All-optical intrinsic atomic gradiometer with sub-20 fT/cm/√Hz sensitivity in a 22 µT earth-scale magnetic field

In this work we demonstrate a high sensitivity atomic gradiometer capable of operation in earth-field level environments. We apply a light-pulse sequence at four times the Larmor frequency to achieve gradiometer sensitivity <20 fT/cm/Hz at the finite field strength of 22 µT. The experimental timing sequence can be tuned to the field magnitude of interest. Our all-optical scalar gradiometer performs a differential measurement between two regions of a single vapor cell on a 4 cm baseline. Our results pave the way for extensions to operation in higher dimensions, vector sensitivity, and more advanced gradiometers.

AB1357-HPR DESIGNING THE ROYAL COLLEGE OF NURSING COMPETENCY FRAMEWORK FOR RHEUMATOLOGY NURSES

Background:

The 1st Edition of the RCN Competency Framework for Rheumatology Nurse Specialists (RNS) will be published in March 2020. The role of the RNS is complex, and can include caring for children and young people. The importance of RNS’s was highlighted by the National Rheumatoid Arthritis Society (NRAS 2017). The British Society for Rheumatology (BSR) outlined the need for education, training supervision and work force development. Education for RNS isn’t currently centralized but is key to improving skills and developing workforce for the future. RNS are in short supply resulting in problems of access to services and delays in care (BSR 2019). In all 4 UK nations the titles of RNS and proficiency vary greatly (Titrate trial 2019) This is likely to have an impact on patient experience and outcomes. The European League Against Rheumatism (EULAR) developed recommendations for the role of the RNS which were recently updated (Beech et al, 2019). This framework maps all of these requirements.

Objectives:

This work supports the development of roles, improve access for patients and reduce. This document will act as a foundation for building sustainability and a more robust education and role development strategy. This work will strengthen rheumatology nursing and support all 4 UK nation’s issues regarding recruitment, retention, sustainability, succession planning and benchmarking. Dissemination is key and we will work hard with stakeholders to ensure centralization of a nationally adopted framework. This abstract submission will increase dissemination opportunities.

Methods:

Online data sources were searched for the most relevant and current evidence. Where research evidence wasn’t available, existing and new knowledge was utilised from a consensus of clinical expert and patient opinions, several rounds of discussions took place virtually and face to face. RCN Rheumatology Nurse Forum Workshop attendees in June 2019 also answered a questionnaire to elicit views and demographic information regarding roles.

Results:

The questionnaire results demonstrated 100% (n37) agreement with the development of the framework and that only 2 respondents had completed a competency process. 60% were RNS. Of these 52% (n13) were band 6, 47% (n9) were band 7, and 1% were band 8 consultant nurses. The questionnaire highlighted the need to develop the framework. Results were fed back to the working party to inform the domains to be included.

Conclusion:

Document will be at BSR 2020 having successfully submitted a session proposal and abstract. Evaluation will begin later in the year 6 to 12 months from launch. We will measure impact using a variety of methods including membership Facebook pages and the questionnaire at point of download request. We will measure where and how the competency is being used and adoption of the framework throughout the UK.

References:

[1]Beech B, Primdahl J, van Tubergen A, et al., (2019) 2019 update of the EULAR recommendations for the role of the nurse in the management of chronic inflammatory arthritis. Ann Rheum Dis.http://dx.doi.org/10.1136/annrheumdis-2019-215458 (accessed 13 December 2019). Benner, P (1984) From novice to expert, excellence

[2]British Society of Rheumatology (2019) State of Play, London: BSR. Available at: www. rheumatology.org.uk/Portals/0/Documents/ Policy/BSR_State_Of_Play_Scotland2018. pdf?ver=2019-03-11-094117-440 (accessed 13 December 2019).

[3]Martin N, Ibrahim F, Tom B, et al., (2017) Does intensive management improve remission rates in patients with intermediate rheumatoid arthritis? (the TITRATE trial): study protocol for a randomized controlled trial. Trials. 2017;18:591. doi.org/10.1186/s13063-017-2330-8.

Disclosure of Interests:

Polly Livermore: None declared, Diana Finney Speakers bureau: Nordic

Abbvie, Julie Begum: None declared, Ruth Wyllie: None declared, Trish Cornell Employee of: Consultant Nurse for Abbvie, Helen Smith: None declared, Lisa Howie: None declared, Louise Parker: None declared

Note: Pneumatically actuated and kinematically positioned optical mounts compatible with laser-cooling experiments

We present two complementary designs of pneumatically actuated and kinematically positioned optics mounts: one designed for vertical mounting and translation, the other designed for horizontal mounting and translation. The design and measured stability make these mounts well-suited to experiments with laser-cooled atoms.

Suppression of spin-exchange relaxation using pulsed parametric resonance

We demonstrate that spin-exchange dephasing of Larmor precession at near-Earth-scale fields is effectively eliminated by dressing the alkali-metal atom spins in a sequence of ac-coupled 2π pulses, repeated at the Larmor precession frequency. The contribution of spin-exchange collisions to the spectroscopic linewidth is reduced by a factor of the duty cycle of the pulses. We experimentally demonstrate resonant transverse pumping in magnetic fields as high as 0.1 G, present experimental measurements of the suppressed spin-exchange relaxation, and show enhanced magnetometer response relative to a light-narrowed scalar magnetometer.

Diffusive suppression of AC-Stark shifts in atomic magnetometers

In atomic magnetometers, the vector AC-Stark shift associated with circularly polarized light generates spatially varying effective magnetic fields, which limit the magnetometer response and serve as sources of noise. We describe a scheme whereby optically pumping a small subvolume of the magnetometer cell and relying on diffusion to transport polarized atoms allows a magnetometer to be operated with minimal sensitivity to the AC-Stark field.

Magnetocardiography with a modular spin-exchange relaxation-free atomic magnetometer array

We present a portable four-channel atomic magnetometer array operating in the spin-exchange relaxation-free regime. The magnetometer array has several design features intended to maximize its suitability for biomagnetic measurement, specifically foetal magnetocardiography, such as a compact modular design and fibre-coupled lasers. The modular design allows the independent positioning and orientation of each magnetometer. Using this array in a magnetically shielded room, we acquire adult magnetocadiograms. These measurements were taken with a 6-11 fT Hz(-1/2) single-channel baseline sensitivity that is consistent with the independently measured noise level of the magnetically shielded room.

Breakdown of angular momentum selection rules in high pressure optical pumping experiments

We present measurements, by using two complementary methods, of the breakdown of atomic angular momentum selection rules in He-broadened Rb vapor. Atomic dark states are rendered weakly absorbing due to fine-structure mixing during Rb-He collisions. The effect substantially increases the photon demand for optical pumping of dense vapors.

Endoscopic deployment of the wireless capsule using a capsule delivery device in pediatric patients: a case series

The aim of this study was to review the use of the AdvanCE capsule endoscopy delivery device (US Endoscopy, Mentor, Ohio, USA) in pediatric patients who are too young to safely follow the wireless capsule swallowing instructions. Nine patients (mean age 6.6 years; SD +/- 1.8 years) underwent capsule deployment. Indications for the procedure were the evaluation of suspected inflammatory bowel disease in eight patients and evaluation of protein-losing enteropathy in one patient. The capsule was successfully deployed in the first part of the duodenum in seven patients and in the pyloric canal in one patient. In another patient the capsule was deployed in the gastric antrum and required endoscopic retrieval due to abdominal pain and failure of the capsule to traverse the pylorus. The wireless capsule successfully passed in the remaining eight patients without any complications. The AdvanCE capsule endoscopy delivery device appears to be a safe and technically easy method of wireless capsule delivery in pediatric patients. Capsule deployment should be in the duodenum whenever possible. Further studies of the use of this device in pediatric patients are warranted.

Mycobacterium triplex infection in a liver transplant patient

Mycobacterium triplex was first named in 1996 as an acid-fast bacillus with features that most resemble Mycobacterium simiae and Mycobacterium avium-intracellulare complex but which possesses a distinct mycolic acid pattern as well as a distinctive 16S rRNA hypervariable region. It has been isolated from lymph node, sputum, and cerebrospinal fluid specimens, but to date only rare clinical cases of this organism have been reported in the literature. The following is a case report of M. triplex that was isolated from the pericardial and peritoneal fluid of a 13-year-old female liver transplant patient.

Use of infliximab in the treatment of Crohn's disease in children and adolescents

BACKGROUND

Crohn's disease is often poorly responsive to conventional therapy with corticosteroids and immunomodulators. A novel chimeric antibody to tumor necrosis factor-alpha, infliximab, has shown utility in the treatment of refractory Crohn's disease in adults.

PURPOSE

To evaluate the efficacy of open-label administration of infliximab in children and adolescents with active intestinal Crohn's disease.

METHODS

Chart review of the experience with 19 subjects (mean age 14.4 years, range 9 to 19 years) receiving 1 to 3 infusions of infliximab (5 mg/kg/dose) over a 12-week period for corticosteroid-resistant disease (n = 7) or corticosteroid dependence (n = 12). Disease activity was monitored by physician global assessment and the Pediatric Crohn's Disease Activity Index.

RESULTS

Significant initial improvement (first 4 weeks after infusion) was noted in all subjects, with Pediatric Crohn's Disease Activity Index values decreasing significantly (mean +/- SD, 42.1 +/- 13.7 to 10.0 +/- 5.6, P <.0001). Over the subsequent 8-week period, 8 of 19 treated subjects had worsening of symptoms, although none deteriorated to severe activity. The mean Pediatric Crohn's Disease Activity Index at 12 weeks was 26.8 +/- 16. 4. The mean daily prednisone dosages at baseline, 4 weeks, and 12 weeks were 28 +/- 14 mg, 20 +/- 12 mg, and 8 +/- 12 mg, respectively (P <.01). Adverse effects were noted in 3 patients during infusion (dyspnea, rash) and were self-limited.

CONCLUSIONS

Infliximab is associated with short-term clinical improvement in children and adolescents with severe Crohn's disease. The rapid return of disease activity in some patients suggests that additional dosing strategies may be required. Long-term safety necessitates close monitoring.

Electrogastrography versus gastric emptying scintigraphy in children with symptoms suggestive of gastric motility disorders

BACKGROUND

Cutaneous electrogastrography is a method of recording gastric electrical activity. Abnormalities of the electrogastrogram have been described in a variety of disorders. The purpose of the study was to correlate the electrogastrograms of children with vomiting and dyspepsia with the results of radionucleotide gastric emptying studies.

METHODS

Nine patients (5-16 years old) with gastrointestinal symptoms of vomiting and/or abdominal pain were studied. The electrogastrogram was recorded using surface electrodes for 30 minutes in the fasting state and for 120 minutes after a radioisotope-labeled solid meal. Gastric emptying was simultaneously monitored for 120 minutes. The postprandial change in dominant power (power ratio: postprandial/fasting dominant power), percentages of normal slow wave, bradygastria, and tachygastria were recorded and analyzed.

RESULTS

The patients were divided into two groups. The first group (four patients; five studies) had normal gastric emptying, whereas the second group (five patients) had delayed emptying (half-life, >90 minutes). The median power ratio in the first group was 1.69 and in the second group was 2.78; the difference was not statistically significant (P = 0.90). The median difference in slow wave percentages in the fasting and postprandial periods was 0.99 in the first group and 0.73 in the second group; again, the difference was not statistically significant (P = 0.27).

CONCLUSIONS

Although it is a method of assessing gastric myoelectrical activity and gastric motility disorders, electrogastrogram does not correlate with nuclear scintigraphic gastric emptying studies in children.

Dose-related nephrotoxicity of carboplatin in children

This study investigated changes and the time course of these changes in renal function in children following treatment with carboplatin, and identified risk factors for nephrotoxicity. Glomerular and proximal renal tubular function were investigated before and up to 2 years after treatment in 23 children who received carboplatin. The main findings were reduced glomerular filtration rate (GFR), and increased renal tubular loss of magnesium, manifested by a low serum magnesium (S Mg). The mean fall in GFR was 22 ml min(-1) 1.73 m(-2) (P = 0.012), and in S Mg it was 0.17 mmol l(-1) (P = 0.0077). No patient had a clinically important reduction in GFR, and only one patient had symptomatic hypomagnesaemia. GFR and S Mg did not change over time after completion of treatment. Cumulative dose (CD) of carboplatin was inversely related to mean S Mg at the end of treatment (P = 0.031), and directly related to the fall in S Mg (P < 0.001). Calculated cumulative area under the plasma concentration versus time curve (AUC) of carboplatin was inversely related to S Mg after treatment (P = 0.004). Dose intensity (DI) of carboplatin was not shown to be related to S Mg following treatment. CD, AUC and DI of carboplatin were not related to GFR, nor change in GFR, after treatment. High CDs of carboplatin may be associated with evidence of renal damage qualitatively similar to but less severe than that caused by cisplatin. GFR and SMg should be carefully monitored when high CDs of carboplatin are used, or if carboplatin is combined with other nephrotoxic chemotherapy.

Incidence of dysplasia in pelvic pouches in pediatric patients after ileal pouch-anal anastomosis for ulcerative colitis

BACKGROUND

The purpose of this study was to evaluate the incidence of dysplasia and the mucosal adaptation patterns of pelvic pouches in children and adolescents who had undergone ileal pouch-anal anastomosis for ulcerative colitis.

METHODS

Between 1982 and 1996, 176 pediatric patients with ulcerative colitis underwent ilial pouch-anal anastomosis. Seventy-six patients were followed up after surgery at the Cleveland Clinic. Pouch biopsy specimens were reviewed for dysplasia and to determine mucosal adaptation patterns. Fifty-eight of the 76 patients had an average of three mucosal biopsies during a mean follow-up of 5 years. Demographic and surgical data were abstracted from archives of medical records. All previously obtained pouch biopsy specimens were re-evaluated by a single pathologist to ensure standardized interpretation.

RESULTS

No dysplasia was identified in screening specimens of 76 children and adolescents including 5 patients who showed dysplasia in resected colon specimens. The pattern of mucosal adaptation was categorized using previously reported criteria. Type A was defined as normal mucosa or mild villous atrophy with no or mild inflammation. Type B mucosa showed transient atrophy with temporary moderate inflammation followed by normalization of architecture. Type C mucosa was defined as a pattern of persistent atrophy with severe inflammation. In the study cohort, the patterns of mucosal adaptation, type A (56.9%; n = 33), type B (32.8%; n = 19), and type C (10.3%; n = 6), were comparable with those reported in adults. The rate of pouch failure and diagnosis of Crohn's disease were similar in each group and were not related to the specific adaptation pattern. Most of the patients with type C mucosa had clinical symptoms of pouchitis requiring periodic antibiotic therapy. No dysplasia was identified in any biopsy specimen reviewed.

CONCLUSIONS

Similar morphologic changes can be seen in ileal pouches in pediatric and adult patients. There seemed to be no increased risk of dysplasia in children and young adults who had undergone ilial pouch-anal anastomosis surgery for ulcerative colitis during a 5 year follow-up. Because the long-term risk of development of dysplasia is unknown, an initial screening should be performed 5 years after the creation of a pelvic pouch in children or when the total disease duration exceeds 7 years. Once identified, patients with Type C mucosa should have annual screening for dysplasia until further data become available.

The effects of a psychological preparation program on anxiety in children and adolescents undergoing gastrointestinal endoscopy

BACKGROUND

Like adults, children often experience anxiety associated with medical procedures. The purpose of this study was to investigate the effects of a program of psychological preparation for children undergoing endoscopy.

METHODS

Sixty patients aged 6 to 19 years (mean, 12.2 years) were randomized into one of two groups. Group 1 received routine preparation before endoscopy. Group 2 received psychological preparation consisting of demonstration of materials that would be encountered during the procedure, use of a doll as a model, or use of a book with photographs of a child who had previously undergone endoscopy. Patients in both groups completed the Spielberger State-Trait Anxiety Inventory in the clinic and just before endoscopy. The Observational Scale of Behavioral Distress was completed by a blinded observer during each procedure. The attending physician (blinded) assessed patient cooperation. Vital signs were recorded in clinic and just before endoscopy. Parents and patients completed questionnaires after endoscopy.

RESULTS

Analysis of the Spielberger State-Trait Anxiety Inventory showed patients in group 2 were significantly less anxious before endoscopy (p < 0.0001). They also required less meperidine (p < eq 0.04) per kilogram body weight and were more cooperative during the examination (p = 0.042). There was significantly less autonomic nervous system stimulation in those who had undergone psychological preparation (change in heart rate, p < 0.001; change in systolic blood pressure, p = 0.04). Statistically significant differences were found in the patients' response to questions after endoscopy regarding perceived anxiety during the procedure (p = 0.003) and the parents' response to questions regarding their own conditions (p = 0.026) and that of their child (p < 0.001).

CONCLUSION

Psychological preparation before endoscopy significantly decreases patient and parental anxiety. Such preparation may allow for a reduction in sedative medications and thereby enhance procedural safety.

Reproducibility of 24-hour intraesophageal pH monitoring in pediatric patients

OBJECTIVE

Despite the widespread use of 24-hour intraesophageal pH monitoring for evaluation of gastroesophageal reflux in infants and children, there is little published information regarding the reproducibility of ambulatory pH studies in this patient population. The purpose of our study was to evaluate the reproducibility of 24-hour intraesophageal pH monitoring in pediatric patients.

METHODS

We prospectively investigated 26 patients with symptoms suggestive of gastroesophageal reflux (14 females and 12 males) ranging in age from 1 month to 18 years (mean, 9.2 years). The patients underwent extended intraesophageal pH monitoring over two consecutive 24-hour periods.

RESULTS

Data analysis revealed that the overall reproducibility of ambulatory 24-hour pH monitoring is only 69% (r = 0.32). Eight of 26 patients had conflicting results on day 1 compared with results on day 2. Of the 8 patients with conflicting results on day 1 versus day 2, 5 had normal studies on day 1, but demonstrated pathologic reflux on day 2. Thus, the false-negative rate for day 1 was 19.2%. The kappa statistic calculated for the total time the pH was abnormal was 0.32, with values < 0.4 representing poor correlation. Spearman correlation coefficients indicated that the percentage of time with pH < 4 (r = 0.64) and the number of reflux episodes (r = 0.71) per 24-hour period are the most reproducible pH parameters.

CONCLUSION

The reproducibility of 24-hour intraesophageal pH monitoring in the pediatric population is suboptimal. The investigation should be extended or repeated if the result does not correlate with the patient's clinical history.

Delayed gastric emptying affects outcome of Nissen fundoplication in neurologically impaired children

BACKGROUND

Nissen fundoplication (NF) has a relatively high failure rate in neurologically impaired children with gastroesophageal reflux (GER). In 1990 we began to use routine technetium 99m sulfur colloid emptying scans and pyloroplasty with NF for delayed gastric emptying (DGE) in our neurologically impaired patients. The aim of this study was to determine the influence of DGE and pyloroplasty on the outcome of NF in neurologically impaired children.

METHODS

One hundred neurologically impaired children underwent NF by a single surgeon between August 1986 and July 1995. Beginning in January 1990 emptying scans were routinely obtained, and patients with DGE underwent pyloroplasty with NF. Outcome analysis was performed for recurrence/wrap failure and other parameters. Mean follow-up was 5.8 years, with a minimum of 18 months.

RESULTS

DGE was found in 35 (65%) of the 54 children who had emptying scans. All 11 children with normal scans had successful NF without recurrent reflux (100%). Forty (93%) of 43 children who underwent pyloroplasty and NF had successful outcomes. Thirty-eight children underwent NF without evaluation of gastric emptying with success in 30 of them (78.9%). Overall success improved from 34 (83%) of 41 in the first half of the study, when 3 (7%) of 41 children underwent emptying scans, to 55 (93%) of 59 in the second half, when 51 (86%) of 59 of the children underwent emptying scans.

CONCLUSIONS

DGE is common in neurologically impaired children with GER. NF in children with normal gastric emptying has a high probability of success. Pyloroplasty improves the outcome of NF in children with DGE. Neurologically impaired children should be evaluated for DGE before operation for GER.

Cisplatin pharmacokinetics in children with cancer

Cisplatin is an important drug in the treatment of a number of paediatric cancers yet, despite widespread use, there are only very limited data on the pharmacokinetics of the drug in children. Cisplatin pharmacokinetics were studied in 21 patients following a 24 h infusion of 50-120 mg/m2 cisplatin. Total and free platinum (Pt) levels in plasma and Pt in urine, were measured by atomic absorption spectrophotometry. Pharmacokinetic parameters were determined by non-compartmental and compartmental analyses. There was 3-fold interpatient variability in free drug exposure (area under the plasma concentration versus time curve--AUC) for a given surface area-based dose of cisplatin. The mean (+/- SD) pharmacokinetic parameters for free Pt were: AUC 0.47 +/- 0.13 mg/ml.min/100 mg/m2, Vdss 12.5 +/- 2.7 l/m2, t1/2 39 +/- 9 min, Ke 0.019 +/- 0.006 min-1, Clrenal 62 ml/min/m2, Cltotal 233 +/- 455 ml/min/m2, Cpss 0.31 +/- 0.09 microgram/ml. The total free Pt clearance was 1.5-5.8-fold higher (3.4 +/- 1.0) than the glomerular filtration rate (GFR). The renal clearance of cisplatin was not related to GFR and cisplatin was subject to only limited urinary excretion (27% administered dose 0-48 h), indicating that there are other important pathways of clearance beside renal elimination. Patient and treatment heterogeneity precluded the investigation of pharmacokinetic-pharmacodynamic relationships; however, the degree of interpatient pharmacokinetic variability observed suggests that body surface area-based dosing of cisplatin in children is not satisfactory.

The safety of gastrostomy in patients with Crohn's disease

OBJECTIVE

To evaluate the safety of gastrostomy tube placement in patients with Crohn's disease.

METHODS

We retrospectively reviewed the charts of 25 patients with Crohn's disease who underwent surgical or endoscopic gastrostomy tube placement. Additional follow-up information was obtained by contacting the patients by telephone.

RESULTS

Twenty-five patients with Crohn's disease underwent either surgical or percutaneous gastrostomy tube placement for prolonged enteral nutrition or gastric decompression after abdominal surgery. Gastrostomies were placed without difficulty in all cases. No major complications occurred after the procedures. Minor complications occurred in five patients, including one case of local wound infection, one case of persistent pain at the gastrostomy site, and three cases of peristomal leakage. These minor complications occurred in 22% of those who underwent percutaneous gastrostomy tube placement and 16% of those who underwent surgical gastrostomy. There was a higher incidence of minor complications in those who underwent gastrostomy for gastrointestinal decompression than in those who underwent the procedure for nutritional supplementation (14% versus 3.5%). A prior history of fistula formation did not predispose to complications related to gastrostomy placement. After gastrostomy tube removal, rapid closure of the site occurred in 96%. No cases of gastrocutaneous fistula formation occurred during follow-up, which ranged from 45 days to 8.7 yr (mean = 2.6 yr).

CONCLUSIONS

We conclude that gastrostomy placement is safe in patients with Crohn's disease and does not result in an increased incidence of peristomal disease or formation of prolonged gastrocutaneous fistulas after gastrostomy tube removal.

Use of conscious sedation for lower and upper gastrointestinal endoscopic examinations in children, adolescents, and young adults: a twelve-year review

BACKGROUND

Over the past decade, many pediatric endoscopists have replaced general anesthesia with conscious sedation. Sedation is commonly used to minimize discomfort.

METHODS

To evaluate the safety and efficacy of conscious sedation we reviewed 2711 reports of lower and upper gastrointestinal endoscopic examinations performed in 2026 patients between July 1981 and December 1992.

RESULTS

Intravenous sedation was accomplished using meperidine and diazepam (914 examinations, 35%) or meperidine and midazolam (1427 examinations, 55%). Single agents were used for 83 examinations (3%), and 96 examinations (3.5%) were performed with the patient under general anesthesia. In the lower endoscopy group sedated intravenously (n = 713), the cecum was reached in 82% of examinations. The procedure could not be completed in 17 cases in which patients were uncooperative despite sedation. In the upper endoscopy group sedated intravenously (N = 1653), all but 91 endoscopies were completed to the descending duodenum. Esophagoscopy had been planned in 76% of these procedures. Minor complications occurred in 7 patients (0.3%). This included two episodes of significant oxygen desaturation that responded to oxygen administration and narcotic reversal. A major complication occurred in 1 patient (0.04%) who had a gastric perforation during esophageal dilation over a defective guide wire. There were no deaths, episodes of cardiorespiratory arrest, or pulmonary aspirations in our series. The combined major and minor complication rate was 0.3%.

CONCLUSIONS

Intravenous conscious sedation is safe and effective in children undergoing endoscopic examination of the gastrointestinal tract. Selected patients will require general anesthesia.

The influence of ifosfamide scheduling on acute nephrotoxicity in children

Nephrotoxicity is a significant problem in children after treatment with ifosfamide. Acute changes in renal function were compared in 16 children receiving 9 g m(-2) of ifosfamide as a 72-h continuous infusion on one occasion and, on another course, divided into three 1-h infusions on consecutive days. Subclinical acute nephrotoxicity was demonstrated with both schedules, but there were no significant differences in severity.

Antioxidants in hereditary pancreatitis

OBJECTIVE

The cause of hereditary pancreatitis (HP) remains unknown. This study evaluated the hypothesis that patients with HP have genetically determined low concentrations of antioxidants that may predispose them to repetitive pancreatic injury.

METHODS

This cross-sectional analysis compared antioxidant levels in four groups of patients. Group 1 included 14 related people with chronic pancreatitis. Group 2 (11 individuals) belonged to the same kindred but did not have pancreatitis. Group 3 was a group of 65 unrelated control subjects, and Group 4 consisted of seven unrelated children with chronic pancreatitis from other causes. The antioxidant levels analyzed included glutathione peroxidase, superoxide dismutase, glutathione reductase, glutathione transferase, selenium, and vitamin E. Amylase levels were measured in all patients in groups 1, 2, and 4.

RESULTS

People with chronic pancreatitis or relatives of people with hereditary pancreatitis (groups 1, 2, and 4) had significantly lower mean glutathione peroxidase values than controls (group 3, p < 0.001). Group 1 also had significantly lower selenium levels than groups 2 and 3 (p < 0.001) but greater levels than group 4 (p = 0.029). Vitamin E levels were lower in group 1 than in groups 2 and 4. The superoxide dismutase levels were significantly different between each group (p < 0.001), and group 1 had the highest level. The glutathione reductase, glutathione transferase, and amylase levels did not differ significantly between groups. However, group 1 had a significantly higher glutathione transferase level than group 4.

CONCLUSION

We identified antioxidant deficiencies in a group of patients with hereditary pancreatitis. Higher selenium and vitamin E levels may have prevented their relatives in group 2 from having pancreatitis secondary to oxidant injury, despite low glutathione peroxidase levels. Supplementation with selenium or vitamin E or both may be a beneficial therapeutic option in these patients to decrease the frequency of pancreatitis.

Intrasubject variation in children of ifosfamide pharmacokinetics and metabolism during repeated administration

The aim of this study was to investigate intrasubject variability in ifosfamide (IFO) pharmacokinetics and metabolism which may influence clinical effect, since the pharmacology of this drug is dependent on metabolism. A group of 11 patients (ages 1-16 years) were studied on at least two occasions. IFO, 9 gm-2 was administered as a continuous infusion over 72 h. Plasma and urine samples were collected and concentrations of IFO and its metabolites were determined. Comparisons were made between courses in the same subject, allowing for differences in age and prior IFO treatment. There was a wide variation in drug (twofold) and metabolite (up to tenfold) AUCs between courses in the same patient. Although some patients did show an increase in clearance between courses (up to threefold), there was no significant consistent change in overall pharmacokinetics among the different courses studied in the same patient. There was a significant decrease (up to 63%) in the AUC of the inactive metabolite 3-dechloroethylifosfamide (3-DCI) in later courses compared with the first course studied (P = 0.032, paired t-test). This was matched by an increase in the AUC of the total dechloroethylated metabolites with course (P = 0.015, paired t-test). None of the other metabolites measured showed any consistent change in plasma or urine levels between courses. Overall, the AUC of parent drug correlated with age (r2 = 0.86, P = 0.011), and postinfusion half-life correlated with plasma bilirubin (r2 = 0.89, P = 0.007). This study demonstrated large and seemingly unpredictable intrasubject variability in IFO pharmacokinetics and metabolism during repeated administrations. Investigations relating the clinical effects of IFO to pharmacokinetics and metabolism must take this variation into account.

The effect of treatment with high dose melphalan, cisplatin or carboplatin on levels of glutathione in plasma, erythrocytes, mononuclear cells and urine

Glutathione(GSH) has been implicated as an important factor in the detoxification of many electrophilic xenobiotics, including agents used in cytotoxic chemotherapy. Maintenance of high levels of GSH in normal tissues is believed to be important in the prevention of drug-induced toxicity. Previous studies have indicated that exposure of cells to some toxic electrophiles both in vitro and in vivo can cause a temporary decrease in intracellular levels of GSH. In this paper we report that in a series of 22 children and young adults treated with high dose melphalan (ten courses studied, all 200 mg/m2), cisplatin (eight courses, 80-104 mg/m2) or carboplatin (seven courses, 507-750 mg/m2) there was no significant alteration in the level of plasma, erythrocyte or urine GSH in the period immediately following drug administration. Fluctuations in the level of GSH in mononuclear cells were observed in some patients but did not follow any consistent pattern and were similar to those observed in a series of nine normal adult controls over the same time course. These results suggest that for melphalan, cisplatin and carboplatin, drug-GSH adduct formation is insufficient to cause a measurable decrease in intracellular GSH levels in normal peripheral haematopoietic cells during the course of treatment.

Therapeutic intervention for nonvariceal gastrointestinal hemorrhage

The choice of therapeutic endoscopic technique depends on the training and equipment available to the endoscopist. If the technique is properly performed, the results are similar using injection, thermal coagulation, or laser therapy. We recommended that pediatric endoscopists concentrate on one thermal and one injection technique, since individual bleeding lesions may be more amenable to one method than another based on their anatomic location or briskness of bleeding.

Cyclophosphamide pharmacokinetics in children

1. Cyclophosphamide pharmacokinetics were measured in 38 children with cancer. 2. A high degree of inter-patient variation was seen in all pharmacokinetic parameters. Cyclophosphamide half-life varied between 1.1 and 16.8 h, clearance varied between 1.2 and 10.61 h-1 m-2 and volume of distribution varied between 0.26 and 1.48 1 kg-1. 3. The half-life of cyclophosphamide was prolonged at high dose levels (P = 0.008). 4. Children who had received prior treatment with dexamethasone showed a mean increase in clearance of 2.51 h-1 m-2 (P = 0.001) presumably as a result of CYP450 enzyme induction. 5. Treatment with allopurinol or chlorpromazine was associated with a significant increase in cyclophosphamide half-life (P < 0.001 in both cases). 6. Dose and concurrent treatment may influence cyclophosphamide metabolism in vivo and thus potentially alter the drugs therapeutic effect.