The role of popliteal vein incompetence in the diagnosis of saphenous-popliteal reflux using continuous wave doppler

INTRODUCTION

continuous wave Doppler (CWD) has good discriminatory power at the groin in the assessment of saphenous femoral junction (SFJ); however, it is not as accurate as duplex ultrasound scanning (DUS) in the popliteal fossa for assessment of saphenous popliteal junction (SPJ) in patients with primary short saphenous vein incompetence.

AIM

the aim of this study was to compare the findings of CWD with those of DUS at the SPJ and assess the role of popliteal vein incompetence in the accuracy of CWD.

METHOD

prospective study of consecutive patients presenting to a vein clinic requiring a duplex scan of their SPJ. Each patient was examined by one surgeon using CWD and by one radiologist using DUS. Each observer was unaware of the other's findings. Additional information on the competence of the popliteal vein on DUS was also recorded.

RESULTS

some 171 limbs in 128 patients with varicose veins were studied. One hundred and sixteen limbs had reflux at SPJ on CWD whilst 55 did not. Their mean age was 54 (range 18-85). Female to male ratio was 3:1. Spearman's rank correlation between CWD and DUS has 0.49 (p =0.0001). CWD has a sensitivity of 92% and specificity of 53% (PPV=62%, NPV=89%, accuracy=70%). Twenty-nine limbs had an incompetent popliteal vein (IPV). Of those, 12 limbs also had incompetence on CWD and competence on DUS at the SPJ, which represent 28% of the total number of limbs with these findings (n =43).

CONCLUSION

CWD is sensitive in detecting incompetence at SPJ, though its specificity is low. In this study 17% (n =29) of all patients had incompetence of popliteal vein. Up to 25% ( n =12) of patients with SPJ incompetence on CWD (Doppler +) and competence on DUS (duplex -) had incompetence of the underlying popliteal vein, which may explain the low specificity. The presence of SPJ incompetence on CWD should be confirmed on DUS prior to surgery.

Drug targeting Mycobacterium tuberculosis cell wall synthesis: genetics of dTDP-rhamnose synthetic enzymes and development of a microtiter plate-based screen for inhibitors of conversion of dTDP-glucose to dTDP-rhamnose

An L-rhamnosyl residue plays an essential structural role in the cell wall of Mycobacterium tuberculosis. Therefore, the four enzymes (RmlA to RmlD) that form dTDP-rhamnose from dTTP and glucose-1-phosphate are important targets for the development of new tuberculosis therapeutics. M. tuberculosis genes encoding RmlA, RmlC, and RmlD have been identified and expressed in Escherichia coli. It is shown here that genes for only one isotype each of RmlA to RmlD are present in the M. tuberculosis genome. The gene for RmlB is Rv3464. Rv3264c was shown to encode ManB, not a second isotype of RmlA. Using recombinant RmlB, -C, and -D enzymes, a microtiter plate assay was developed to screen for inhibitors of the formation of dTDP-rhamnose. The three enzymes were incubated with dTDP-glucose and NADPH to form dTDP-rhamnose and NADP(+) with a concomitant decrease in optical density at 340 nm (OD(340)). Inhibitor candidates were monitored for their ability to lower the rate of OD(340) change. To test the robustness and practicality of the assay, a chemical library of 8,000 compounds was screened. Eleven inhibitors active at 10 microM were identified; four of these showed activities against whole M. tuberculosis cells, with MICs from 128 to 16 microg/ml. A rhodanine structural motif was present in three of the enzyme inhibitors, and two of these showed activity against whole M. tuberculosis cells. The enzyme assay was used to screen 60 Peruvian plant extracts known to inhibit the growth of M. tuberculosis in culture; two extracts were active inhibitors in the enzyme assay at concentrations of less than 2 microg/ml.

Comparison of elderly people's technique in using two dry powder inhalers to deliver zanamivir: randomised controlled trial

OBJECTIVE

To determine whether elderly people can learn to use the inhaler used to deliver zanamivir (Relenza Diskhaler) as effectively as the Turbohaler and to identify which aspects of inhaler technique are most problematic.

DESIGN

Randomised, controlled, intervention study.

SETTING

Wards for acute elderly care in a large district general hospital.

PARTICIPANTS

73 patients who were unfamiliar with the use of an inhaler, aged 71 to 99 (mean 83) years.

MAIN OUTCOME MEASURES

Initial scores and changes in scores 24 hours later using a 10 point scoring system of five aspects of inhaler technique.

RESULTS

38 patients were allocated the Relenza Diskhaler and 35 the Turbohaler. The mean total score was significantly greater in the Turbohaler than Diskhaler groups both initially (8.74 v 7.05) and after 24 hours (8.28 v 5.43). The major difference between inhalers was in loading and priming. After tuition 50% (19 of 38) of patients allocated the Diskhaler were unable to load and prime the device and 65% (24 of 37) were unable to do so 24 hours later. Of those allocated the Turbohaler, two patients were unable to load and prime the device after initial review and one after 24 hours.

CONCLUSION

Most elderly people cannot use the inhaler device used to deliver the anti-influenza drug zanamivir. Treatment with this drug is unlikely to be effective in elderly people unless the delivery system is improved.

Simulation of tibial counterface wear in mobile bearing knees with uncoated and ADLC coated surfaces

A multidirectional pin-on-plate reciprocating machine was used to compare the wear performance of UHMWPE sliding against cast cobalt chrome (CoCr) plates that were either untreated or coated with Amorphous Diamond Like Carbon (ADLC). The test conditions were based on a 1/5 scale model representative of in vivo motion at the tibial counterfaces of unconstrained mobile bearing knees. The average +/- STERR wear rates were 13.78+/-1.06 mm3/Mcycles for the ADLC counterfaces and 0.504+/-0.12 mm3/Mcycles for the control CoCr counterfaces. All of the pins run on the ADLC counterfaces exhibited the same patterns of blistering along the central axis, and severe abrasion elsewhere to the extent that all of the original machining marks were removed after just one week of testing. The average value of friction coefficient was 0.24 for the ADLC counterfaces and 0.073 for the control CoCr counterfaces. The factor of 3.5 increase was statistically significant at p < 0.05. In the tribological evaluation of ADLC coatings for tibial trays in mobile bearing knees, this study shows that this specific Physical Vapour Deposition (PVD) ADLC showed significantly poorer frictional and wear performance than uncoated surfaces which was sufficient to negate any potential benefits of improved resistance to third body damage.

Practical and theoretical considerations in the gas chromatography/combustion/isotope ratio mass spectrometry delta(13)C analysis of small polyfunctional compounds

Carbohydrates and proteins are among the most abundant naturally occurring biomolecules and so suitable methods for their reliable stable isotope analysis by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) are required. Due to the non-volatile nature of these compounds they require hydrolytic cleavage to their lower molecular weight subunits and derivatisation prior to GC/C/IRMS analysis. The addition of carbon to the molecules and any kinetic isotopic fractionation associated with derivatisation must be accounted for in order to provide meaningful stable isotope values and estimates of propagated errors. To illustrate these points amino acid trifluoroacetate/isopropyl esters and alditol acetates were prepared from authentic amino acids and monosaccharides, respectively. As predicted from the derivatisation reaction mechanisms, a kinetic isotope effect was observed which precludes direct calculation of delta(13)C values of the amino acids and monosaccharides by simple mass balance equations. This study shows that the kinetic isotope effect associated with derivatisation is both reproducible and robust, thereby allowing the use of correction factors. We show how correction factors can be determined and accurately account for the addition of derivative carbon. As a consequence of the addition of a molar excess of carbon and the existence of a kinetic isotope effect during derivatisation, errors associated with determined delta(13)C values must be assessed. We illustrate how such errors can be quantified (for monosaccharides +/-1.3 per thousand and for amino acids between +/-0.8 per thousand and +/-1.4 per thousand). With the magnitude of the errors for a given delta(13)C value of a monosaccharide or amino acid quantified, it is possible to make reliable interpretations of delta(13)C values, thereby validating the determination of delta(13)C values of amino acids as TFA/IP esters and monosaccharides as alditol acetates.

Topical treatment: which dressing to choose

Wounds have existed since the beginning of time. The interest in this subject has been stimulated in the main by conflict and war that have necessitated the development of new ways of managing wounds. In the 1960s the development of new materials that maintained a moist environment in the wound area encouraged a number of commercial companies to produce a wide variety of new materials with physical and chemical properties that might provide a moist environment. However the data to support the use of such materials are limited if one requires evidence that they have produced more rapid healing in chronic wounds kept moist as to those kept dry. Is this due to a problem with the outcome measure rather than a problem with the materials themselves? Rather than seeing this as justification for not using such materials, it should instead lead clinicians to question the validity of endpoint studies in wound healing experiments. There is a lack of evidence regarding the ability of such materials to improve the speed of healing in chronic wounds. Nevertheless considerable clinical experience, obtained from treating many patients, has indicated that not only are such new treatments cost effective, but that they are also proving to be extremely beneficial and acceptable to patients, on account of their ability to reduce pain, odour or leakage from a wound.

Properties of HLA class II molecules divergently associated with Goodpasture's disease

Goodpasture's disease provides an opportunity to analyse molecular mechanisms that may underlie MHC class II associations with autoimmune disease because it is caused by autoimmunity to a defined antigen [the 230 amino acid NC1 domain of the alpha3 chain of type IV collagen (alpha3(IV)NC1)] and has strong HLA class II associations. We compared the alpha3(IV)NC1 peptide binding of class II molecules with strong positive (DR15) and dominant negative (DR7/1) associations using an inhibition binding assay and short synthetic peptides spanning the sequence of alpha3(IV)NC1. DR15 in general bound the peptides with low affinity (three of 23 < 100 nM) compared to DR1 and DR7 (12 and 10 < 100 nM respectively), and no peptide bound DR15 with much higher affinity (>10-fold) than both DR1 and DR7. Thus DR15 molecules are unlikely to increase susceptibility to Goodpasture's disease by presenting a particular alpha3(IV)NC1-derived peptide uniquely well and DR1/7 are unlikely to protect by their inability to present particular peptides. However DR1/7 could protect by capturing alpha3(IV)NC1 peptides and preventing their display bound to DR15; the binding data suggest that all the major (biochemically detectable) alpha3(IV)NC1 peptides presented bound to DR15 by DR15 homozygous antigen-presenting cells (APC) would bind preferentially to DR1/7 in DR15, 1/7 heterozygote APC.

An experimental model of tibial counterface polyethylene wear in mobile bearing knees: the influence of design and kinematics

Current designs of mobile bearing knees have different kinematics at the tibial counterface articulation; unidirectional represented by linear tracks and rotating platform designs, and multidirectional represented by reduced constraint designs with motion of the tibial surface in A-P and M-L directions simultaneously. One fifth scale experimental models of the tibial counterface articulation have been developed with mean contact stresses of 0.6 MPa. The unidirectional model had a linear reciprocating motion with a 10 mm stroke, the multidirectional model had a reciprocating motion with a 10 mm stroke and simultaneous rotation of +/- 7.5 degrees. Six specimens of GUR415 polyethylene were tested for each model, sliding on polished cobalt chrome counterfaces with Ra < 0.01 micron in 25% bovine serum lubricant. The mean +/- STERR wear rates were: unidirectional 0.045 +/- 0.015 mm3/million cycles and multidirectional 0.44 +/- 0.15 mm3/million cycles. Applying the scaling factor of 5, the predicted wear rates in actual knee prostheses were: unidirectional 0.23 mm3/million cycles and multidirectional 2.2 mm3/million cycles. The order of magnitude increase in wear rate was statistically significant (p = 0.05).

A comparison of large volume spacer, breath-activated and dry powder inhalers in older people

AIMS

To see if elderly people can use the breath-activated (Easi-breathe) and dry powder (Turbohaler) inhalers as effectively as the metered-dose inhaler and Volumatic system.

METHODS

102 inhaler-naive patients (aged 75-101, mean 84 years), without cognitive impairment, were randomly allocated one of Easi-breathe, Turbohaler or metered-dose inhaler and Volumatic placebo inhalers. Standardized tuition was done on enrolment and at 6 h review. Inhaler technique was assessed immediately after enrolment tuition and at 6 and 24 h. Assessment was by scoring (0 = poor, 1 = moderate, 2 = perfect) five aspects of technique.

RESULTS

Mean total scores were significantly (P < 0.005) higher for Turbohaler and Easi-breathe than metered-dose inhaler and Volumatic on enrolment and 6 h and at 24 h (P < 0.045). Fewer patients achieved excellent scores of 9 or 10 when using metered-dose inhaler and Volumatic. The main difficulties were in assembling the metered-dose inhaler and Volumatic and detecting when the metered-dose inhaler and Volumatic or Easi-breathe was empty.

CONCLUSIONS

Breath-activated and dry powder inhalers were more likely to be used correctly than metered-dose inhalers with large volume spacers.

Memories are made of this: the effects of time on stored visual knowledge in a case of visual agnosia

We report the effects of the passage of time on the longterm visual knowledge for objects in a patient with visual agnosia (H.J.A.). The naming of real objects was found to have improved, although this was not associated with any change in H.J.A.'s basic perceptual abilities which were stable over a 16-year period. The improvement in object naming was attributed to better use of non-contour-based visual information (such as surface detail and depth cues). In addition, we demonstrate a deterioration in H.J.A.'s long-term memory for the visual properties of objects, and argue that this has occurred as a result of his having impaired perceptual input. The deterioration was only apparent in drawing from memory and in the verbal descriptions of items; with forced-choice testing, H.J.A. operated at ceiling; we propose that current tests of visual imagery may not be sufficiently sensitive to detect subtle impairments of visual memory. Our findings can be taken to indicate that perceptual and memorial processes are not functionally independent, but are linked in an interactive manner.

Anti-MUC1 class I restricted CTLs in metastatic breast cancer patients immunized with a synthetic MUC1 peptide

Sixteen metastatic breast cancer patients were immunized with a low dose (5 micrograms) of a 16 amino acid MUC1 peptide (GVTSAPDTRPAPGSTA) conjugated to KLH (BP16-KLH) plus DETOX adjuvant and evaluated for antibody titers against MUC1 peptide and KLH and for cytotoxic lymphocyte (CTL) activity using class 1 HLA-matched MUC1-positive tumor targets. All patients generated strong anti-KLH IgG responses. Only 3 patients developed an anti-MUC1 IgG response, which was weak in magnitude. As it is controversial whether human cancer patients generate class-1-restricted CTL against MUC1, we examined anti-MUC1 CTL activity of PBLs following 4 immunizations with BP16-KLH. The generation of MUC1-specific CTLs required only a 6-day in vitro stimulation of patients' T-cells with synthetic MUC1-peptide-pulsed autologous APCs. The assay for CTL activity was a 4 hour 51Cr release from labeled adenocarcinoma target cells. Eleven of the 16 immunized patients were tested for CTL activity using class-1-matched adenocarcinoma target cell lines. Evidence for class-1-restricted killing of MUC1-expressing tumor cell lines was obtained in 7 of these 11 patients.

Phase I trial of retinoic acid and cis-platinum for advanced squamous cell cancer of the head and neck based on experimental evidence of drug synergism

OBJECTIVE

Cis-platinum and 13-cis-retinoic acid have received much attention in the treatment of head and neck squamous cell cancer. Even though they have different mechanisms of action, little information is available on their interaction. This paper reviews experimental evidence for retinoic acid-cis-platinum synergy and presents toxicity data from patients with stage IV head and neck squamous cell cancer participating in a phase I trial combining 13-cis-retinoic acid and cis-platinum.

METHODS

Patients were given 13-cis-retinoic acid orally daily for 7 days before and daily during high-dose (150 mg/m2 per week for 4 weeks) intraarterial cis-platinum treatment with concurrent radiation. Toxicity was scored with use of the cancer and leukemia group B scale.

RESULTS

In the phase I clinical trial, 15 patients were treated to determine a maximum tolerated dosage for 13-cis-retinoic acid of 20 mg/day. Grade 4 hematologic toxicity was dose limiting in 3 of 8 patients treated with 40 mg/day and in 1 patient treated with 60 mg/day. There were no deaths caused by toxicity; 12 of the 15 patients received all four weekly doses and the remaining 3 received three doses. Of 10 patients with fully evaluable data, all achieved a complete response at the primary site and 9 had a complete response in the neck. One patient had persistent neck disease after chemoradiation, and this tumor was removed with neck dissection.

CONCLUSIONS

13-Cis-retinoic acid and cis-platinum are strongly synergistic against head and neck squamous cell cancer in vitro. Pretreatment with retinoic acid results in stronger synergy than concurrent drug exposure alone. Preliminary clinical experience with combined retinoic acid and cis-platinum in a design that parallels the in vitro study indicates that toxicity is acceptable with 13-cis-retinoic acid dosages of 20 mg/day in a high-dose-intensity intraarterial chemoradiation regimen.

Protein markers in cerebrospinal fluid from BSE-affected cattle

Two-dimensional gel electrophoresis was used to analyse cerebrospinal fluid (CSF) from 75 suspect cases of bovine spongiform encephalopathy (BSE), 61 of which were confirmed by post mortem brain histopathology, and 38 normal cattle. CSF samples were also examined from cattle killed at periodic intervals through the incubation period following experimental challenge. Consistent changes were recorded in all CSF samples from the confirmed cases of natural BSE and also from cattle showing early signs of experimental disease. The changes consisted of an increased intensity of staining of apolipoprotein E and the presence of two protein spots, as yet unidentified, of molecular weights 35 and 36 kDa, both with a pI of 5.5. These changes were absent in the CSF samples from the normal cattle, from the clinically suspect cattle which were not confirmed as BSE and from the experimentally challenged cattle in the preclinical phase of infection.

Caring for children with wounds

An update on the problems associated with managing children with wounds and their families