. CONCLUSIONS: Children with a urinary tract infection but unscarred kidneys after the third birthday have about a 1 in 40 risk of developing a scar subsequently, but after the fourth birthday the risk is either very low or zero. Thus the need for urinary surveillance is much reduced in a large number of children.

Do systemic symptoms predict the risk of kidney scarring after urinary tract infection?

BACKGROUND AND AIMS: In the NICE guideline on childhood urinary tract infection (UTI), it is assumed that the presence or severity of systemic symptoms, especially fever, predicts for renal scarring, and different management is recommended accordingly. We aimed to test this hypothesis by retrospective case note analysis. DESIGN AND SUBJECTS: Notes of children aged under 5 years referred with a first UTI who were assessed for scarring were reviewed. MAIN OUTCOME CRITERIA: Ability to predict for single or multiple scarring from age, sex, fever, vomiting or anorexia or malaise, or need for hospitalisation, within the age bands used by NICE. RESULTS: There were 51 (65% girls) scarred and 140 (69% girls) unscarred children. Fever, systemic symptoms and hospitalisation were all commoner among younger children (<6 months vs 6 months-3 years vs >3 years; fever 0.67 vs 0.38 vs 0.38; systemic symptoms 0.78 vs 0.62 vs 0.43; hospitalisation 0.67 vs 0.29 vs 0.19; p<0.001 for all). Having vomiting, anorexia or malaise at presentation correlated weakly with single or multiple renal scarring (R(2) = 0.03; p = 0.02), but sex, age, fever or hospitalisation did not (p>0.5 for all). Sensitivity and specificity data, and plots of proportionate reduction of uncertainty showed that none of these variables was useful for predicting any scarring in children aged <3 years and that they were only weakly predictive in older children. CONCLUSIONS: Clinical signs at presentation in childhood UTI cannot be used to predict for mild or multiple scarring, and should not be used to guide management. NICE's recommendation to do so is not justified.

Investigating suspected acute pulmonary embolism - what are hospital clinicians thinking?

AIMS: To assess local clinical knowledge of the appropriate investigation of suspected acute pulmonary embolism (PE) and this compare with the 2003 British Thoracic Society (BTS) guidelines as a national reference standard. METHODS: A clinical questionnaire was produced based on the BTS guidelines. One hundred and eight-six participants completed the questionnaires at educational sessions for clinicians of all grades, within a single NHS Trust. The level of experience amongst participants ranged from final year medical students to consultant physicians. RESULTS: The clinicians were divided into four groups based on seniority: Pre-registration, Junior, Middle, and Senior. Forty-six point eight percent of all the clinicians correctly identified three major risk factors for PE and 25.8% recognized the definition of the recommended clinical probability score from two alternatives. Statements regarding the sensitivity of isotope lung imaging and computed tomography pulmonary angiography (CTPA) received correct responses from 41.4 and 43% of participants, respectively, whilst 81.2% recognized that an indeterminate ventilation-perfusion scintigraphy (V/Q) study requires further imaging. The majority of clinicians correctly answered three clinical scenario questions regarding use of D-dimers and imaging (78, 85, and 57.5%). There was no statistically significant difference between the four groups for any of the eight questions. CONCLUSIONS: The recommended clinical probability score was unfamiliar to all four groups of clinicians in the present study, and the majority of doctors did not agree that a negative CTPA or isotope lung scintigraphy reliably excluded PE. However, questions based on clinical scenarios received considerably higher rates of correct responses. The results indicate that various aspects of the national guidelines on suspected acute pulmonary embolism are unfamiliar to many UK hospital clinicians. Further research is needed to identify methods to improve this situation, as both clinicians and radiologists have a duty to ensure that patients are appropriately investigated.

Duodenal loop widening in pancreatic diseases.

The magnitude of the duodenal loop in patients with a variety of pancreas-associated disease has been accurately measured and compared with those values encountered in a series of normal subjects in order to assess if any widening had occurred. Using a Student's t-test all the patients with pancreatic disease were indistinguishable from the control subjects at the 5% level, and the validity of this effect as a diagnostic tool is questioned.

Correlations between duodenal loop size and external body measurements.

Measurements of the area, height and width of duodenal loops in male and female controls were correlated with their body height, weight, surface area, lean body mass and adjusted body surface area in order to assess the possibility of predicting loop size from body habitus. In male subjects the most marked correlations were between bodyweight and loop area (r = 0.58) and between true body surface area and loop area (r = 0.57). No relationship was observed between the size of the duodenal loop and body size in females.