Effect of copper oxide nanoparticles on two varieties of sweetpotato plants.

Little information is available on the interaction of CuO nanoparticles (nCuO) with tuberous roots. In this study, Beauregard-14 (B-14, low lignin) and Covington (COV, high lignin) sweetpotato varieties were cultivated until maturity in soil amended with nCuO, bulk copper oxide (bCuO) and CuCl2 at 25-125 mg/kg. The Cu treatments had no significant influence on chlorophyll content. Gas exchange parameters were not affected in B-14. In COV, however, at 125 mg/kg treatments, bCuO reduced the intercellular CO2 (11%), while CuCl2 increased it by 7%, compared with control (p ≤ 0.035). At 25 mg/kg nCuO increased the length of COV roots (20.7 ± 2.0 cm vs. 14.6 ± 0.8 cm, p ≤ 0.05). In periderm of B-14, nCuO, at 125 mg/kg, increased Mg by 232%, while the equivalent concentration of CuCl2 reduced P by 410%, compared with control (p ≤ 0.05). The data suggest the potential application of nCuO as nanofertilizer for sweetpotato storage root production.

Two-Photon Microscopy and Spectroscopy Studies to Determine the Mechanism of Copper Oxide Nanoparticle Uptake by Sweetpotato Roots during Postharvest Treatment.

The interaction of engineered nanoparticles with plant tissues is still not well understood. There is a lack of information about the effects of curing (postharvest treatment) and lignin content on copper uptake by sweetpotato roots exposed to copper-based nanopesticides. In this study, Beauregard-14 (lower lignin) and Covington (higher lignin) varieties were exposed to CuO nanoparticles (nCuO), bulk CuO (bCuO), and CuCl2 at 0, 25, 75, and 125 mg/L. Cured and uncured roots were submerged into copper suspensions/solutions for 30 min. Subsequently, root segments were sliced for imaging with a 2-photon microscope, while other root portions were severed into periderm, cortex, perimedulla, and medulla. They were individually digested and analyzed for Cu content by inductively coupled plasma-optical emission spectroscopy. Microscopy images showed higher fluorescence in periderm and cortex of roots exposed to nCuO, compared with bCuO. At 25 mg/L, only bCuO showed higher Cu concentration in the periderm and cortex of Beauregard-14 (2049 mg/kg and 76 mg/kg before curing; 6769 mg/kg and 354 mg/kg after curing, respectively) and in cortex of Covington (692 mg/kg before curing and 110 mg/kg after curing) compared with controls ( p ≤ 0.05). In medulla, the most internal tissue, only Beauregard-14 exposed to 125 mg bCuO/L showed significantly ( p ≤ 0.05) more Cu before curing (17 mg/kg) and after curing (28 mg/kg), compared with control. This research has shown that the 2-photon microscope can be used to determine CuO particles in nondyed plant tissues. The lack of Cu increase in perimedulla and medulla, even in roots exposed to high CuO concentrations (125 mg/L), suggests that nCuO may represent a good alternative to protect and increase the shelf life of sweetpotato roots, without exposing consumers to excess Cu.

Estimation of lean body mass in children.

BACKGROUND: In adults, dosages of some anaesthetic agents are based on lean body mass (LBM) rather than body weight. Our aim was to derive an equation for estimating LBM in children. METHODS: Patients comprised three groups: prospective kidney transplant donors from two separate centres (centres 1 and 3) and children referred to a further centre (centre 2) for the routine clinical measurement of glomerular filtration rate (GFR). GFR and extracellular fluid volume (ECV) were measured using Cr-51-EDTA. LBM was directly estimated (eLBM) in adults using an equation based on height and weight. ECV in children was estimated (eECV) from another equation based on height and weight, converted to eLBM using the relationship between eLBM and ECV determined in the adults from centre 1 and then compared with adult data from centre 3. RESULTS: In children, the ratio of eECV to ECV was 1.04 (SD 0.18). In centre 1, eLBM (kg) was 3.81 (SD 0.55) times greater than ECV (litres) in men (n=50) and 3.77 (0.77) times greater in women (n=51). eLBM in children was therefore derived by multiplying eECV by 3.8. In children, eLBM showed a close linear correlation with measured ECV (eLBM=3.50ECV+2.0; R(2)=0.857), similar to adults (eLBM=2.82ECV+14.5; R(2)=0.582). In all groups, eLBM/weight correlated inversely with weight. CONCLUSIONS: In terms of the relationships between eLBM, ECV, and weight, children are similar to adults. Therefore, drug dosage in children should also be based on eLBM rather than weight.

Prospective assessment of patient directed outpatient communication from a patient and general practitioner perspective.

BACKGROUND: Following the NHS Cancer Plan of 2000, patients should automatically be offered copies of correspondence between NHS clinicians. All patients in this centre increasingly receive a copy of correspondence between the hospital clinicians and general practitioners (GPs). However, we challenged this further by providing patients with a letter written directly to them and sending a copy of this correspondence to the GP. METHODS: 125 patients were requested to complete a 22 item questionnaire to assess the satisfaction of the clinic letter and appointment between May and June 2007. We sent 234 GPs, who refer patients to the Royal Devon & Exeter Hospital, two samples of the new style clinic letters and a 9 item structured questionnaire to assess their satisfaction with these clinic letters. RESULTS: The study had a 90% response rate from patients and 61% from GPs, respectively. Patients felt the clinic letters accurately reflected their clinic appointment, with 94% of patients either satisfied or highly satisfied with the clinic letters. Overall 75% of patients preferred to receive patient directed letters to receiving a copy of the GP letter. However, only 79% of GPs felt patients should routinely receive a clinic letter. CONCLUSIONS: The majority of patients were satisfied with this new style of clinic letters and expect to receive them in the future. The high satisfaction rates could be attributed to the simple and clear language used in the letters. However, the views of patients have not been reflected by GPs, with 20% of GPs preferring to receive a personally directed letter.

Reliability of the MDRD method for estimating glomerular filtration rate in relation to gender, body mass index and extracellular fluid volume.

BACKGROUND: The accuracy of estimating glomerular filtration rate from plasma creatinine (eGFR) has been questioned but it is unclear how much covert error in several reference methods that have been used has contributed to this perceived inaccuracy. The aim of the study was to evaluate eGFR in comparison with a second 'gold standard' to test the performance of the primary gold standard and to examine the influence of patient demographics (age, body mass index (BMI), extracellular fluid volume (ECV) and gender). DESIGN: Non-fasting multisample GFR and ECV were measured in 80 subjects simultaneously and independently with Cr-51-EDTA (GFR(EDTA)) and iohexol (GFR(iohexol)). Percentage bias and imprecision in the prediction of, and disagreement with, GFR(EDTA) were compared between eGFR and GFR(iohexol). Another simplified method for measuring GFR, the slope-only method ((SO)GFR), was also evaluated against multisample GFR (measured with the opposing indicator). Accuracies were assessed in all subjects and across age, BMI and ECV boundaries of 65 y, 29 kg m(-2) and 14 L. RESULTS: eGFR was less precise than GFR(iohexol) (imprecisions of 22.3% and 12.9%; P < 0.01). The precision of (SO)GFR was intermediate between eGFR and GFR(iohexol). Both GFR(iohexol) and eGFR were less precise in the elderly, the obese and men, but minimally influenced by ECV. (SO)GFR was minimally influenced by subject demographics. CONCLUSION: Although eGFR does not predict GFR (based on a primary gold standard) as accurately as a second gold standard, a significant component of its poor performance is the result of inaccuracy in the primary gold standard. (SO)GFR measured with Cr-51-EDTA is superior to eGFR.

Association between glomerular filtration rate and extracellular fluid volume in normal subjects and patients with renal impairment.

The aim of the study was to determine the extent to which glomerular filtration rate (GFR) measured with one filtration marker is associated with extracellular fluid volume (ECV) measured independently with another. Cr-51-EDTA and iohexol were injected simultaneously into opposite arms in 20 normal volunteers and 60 patients. Cubital samples taken bilaterally at 20, 40, 60, 120, 180 and 240 min were assayed for marker injected contralaterally. GFR was scaled to body surface area of 1.73 m(2) (GFR/BSA). GFR was also expressed as marker transit time (GFR/ECV) and ECV as the product of marker transit time and GFR/BSA. In normal subjects, changes between fasting and non-fasting ECV/BSA correlated positively with changes in GFR/BSA, but not GFR/ECV. GFR/BSA and GFR/ECV correlated positively (regression slope approximately 4 ml.min(-1).litre(-1)) and negatively (-2.7 ml x min(-1) x litre(-1)), respectively, with ECV/BSA. The difference, 6.7 ml x min(-1) x litre(-1), expressed as a fraction of average scaled GFR ( approximately 90 ml x min(-1)) is close to the reciprocal of average ECV/BSA (13.5 litres.1.73 m(-2)), consistent with the expected slope of the regression on ECV/BSA of the difference-to-average ratio of GFR/BSA and GFR/ECV. In contrast, in 29 patients with impaired GFR (estimated from plasma creatinine), ECV/BSA correlated inversely with GFR/ECV (slope approximately -5 ml x min(-1) x litre(-1)) but showed no relation with GFR/BSA. We conclude that in normal subjects GFR/BSA increases in response to increasing ECV/BSA, but the increase is not proportionate, leading to a weak inverse association between GFR/ECV and ECV/BSA. When ECV is expanded in patients with renal impairment, however, there is no GFR response, leading to a reduction in GFR/ECV.

A comparison of performance of three gamma camera systems for positron emission tomography.

The development of coincidence positron imaging using a gamma camera should significantly increase PET utilization. This study has compared the performance of three such systems with each other and with an equivalent single photon emission computed tomography (SPECT) measurement. A Carlson phantom, which consisted of a 20 cm diameter cylinder containing areas of uniform activity, hot lesions, cold lesions and orthogonal alternate hot and cold lines, was filled with an activity of 18F chosen to try and best exploit each camera and imaged for a fixed time (27 min). The image quality of 9 mm thick slices in each section of the phantom was compared visually. Several image quality parameters were also compared including line source resolution and noise equivalent count rate. There were considerable differences in PET image quality between the three cameras but all were at least as good as the SPECT image. The full width at half maximum (FWHM) resolution of all systems was similar (approximately 4.5 mm) but the maximum noise equivalent count rates in a 20 cm cylinder were significantly different (6.3, 2.6 and 1.6 kcps) (where cps is counts per second) and correlated with the phantom image quality.

Which patients with prostatic carcinoma require a staging bone scan?

OBJECTIVE: To determine whether the level of prostate-specific antigen (PSA) can be used to decide which patients with newly diagnosed prostatic carcinoma require a staging bone scan. PATIENTS AND METHODS: Of patients referred during an 18-month period for a staging bone scan, 98 (median age 72 years, range 52-89) had had their serum PSA level determined within 4 weeks of the bone scan and were assessed retrospectively for the presence of bony metastases. RESULTS: Of the 98 patients, 26 who had bone scans showing bony metastases had a PSA level > 40 ng/mL. Reviewing the other published studies showed that in those newly diagnosed patients with a PSA level of < 20 ng/mL, the probability of having bony metastases detected on a bone scan was < 1%. CONCLUSIONS: A staging bone scan can be omitted in the vast majority of patients with newly diagnosed prostatic carcinoma and a PSA level < 20 ng/mL.

Home reporting for the nuclear clinician?

The computer-based 'home office' is becoming a widely accepted mode of operation for modern businesses. It is implausible to believe that a nuclear medicine department can be covered permanently at a distance by a single physician, but it should be possible to provide cover for colleagues during sickness or at night or weekends. We have used a 486 PC with a high-resolution screen and software provided by LINK Medical Ltd to obtain images from hospital sites using a modem link to ADAC, Bartec and Nuclear Diagnostic SUN workstations. The data were transferred via standard telephone lines to the homes of two of the authors. During a trial period lasting several months, 60 lung scans, 20 bone scans, 1 gastrointestinal bleeding study, 4 leukocyte scans, 5 bone tomograms, 9 renograms, 6 myocardial perfusion tomograms and 2 gated cardiac studies were transferred. The system allowed transfer of a 128 x 128 eight-view lung scan to be completed in approximately 2 min. The program on the PC allowed alteration of individual image contrast, image rotation, cine display and a variety of colour scales to enhance image interpretation. A system to transfer chest X-rays has been developed and typical transfer times are approximately 3.5 min. Within the viewing protocol on the PC, a reporting window was available with the ability to fax the report directly to the hospital. The system allowed consultants who live at a distance from their nuclear medicine departments to provide cover and is now used as an integral part of our out-of-hours service. The system also allows cover of satellite units or to provide cover for junior staff at night or weekends.

Gastric emptying in patients with chronic renal failure on continuous ambulatory peritoneal dialysis.

Radionuclide gastric emptying studies were carried out on 20 patients with end-stage renal failure (ESRF) undergoing continuous ambulatory peritoneal dialysis (CAPD). Nine of the patients had diabetes mellitus. Eight normal volunteers were also studied to establish normal ranges. Solid and liquid emptying patterns were investigated simultaneously using a meal made up of a solid phase labelled with 99mTechnetium and a liquid phase labelled with 111Indium. The solid emptying fitted a model with a lag phase followed by a linear emptying phase and the liquid emptying fitted a single exponential. Nine of the 20 patients (four diabetic, five non-diabetic) were found to have delayed solid emptying, and four of these (two diabetic, two non-diabetic) also had delayed liquid emptying. No correlation was found between any of the parameters studied and the clinical symptoms of the patients. It is concluded that almost half of the patients studied had abnormal gastric emptying, but that many of these did not suffer from severe symptoms.