RENEB Inter-Laboratory Comparison 2021: Inter-Assay Comparison of Eight Dosimetry Assays

Tools for radiation exposure reconstruction are required to support the medical management of radiation victims in radiological or nuclear incidents. Different biological and physical dosimetry assays can be used for various exposure scenarios to estimate the dose of ionizing radiation a person has absorbed. Regular validation of the techniques through inter-laboratory comparisons (ILC) is essential to guarantee high quality results. In the current RENEB inter-laboratory comparison, the performance quality of established cytogenetic assays [dicentric chromosome assay (DCA), cytokinesis-block micronucleus assay (CBMN), stable chromosomal translocation assay (FISH) and premature chromosome condensation assay (PCC)] was tested in comparison to molecular biological assays [gamma-H2AX foci (gH2AX), gene expression (GE)] and physical dosimetry-based assays [electron paramagnetic resonance (EPR), optically or thermally stimulated luminescence (LUM)]. Three blinded coded samples (e.g., blood, enamel or mobiles) were exposed to 0, 1.2 or 3.5 Gy X-ray reference doses (240 kVp, 1 Gy/min). These doses roughly correspond to clinically relevant groups of unexposed to low exposed (0-1 Gy), moderately exposed (1-2 Gy, no severe acute health effects expected) and highly exposed individuals (>2 Gy, requiring early intensive medical care). In the frame of the current RENEB inter-laboratory comparison, samples were sent to 86 specialized teams in 46 organizations from 27 nations for dose estimation and identification of three clinically relevant groups. The time for sending early crude reports and more precise reports was documented for each laboratory and assay where possible. The quality of dose estimates was analyzed with three different levels of granularity, 1. by calculating the frequency of correctly reported clinically relevant dose categories, 2. by determining the number of dose estimates within the uncertainty intervals recommended for triage dosimetry (±0.5 Gy or ±1.0 Gy for doses <2.5 Gy or >2.5 Gy), and 3. by calculating the absolute difference (AD) of estimated doses relative to the reference doses. In total, 554 dose estimates were submitted within the 6-week period given before the exercise was closed. For samples processed with the highest priority, earliest dose estimates/categories were reported within 5-10 h of receipt for GE, gH2AX, LUM, EPR, 2-3 days for DCA, CBMN and within 6-7 days for the FISH assay. For the unirradiated control sample, the categorization in the correct clinically relevant group (0-1 Gy) as well as the allocation to the triage uncertainty interval was, with the exception of a few outliers, successfully performed for all assays. For the 3.5 Gy sample the percentage of correct classifications to the clinically relevant group (≥2 Gy) was between 89-100% for all assays, with the exception of gH2AX. For the 1.2 Gy sample, an exact allocation to the clinically relevant group was more difficult and 0-50% or 0-48% of the estimates were wrongly classified into the lowest or highest dose categories, respectively. For the irradiated samples, the correct allocation to the triage uncertainty intervals varied considerably between assays for the 1.2 Gy (29-76%) and 3.5 Gy (17-100%) samples. While a systematic shift towards higher doses was observed for the cytogenetic-based assays, extreme outliers exceeding the reference doses 2-6 fold were observed for EPR, FISH and GE assays. These outliers were related to a particular material examined (tooth enamel for EPR assay, reported as kerma in enamel, but when converted into the proper quantity, i.e. to kerma in air, expected dose estimates could be recalculated in most cases), the level of experience of the teams (FISH) and methodological uncertainties (GE). This was the first RENEB ILC where everything, from blood sampling to irradiation and shipment of the samples, was organized and realized at the same institution, for several biological and physical retrospective dosimetry assays. Almost all assays appeared comparably applicable for the identification of unexposed and highly exposed individuals and the allocation of medical relevant groups, with the latter requiring medical support for the acute radiation scenario simulated in this exercise. However, extreme outliers or a systematic shift of dose estimates have been observed for some assays. Possible reasons will be discussed in the assay specific papers of this special issue. In summary, this ILC clearly demonstrates the need to conduct regular exercises to identify research needs, but also to identify technical problems and to optimize the design of future ILCs.

RENEB Inter-Laboratory Comparison 2021: The Gene Expression Assay

Early and high-throughput individual dose estimates are essential following large-scale radiation exposure events. In the context of the Running the European Network for Biodosimetry and Physical Dosimetry (RENEB) 2021 exercise, gene expression assays were conducted and their corresponding performance for dose-assessment is presented in this publication. Three blinded, coded whole blood samples from healthy donors were exposed to 0, 1.2 and 3.5 Gy X-ray doses (240 kVp, 1 Gy/min) using the X-ray source Yxlon. These exposures correspond to clinically relevant groups of unexposed, low dose (no severe acute health effects expected) and high dose exposed individuals (requiring early intensive medical health care). Samples were sent to eight teams for dose estimation and identification of clinically relevant groups. For quantitative reverse transcription polymerase chain reaction (qRT-PCR) and microarray analyses, samples were lysed, stored at 20°C and shipped on wet ice. RNA isolations and assays were run in each laboratory according to locally established protocols. The time-to-result for both rough early and more precise later reports has been documented where possible. Accuracy of dose estimates was calculated as the difference between estimated and reference doses for all doses (summed absolute difference, SAD) and by determining the number of correctly reported dose estimates that were defined as ±0.5 Gy for reference doses <2.5 Gy and ±1.0 Gy for reference doses >3 Gy, as recommended for triage dosimetry. We also examined the allocation of dose estimates to clinically/diagnostically relevant exposure groups. Altogether, 105 dose estimates were reported by the eight teams, and the earliest report times on dose categories and estimates were 5 h and 9 h, respectively. The coefficient of variation for 85% of all 436 qRT-PCR measurements did not exceed 10%. One team reported dose estimates that systematically deviated several-fold from reported dose estimates, and these outliers were excluded from further analysis. Teams employing a combination of several genes generated about two-times lower median SADs (0.8 Gy) compared to dose estimates based on single genes only (1.7 Gy). When considering the uncertainty intervals for triage dosimetry, dose estimates of all teams together were correctly reported in 100% of the 0 Gy, 50% of the 1.2 Gy and 50% of the 3.5 Gy exposed samples. The order of dose estimates (from lowest to highest) corresponding to three dose categories (unexposed, low dose and highest exposure) were correctly reported by all teams and all chosen genes or gene combinations. Furthermore, if teams reported no exposure or an exposure >3.5 Gy, it was always correctly allocated to the unexposed and the highly exposed group, while low exposed (1.2 Gy) samples sometimes could not be discriminated from highly (3.5 Gy) exposed samples. All teams used FDXR and 78.1% of correct dose estimates used FDXR as one of the predictors. Still, the accuracy of reported dose estimates based on FDXR differed considerably among teams with one team's SAD (0.5 Gy) being comparable to the dose accuracy employing a combination of genes. Using the workflow of this reference team, we performed additional experiments after the exercise on residual RNA and cDNA sent by six teams to the reference team. All samples were processed similarly with the intention to improve the accuracy of dose estimates when employing the same workflow. Re-evaluated dose estimates improved for half of the samples and worsened for the others. In conclusion, this inter-laboratory comparison exercise enabled (1) identification of technical problems and corrections in preparations for future events, (2) confirmed the early and high-throughput capabilities of gene expression, (3) emphasized different biodosimetry approaches using either only FDXR or a gene combination, (4) indicated some improvements in dose estimation with FDXR when employing a similar methodology, which requires further research for the final conclusion and (5) underlined the applicability of gene expression for identification of unexposed and highly exposed samples, supporting medical management in radiological or nuclear scenarios.

RENEB Inter-Laboratory Comparison 2021: The Dicentric Chromosome Assay

After large-scale radiation accidents where many individuals are suspected to be exposed to ionizing radiation, biological and physical retrospective dosimetry assays are important tools to aid clinical decision making by categorizing individuals into unexposed/minimally, moderately or highly exposed groups. Quality-controlled inter-laboratory comparisons of simulated accident scenarios are regularly performed in the frame of the European legal association RENEB (Running the European Network of Biological and Physical retrospective Dosimetry) to optimize international networking and emergency readiness in case of large-scale radiation events. In total 33 laboratories from 22 countries around the world participated in the current RENEB inter-laboratory comparison 2021 for the dicentric chromosome assay. Blood was irradiated in vitro with X rays (240 kVp, 13 mA, ∼75 keV, 1 Gy/min) to simulate an acute, homogeneous whole-body exposure. Three blood samples (no. 1: 0 Gy, no. 2: 1.2 Gy, no. 3: 3.5 Gy) were sent to each participant and the task was to culture samples, to prepare slides and to assess radiation doses based on the observed dicentric yields from 50 manually or 150 semi-automatically scored metaphases (triage mode scoring). Approximately two-thirds of the participants applied calibration curves from irradiations with γ rays and about 1/3 from irradiations with X rays with varying energies. The categorization of the samples in clinically relevant groups corresponding to individuals that were unexposed/minimally (0-1 Gy), moderately (1-2 Gy) or highly exposed (>2 Gy) was successfully performed by all participants for sample no. 1 and no. 3 and by ≥74% for sample no. 2. However, while most participants estimated a dose of exactly 0 Gy for the sham-irradiated sample, the precise dose estimates of the samples irradiated with doses >0 Gy were systematically higher than the corresponding reference doses and showed a median deviation of 0.5 Gy (sample no. 2) and 0.95 Gy (sample no. 3) for manual scoring. By converting doses estimated based on γ-ray calibration curves to X-ray doses of a comparable mean photon energy as used in this exercise, the median deviation decreased to 0.27 Gy (sample no. 2) and 0.6 Gy (sample no. 3). The main aim of biological dosimetry in the case of a large-scale event is the categorization of individuals into clinically relevant groups, to aid clinical decision making. This task was successfully performed by all participants for the 0 Gy and 3.5 Gy samples and by 74% (manual scoring) and 80% (semi-automatic scoring) for the 1.2 Gy sample. Due to the accuracy of the dicentric chromosome assay and the high number of participating laboratories, a systematic shift of the dose estimates could be revealed. Differences in radiation quality (X ray vs. γ ray) between the test samples and the applied dose effect curves can partly explain the systematic shift. There might be several additional reasons for the observed bias (e.g., donor effects, transport, experimental conditions or the irradiation setup) and the analysis of these reasons provides great opportunities for future research. The participation of laboratories from countries around the world gave the opportunity to compare the results on an international level.

Health-related quality of life trajectories in melanoma patients after electrochemotherapy: real-world insights from the InspECT register

BACKGROUND

Electrochemotherapy (ECT) effectively controls skin metastases from cutaneous melanoma.

OBJECTIVES

This study aimed to evaluate health-related quality of life (HRQoL) in melanoma patients pre-/post-ECT and its effect on treatment outcome.

METHODS

The analysis included prospective data from the International Network for Sharing Practices of ECT register. Following the Standard Operating Procedures, patients received intravenous or intratumoural bleomycin (15,000 IU/m2 ; 1000 IU mL/cm3 ) followed by 100-microsecond, 1000-V/cm electric pulses. Endpoints included response (RECIST v3.0), local progression-free survival (LPFS), toxicity (CTCAE v5.0), and patient-reported HRQoL at baseline, one, two, four and ten months (EuroQol [EQ-5D-3L], including 5-item utility score [EQ-5D] and visual analogue scale for self-reported health state [EQ-VAS]). Comparisons within/between subgroups were made for statistical and minimal important differences (MID). HRQoL scores and clinical covariates were analysed to identify predictors of response in multivariate analysis.

RESULTS

Median tumour size was 2 cm. Complete response rate, G3 toxicity and one-year LPFS in 378 patients (76% of the melanoma cohort) were 47%, 5%, and 78%. At baseline, age-paired HRQoL did not differ from the general European population. Following ECT, both EQ-5D and EQ-VAS scores remained within MID boundaries, particularly among complete responders. A subanalysis of the EQ-5D items revealed a statistically significant deterioration in pain/discomfort and mobility (restored within four months), and self-care and usual activities (throughout the follow-up) domains. Concomitant checkpoint inhibition correlated with better EQ-5D and EQ-VAS trajectories. Baseline EQ-5D was the exclusive independent predictor for complete response (RR 14.76, p=0.001).

CONCLUSIONS

HRQoL of ECT melanoma patients parallels the general population and is preserved in complete responders. Transient deterioration in pain/discomfort and mobility and persistent decline in self-care and usual activities may warrant targeted support interventions. Combination with checkpoint inhibitors is associated with better QoL outcomes. Baseline HRQoL provides predictive information which can help identify patients most likely to respond.

Real-life measurement of size-fractionated aerosol concentration in a plethysmography box during the COVID-19 pandemic and estimation of the associated viral load

Introduction

There are concerns about pulmonary function tests (PFTs) being associated with aerosol generation and enhanced virus transmission. As a consequence, the number of PFTs was reduced significantly during the coronavirus disease 2019 pandemic. However, there are no robust data supporting this fear.

Objectives

To perform real-life measurement of aerosol concentrations in a PFT laboratory to monitor the concentration of particles near the patient, and to model the associated potential viral load.

Methods

Two optical particle counters were used to sample the background concentration and the concentration of particles near the patient's mouth in a whole-body plethysmography box. Statistical evaluation of the measured particle concentration time series was completed. The particle exhalation rate was assessed based on the measured particle concentration data by applying the near-field/far-field theory. The number of exhaled viruses by an infected patient during the test was compared with the emission of viruses during quiet breathing and speaking.

Results

Twenty-five patients were included in the study. Eighteen patients showed a significant increase in aerosol concentration [mean 1910 (standard deviation 593) particles/L]. Submicron particles dominated the number size distribution of the generated particles, but large particles represented a higher volume fraction in the generated particles compared with background. An average gene exhalation rate of 0.2/min was estimated from this data. This is one order of magnitude higher than the release rate for the same infected person during quiet breathing, and of the same order of magnitude as the release rate during normal speaking.

Conclusions

This study demonstrated that PFTs are aerosol-generating procedures. Based on these results, the moderate increase in viral load does not underpin stopping such examinations.

Is it Necessary to Perform Sentinel Lymph Node Biopsy in Thin Melanoma? A Retrospective Single Center Analysis

Sentinel lymph node biopsy (SLNB) is a standard procedure for regional lymph node staging and still has the most important prognostic value for the outcome of patients with thin melanoma. In addition to ulceration, SLNB had to be considered even for a single mitotic figure in thin (<1 mm) melanoma according to AJCC7th guideline, therefore, a retrospective review was conducted involving 403 pT1 melanoma patients. Among them, 152 patients suffered from pT1b ulcerated or mitotic rate ≥ 1/ mm2 melanomas according to the AJCC7th staging system. SLNB was performed in 78 cases, of which nine (11.5%) showed SLN positivity. From them, interestingly, we found a relatively high positive sentinel rate (6/78-8%) in the case of thin primary melanomas ˂0.8 mm. Moreover, the presence of regression increased the probability of sentinel positivity by 5.796 fold. After reassessing pT stage based on the new AJCC8th, 37 pT1b cases were reordered into pT1a category. There was no significant relation between other characteristics examined (age, gender, Breslow, Clark level, and mitosis index) and sentinel node positivity. Based on our data, we suggest that mitotic rate alone is not a sufficiently powerful predictor of SLN status in thin melanomas. If strict histopathological definition criteria are applied, regression might be an additional adverse feature that aids in identifying T1 patients most likely to be SLN-positive. After reassessing of pT1b cases according to AJCC8th regression proved to be independent prognostic factor on sentinel lymph node positivity. Our results propose that sentinel lymph node biopsy might also be considered at patients with regressive thin (˂0.8 mm) melanomas.

P3445Subclinical myocardial dysfunction in pediatric kidney transplant recipients: a two-dimensional speckle-tracking echocardiography study

Chronic kidney disease is associated with increased risk of cardiovascular mortality and morbidity in pediatric patients as well. Renal transplantation results in improved survival, however, several factors contribute to markedly elevated cardiovascular complication rate compared to the healthy population. While major cardiac events occur rarely in pediatric population, detection of subclinical changes in cardiac morphology and function may be of high interest to effectively identify high-risk patients.

Accordingly, our aim was to investigate left (LV)- and right ventricular (RV) morphology and function using conventional and two-dimensional (2D) speckle-tracking echocardiography (STE) in pediatric renal transplant recipients.

Our study group consisted of 41 kidney transplanted children (RTX; mean age: 14±3 years, m/f: 25/16) and 39 age- and gender matched healthy controls. Using 2D echocardiography, LV and RV focused apical loops were obtained and LV end-diastolic volume index (EDVi), ejection fraction (EF), mass index (Mi), RV end-diastolic area index (EDAi) and fractional area change (FAC) were measured. Using STE, we have determined LV global longitudinal (GLS) and circumferential strain (GCS), RV GLS, and LV and RV early diastolic longitudinal strain rate (LSrE).

LV EDVi did not differ between RTX and controls (51±13 vs. 52±10 mL/m2, p=NS), while LVMi was markedly higher in RTX patients (36±8 vs. 28±6 g/m2, p<0.0001). LVEF was comparable between the two groups (62±5 vs. 62±3%; p=NS), while LV GLS was significantly lower in RTX (−20.6±2.1 vs. −21.8±2.1%, p=0.01) along with a tendential increase in LV GCS (−31.6±4.3 vs. −29.7±4.6%, p=0.06). LV LSrE was significantly lower in RTX patients (1.29±0.29 vs. 1.45±0.27 1/s, p<0.05). RV EDAi did not differ between the two groups (11.2±2.3 vs. 11.6±2.0 cm2/m2, p=NS). Interestingly however, RTX patients had significantly higher RV FAC and RV GLS (FAC: 46±7 vs. 42±4%, GLS: −24.6±3.7 vs. −22.4±2.6%, both p<0.01) along with lower RV LSrE (1.32±0.57 vs. 1.60±0.43, p<0.05).

Cardiac morphology and function shows distinct changes after RTX. Along with comparable ventricular dimensions, LV hypertrophy and subclinical systolic and diastolic dysfunction is present. RV systolic function is relatively increased accompanied by subclinical diastolic dysfunction of the chamber, which may refer to previous RV overload. STE may be a useful tool to reveal early myocardial dysfunction in pediatric kidney transplant recipients.

Post-transplant diabetes mellitus in children following renal transplantation

PTDM plays a role in chronic allograft nephropathy and decreases graft and patient survival. Considering the serious outcome of chronic hyperglycemia, the importance of early recognition and the few data in children, in this retrospective analysis we studied the characteristics and risk factors of PTDM in 45 pediatric renal transplant recipients receiving Tac or CyA-based immunosuppression. Fasting blood sampling and OGTT were performed. PTDM has been developed in six patients (13%), while seven children (16%) had IGT, with the overall incidence of a glucose metabolic disorder of 29% in pediatric renal transplants. Patients in the PTDM + IGT group were younger and had higher systolic blood pressure and serum triglyceride level than children with normal glucose tolerance. Multivariate analysis identified Tac treatment, Tac trough level, steroid pulse therapy and family history of diabetes to be associated with the onset of PTDM. In pediatric renal transplants, OGTT and frequent assessment of blood glucose levels might be essential not only in the post-transplant management, but also prior to transplantation, particularly with family history of diabetes. Careful monitoring and modified protocols help to minimize the side effects of Tac and corticosteroids.

Leflunomide and its metabolite A771726 are high affinity substrates of BCRP: implications for drug resistance

BACKGROUND

Earlier publications have suggested a possible role for the efflux transporter breast cancer resistance protein (BCRP) in acquired resistance to disease-modifying antirheumatic drugs (DMARDs) such as leflunomide and its metabolite A771726 (teriflunomide). However, there is no direct evidence that BCRP interacts with these drugs.

OBJECTIVES

To characterise the interaction between BCRP transporter and leflunomide and its active metabolite A771726, with emphasis on the nature of the interaction (substrate or inhibitor) and the kinetic characterisation of the interactions.

METHODS

Different in vitro membrane-based methods (ATPase and vesicular transport assay) using BCRP-HAM-Sf9 membrane preparations and cellular assays (Hoechst assay and cytotoxicity assay) were performed on PLB985-BCRP and HEK293-BCRP cell lines overexpressing BCRP.

RESULTS

In all assays used, an interaction between the investigated drugs and BCRP was detected. In the vesicular transport assay, both leflunomide and its metabolite inhibited BCRP-mediated methotrexate transport. Both compounds are likely substrates of BCRP as shown by the vanadate-sensitive ATPase assay. In line with the membrane assays, leflunomide and A771726 inhibited BCRP-mediated Hoechst efflux from PLB985-BCRP cells. In the cytotoxicity assay, overexpression of BCRP conferred 20.6-fold and 7.5-fold resistance to HEK293 cells against leflunomide and A771726, respectively. The resistance could be reversed by Ko134, a specific inhibitor of BCRP.

CONCLUSION

Based on these results, BCRP could play an important role in the resistance to leflunomide and A771726 via interactions with these drugs. BCRP may also mediate drug-drug interactions when leflunomide is administered with other BCRP substrate drugs such as methotrexate.

Haloperidol Attenuates β-Amyloid-Induced Calcium Imbalance in Human Fibroblasts

BACKGROUND

Antipsychotics are widely used in the treatment of behavioral and psychological symptoms of dementia. A low frequency of Alzheimer's disease in patients with schizophrenia is reported, and it has been proposed that antipsychotic medications, such as haloperidol, may be responsible. Disruption of intracellular calcium levels is considered to play a key role in beta-amyloid-induced neurotoxicity in Alzheimer's disease. Haloperidol has also been reported to interact with calcium homeostasis through dopamine-2 and sigma-1 receptors, and other, yet unknown mechanisms.

OBJECTIVE

Therefore, we investigated whether differences in the basal intracellular free calcium levels of cultured cutaneous fibroblasts--cells that do not express dopamine-2 and sigma-1 receptors--derived from sporadic Alzheimer patients and from age-matched control individuals after haloperidol treatment might be present.

METHODS

Intracellular calcium level was measured in Fura-2AM-loaded human fibroblasts by dual wavelength spectrofluorimetry.

RESULTS

Alzheimer cells exhibited significantly lower calcium level as compared to the control cultures. Exposure of fibroblasts to beta-amyloid peptide resulted in increased calcium concentration of the control cells, but not of Alzheimer fibroblasts. Co-incubation of cultures with a therapeutic dose of haloperidol blocked the beta-amyloid-induced elevation of calcium.

CONCLUSION

This finding indicates that haloperidol efficiently countervails ionic imbalance and suggests that it may serve as a potential agent in alleviating neurotoxic effects of beta-amyloid peptide.

Changes in gastric myoelectrical activity in hypertrophic pyloric stenosis and after surgical correction

The changes of gastric myoelectrical activity were investigated in 20 infants by cutaneous electrogastrography (EGG) before and after the surgical correction of infantile hypertrophic pyloric stenosis (IHPS). The dominance of 2-4 cycles per minute (CPM) "slow waves" is typical of the healthy gastric function. The shift of the dominant frequencies towards the slower frequency (0-2 CPM) is defined as bradygastria, whereas a shift towards the more frequent waves (4-10 CPM) is called tachygastria. Unlike with healthy infants, the electrogastrogram showed pathologic patterns in 85% (18 out of 20) of IHPS patients. In all except two of these infants with pathologic electrical patterns, the frequency of the waves significantly shifted towards tachygastria. The effect of feeding on the gastric myoelectrical activity could only be studied in limited (9/20) cases because of recurring vomiting during the preoperative period. In IHPS infants, a significant increase in the bradygastria group was observed in the postprandial period compared with healthy infants. Three to 5 days after surgical repair (pyloromyotomy) and the reintroduction of feeding in gradually increasing amounts, the gastric myoelectrical activity showed physiologic patterns again, showing that the pyloric function was back to normal. Cutaneous EGG is a useful, noninvasive method to obtain indirect information about the motor function of the stomach and might be further applicable to pediatric gastric motility disorders.

Comparative study of the neuronal plasticity along the neuraxis of the vibrissal sensory system of adult rat following unilateral infraorbital nerve damage and subsequent regeneration

The aim of the present study was to examine the physiological consequences of a unilateral infraorbital nerve lesion and its regeneration at different levels of the somatosensory neuraxis. In animals whose right infraorbital nerve had been crushed, a large unresponsive area was found in the main brainstem trigeminal nucleus (Pr5). Responses evoked by ipsilateral vibrissal deflection in the middle of Pr5 reappeared only on days 22-35 after the nerve had been transected, whereas recovery from the nerve crush took only 7-9 days. However, no sign of short-term neuronal plasticity was observed in Pr5 after peripheral nerve injury. An enlargement of the receptive fields in two-thirds of the units and a lengthening in the delay of the evoked responses were observed as long-term plastic changes in Pr5 neurons after peripheral-nerve regeneration. In the ventral posteromedial nucleus of the thalamus (VPM) of partly denervated animals, however, only minutes or hours after the nerve crush, certain units were found to respond in some cases not only to the vibrissae, but also to mechanical stimulation of the face over the eye (two units), the nose (one unit), and the midline (one unit). Apart from the experiments involving incomplete denervation, the vibrissal representation areas of the VPM were unresponsive to stimulation of both the vibrissae and other parts of the face until nerve regeneration had occurred. In the somatosensory cortex, an infraorbital nerve crush immediately resulted in a large cortical area being unresponsive to vibrissal deflection. It was noteworthy, however, that shortly after the nerve crush, this large unresponsive whisker representation cortical area was invaded from the rostromedial direction by responses evoked by stimulation of the forepaw digits. In spite of the reappearance of vibrissa-evoked responses 7-10 days after the nerve crush, an expanded digital representation could still be observed 3 weeks after the nerve crush, resulting in an overlapping area of digital and vibrissal representations. The withdrawal of the expanded representation of forepaw digits was completed by 60 days after the nerve crush. The results obtained in Pr5, the VPM, and the cortex strongly suggest that the higher the station in the neuraxis, the greater the degree of plasticity after infraorbital nerve injury.

[Preventive treatment in internal medicine by low-molecular-weight heparin (nadroparine calcium)]

On the basis of literature data the authors discuss the preventive treatment of the low-molecular-weight heparin in various non-surgical disorders. The method was compared with unfractionated heparin in the treatment of 20 high risk patients. The efficacy of the two different heparins was examined on the liver and renal function, blood lipids and the hematologic and hemostaseologic parameters. The thromboembolic and hemorrhagic complications were observed. Significant difference was not found with the comparison of the two preparations. The authors emphasize the simplicity, safety, home treatment possibility of the low-molecular-weight heparin and the regular control of thrombocyte-count only, too.

[Renal candidiasis following treatment of infantile osteomyelitis]

Systemic candidiasis with renal complications is a rather rare phenomenon in young infants. Authors report on a 4.5 month-old baby (preterm) who, during an antibiotic therapy of wide spectrum--because of osteomyelitis--acquired a mycotic infection causing bilateral pyelon and pyeloureteral obstruction. In addition to systemic antimycotic therapy surgical intervention was needed to eliminate the mycotic bezoar.

[Usefulness of ultrasound in the diagnosis of vesico-ureteral reflux in neonates and infants]

PURPOSE

Postnatal ultrasound (US) findings were assessed in an infant population with primary vesicoureteral reflux (VUR) and the findings of voiding cystourethrography (VCUG) were compared with those of sonography.

MATERIALS AND METHODS

Between 1988 and 1997 55 babies (43 boys and 12 girls) with primary VUR were diagnosed. US criteria for suspected VUR included unexplained or transient fullness of the collecting system, pelvic wall thickening and signs of renal dysplasia.

RESULTS

Among 55 patients reflux was unilateral in 32 cases, and bilateral in 23 patients, altogether 78 refluxing units were investigated. VUR Grade III-V, were detected in 62 units (79%). At least one US anomaly was present in 66 units (85%). No ultrasound anomaly was found in 12 renal units (15%). In 34 cases (44%) conservative treatment was performed, 40 renal units (51%) underwent ureteric reimplantation, and in 4 (5%) cases nephrectomy was carried out.

CONCLUSIONS

The correct detection and grading of reflux is not reliable by sonography, although with careful US examination of the neonatal urinary tract in 85% of VUR cases at least one sonographic abnormality has been found. However, the US negative group, (15%) showed severe reflux on VCUG in a few cases. Therefore, all neonates with ultrasound pathology of unknown origin detected prenatal or postnatal, should undergo VCUG to exclude VUR.

The role of ultrasound in the follow-up of postoperative changes after pyeloplasty

BACKGROUND

Pyeloplasty is an established treatment for pelviureteric junction (PUJ) obstruction. The postoperative change in the size of the renal pelvis and the kidney parenchyma are variable.

OBJECTIVE

To document the changes in renal pelvic size and renal parenchymal thickness following pyeloplasty and to establish that improvement of both parameters are good markers for improved urine flow.

MATERIALS AND METHODS

A group of 267 newborns and young infants with suspected PUJ obstruction were investigated by ultrasound. Pyeloplasty was performed on 102 babies, and 165 patients were followed conservatively. Postoperative ultrasonography at 6 and 12 months was available in 88 patients.

RESULTS

One year after surgery, the renal pelvis was smaller in 76 % of the cases. The renal parenchyma was normal or had increased in 92 % of cases.

CONCLUSION

Resolution of hydronephrosis after surgery is relatively slow, but renal parenchymal growth is rapid. Mild postoperative pelvic dilatation is frequent and does not indicate continued obstruction.

[Diagnosis of neonatal liver hemangioma]

The hepatic hemangiomas of infancy are rare, benign vascular tumours, differentiated in their morphologic and clinical appearances. They may manifest either as asymptomatic liver masses, or with the potentially fatal complication of congestive heart failure. They can be large in infancy, act as arteriovenous fistulas and may result in massive arteriovenous shunt. Multiple imaging modalities have been employed in the diagnosis, including ultrasonography (US), computed tomography (CT), radionuclide studies, angiography, magnetic resonance (MR) imaging. Generally the US, Doppler and CT appearances of hepatic hemangiomas may be diagnostic. Biopsy in often needed for diagnosis, especially if classic signs and symptoms are lacking. The diagnostic possibilities and difficulties in three patients are discussed. Different US images were present in all three cases, with atypical CT appearance in one. Doppler signals were lacking in two cases. Sonographic appearance of infantile hepatic hemangioma is variable, non-specific, but Doppler US is useful as a non-invasive method in the follow-up of hemangiomas.

[A specific antidote for the treatment of digitalis poisoning in uremic patients]

Two chronic haemodialyzed patients with digitalis intoxication are reported. One of them took digoxin 0.25 mg three times daily for an unknown period and the other took digitoxin 0.1 mg twice daily for two weeks. The symptoms of intoxication were mainly concealed by uremic syndrome. The diagnosis was established by noticed sinus bradycardia, first- and second-degree atrioventricular block in ECG and the determination of sera levels of glycosides (serum digoxin concentration was 7.36 ng/ml, serum digitoxin concentration was 46.5 ng/ml) in both cases. Considering the probable long elimination period of digitalis and the potentially life-threatening situation the patients were given digoxin-specific antibody (Fab) fragments with potassium replacement therapy. The symptoms disappeared within a few hours after therapy, side effects and rebound toxicity did not develop. In connection with these cases the aim of this report is to publish a method which can reverse the life-threatening digitalis intoxication in patients suffering from renal failure as well. As to the above method, the authors have not found any similar case reports in the Hungarian medical literature.

[Porphyria cutanea tarda in a long-term hemodialysis patient]

A 61 year old man developed bullous skin lesions typical for porphyria cutanea tarda (PCT) after being on maintenance hemodialysis for 3 years. The porphyrin level in the urine, plasma, erythrocytes and stool supported the diagnosis of porphyria cutanea tarda, a very rare disease in patients with chronic renal failure on hemodialysis. Therapeutic possibilities are reviewed.

[Postoperative ultrasonic studies in infants undergoing surgery for pyeloureteral obstruction]

134 newborns and young infants were investigated by ultrasound because of pelviureteric junction obstruction. Operation has been performed in 47 babies, 87 patients were followed nonoperatively. The results of the ultrasound studies were elaborated in 35 patients in 6 and 12 months postoperatively. One year after surgery pyelectasy decreased in 77 percent of the cases, the size of the renal parenchyma was normal or increased in the 91 percent of the cases. The postoperative mild dilatation of the pelvis is often observed without any sign of obstruction.

[Glossopharyngeal neuralgia with syncope]

Glossopharyngeal neuralgia an uncommon craniofacial pain syndrome. An association with syncope is even less common. The authors give a short case report of 74-year old woman, who has glossopharyngeal neuralgia associated with syncope. During attacks 10 secundum asystolia was recorded in the ECG. The electrophysiologic study of heart was normal, the carotid test resulted 3 secundum asystolia without clinical symptoms. The electroencephalogram and computertomogram of brain were normal. Carbamazepine and demand pacemaker were effective in controlling the symptoms of the patient. Finally, aetiology, pathogenesis and treatment of glossopharyngeal neuralgia are discussed.

[Biliary calculi in infancy and childhood]

Authors analyse the data of 48 children with cholelithiasis (29 girls, 19 boys, mean age: 8,7 years). In the infants the gallstones developed mostly on the basis of predisposing disease and in them the spontaneous stone dissolution is frequent. Patients were divided into two groups. In the I. group gallstones developed at the presence of predisposing diseases, in the II. group such disease were not identified. In childhood more patients belong to the I. group as our results and earlier reports show, in this group characteristic symptoms cannot be found. In the II. group the vague abdominal pain was the most frequent symptom. Beyond the age of 10 years the sex ratio and the symptoms are similar to those of adults. In the I. group in 8 cases, while in the II. in 16 cases was operation done. In the latter group in two patient stone dissolution took place with Ursodeoxycholicacid. In childhood complication are infrequent. The ultrasound examination is a very useful tool in the diagnosis and follow up of these patients.

[Obstructive ectopic ureterocele: review of the literature in the light of the authors' own experience]

The epidemiology, clinical presentation, evaluation and methods of surgical management of ectopic ureteroceles was studied. The prenatal detection of hydronephrosis of the upper pole of duplex systems allows early surgical correction, and this effectively decreases the risk of urinary tract infection, urosepsis and irreversible loss of renal function. Yet a precise prenatal diagnosis of accompanying ureterocele is not necessary for efficient postnatal management.

[Extrahepatic cholestasis in infancy and childhood: the role of ultrasonography]

Of 23 children with extrahepatic cholestatic syndromes, who were studied with sonography, there were found to have biliary atresia, choledochal cyst, cholelithiasis, stenosis of bile duct, gallbladder duplication, cholecystitis. Ultrasonography is the most useful initial investigation of choice, and in most of the cases the only investigation.

[Pelvic masses in childhood: ultrasonographic imaging]

The echographic appearance of pelvic masses in children was examined in 38 patients. Sonography was correct in determining the site of origin in all cases. Cystic uterine masses and cystic ovarian masses were the most specific, representing hydrometrocolpos and benign ovarian cysts. A nonspecific sonographic pattern was encountered with complex masses, which proved to be ovarian teratomas, hemorrhagic ovarian cysts and pelvic abscesses. Although a number of characteristic features of teratomes have been described, these signs were seen very rarely in children.

[Importance of pre- and post-natal ultrasonic examination in neonatal hydronephrosis]

The widespread use of obstetric and neonatal sonography has resulted an increasing number of neonatal hydronephrosis, and some of them are asymptomatic. From November 1987 to May 1990 49 neonates with hydronephrosis or multicystic dysplastic kidney were seen. The most common conditions found were obstruction of the distal ureter (10), multicystic dysplatic kidney (12). Fifty-three percent of the cases were discovered on fetal screening during obstetric sonography, seven of them were asymptomatic at birth, but 4 of the asymptomatic babies underwent operation in the neonatal period. Nine of the postnatal diagnosed cases were incidental findings. The major benefit of prenatal echography is to allow early recognition of major uropathic conditions before postnatal infection worsens the prognosis. A correct postnatal ultrasound diagnosis was established in all cases.

[Ultrasonic follow up of spontaneous regression of neonatal abdominal cystic changes]

Abdominal cyst was diagnosed in 14 babies by ultrasound examination (9 multicystic dysplastic kidneys, 4 ovarian cysts, 1 bowel duplication). The cysts were followed up in 6 patients by ultrasound, and marked reduction of multicystic dysplastic kidneys was observed in 2 patients, and 1 ovarian cyst was disappeared. Their experience and a review of the literature suggest that conservative management with sonographic reevaluation is an acceptable alternative to surgical therapy in uncomplicated cases.

Bacterial colonization of newborn infants in an intensive care unit

Bacterial screening of external ear, umbilical and gastric fluid samples from infants at admission to the intensive care unit yielded opportunistic pathogens in 22% and 12% in the years 1980 and 1982, respectively. As a result of improved hygienic measures and more rational use of antibiotics, bacterial colonization of infants staying longer than 3 days decreased from 56% to 19%. Antibiotic treatment is not indicated if opportunistic pathogens except Streptococcus agalactiae (group B), are cultured from infants without clinical symptoms.

[Iron-deficiency and replacement in infancy]

The frequency of iron-deficiency anaemia was investigated in 376 children with the aid of serum ferritin determinations. The children, resident in Budapest or Miskolc were 6 months to 3 years old. Marked iron-deficiency (serum ferritin less than 10 micrograms/l) could be demonstrated in 33.8% of the investigated population. The frequency of iron-deficiency was related to the socio-economic and cultural status of the mother, a factor which is thought to influence the feeding habits. In areas where iron-deficiency is frequently detected regular iron-prophylaxis is recommended.