Ethical and societal aspects of radiological protection for offspring and next generations

PURPOSE

Over the last decade or so, ethical and societal aspects of radiological protection have received increasing attention. This is also reflected in the publications of the International Commission on Radiological Protection (ICRP). The current paper aims at identifying relevant ethical and societal topics which should receive attention in the context of radiological protection for offspring and next generations.

MATERIALS AND METHODS

We present a non-comprehensive review of the subject, based on presentation made at an ICRP workshop in Budapest in 2022. We first discuss the ethical values promoted by ICRP, and the application of these values in cases of (potential) pre-conceptual and prenatal radiation exposures. We then consider experience gained after the Fukushima accident indicating particular societal concerns about the health effects of such exposures.

RESULTS AND CONCLUSIONS

Beneficence/non-maleficence, prudence, justice and dignity, the "core values" of the system of radiological protection have special roles to play when heritable and/or in utero effects are to be considered. Prudence, in particular, must be taken account of in view of the fact that solid scientific data in humans are largely lacking in this area, and it is necessary to rely on insights from animal experiments as well as theoretical considerations. As regards societal considerations, the perception of risk among (potentially) affected populations needs to be taken seriously. Accountability, transparency, and inclusivity, the "procedural values" promoted by ICRP for the practical implementation of the system of radiological protection play a central role in overcoming skepticism and creating trust. Stakeholder involvement should emphasize cooperation and dialogue, which allows for the joint evaluation of an exposure situation by experts and affected people.

The injury patterns, management and outcomes of retroperitoneal haemorrhage caused by lumbar arterial bleeding at a Level-1 Trauma Centre: A 10-year retrospective review

PURPOSE

Haemorrhagic shock remains a leading preventable cause of death amongst trauma patients. Failure to identify retroperitoneal haemorrhage (RPH) can lead to irreversible haemorrhagic shock. The arteries of the middle retroperitoneal region (i.e., the 1st to 4th lumbar arteries) are complicit in haemorrhage into the retroperitoneal space. However, predictive injury patterns and subsequent management implications of haemorrhage secondary to bleeding of these arteries is lacking.

MATERIALS AND METHODS

We performed a retrospective cohort study of patients diagnosed with retroperitoneal haemorrhage who presented to our Level-1 Trauma Centre (2009-2019). We described the associated injuries, management and outcomes relating to haemorrhage of lumbar arteries (L1-4) from this cohort to assess risk and management priorities in non-cavitary haemorrhage compared to RPH due to other causes.

RESULTS

Haemorrhage of the lumbar arteries (LA) is associated with a higher proportion of lumbar transverse process (TP) fractures. Bleeding from branches of these vessels is associated with lower systolic blood pressure, increased incidence of massive transfusion, higher shock index, and a higher Injury Severity Score (ISS). A higher proportion of patients in the LA group underwent angioembolisation when compared to other causes of RPH.

CONCLUSION

This study highlights the injury patterns, particularly TP fractures, in the prediction, early detection and management of haemorrhage from the lumbar arteries (L1-4). Compared to other causes of RPH, bleeding of the LA responds to early, aggressive haemorrhage control through angioembolisation. These injuries are likely best treated in Level-1 or Level-2 trauma facilities that are equipped with angioembolisation facilities or hybrid theatres to facilitate early identification and management of thoracolumbar bleeds.

Feasibility study of computational occupational dosimetry: evaluating a proof-of-concept in an endovascular and interventional cardiology setting

Individual monitoring of radiation workers is essential to ensure compliance with legal dose limits and to ensure that doses are As Low As Reasonably Achievable. However, large uncertainties still exist in personal dosimetry and there are issues with compliance and incorrect wearing of dosimeters. The objective of the PODIUM (Personal Online Dosimetry Using Computational Methods) project was to improve personal dosimetry by an innovative approach: the development of an online dosimetry application based on computer simulations without the use of physical dosimeters. Occupational doses were calculated based on the use of camera tracking devices, flexible individualised phantoms and data from the radiation source. When combined with fast Monte Carlo simulation codes, the aim was to perform personal dosimetry in real-time. A key component of the PODIUM project was to assess and validate the methodology in interventional radiology workplaces where improvements in dosimetry are needed. This paper describes the feasibility of implementing the PODIUM approach in a clinical setting. Validation was carried out using dosimeters worn by Vascular Surgeons and Interventional Cardiologists during patient procedures at a hospital in Ireland. Our preliminary results from this feasibility study show acceptable differences of the order of 40% between calculated and measured staff doses, in terms of the personal dose equivalent quantity H_p(10), however there is a greater deviation for more complex cases and improvements are needed. The challenges of using the system in busy interventional rooms have informed the future needs and applicability of PODIUM. The availability of an online personal dosimetry application has the potential to overcome problems that arise from the use of current dosimeters. In addition, it should increase awareness of radiation protection among staff. Some limitations remain and a second phase of development would be required to bring the PODIUM method into operation in a hospital setting. However, an early prototype system has been tested in a clinical setting and the results from this two-year proof-of-concept PODIUM project are very promising for future development.

Personal dosimetry for positron emitters, and occupational exposures from clinical use of gallium-68

The current status and issues regarding positron dosimetry in nuclear medicine are summarized. The suitability of the United Kingdom Health Security Agency extremity and eye beta-gamma personal thermoluminescence dosemeters are then considered. Monte Carlo modelling is performed to determine their responses and derive sets of calibration factors, along withH_p(0.07) andH_p(3) conversion coefficients, for carbon-11, nitrogen-13, oxygen-15, fluorine-18 and gallium-68 sources, which are commonly used in positron emission tomography (PET) computed tomography; data for these isotopes is assumed extrapolatable to other positron sources. It is found that the dosemeters are adequate for assessing exposures to PET radionuclides, even if their routine calibrations to caesium-137 were maintained. An idealized set of measurements representing gallium-68 exposure scenarios is then described, including reproducible mock-ups of individuals manipulating vials and syringes. Finally, a short case-study is presented that explores occupational doses during routine clinical use of gallium-68. The extremity dosemeter results demonstrated significant variations dependent upon the exposure conditions, with some seen to be comparatively large; whole-body and eye dose rates per activity were found to be lower. The importance of routine dose monitoring of workers is emphasized, with the need for a longer-termed follow-up study demonstrated.

The Impact of COVID-19 Vaccinations on Emergency Department Presentations

Objective

The aim of the present study was to describe the burden of patients presenting to the ED with symptoms occurring after receiving a COVID‐19 vaccination.

Methods

This was a retrospective cohort study performed over a 4‐month period across two EDs. Participants were eligible for inclusion if it was documented in the ED triage record that their ED attendance was associated with the receipt of a COVID‐19 vaccination. Data regarding the type of vaccine (Comirnaty or ChAdOx1) were subsequently extracted from their electronic medical record. Primary outcome was ED length of stay (LOS) and secondary outcomes included requests for imaging and ED disposition destination.

Results

During the study period of 22 February 2021 to 21 June 2021, 632 patients were identified for inclusion in the present study, of which 543 (85.9%) had received the ChAdOx1 vaccination. The highest proportion of COVID‐19 vaccine‐related attendances occurred in June 2021 and accounted for 21 (8%) of 262 total daily ED attendances. Patients who had an ED presentation related to ChAdOx1 had a longer median ED LOS (253 vs 180 min, P < 0.001) compared to Comirnaty and a higher proportion had haematology tests and imaging requested in the ED. Most patients (n = 588, 88.8%) were discharged home from the ED.

Conclusion

There was a notable proportion of ED attendances related to recent COVID‐19 vaccination administration, many of which were associated with lengthy ED stays and had multiple investigations. In the majority of cases, the patients were able to be discharged home from the ED.

The mortality rate from self-harm in Iran

BACKGROUND

Self-harm-related death is one of the most unfortunate, tragic, and regrettable types of death owing to injuries with a variety of socio-economic and cultural causes. The study aimed to determine the trend in the mortality of self-harm by sex and age at national and provincial levels in Iran over a period of 26 years.

METHODS

The Iran Death Registration System (DRS), cemetery databanks in Tehran and Esfahan, and the national population and housing censuses of Iran were used for this study. Using a growth model, the population was estimated in the age groups. Incompleteness, misalignment, and misclassification in the DRS were all considered and addressed accordingly. We used a spatio-temporal and Gaussian process regression model to estimate mortality rates in children and adults.

RESULTS

Over the study period, 67,670 deaths were estimated owing to self-harm across the country. The overall age-standardized mortality rate decreased from 4.32 per 100,000 (95% unit interface (UI): 3.25-5.75) to 2.78 (2.15-3.59) per 100,000 between 1990 and 2015, a reduction of approximately 35.65%. The M/F ratio was 2.03:1 with an annual percent change of -2.38% and -1.37% for women and men, respectively. The annual self-harm mortality rate was higher among individuals aged 15-24 years, as well as it was more in men during the study period.

CONCLUSION

Mortality from self-harm has declined over the study period in Iran. Higher rates in men and in population aged 15-24 years, with considerable variation by province, were the distinguishing features of self-harm. Iran needs to improve monitoring through a comprehensive multisectoral strategy; and most importantly, provide timely, effective and low-cost preventive interventions.

Trend of fatal poisoning at national and provincial levels in Iran from 1990 to 2015

OBJECTIVES

Comprehensive and up-to-date data on fatal injury trends are critical to identify challenges and plan priority setting. This study provides a comprehensive assessment of poisoning mortality trends across Iran.

STUDY DESIGN

The data were gathered from various resources, including death registration systems, cemetery databases of Tehran and Esfahan, the Demographic and Health Survey of 2000, and three rounds of national population and housing censuses.

METHODS

After addressing incompleteness for child and adult death data separately and using a spatio-temporal model and Gaussian process regression, the level and trend of child and adult mortality were estimated. For estimating cause-specific mortality, the cause fraction was calculated and applied to the level and trend of death.

RESULTS

From 1990 to 2015, 40,586 deaths due to poisoning were estimated across the country. The poisoning-related age-standardized death rate per 100,000 was estimated to have changed from 3.08 (95% uncertainty interval [UI]: 2.32-4.11) in 1990 to 0.96 (95% UI: 0.73-1.25) in 2015, and the male/female ratio was 1.35 during 25 years of study with an annual percentage change of -5.4% and -4.0% for women and men, respectively. The annual mortality rate was higher among children younger than 5 years and the elderly population (≥70 years) in the study period.

CONCLUSIONS

This study showed that mortality from poisoning declined in Iran over the period from 1990 to 2015 and varied by province. Understanding the reasons for the differences of poisoning mortality by province will help in developing and implementing measures to reduce this burden in Iran.

Innovations in the Use of Interactive Technology to Support Weight Management

New and emerging mobile technologies are providing unprecedented possibilities for understanding and intervening on obesity-related behaviors in real time. However, the mobile health (mHealth) field has yet to catch up with the fast-paced development of technology. Current mHealth efforts in weight management still tend to focus mainly on short message systems (SMS) interventions, rather than taking advantage of real-time sensing to develop just-in-time adaptive interventions (JITAIs). This paper will give an overview of the current technology landscape for sensing and intervening on three behaviors that are central to weight management: diet, physical activity, and sleep. Then five studies that really dig into the possibilities that these new technologies afford will be showcased. We conclude with a discussion of hurdles that mHealth obesity research has yet to overcome and a future-facing discussion.

Occupational radiation dose to eyes from interventional radiology procedures in light of the new eye lens dose limit from the International Commission on Radiological Protection

OBJECTIVE

In 2011, the International Commission on Radiological Protection (ICRP) recommended a substantial reduction in the equivalent dose limit for the lens of the eye, in line with a reduced threshold of absorbed dose for radiation-induced cataracts. This is of particular relevance in interventional radiology (IR) where it is well established that staff doses can be significant, however, there is a lack of data on IR eye doses in terms of Hp(3). Hp(3) is the personal dose equivalent at a depth of 3 mm in soft tissue and is used for measuring lens dose. We aimed to obtain a reliable estimate of eye dose to IR operators.

METHODS

Lens doses were measured for four interventional radiologists over a 3-month period using dosemeters specifically designed to measure Hp(3).

RESULTS

Based on their typical workloads, two of the four interventional radiologists would exceed the new ICRP dose limit with annual estimated doses of 31 and 45 mSv to their left eye. These results are for an "unprotected" eye, and for IR staff who routinely wear lead glasses, the dose beneath the glasses is likely to be significantly lower. Staff eye dose normalized to patient kerma-area product and eye dose per procedure have been included in the analysis.

CONCLUSION

Eye doses to IR operators have been established using a dedicated Hp(3) dosemeter. Estimated annual doses have the potential to exceed the new ICRP limit.

ADVANCES IN KNOWLEDGE

We have estimated lens dose to interventional radiologists in terms of Hp(3) for the first time in an Irish hospital setting.

A procedural check list for pleural decompression and intercostal catheter insertion for adult major trauma

BACKGROUND

Intercostal catheter (ICC) insertion is the standard pleural decompression and drainage technique for blunt and penetrating traumatic injury. Potentially high complication rates are associated with the procedure, with the literature quoting over 20% in some cases (1-4). Empyema in particular is a serious complication. Risk adverse industries such as the airline industry and military services regularly employ checklists to standardise performance and decrease human errors. The use of checklists in medical practice is exemplified by introduction of the WHO Surgical Safety checklist.

METHODS

The Alfred Hospital in Melbourne, Australia is an Adult Level 1 Trauma Centre. In August 2009 The Alfred Trauma Service introduced an evidence-based checklist system for the insertion of ICCs, combined with standardised formal training for resident medical staff, in an attempt to minimise the incidence of ICC related empyema.

RESULTS

Between January 2003 and July 2009 the incidence of empyema was 1.44% (29 in 2009 insertions). This decreased to 0.57% between August 2009 and December 2011 (6 in 1060 insertions) when the measures described above were introduced [p=0.038 Fisher's exact test, 2-tailed].

CONCLUSION

Quality control checklists - such as the ICC checklist described - are a sensible and functional means to standardise practice, to decrease procedural error and to reduce complication rates during trauma resuscitation.

Eye dose monitoring of PET/CT workers

OBJECTIVE

The objective of the study was to measure eye dose [Hp(3)] to workers in a busy positron emission tomography (PET)/CT centre. Doses were compared with the proposed new annual dose limit of 20 mSv.

METHODS

We used a newly designed dosemeter to measure eye dose [Hp(3)]. Eye dosemeters were worn with an adjustable headband, with the dosemeter positioned adjacent to the left eye. The whole-body dose was also recorded using electronic personal dosemeter (EPD® Mk2; Thermo Electron Corporation, Waltham, MA). Exposed staff included radiographers, nurses and healthcare assistants.

RESULTS

The radiographers received the highest exposure of the staff groups studied, with one radiographer receiving an exposure of 0.5 mSv over the 3-month survey period. The estimated maximum eye dose for 1 year is approximately 2 mSv. The numeric value for eye dose was compared with the numeric value for personal dose equivalent to see if one could be used as an indicator for the other. From our data, a conservative estimate of eye dose Hp(3) (mSv) can be made as being up to approximately twice the numeric value for whole-body dose [Hp(10)] (mSv).

CONCLUSION

Eye dose was found to be well within the new proposed annual limit at our PET/CT centre. Routine whole-body dose measurements may be a useful starting point for assessing whether eye dose monitoring should be prioritized in a PET facility.

ADVANCES IN KNOWLEDGE

Following the proposal of a reduced eye dose limit, this article provides new measurement data on staff eye doses for PET/CT workers.

Practical application of suspension criteria scenarios in general radiography, computed radiography,digital radiography and fluoroscopy

Radiological equipment must be assessed against criteria for acceptability to ensure that it meets the minimum standards for patient safety. This assessment is typically led by a medical physicist with input from radiology staff and the equipment supplier. Equipment that does not meet the criteria requires action and may be suspended from clinical use. European Commission report RP 91 will be revised and replaced as RP 162. It has been drawn up to aid medical physicists with the assessment process and provide guidance on suspension levels. This paper details several cases where the criteria in the proposed RP 162 were applied in general radiography, computed radiography, digital radiography and fluoroscopy. The factors considered by the medical physicist and the outcome of each case are presented. The proposed RP 162 report improves on its predecessor and provides a robust set of criteria for ensuring that patient safety within the EU medical exposures framework is optimised.

Doses measured using AEC on direct digital radiographic (DDR) X-rays systems: updated results with an RP 162 perspective

As digital technology in diagnostic radiology systems becomes more prevalent, there is a need to provide comparative dose information for these new systems. This is needed in particular for testing the automatic exposure control (AEC) devices on direct digital radiography (DDR) systems as there is no consensus on the receptor dose level in the current guidelines. The new European Commission RP 162 document sets the suspension level for the 'verification of kerma at receptor entrance in computed radiography and DDR systems under AEC' as ≥10 µGy. This document also notes that alternate methodologies are acceptable, and may require adjustment in the suspension level if used. This study provides a range of typical doses under AEC for DDR systems, for a variety measurement methodologies, including that described in RP 162.

Occupational radiation dose to eyes from endoscopic retrograde cholangiopancreatography procedures in light of the revised eye lens dose limit from the International Commission on Radiological Protection

OBJECTIVE

Endoscopic retrograde cholangiopancreatography (ERCP) is a common procedure that combines the use of X-ray fluoroscopy and endoscopy for examination of the bile duct. Published data on ERCP doses are limited, including staff eye dose from ERCP. Occupational eye doses are of particular interest now as the International Commission on Radiological Protection (ICRP) has recommended a reduction in the dose limit to the lens of the eye. The aim of this study was to measure occupational eye doses obtained from ERCP procedures.

METHODS

A new eye lens dosemeter (EYE-D(™), Radcard, Krakow, Poland) was used to measure the ERCP eye dose, H(p)(3), at two endoscopy departments in Ireland. A review of radiation protection practice at the two facilities was also carried out.

RESULTS

The mean equivalent dose to the lens of the eye of a gastroenterologist is 0.01 mSv per ERCP procedure with an undercouch X-ray tube and 0.09 mSv per ERCP procedure with an overcouch X-ray tube. Staff eye dose normalised to patient kerma area product is also presented.

CONCLUSION

Staff eye doses in ERCP have the potential to exceed the revised ICRP limit of 20 mSv per annum when an overcouch X-ray tube is used. The EYE-D dosemeter was found to be a convenient method for measuring lens dose. Eye doses in areas outside of radiology departments should be kept under review, particularly in light of the new ICRP eye dose limit.

ADVANCES IN KNOWLEDGE

Occupational eye lens doses from ERCP procedures have been established using a new commercially available dedicated H(p)(3) dosemeter.

Non-medical exposures--ethical concerns

The scope of the Medical Exposure Directive (MED), 97/43/Euratom (Council Directive 97/43/EURATOM, on the health protection of individuals against the dangers of ionising radiation in relation to medical exposures. OJ L 180 of 09.07.1997), is such that it includes not only those exposures which are part of the normal diagnosis and treatment of patients but also exposures for occupational health surveillance, health-screening programmes, research and medico-legal exposures. This is the first time that radiation protection legislation has tried to deal explicitly with the issue of medico-legal exposures in a European Directive. However, it has done so in the context of a Directive whose primary focus is the protection of patients undergoing diagnostic or therapeutic medical exposures. This may not be an appropriate framework for medico-legal exposures. In considering medico-legal exposures, a significant number of ethical considerations arise. The MED may not adequately take account of these matters and in fact may not be a suitable legal instrument for dealing with them. This paper looks specifically at the issues surrounding medico-legal exposures and considers whether or not the current system provides adequate protection for the individuals exposed.

Rapporteurs' report: workshop on ethical issues in diagnostic radiology

This paper presents the summary reports of the session rapporteurs at the Workshop on Ethical Issues in Diagnostic Radiology. The summaries reflect the extent to which the topics discussed are well reflected in the papers presented in this proceedings.

The Plate cage Benezech implant as an alternative to autologous bone graft in the treatment of cervical spondylosis: clinical and functional outcome

Plate cage Benezech (PCB) is a titanium-made implant introduced recently in spinal surgery as a new substitute for autograft in cervical spine interbody fusion. It has a plate attached to the anterior surface of the cage to prevent any displacement of the cage, and to provide additional support in patients with dynamic instability. A small number of studies have shown the PCB cage is safe and efficient. We conducted a retrospective study on 54 consecutive patients with cervical spondylosis who underwent anterior cervical discectomy and interbody fusion (ACDF) with a PCB cage between the year 2001 and 2005 with a mean follow up of 24 months (9-62 months). The mean age was 51 years, 27 patients presented with radiculopathy, 15 patients with myelopathy, and eight patients with both. Clinical and functional outcomes were assessed by using Prolo scale, Japanese orthopaedic association (JOA) score, and Visual analogue scale (VAS). Prolo results were documented good to excellent in 43 (86%) of cases and poor in 7 (14%) of cases. Mean preoperative Prolo scale of 4.7 (SD 1.63) improved postoperatively to 8.22 (SD 2.12.) The average preoperative JOA score was 11.7 (SD 2.51) compared with 15.42 (SD 2.20) postoperatively with a mean recovery rate of 76.3%. VAS score improved from 6.65 (SD 1.77) to 1.76 (SD 2.40). All the results were statistically significant (p-value <0.0001).This study suggests that Plate cage Benezech implant is a safe and effective device for anterior cervical discectomy and interbody fusion.

Development of training syllabi for radiation protection and quality assurance of dual-energy X-ray absorptiometry (DXA) systems

The use of dual-energy X-ray absorptiometry (DXA) scanners for measuring bone mineral density (BMD) is on the increase. A single DXA scan is a relatively low-dose diagnostic X-ray examination; however, radiation protection (RP) issues should not be trivialised. One objective of the EU 6th Framework SENTINEL co-ordination action was to develop training syllabi in RP and quality assurance (QA) for BMD, and this study presents the results. An EU-wide survey was carried out which confirmed that there was a need for an accredited DXA RP training course in many EU states. There is also limited published guidance on acceptance testing/QA for DXA. Two training syllabi were developed: one on RP and one on QA of DXA systems. A training course was delivered in Ireland in 2006 by the Medical Physics & Bioengineering Department of St James's Hospital, Dublin. Following the training course, a PC-based training CD was developed and will be made available. A harmonised approach to training will promote consistent approaches to radiation safety across the EU.

Commissioning and quality assurance protocol for dual energy X-ray absorptiometry (DEXA) systems

This study reports on the development and evaluation of a protocol for testing DEXA systems, which can be incorporated into a routine medical physics/engineering service. Methodologies are reported for (1) scatter measurement, (2) estimation of reference dose and (3) enquiry into potential sources of overexposure. Results show that fan-beam and cone-beam systems require shielding if the walls or operator are within 1 m of the table. Patient reference dose was estimated using the dose-area product (DAP). This varied over an order of magnitude from 2 to 36 mGy cm2 in the range of systems studied. The inquiry into potential sources of overexposure revealed some weaknesses in current practise including a design which prevents the inclusion of DAP metres; beam non-uniformity; incorrect specification of patient dose and the risk of overexposure when tube operates during patient positioning.

Exposure variations under error conditions in automatic exposure controlled film-screen projection radiography

Improper automatic exposure control (AEC) termination may result in high overexposures on some radiographic systems. Under AEC, X-ray factors are adjusted automatically to compensate for differences in patient thickness and density. In radiography, AEC is implemented using ionization chambers placed in the film bucky. In this study we deliberately chose incorrect set-up conditions and assessed the response of the AEC system. Two types of incorrect set-up were studied: (1) incorrect selection of bucky radiation detector and (2) simulated misalignment between the X-ray field and light field. The systems tested varied in age from 1 year to in excess of 10 years. In the first test, overexposures of 90 mGy were recorded. Two systems did not meet EC guidelines for improper AEC termination. The second test, misalignment of the X-ray field, was observed to affect the exposure delivered by approximately +/-22%. The maximum dose increase observed, with a chest phantom in the beam, was 165 microGy. Misalignments also resulted in reduced exposures, which may impact on image quality.

Malignant eccrine poroma with spinal and cerebrospinal fluid metastases: case report

OBJECTIVE AND IMPORTANCE

A rare case of metastasizing malignant eccrine poroma (porocarcinoma) is described. This case is unique because metastasis resulted in hydrocephalus in the cerebrospinal fluid and spinal cord compression in the lumbar spine.

CLINICAL PRESENTATION

A 57-year-old man presented with acute confusion, lower limb weakness, and urinary concerns. Investigation revealed acute hydrocephalus and extradural cord compression of the lumbar spine.

INTERVENTION

The acute hydrocephalous was treated with a ventriculoperitoneal shunt. The spinal cord and conus were decompressed by laminectomy and supplemented with pedicular screw fixation.

CONCLUSION

The case reported here is the first with metastases from a malignant eccrine poroma causing spinal cord compression and acute hydrocephalus. Our observation is compared with a review of the literature.

Percutaneous endoscopic gastrostomy in patients with ventriculoperitoneal shunts

BACKGROUND

Percutaneous endoscopic gastrostomy (PEG) may be required in neurosurgical patients with a persistently depressed neurological status or severe lower cranial nerve palsies. Such patients may have a coexisting hydrocephalus requiring cerebrospinal fluid (CSF) diversion. Despite the risk of infection resulting from exposure to oropharyngeal flora by the pull-through PEG technique and the secondary pneumoperitoneum seen in one-third of patients, simultaneous peritoneal placement of CSF shunt catheters with PEG is the current practice. The aim of the study was to determine the frequency of CSF diversionary procedures in neurosurgical patients undergoing PEG insertion and the occurrence of infective complications in patients with simultaneous placement of a PEG and a ventriculoperitoneal (VP) shunt.

METHODS

This was a retrospective review of all neurosurgical patients undergoing PEG. The presence of hydrocephalus, mode of CSF diversion and the development of subsequent infection in those having coexistent distal peritoneal catheter placement and PEG were determined.

RESULTS

PEGs were placed in 42 neurosurgical patients (9.3 per cent of all PEGs inserted), of whom 21 had a coexisting hydrocephalus. Eight of 16 shunts with distal catheter placement in the peritoneal cavity developed infection requiring revision. Infections occurred with greater frequency in patients with a tracheostomy. There were no shunt infections requiring revision in a second group of 21 patients who had a coexisting shunt and tracheostomy without PEG.

CONCLUSION

Simultaneous placement of a PEG and a VP shunt should be avoided in the acute phase of a patient's hospital admission.

Intraoperative anaphylaxis during neurosurgery

Intra-operative anaphylaxis is of particular concern in neurosurgery. Not only is there an increased risk of major anaphylaxis, but the frequent placement of patients in the prone or sitting position may make resuscitation difficult. We describe two cases of per-operative anaphylaxis during neurosurgery and the techniques used in the successful management and investigation of these patients.

Quality assurance programme applied to mobile C-arm fluoroscopy systems

The importance of quality assurance (QA) of X-ray equipment in diagnostic imaging departments is well recognised. However, practically no attention has been paid in the literature to the application of QA programmes to mobile C-arm fluoroscopy systems. This equipment is sometimes omitted from these programmes because it is often "off-site" from the main radiological facility and suitable QA protocols are unavailable. The need for QA can be substantiated by the fact that these systems are finding greater clinical use in orthopaedic, vascular and cardiac applications. Hence, there is a growing awareness among users for the need of good image quality and low patient radiation dose. In view of this, the objective of this study was to review the existing literature, design a suitable QA protocol for this equipment and use it to survey 10 C-arms in clinical use. The protocol was designed to address mechanical and electrical safety in addition to radiation safety and image quality. Results indicate substantial performance differences between systems with significant variations in input air kerma rate to the image receptor. The authors believe that such a protocol is necessary with a view to establishing optimal performance levels and assist in the development of suitable "write-off" criteria for such systems.

Expression of endothelin peptides and mRNA in the human heart

1. We have examined the expression of endothelin isoforms and their precursors in the human heart using RIA, HPLC, immunocytochemistry and reverse transcriptase-polymerase chain reaction assays. 2. Highly specific RIAs were used to measure the levels of mature endothelin and big endothelin-1 immunoreactivity in extracts of human right ventricle. There was no significant difference between samples from patients with ischaemic heart disease and idiopathic dilated cardiomyopathy. 3. HPLC coupled with RIAs allowed the separation and identification of the three mature isoforms of endothelin, big endothelin-1 and the C-terminal fragment of big endothelin-1. In extracts of human endocardial endothelial cells, peaks of immunoreactivity that co-eluted with authentic endothelin-1, big endothelin-1 and C-terminal fragment were found. 4. Intense immunocytochemical staining of mature endothelin immunoreactivity was detected in the cytoplasm of endothelial cells of all regions of the heart tested. Big endothelin-1 immunoreactivity mirrored that of the mature peptide and, in two of three individuals tested, big endothelin-2 immunoreactivity was also detected. No big endothelin-3 immunoreactivity was detected in any of the tissues examined. 5. Reverse transcriptase-polymerase chain reaction assays demonstrated endothelin-1 and endothelin-2 mRNA in all three samples of human left ventricle tested. In two of the individuals, additional bands were also detected with the endothelin-2 primers which corresponded to splice variants. There was no evidence for the expression of endothelin-3 mRNA. 6. These data suggest that endothelin-1 is the predominant isoform of endothelin in the human heart and is probably largely synthesized by the endothelial cells within the heart. If released from the endothelial cells in vivo, this potent cardiotonic peptide may play an important paracrine role in human cardiovascular function.

The Sophy valve and the el-Shafei shunt system for adult hydrocephalus

A selected series of 22 adult patients with hydrocephalus were treated by a shunt system incorporating a variable pressure Sophy valve or by ventriculojugular shunting against the direction of blood flow using the El-Shafei system. One patient had insertion of two Sophy valves and an El-Shafei shunt. Patient selection was reserved to those with hydrocephalus thought to be at high risk when shunted with systems containing a conventional unipressure valve. None of the eight patients who had ventriculojugular shunting by the El-Shafei method demonstrated any notable clinical or radiological improvement subsequent to shunt insertion. Of the 16 Sophy devices inserted only seven produced a satisfactory result. The current evaluation of shunt malfunction could be improved by support for a national register.

Intradural lipoma presenting in pregnancy

Progressive peripheral neuropathy is an unusual condition in pregnancy requiring specialist opinion to identify the possible underlying pathology. The case presented is that of a patient with cervical intradural lipoma and worsening neurological symptoms, treated surgically at the time of caesarean section. This rare disease and its management are discussed.

Endothelin ETA and ETB mRNA and receptors expressed by smooth muscle in the human vasculature: majority of the ETA sub-type

1. We measured the ratio of ETA and ETB sub-types in the media (containing mainly smooth muscle) of human cardiac arteries (aorta, pulmonary and coronary), internal mammary arteries and saphenous veins. 2. In saturation experiments, [125I]-endothelin-1 ([125I]-ET-1) bound with high affinity to the media of each vessel (n = 3 individuals or homogenate preparations +/- s.e. mean): coronary artery, KD = 0.14 +/- 0.02 nM, Bmax = 71.0 +/- 21.0 fmol mg-1 protein; pulmonary artery, KD = 0.85 +/- 0.25 nM, Bmax = 15.2 +/- 10.3 fmol mg-1 protein; aorta, KD = 0.51 +/- 0.02 nM, Bmax = 9.4 +/- 4.4 fmol mg-1 protein; internal mammary artery. KD = 0.34 +/- 0.31 nM, Bmax = 2.0 +/- 0.5 fmol mg-1 protein and saphenous vein, KD = 0.28 +/- 0.05 nM, Bmax = 52.8 +/- 1.0 fmol mg-1 protein. In each vessel, over the concentration-range tested, Hill slopes were close to unity and a one site fit was preferred to a two site model. 3. In competition binding assays, the ETA selective ligand, BQ123 inhibited the binding of 0.1 nM [125I]-ET-1 to the media in a biphasic manner. In each case, a two site fit was preferred to a one or three site model: coronary artery, KDETA = 0.85 +/- 0.03 nM, KDETB = 7.58 +/- 2.27 microM, ratio = 89:11%; pulmonary artery, KDETA = 0.27 +/- 0.05 nM, KDETB = 24.60 +/- 5.34 microM, ratio = 92:8%; aorta, KDETA = 0.80 +/- 0.40 nM, KDETB = 2.67 +/- 2.60 microM ratio = 89:11%; saphenous vein, KDETA = 0.55 +/- 0.17 nM, KDETB = 14.4 +/- 0.26 microM, 85:15% (n = 3 individuals or homogenate preparations +/- s.e. mean). BQ123 showed up to 18000 fold selectivity for the ETA over the ETB sub-type. The ETA-selective ligand, [125I]-PD151242 labelled 85% of the receptors detected by a fixed concentration of [125I]-ET-1 in media of internal mammary artery, measured by quantitative autoradiography. In contrast, the density of ETB receptors detected with [125I]-BQ3020 was 7.0 +/- 1.5 amol mm-2, representing about 8% of [125I]-ET-1. 4. A single band corresponding to the expected position for mRNA encoding the ETA receptor (299 base pairs) was found in the media in each of the five vessels (n = 3 individuals) using reverse transcript as epolymerase chain reaction assays. A single band corresponding to the ETB sub-type (428 base pairs) was also always detected.5. 35S-labelled antisense probes to ETA and ETB hybridised to the media of epicardial coronary arteries as well as intramyocardial vessels, confirming the presence of mRNA encoding both sub-types in the vascular smooth muscle of the vessel wall.6 Although mRNA for both receptors was detected, competition binding using BQ123 demonstrated that the majority (at least 85%) of ET receptors present in smooth muscle are the ETA sub-type. These results provide further support for the hypothesis that the ETA sub-type is the receptor that must be blocked in humans to produce a beneficial vasodilatation in pathophysiological conditions where there is an increase in peptide concentration or receptor density.

ETA and ETB endothelin receptors in human myometrium characterized by the subtype selective ligands BQ123, BQ3020, FR139317 and PD151242

ETA selective (BQ123, FR139317, PD151242) and ETB selective (BQ3020) ligands were used to define the binding characteristics and contractile function of endothelin receptor subtypes in human myometrium. In saturation binding assays with 10 microns-thick tissue sections [125I]endothelin-1 (ET-1) bound with a single affinity to receptors in the myometrium (Kd, 1.19 +/- 0.17 nM) and adjacent endometrium (Kd, 1.39 +/- 0.51 nM). Competition binding assays in myometrium revealed a heterogeneous population of receptors with BQ123 (Kd ETA, 1.43 +/- 0.33 nM; Kd ETB, 39.91 +/- 9.06 microM), FR139317 (Kd ETA, 2.54 +/- 0.87 nM; Kd ETB, 89.79 +/- 24.34 microM) and BQ3020 (Kd ETA, 4.57 +/- 0.58 microM; Kd ETB, 90.07 +/- 19.53 nM). The presence of these receptors in myometrium was confirmed by saturation assays with the new ETA selective ligand [125I]PD151242 (Kd, 0.93 +/- 0.08 nM; Bmax 138.7 +/- 1.0 fmol/mg protein) and the ETB selective [125I]BQ3020 (Kd, 0.62 +/- 0.07; Bmax 44.5 +/- 1.1 fmol/mg protein). Reverse-transcriptase PCR assays detected mRNA encoding both receptor subtypes in myometrium. Autoradiography with radiolabelled PD151242 and BQ3020 demonstrated that ETA receptors were the predominant subtype in the myometrium and identified a population of ETB receptors in the endometrium. In tissue bath experiments, an ET-1-induced increase in contractility of myometrial strips was antagonized by 10 microM FR139317 but not by BQ123 at the same concentration. The ETB agonist BQ3020, which is a potent agonist in animal tissue, did not increase contractility when tested at concentrations up to 2 microM.

Vasoconstrictor endothelin receptors characterized in human renal artery and vein in vitro

1. We have identified the endothelin receptors present in the media of human main stem renal artery and vein and characterized the subtypes mediating vasoconstriction in these blood vessels in vitro. 2. Messenger RNA encoding both ETA and ETB receptors was identified in the smooth muscle layer of human renal artery and vein by reverse transcriptase-polymerase chain reaction assay. In cryostat-cut cross-sections of both vessels autoradiographical visualisation suggested a majority of ETA receptors. Intense binding was obtained to the non-selective ligand [125I]-ET-1 and the ETA-selective [125I]-PD151242 but only weak labelling of sites by the ETB-selective [125I]-BQ3020. 3. ET-1 potently constricted renal artery and vein preparations with EC50 values of 4.06 nM and 1.00 nM, respectively. Sarafotoxin 6b was approximately ten times less potent than ET-1 with EC50 values of 36.3 nM and 13.8 nM respectively. In the renal artery, ET-3 and sarafotoxin 6c showed little or no activity up to 300 nM. Responses to these peptides were more variable in the renal vein. Preparations from three individuals did not respond to ET-3 but in three further cases, although ET-3 was much less potent than ET-1, full dose-response curves were obtained. S6c elicited dose-related contractions in vein preparations from 5/6 individuals and although more potent than ET-1, the maximum response was 30-60% of that obtained to ET-1. 4. ET-1-induced vasoconstriction of renal artery and vein was antagonized by the ETA-selective, BQ123 (3-10 microM). The dose-response curves to ET-1 were displaced in a parallel rightward fashion with no attenuation of the maximum responses. pA2 values were estimated to be 6.8 +/- 0.1 and 6.8 +/- 0.4 for artery and vein respectively.5. These data suggest that mRNA encoding both ETA and ETB receptors is present in the media of human main stem renal artery and vein. However, autoradiographical studies indicate that the majority of ET receptors expressed are of the ETA subtype. The relative potencies of ET-1 and ET-3 as vasoconstrictors of renal blood vessels in vitro is consistent with this being an ETA-mediated response,and therefore whilst responses to S6c indicate that constrictor ETB receptors may be present in renal veins from some individuals these are likely to be of less importance in these blood vessels.

Quantification of mRNA in human tissue using fluorescent nested reverse-transcriptase polymerase chain reaction

We report the development of a quantitative nested reverse-transcriptase polymerase chain reaction which utilizes a fluorescence detection system. Using specific primer pairs to study mRNA for endothelin receptors in the human kidney, we synthesized a cRNA construct containing the same sequences but yielding a PCR product some 300 base pairs larger than native mRNA. Inclusion of a known amount of construct as internal standard with tissue RNA prior to cDNA synthesis allowed all reactions to occur under the same conditions in the same tube. In the nested PCR reaction, serial dilutions made before the second round enabled construction of a standard curve for each assay, and confirmation that standard and sample curves remained parallel. This indicates that both cDNAs amplified at the same rate. One internal primer was fluorescently labeled. Quantification of products using an ABI 373A sequencer with Genescan software gave sensitive and reproducible results. Analysis of a needle biopsy (10 mg) of histologically normal cortex gave 0.4 amol ETA mRNA and 1.6 amol ETB mRNA/micrograms total RNA. In medulla these values were 0.46 and 1.16 amol/micrograms, respectively. Ratios of ETB to ETA message were 74:26 in cortex and 77:23 in medulla, agreeing with previous ligand binding studies of receptor protein. Intra- and interassay coefficients of variation were 4.5 and 5.3%. This new method has potential for widespread application to the study of low copy-number mRNA or where only very small amounts of tissue are available, such as biopsy specimens.

Trochlear nerve schwannomas: a case report and literature review

Trochlear nerve sheath tumours are extremely uncommon, only six cases diagnosed during life having been presented previously. In none of these earlier cases were magnetic resonance imaging studies obtained. We report here upon the clinical presentation, surgical management and post-operative course of a case where the diagnosis was suspected pre-operatively from MRI studies. The radiological appearances are described, together with a review of all previously published accounts of this rare tumour.

Lateral parascapular extrapleural approach for single-stage excision of dumb-bell neurofibroma

An excision of a T1 dumb-bell neurofibroma via a single-stage lateral parascapular extrapleural approach is described. The different surgical approaches that can be used to approach dumb-bell tumours are reviewed, together with the relevant literature.

Alternatively spliced mRNAs for human endothelin-2 and their tissue distribution

The cDNA for Endothelin-2 (ET-2) has been previously cloned and characterised; however, ET-2 remains the least studied of the endothelin isopeptides and little is known of its function and location. In the present study reverse transcriptase-polymerase chain reaction revealed the presence of seven alternatively spliced mRNA variants encoding ET-2, with a specific pattern of distribution in various human tissues. Computer alignment and analysis of the DNA sequences demonstrated alternative splicing of five exons of 52, 169, 123, 99 and 174 base pairs, in the carboxy terminal region of the mRNA encoding preproET-2. This region contains sites for the post-transcriptional processing of preproET-2 into mature ET-2, therefore we postulate that post-transcriptional processing may be disrupted or altered in these variants.

Identification of an actin binding region in aldolase

Fragmentation of the actin binding glycolytic enzyme, aldolase, with cyanogen bromide yields an 18K actin binding fragment which corresponds to residues 1-164 of the aldolase sequence. Within this fragment there is a region of sequence (residues 32-52) which is highly homologous to a region of sequence near the C-terminus of actin itself and which is also found in the actin binding domains of a number of other actin binding proteins. A synthetic peptide corresponding to the aldolase sequence 32-52 encompassing this region of homology binds to F-actin and specifically competes with native aldolase for binding to this cytoskeletal protein.

Characterization and localization of endothelin receptor subtypes in the human atrioventricular conducting system and myocardium

The characterization and localization of endothelin A (ETA) and endothelin B (ETB) receptors have been determined in tissue sections of the human atrioventricular conducting system, surrounding regions of atrial and ventricular myocardium, and the left ventricular free wall by use of radioligand binding, polymerase chain reaction, and in situ hybridization. Selective ETA (BQ123) and ETB (BQ3020) compounds in conjunction with [125I]endothelin-1 revealed the presence of ETA and ETB receptors in the left ventricular free wall (BQ123: 57 +/- 5% ETA, 43 +/- 2% ETB, n = 3; BQ3020: 67 +/- 3% ETA, 33 +/- 3% ETB, n = 3). Autoradiography using [125I]endothelin-1 in the absence or presence of BQ3020, BQ123, or endothelin-1 showed ETA and ETB receptors localized to atrial and ventricular myocardium, the atrioventricular conducting system, and endocardial cells. There was a higher proportion of ETB receptors in the atrioventricular node and the penetrating and branching bundles of His than in the surrounding interventricular and interatrial septa (p < 0.0001). There was a lower density of ETB receptors in the interventricular septum compared with the interatrial septum and the atrioventricular conducting system (p = 0.009) and a lower density of ETA receptors in the atrioventricular conducting system compared with interatrial and interventricular septa (p = 0.008). Isolated right atrial myocytes showed a higher proportion of ETA receptors (91 +/- 12%, n = 3). Amplification of left ventricular free wall cDNA by polymerase chain reaction revealed the presence of ETA and ETB receptor mRNA. mRNA for both subtypes was detected in isolated atrial myocytes. In situ hybridization showed ETA and ETB receptor mRNA localization to atrial and ventricular myocardium, the atrioventricular conducting system, and endocardial cells. These studies demonstrate the presence of ETA and ETB receptors in human myocardium and the atrioventricular conducting system.

Myelography in the assessment of children with medulloblastoma

Forty-seven out of 49 patients with a histologically-proven diagnosis of medulloblastoma admitted to our institution between 1 January 1984 and 13 December 1990 were examined post-operatively using either myelography or gadolinium-enhanced magnetic resonance imaging in an attempt to detect clinically occult spinal metastatic disease. Spinal spread of the tumour was identified in nine (19%) patients. Of the 16 patients for whom a 5-year follow-up has been available 12 had no myelographic evidence of spinal disease and of these 10 (83%) remain disease-free. Of the six who have died during this period four had evidence of spinal metastases at presentation. Of all the children in the series with spinal spread identified at the time of their initial hospitalization, only one survives to date (15 months after diagnosis). The remainder had an average life expectancy of 18 months.

Human endothelin receptors characterized using reverse transcriptase-polymerase chain reaction, in situ hybridization, and subtype-selective ligands BQ123 and BQ3020: evidence for expression of ETB receptors in human vascular smooth muscle

Our aim was to characterize and determine the function of endothelin (ET) receptor subtypes in human vascular tissue. Reverse transcriptase-polymerase chain reaction with nested oligonucleotide primers detected the presence of mRNA encoding both ETA and ETB receptors in the media from aorta and pulmonary and coronary arteries. In situ hybridization confirmed the presence of mRNA for both subtypes in the media of coronary arteries. Saturation binding assays using 125I-ET-1 found a single population of high-affinity ET receptors (n = three patients, +/- SEM) in aorta (Kd = 0.507 +/- 0.020 nM; Bmax = 9 +/- 4 fmol/mg protein) and pulmonary (Kd = 0.845 +/- 0.245 nM; Bmax = 15 +/- 10 fmol/mg protein) and coronary arteries (Kd = 0.141 +/- 0.020 nM; Bmax = 71 +/- 21 fmol/mg protein). Using media from coronary arteries, the ETA-selective ligand BQ123 (cyclo[D-Asp-L-Pro-D-Val-L-Leu-D-Trp]) and the ETB-selective ligand BQ3020 (Ala11,15-Ac-ET-1[6-21]) both produced biphasic competition binding curves against 125I-ET-1, confirming the presence of high- and low-affinity sites corresponding to the two subtypes: BQ123 (KdETA = 0.85 +/- 0.03 nM; KdETB = 7.58 +/- 2.27 microM; ETA/ETB, 87%:13%) and BQ3020 (KdETA = 0.22 +/- 0.04 microM; KdETB = 0.77 +/- 0.34 nM; ETA/ETB, 62%:38%). BQ123 (0.1 microM) caused a significant parallel rightward shift of ET-1-induced vasoconstriction of coronary arteries in vitro, but BQ3020 and Ala1,3,11,15-ET-1 failed to show any agonist activity when tested at concentrations of < or = 3 microM in three vessels.(ABSTRACT TRUNCATED AT 250 WORDS)

Endothelin-2 mRNA splice variants detected by RT-PCR in cultured human vascular smooth muscle and endothelial cells

Our aim was to examine the hypothesis that vascular smooth-muscle cells (VSMCs) express only ETA mRNA and endothelial cells express only ETB mRNA and to determine which ET mRNA isoforms are expressed in these cell cultures. Using the reverse transcriptase polymerase chain reaction, we were able to detect ETB, ET-1 and splice variant ET-2 mRNA in cultured human umbilical vein endothelial cells (HUVECs) and ETA and splice variant ET-2 mRNA in cultured aortic smooth-muscle cells. The presence of ET-2 mRNA in cultured VSMCs has not been previously reported. These results agree with the hypothesis that ET-1 may be released from vascular endothelial cells to act predominantly on ETA receptors on VSMCs to stimulate contraction of the underlying smooth-muscle cells, and that endothelium-derived relaxing factor release may be mediated predominantly via the ETB receptors on HUVECs. The role of ET-2 expression from HUVECs and VSMCs is less clear.

Presence of messenger ribonucleic acid for endothelin-1, endothelin-2, and endothelin-3 in human endometrium and a change in the ratio of ETA and ETB receptor subtype across the menstrual cycle

The aim of the present study was to determine whether mRNA for the three endothelin peptides (endothelin-1, endothelin-2, and endothelin-3) and the two known receptor subtypes (ETA and ETB) was present in human endometrium at different stages of the menstrual cycle (menstrual, early and mid-proliferative, and early, mid-, and late secretory). Endometrium was obtained from women undergoing surgery for benign disease, and total RNA was extracted using a guanidinium isothiocyanate method. mRNA for endothelin peptide and receptor was detected using the reverse transcriptase-polymerase chain reaction with nested oligonucleotide primers. mRNA for endothelin-1, endothelin-2, and endothelin-3 was demonstrated throughout the menstrual cycle, and three splice variants of mRNA encoding endothelin-3 were found in all samples. The ratio of ETA to ETB receptor mRNA was found to change throughout the menstrual cycle. In the proliferative phase, amplified cDNA product was almost exclusively confined to the ETA receptor, whereas an increase in the amplified product of the ETB receptor cDNA was seen in the secretory and menstrual phases. These studies show that mRNA for endothelin-1, endothelin-2, and endothelin-3 is present in human endometrium at all stages of the menstrual cycle and suggest that different physiological actions of the endothelin peptides may be mediated through changes in the ratio of the ETA and ETB receptor subtypes.

Visual neglect during intracarotid amobarbital testing

The unilateral suppression of hemispheric function by sodium amobarbital may result in hemispatial visual neglect, as measured by performance on a random letter cancellation task. Our study not only investigates this hypothesis but also attempts to identify more precisely the anatomic locus of control for directed attention to extrapersonal space by correlating scanning performance with EEG activity. Forty-eight consecutive patients with epilepsy underwent preoperative intracarotid amobarbital tests. The results indicated that disruption of scanning and contralateral neglect occurred only after right-hemisphere suppression and seemed specifically related to changes in right frontal lobe EEG activity. This pattern of performance held not only for right-handed subjects, but also for those who were left-handed, and even for those who had right-hemisphere language dominance.

The effects of one month high fructose intake on plasma glucose and lipid levels in non-insulin-dependent diabetes

The effects of a high fructose diet on the control of blood glucose and serum lipids were studied in 10 non-insulin-dependent diabetic patients (mean age 64.4 years, mean duration of diabetes 5.6 years). Comparison was made following 28 days on the usual diabetic diet and 28 days during which 25% of the usual carbohydrate was substituted with fructose. There was no change in mean (+/- SEM) fasting plasma glucose (on usual diet 9.2 +/- 0.5 mmol/l, on fructose diet, 9.1 +/- 0.4 mmol/l), but there was a fall in mean plasma glucose levels at 30, 60, and 120 min in a 75 g OGTT following the fructose diet. There was no significant change in fasting lipids: on usual diet mean serum cholesterol 5.8 +/- 0.2 mmol/l, on fructose diet 5.6 +/- 0.2 mmol/l; serum triglyceride, on usual diet 1.3 +/- 0.1 mmol/l, on fructose diet 1.3 +/- 0.1 mmol/l; HDL cholesterol on usual diet 1.4 +/- 0.1 mmol/l, on fructose diet 1.4 +/- 0.1 mmol/l. Mean body weight did not vary significantly between the two diets. Incorporation of fructose into the diabetic diet may lower post-prandial glucose levels without disturbing serum lipids.

A new slide holder for immune staining

The construction of a Perspex slide holder for use in immune staining is described. The apparatus allows large numbers of slides to be stained at once and makes the procedure less tedious than it would otherwise be.

Limitations of visual assessment of redistribution in thallium images

Potential limitations of visual assessment of redistribution in thallium (TI) images were studied and results were compared with computer assessment of redistribution. A four-section phantom filled with TI was imaged (300K counts, 128 X 128 matrix) with appropriate background activity and scatter material. Activity in a "defect" section (DS) was varied from 20% to 100% of reference sections (RS). After interpolative background correction, pseudo "initial" and "late" image pairs (N = 35) were photographed on polaroid film and read by three "blinded" observers using an 0-2, 1/2 step, scale (0 = absent and 2 = normal activity). Scan defects were detected by all readers when DS activity was less than or equal to 59% of RS activity. No reader detected a defect when DS activity was greater than or equal to 67% of RS activity. All "initial" defects were detected by computer analysis. Visual assessment of "initial" DS:RS activity ratio did not correlate well with DS:RS activity ratio of the phantom. In contrast, computer assessment of "initial" DS:RS activity ratio correlated well with phantom DS:RS activity ratio (r = 0.96, p less than .0001). Although 22 of 27 scan pairs with partial (N = 26) or full (N = 1) redistribution were correctly identified as showing redistribution by at least two of three observers, the extent of redistribution was not estimated well by visual analysis. Thus, visual assessment of absolute change ("initial"-to-"late") in DS:RS activity ratio showed considerable scatter in relations to actual changes in DS:RS activity ratio of the phantom.(ABSTRACT TRUNCATED AT 250 WORDS)