706 Frailty Score Is an Independent Predictor of Outcome Following Fragility Fracture

Background

Frailty has been linked to greater hospitalisation, morbidity, and mortality, and is being increasingly recognised as a possible factor affecting outcomes in trauma. A 2017 TARN report identified that further research was needed to determine the effect of frailty on outcomes in trauma patients. With fragility (low energy) fractures now make up a significant burden of trauma within UK hospitals, this retrospective cohort study investigated whether frailty has a significant effect on outcomes in patients presenting with fragility fractures.

Method

Notes from all patients aged >60 admitted to a large District General hospital over 1 year with any fragility fracture were reviewed. Age, injury, length of stay, and mortality were recorded. A Rockwood Clinical Frailty Score (CFS) was assigned retrospectively.

Results

886 patients were reviewed (male:female 266:620, mean age 82.75). CFS was independently associated with a significant increase in mortality, with every step up in CFS increasing 30-day and 1-year odds of death by 54.8% and 56.2% respectively (P < 0.001). Every step up in CFS independently increased percentage length of stay by 10.1%.

Conclusions

CFS independently predicts adverse outcome in hospitalised trauma patients with fragility fractures. CFS should be used routinely to identify patients at risk and may assist in allocating limited orthogeriatric resources and supporting national guidelines. Future research should investigate how resources impact outcomes for patients of varying CFS.

476 The Role of Medical Students in an International, Collaborative, Multi-Centre Global Surgery Study

Introduction

The gaps in formal education caused by the pandemic have provided medical students with opportunities to redefine their role in settings across clinical medicine, education and research. This task shifting could provide avenues for students to engage with global surgery, where the cultivation of research skills, networking, and global collaboration amongst students is imperative for sustainable progress.

COVIDPaedsCancer is an international collaborative cohort study assessing the impact of the pandemic on paediatric cancer services. We aimed to trial a student and junior doctor-lead team to perform the day-to-day running of this research.

Method

An operations team of 47 students and junior doctors across 11 countries was assembled. Sub-teams were created for social media, network management, email communications, REDCap, research support and graphics. Together, they ran the study under guidance from the steering committee.

Results

To date, the operations team has coordinated study collaborators in collecting data for 1252 patients from 78 centres across 39 countries. Cooperation between sub-teams enabled the recruitment of collaborators from 558 hospitals in total. They also identified 2 errors in the protocol and resolved them with steering committee input, and continuously managed hospital leadership issues and general queries throughout the course of the study. The team was able to adapt in response to the evolving needs of collaborators and the steering committee.

Conclusions

Medical students were able to aid the delivery of an international, multicentre, collaborative, global surgery research study while benefiting from learning opportunities, networking opportunities, and developing interest and understanding of global surgery.

244 Traumatic Brain Injury Related Paediatric Mortality and Morbidity in Low- And Middle-Income Countries: A Systematic Review and Meta-Analysis

Aim

Three million cases of paediatric traumatic brain injury (pTBI) occur annually, the majority of which occur in low-and-middle-income countries (LMICs). However, there is a paucity of data on the outcomes of pTBI available. We aimed to systematically review and synthesise the reported morbidity and mortality from pTBI in the published literature about LMICs.

Method

A systematic review and meta-analysis were conducted. MEDLINE, EMBASE, Global Health, and Global Index Medicus were searched for relevant articles from January 2000 to May 2020. Observational or experimental studies on pTBI (individuals between the ages of 0 to 16 years) in LMICs were included. Morbidity data were descriptively analysed, and a random-effects model was used to pool mortality rates. PROSPERO ID: CRD42020171276.

Results

We included 145 studies from 38 countries representing 174073 patients with pTBI. Males were twice (95% CI: 1.6 – 2.4) as likely to have a pTBI than females. Where available, mild TBI represented ≥ 60% of all pTBI cases in most reports (n = 24/43, 56%). The commonest cited cause of pTBI was road traffic accidents (n = 16643/43083, 39%), followed by falls (n = 10927/43083, 25%). 4385 patients (n = 4385/18092, 24%) had a reduction from normal function on discharge. On average, there were 6.7 deaths per 100 cases of pTBI.

Conclusions

Only 38 LMICs have published data on the volume and burden of pTBI in their country. Limited data available suggests that young male children are at a high-risk of pTBIs in LMICs, particularly from road traffic accidents.

AB0701 ANTIBODY RAPID TEST POSITIVE HEALTH CARE WORKERS AT A GERMAN UNIVERSITY HOSPITAL: FIRST WAVE CHARACTERISTICS

Background:

Freiburg was among the most heavily affected German cities during the first wave of Sars-Cov-2 infections in spring 2020. Consequently, the University Medical Center Freiburg was one of the first hospitals in Germany to treat Covid19 patients.

Objectives:

To assess the proportion and characteristics of health care workers (HCW) that have been infected during that first wave SARS-CoV-2 serum IgG and IgM antibodies were measured.

Methods:

HCW (n=902, mean age: 40.7 years) participated in this study, and filled out an epidemiological questionnaire. Serum samples were analysed for SARS-Cov-2 IgG/IgM antibodies via rapid diagnostic test (RT) and via ELISA. Statistical analyses were performed using STATA 14.2. An exposure prevention score was developed to quantify the adherence to preventive measures in everyday life.

Results:

902 HCW were tested by RT, and 499 by ELISA. In total, 11.5% of recruited HCW were antibody-positive in the RT, 12.2% in the ELISA. 87.5% of RT positives, 98% of ELISA-positives reported symptoms, compared to 74.6% and 78% of negatives, respectively. Symptoms such as cough (57%/46%), loss of smell and taste (34%/5.2%), fatigue (68%/45%), fever (48%/24%), body aches (45%/22%), and headaches (58%/46%) were reported by significantly more RT positives compared to negatives. The respective differences were even more pronounced (p<0.001) among ELISA-positives compared to negatives with >50% of those positive reported impaired smell or taste compared to less than 7% among the group of ELISA-negatives (p<0.00001).

In logistic regression models, shift work and belonging to the lowest quartile of the exposure prevention score were significantly associated with seropositivity in both tests. Exposure towards children was inversely associated with seropositivity, however, in the finally adjusted model only significant for those that were RT-positive, but not ELISA-positive, reflecting the lower specificity of the former.

Conclusion:

The endemic infection rate in HCW was high. HCW adhering to preventive measures in everyday life had lower infection rates.

Disclosure of Interests:

Manuel Beck: None declared, Alexandra Nieters: None declared, Marta Rizzi: None declared, Ulrich Salzer: None declared, Jens Thiel Speakers bureau: BMS, Nils Venhoff Speakers bureau: Novartis, Nicole Peter: None declared, Hermann Eibel: None declared, Reinhard Voll Speakers bureau: Novartis, Grant/research support from: BMS, Pfizer, Novartis, Stephanie Finzel Speakers bureau: Novartis

Skin sensitization to fragrance hydroperoxides: interplay between dendritic cells, keratinocytes and free radicals

BACKGROUND

Skin sensitization to hydroperoxides (R-OOHs) of the commonly used fragrance terpenes limonene, linalool and citronellol is frequently reported. R-OOHs are believed to initiate the process leading to sensitization and allergic contact dermatitis through mechanisms involving radical intermediates. Thus, radical intermediates, keratinocytes and dendritic cells (DCs) may act in concert to initiate the process.

OBJECTIVES

To evaluate individual DC activation profiles by R-OOHs in the context of keratinocytes with regard to frequency, specificity and magnitude of upregulation.

METHODS

We used 2D and 3D cocultures with keratinocytes/reconstructed human epidermis (RHE) and DCs to evaluate cell surface levels of the costimulatory molecules CD86, CD80 and the adhesion molecule CD54 on cocultured DCs. Analysis of radical formation from limonene hydroperoxides in RHE was performed using electron paramagnetic resonance combined with the spin trapping technique.

RESULTS

R-OOHs induce donor-dependent DC activation. Major differences were found between the limonene-OOHs. Limonene-1-OOH was stronger with respect to both frequency and magnitude of response. Using a 3D coculture model, no DC activation was detected after topical application of 0·2% limonene-OOHs (20 µg cm^-2 ), while 1·2% limonene-1-OOH or 2% limonene-2-OOH induced DC activation. Furthermore, we demonstrated differences in the carbon and oxygen radicals formed from the limonene-OOHs using RHE, mimicking what may happen in vivo.

CONCLUSIONS

We report clear individual differences in DC maturation induced by the most important hydroperoxides. Response rates and magnitude of response both indicate that very small structural alterations in the hydroperoxides are translated into specific DC responses. In addition, we provide more insight into the amounts of hydroperoxides that can activate DCs and induce sensitization.

Barriers to Women Entering Surgical Careers: A Global Study into Medical Student Perceptions

BACKGROUND

Barriers to female surgeons entering the field are well documented in Australia, the USA and the UK, but how generalizable these problems are to other regions remains unknown.

METHODS

A cross-sectional survey was developed by the International Federation of Medical Students' Associations (IFMSA)'s Global Surgery Working Group assessing medical students' desire to pursue a surgical career at different stages of their medical degree. The questionnaire also included questions on students' perceptions of their education, resources and professional life. The survey was distributed via IFMSA mailing lists, conferences and social media. Univariate analysis was performed, and statistically significant exposures were added to a multivariate model. This model was then tested in male and female medical students, before a further subset analysis by country World Bank income strata.

RESULTS

639 medical students from 75 countries completed the survey. Mentorship [OR 3.42 (CI 2.29-5.12) p = 0.00], the acute element of the surgical specialties [OR 2.22 (CI 1.49-3.29) p = 0.00], academic competitiveness [OR 1.61 (CI 1.07-2.42) p = 0.02] and being from a high or upper-middle-income country (HIC and UMIC) [OR 1.56 (CI 1.021-2.369) p = 0.04] all increased likelihood to be considering a surgical career, whereas perceived access to postgraduate training [OR 0.63 (CI 0.417-0.943) p = 0.03], increased year of study [OR 0.68 (CI 0.57-0.81) p = 0.00] and perceived heavy workload [OR 0.47 (CI 0.31-0.73) p = 0.00] all decreased likelihood to consider a surgical career. Perceived quality of surgical teaching and quality of surgical services in country overall did not affect students' decision to pursue surgery. On subset analysis, perceived poor access to postgraduate training made women 60% less likely to consider a surgical career [OR 0.381 (CI 0.217-0.671) p = 0.00], whilst not showing an effect in the men [OR 1.13 (CI 0.61-2.12) p = 0.70. Concerns about high cost of training halve the likelihood of students from low and low-middle-income countries (LICs and LMICs) considering a surgical career [OR 0.45 (CI 0.25-0.82) p = 0.00] whilst not demonstrating a significant relationship in HIC or UMIC countries. Women from LICs and LMICs were 40% less likely to consider surgical careers than men, when controlling for other factors [OR 0.59 CI (0.342-1.01 p = 0.053].

CONCLUSION

Perceived poor access to postgraduate training and heavy workload dissuade students worldwide from considering surgical careers. Postgraduate training in particular appears to be most significant for women and cost of training an additional factor in both women and men from LMICs and LICs. Mentorship remains an important and modifiable factor in influencing student's decision to pursue surgery. Quality of surgical education showed no effect on student decision-making.

Barriers to Women Entering Surgical Careers: A Global Study into Medical Student Perceptions

BACKGROUND

Barriers to female surgeons entering the field are well documented in Australia, the USA and the UK, but how generalizable these problems are to other regions remains unknown.

METHODS

A cross-sectional survey was developed by the International Federation of Medical Students' Associations (IFMSA)'s Global Surgery Working Group assessing medical students' desire to pursue a surgical career at different stages of their medical degree. The questionnaire also included questions on students' perceptions of their education, resources and professional life. The survey was distributed via IFMSA mailing lists, conferences and social media. Univariate analysis was performed, and statistically significant exposures were added to a multivariate model. This model was then tested in male and female medical students, before a further subset analysis by country World Bank income strata.

RESULTS

639 medical students from 75 countries completed the survey. Mentorship [OR 3.42 (CI 2.29-5.12) p = 0.00], the acute element of the surgical specialties [OR 2.22 (CI 1.49-3.29) p = 0.00], academic competitiveness [OR 1.61 (CI 1.07-2.42) p = 0.02] and being from a high or upper-middle-income country (HIC and UMIC) [OR 1.56 (CI 1.021-2.369) p = 0.04] all increased likelihood to be considering a surgical career, whereas perceived access to postgraduate training [OR 0.63 (CI 0.417-0.943) p = 0.03], increased year of study [OR 0.68 (CI 0.57-0.81) p = 0.00] and perceived heavy workload [OR 0.47 (CI 0.31-0.73) p = 0.00] all decreased likelihood to consider a surgical career. Perceived quality of surgical teaching and quality of surgical services in country overall did not affect students' decision to pursue surgery. On subset analysis, perceived poor access to postgraduate training made women 60% less likely to consider a surgical career [OR 0.381 (CI 0.217-0.671) p = 0.00], whilst not showing an effect in the men [OR 1.13 (CI 0.61-2.12) p = 0.70. Concerns about high cost of training halve the likelihood of students from low and low-middle-income countries (LICs and LMICs) considering a surgical career [OR 0.45 (CI 0.25-0.82) p = 0.00] whilst not demonstrating a significant relationship in HIC or UMIC countries. Women from LICs and LMICs were 40% less likely to consider surgical careers than men, when controlling for other factors [OR 0.59 CI (0.342-1.01 p = 0.053].

CONCLUSION

Perceived poor access to postgraduate training and heavy workload dissuade students worldwide from considering surgical careers. Postgraduate training in particular appears to be most significant for women and cost of training an additional factor in both women and men from LMICs and LICs. Mentorship remains an important and modifiable factor in influencing student's decision to pursue surgery. Quality of surgical education showed no effect on student decision-making.

Two Interlinked Bistable Switches Govern Mitotic Control in Mammalian Cells

Distinct protein phosphorylation levels in interphase and M phase require tight regulation of Cdk1 activity [1, 2]. A bistable switch, based on positive feedback in the Cdk1 activation loop, has been proposed to generate different thresholds for transitions between these cell-cycle states [3-5]. Recently, the activity of the major Cdk1-counteracting phosphatase, PP2A:B55, has also been found to be bistable due to Greatwall kinase-dependent regulation [6]. However, the interplay of the regulation of Cdk1 and PP2A:B55 in vivo remains unexplored. Here, we combine quantitative cell biology assays with mathematical modeling to explore the interplay of mitotic kinase activation and phosphatase inactivation in human cells. By measuring mitotic entry and exit thresholds using ATP-analog-sensitive Cdk1 mutants, we find evidence that the mitotic switch displays hysteresis and bistability, responding differentially to Cdk1 inhibition in the mitotic and interphase states. Cdk1 activation by Wee1/Cdc25 feedback loops and PP2A:B55 inactivation by Greatwall independently contributes to this hysteretic switch system. However, elimination of both Cdk1 and PP2A:B55 inactivation fully abrogates bistability, suggesting that hysteresis is an emergent property of mutual inhibition between the Cdk1 and PP2A:B55 feedback loops. Our model of the two interlinked feedback systems predicts an intermediate but hidden steady state between interphase and M phase. This could be verified experimentally by Cdk1 inhibition during mitotic entry, supporting the predictive value of our model. Furthermore, we demonstrate that dual inhibition of Wee1 and Gwl kinases causes loss of cell-cycle memory and synthetic lethality, which could be further exploited therapeutically.

PP2A/B55 and Fcp1 regulate Greatwall and Ensa dephosphorylation during mitotic exit

Entry into mitosis is triggered by activation of Cdk1 and inactivation of its counteracting phosphatase PP2A/B55. Greatwall kinase inactivates PP2A/B55 via its substrates Ensa and ARPP19. Both Greatwall and Ensa/ARPP19 are regulated by phosphorylation, but the dynamic regulation of Greatwall activity and the phosphatases that control Greatwall kinase and its substrates are poorly understood. To address these questions we applied a combination of mathematical modelling and experiments using phospho-specific antibodies to monitor Greatwall, Ensa/ARPP19 and Cdk substrate phosphorylation during mitotic entry and exit. We demonstrate that PP2A/B55 is required for Gwl dephosphorylation at the essential Cdk site Thr194. Ensa/ARPP19 dephosphorylation is mediated by the RNA Polymerase II carboxy terminal domain phosphatase Fcp1. Surprisingly, inhibition or depletion of neither Fcp1 nor PP2A appears to block dephosphorylation of the bulk of mitotic Cdk1 substrates during mitotic exit. Taken together our results suggest a hierarchy of phosphatases coordinating Greatwall, Ensa/ARPP19 and Cdk substrate dephosphorylation during mitotic exit.

Five-year retrograde transpopliteal angioplasty results compared with antegrade angioplasty

INTRODUCTION

Retrograde transpopliteal angioplasty (PA) is a potentially useful alternative technique for endovascular treatment of infra-inguinal arterial disease when antegrade transfemoral puncture (FA) is technically not possible or appropriate. This study aimed to investigate the outcomes of PA compared with FA during a 5-year period.

PATIENTS AND METHODS

A retrospective study was performed to assess 88 PA and 275 FA performed between January 2003 and January 2008. Assessments of patients, indication for procedure, disease site, stenosis severity, procedure outcomes and time to further intervention were recorded.

RESULTS

FA was used to treat more patients with critical ischaemia (42.2% vs 30.7%; P = 0.014)). PA was used to treat more proximal superficial femoral lesions (P < 0.001) and occlusive lesions (P = 0.001). Overall, 84.1% of PA and 82.5 % of FA were technically successful. There was no difference in local puncture site complication rates. Significantly more FA resulted in distal thrombus/embolism (8.4% vs 3.4%; P = 0.044). Further intervention was required in 27.3% of PA and 36.0% of FA. The time interval to re-intervention was not different between the groups.

CONCLUSIONS

PA is safe with comparable success rates and long-term outcomes to an FA. PA is a useful alternative approach for treating occlusive, proximal disease.

Impact of stress on paranoia: an experimental investigation of moderators and mediators

BACKGROUND

Vulnerability-stress models ascribe stress a pivotal role in the development of psychosis. However, moderating and mediating mechanisms translating stress into psychosis and the specificity of the association are not clearly established. It is hypothesized that stress will trigger paranoid ideation in vulnerable individuals through an increase in negative emotion.

METHOD

Using a repeated-measures design, 64 healthy participants with varying levels of vulnerability [psychosis symptoms assessed by the Community Assessment of Psychic Experiences (CAPE)] were assigned to a stress and a non-stress condition in random order. Stress was induced by exposing participants to building-site noise (75 dB) applied concurrently with difficult knowledge questions. Symptoms of paranoia, depression and obsessive compulsive disorder (OCD) were assessed by state-adapted versions of clinical scales.

RESULTS

In the stress condition there was an increase in paranoia, depression and negative emotion. Multilevel linear modeling (MLM) revealed the increase in paranoia under stress to be moderated by the level of vulnerability and mediated by anxiety. Although participants generally showed an increase in anxiety under stress, anxiety was more strongly related to paranoia in participants with higher baseline symptomatology.

CONCLUSIONS

The results support and specify the role of emotional reactions to stressors on the pathway from vulnerability to psychosis and highlight the relevance of anxiety.

[High-dose chemotherapy with transplantation of autologous stem cells in advanced germ-cell poor-risk testicular tumors]

Testicular tumors illustrate curable cancer, but 25% patients are resistant to standard therapy. High-dose chemotherapy (HDC) is promising therapy for germ-cell tumors with poor prognosis. HDC and transplantation of autologous stem cells were performed in 13 patients with germ-cell testicular tumors (GTT). In 6 patients of group 1 HDC was first-line treatment in poor prognosis, in 7 patients (group 2) it was a salvage treatment after recurrences. Patients of group 1 had longer mean survival than those of group 2 (31.3 and 11 months, respectively; p = 0.136). Two patients died of HDC complications. Neurological, hematological and other complications occurred. In spite of 50-90% remission after HDC, multicenter prospective randomized trials will give final conclusion on effectiveness of HDC which must be performed in special clinics having many specialists in their staff (urologists, oncologists, chemotherapists, etc.).

HLA, NFKB1 and NFKBIA Gene Polymorphism Profile in Autoimmune Diabetes Mellitus Patients

Type 1 diabetes mellitus (T1DM) is one of the long-time studied autoimmune disorders. The triggering of the autoimmune process has been ascribed to various genes active in the regulation of the cytokine gene transcription including the Rel/NF-kappaB gene family. In our study the gene polymorphism of HLA class II, NFKB1 (nuclear factor of kappa light polypeptide gene enhancer in B-cells 1) and NFKBIA (inhibitor of nuclear factor kappa B) was tested. Patients were divided into the subgroups in relation to the disease type: T1DM in children, T1DM in adults, and Latent Autoimmune Diabetes in Adults (LADA). HLA-DRB1 (*)04 and HLA-DQB1 (*)0302 have been detected as risk factors for T1DM in adults and particularly in children (P<0.0001, OR=22.9 and 46.5 respectively). HLA-DRB1 (*)03 has been found as a single risk factor for LADA (P<0.0001, OR=4.9). We detected 15 alleles for the NFKB1 gene polymorphism (CA-repeats) in the Czech population. The alleles were ranging in size from 114-142 bp corresponding to 10-25 CA repeats. Frequency of the A7 allele of NFKB1 gene has been significantly increased in T1DM adults (P<0.01). There was no difference in A and a G allele frequency of NFKBIA gene between the control group and patients, but the association of the AA genotype of NFKBIA gene has been found for LADA (P<0.05). Summarizing our results we concluded that there is a high probability of association of gene polymorphism from Rel/NF-kappaB family with an autoimmune diabetes course. Due to the results obtained in the epidemiological study we have been looking also for the function significance of the genetic predisposition. No significant changes have been observed by real time PCR testing of HLA-DRB1 (*)04 gene and NFKB1 gene expression between T1DM diabetic group with different HLA, NFKB1, NFKBIA genetic background.

Serum levels and pharmacokinetic of rituximab in Bi-weekly R-CHOP in elderly patients with DLBCL treated in the RICOVER-60 trial:

7537

Background: The combination of Rituximab (R) and CHOP is considered the standard of treatment for DLBCL in elderly patients (pts) but there is hardly any data on the pharmacokinetic of Rituximab in aggressive lymphoma pts. The RICOVER-60 trial using Rituximab + bi-weekly CHOP-14 resulted in improved TTF in 828 elderly DLBCL pts (Blood 106:9a, 2005). Objective: To study serum levels and pharmacokinetic properties of Rituximab when combined with CHOP-14 in elderly DLBCL pts. Methods: Blood samples of 20 pts were taken before and after Rituximab infusion at each chemotherapy cycle. Additional samples were taken after the end of treatment and at the following time points: after 1 week, 1 month, 2 months, 3 months, 6 months and 9 months, respectively. Peak serum samples were taken within a maximum of 30 min, all samples were centrifuged at 1000 g for 10 min (room temperature) and stored at −20 degrees C. Batch samples were shipped to Xendo Laboratories, Groningen, The Netherlands, and analysed. Results: Samples from 20 pts were evaluable for this analysis with 16/20 pts having completed all 8 cycles of treatment, yet. The median (range) of serum Rituximab levels (μg/ml) before each cycle were: #1 0 (0–0); #2 39 (13–62); #3 74 (47–109); #4 95 (40–136); #5 111 (55–157); #6 114 (12–518); #7 125 (72–207);#8 116 (75–304). After therapy median (range) of serum Rituximab levels were: 163 (67–248) at 1 week; 101 (44–163) at 1 month; 55 (1–123) at 2 months; 34 (1–577) at 3 months; 5 (0–103) at 6 months; 1 (0–128) at 9 months. At 9 months samples from 7 pts were evaluable with detectable serum Rituximab levels in 4/7 pts. Conclusion: In the dose dense regimen R+CHOP-14 Rituximab levels increased after each subsequent cycle for the first 4 cycles. During cycle 5- 8 the serum Rituximab levels reached a plateau and decreased constantly after the end of treatment with detectable levels even after 9 months. Based on this data the German High Grade NHL Study Group (DSHNHL) further investigates a densification of Rituximab in the first cycles in order to improve treatment outcome. A final analysis of all 20 pts and a pharmacokinetic model of Rituximab distribution and elimination phase will be presented at the meeting.

[Table: see text]

Pegylated asparaginase in combination with high-dose methotrexate for consolidation in adult acute lymphoblastic leukaemia in first remission: a pilot study

The German Multicentre acute lymphoblastic leukaemia (ALL) study group (GMALL) performed a pilot study using pegylated asparaginase (PEG-ASP) in combination with high-dose methotrexate as consolidation therapy in the 05/93 protocol. The aim of the study was an intra-individual comparison of two different doses of PEG-ASP in 26 patients, with regard to the depletion of asparagine in serum and toxicity. 'Pharmacokinetic' monitoring was performed to evaluate the effect of an intra-individual dose escalation of PEG-ASP from 500 to 1000 U/m2 intravenously in successive doses. Serum asparaginase activity was targeted at > or =100 U/l for 1 week and > or =50 U/l for 10 d. The second course of PEG-ASP was administered to 23 patients. Due to hypersensitivity reactions in five patients, only 18 patients were evaluable for pharmacokinetic monitoring. With respect to the PEG-ASP activity, an effective depletion of asparagine could be postulated in the majority of patients during 10 d after the first administration. The effect of an intraindividual dose escalation form 500 to 1000 U/m2 was evaluable in 17 of 22 patients. An increment in peak PEG-ASP activity >70% was observed in 65% of the patients. PEG-ASP was well tolerated. Despite the long half-life of PEG-ASP, neither pancreatic nor central nervous toxicities occurred among the 26 adult patients treated in this pilot study.

Decrease in growth cone-neurite fasciculation by sensory or motor cells in vitro accompanies downregulation of Aplysia cell adhesion molecules by neurotransmitters

Cell adhesion molecules play important roles in axon guidance and synapse formation. Recent studies suggest that the expression of some of these molecules can be regulated either by electrical activity or by specific neurotransmitters. The expression of neural cell adhesion molecule (NCAM)-like molecules in Aplysia, designated apCAM, is downregulated from the surface of sensory neurons by 5-HT, a transmitter known to evoke long-term changes in the structure and function of these neurons. We tested whether the distribution of apCAM on the surface of other neurons can be regulated by treatments with other neurotransmitters known to evoke long-term functional and structural changes in Aplysia neurons, and we examined the consequences of treatments with the neurotransmitters on the pattern of growth cone-neurite interactions. We report that applications of the neuropeptide Phe-Met-Arg-Phe-amide (FMRFamide) that evoke long-term synaptic depression also reduce apCAM expression on the surface of motor cell L7 via a mechanism that appears to be similar to the mechanism mediating the 5-HT-induced change in the sensory cells. Specific treatments that affect apCAM distribution on the surface of their respective cells, 5-HT on sensory cells or FMRFamide on motor cell L7, mimic treatment with monoclonal antibodies against apCAM by evoking a significant reduction in the fasciculation of growth cones with other neurites extending from homologous cells.(ABSTRACT TRUNCATED AT 250 WORDS)